1

Access Network Design Access Network Design

David TipperAssociate ProfessorAssociate Professor

Department of Information Science and Telecommunications

University of PittsburghSlides 8

httpwwwsispittedu~dtipper2110htmlhttpwwwsispittedu~dtipper2110html

bull A top down network design project should follow the four steps below

Top Down Network Design Approach

ndash Conceptual Modelbull Objectives Requirements Constraints

ndash Logical Modelbull Technology network graph node location link size etc

(where algorithms are used to minimize cost)

ndash Physical Model

TELCOM 2110 2

bull Specific hardwaresoftware implementations

bull (eg wiring diagram repeater locations etc)

ndash Implementation Testing Tuning and Documentation

2

Technology Choicesbull Wireless Access Network Design

ndash Physical design is incorporated in the Logical Design ( Power level Technology Frequency etc)

bull Wired Access Network Design Root

ndash the logical layer may be partially separated from the physical design

ndash Technology Choicesndash For circuit switched voice traffic

bull STM ATM ndash constant bit rate service (CBR) MPLS CBR emulation

ndash For packet data trafficbull STM ATM SMDS X25 Frame Relay Token Ring

FIDDI Ethernet cable modem dSL wireless

21

34 5

TELCOM 2110 3

FIDDI Ethernet cable modem dSL wireless technology etc

ndash Choice depends on cost and features neededndash Given technology selection and logical design

bull create physical design (select equipment addressing wiring etc)

6

Technology Choicesbull For Wired Network Packet Data trafficbull Choice depends in part on distances

ndash Connect Pitt branch campuses and labs (Johnstown Bradford etc) to main Pitt (Jo sto ad o d etc ) to a ttcampus computer center ndashbull Options Private Line (DS-1 DS-3 OC-3 etc) Frame Relay

ATM SMDS IPSTM X25 ISDN MPLS based VPN VPLS etc

ndash Connect hostsservers in different locations of a building to campus backbonebull Ethernet Fast Ethernet Gigabit Ethernet etc

bull Need to factor in performance needs and user

TELCOM 2110 4

requirements (eg lease vs buy security etc)bull Consider LAN physical design

ndash Majority of installations today are Ethernet to the desktop ndash growing deployment of WLAN 80211 to the desktop

3

Classical Ethernet

bull IEEE 8023 Standard 1983bull Bus topology LANbull 10 Mbps

CSMACD medium accessbull CSMACD medium access control protocol

bull 10Base5 ndash coax cabling ndash 10 Mbpsndash 50-ohm coaxial cable busndash Maximum segment length 500

meters ndash extend with repeaters

bull 10Base-T cabling (1987)

TELCOM 2110 5

10Base T cabling (1987)ndash Twisted pair maximum length

100 metersndash Star topology (hub at central

point)

Ethernet Frame StructureSending adapter encapsulates IP datagram (or

other network layer protocol packet) in Ethernet frameframe

Preamble

TELCOM 2110 6

bull 7 bytes with pattern 10101010 followed by one byte with pattern 10101011

bull used to synchronize receiver sender clock rates

4

Ethernet Frame Structure

bull Addresses 6 bytesndash if adapter receives frame with matching

destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol

ndash otherwise adapter discards frame

bull Type indicates the higher layer protocol (mostly IP but others may be supported)

TELCOM 2110 7

bull CRC checked at receiver if error is detected the frame is simply dropped

CSMACD (Collision Detection)

CSMACD carrier sensing multiple access with collision dectection

adapter doesnrsquot transmit if it senses that some otherndash adapter doesn t transmit if it senses that some other adapter is transmitting that is carrier sense

ndash transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection

bull collision detection

TELCOM 2110 8

ndash easy in wired LANs measure signal strengths compare transmitted received signals

5

CSMACD collision detection

TELCOM 2110 9

Jam Signal make sure all other transmitters are aware of collision 48 bits

Ethernet CSMACD algorithm

1 Adaptor receives datagram from net layer amp creates frame

4 If adapter detects another transmission while transmitting aborts and

2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits

3 If adapter transmits entire

sends jam signal

5 After aborting adapter enters exponential backoff after the mth

collision adapter chooses a K at random from

TELCOM 2110 10

pframe without detecting another transmission the adapter is done with frame

012hellip2m-1 Adapter waits K512 bit times and returns to Step 2

6

Ethernet Evolution

bull Ethernet Protocol so wide spread that evolution rather than replacement

bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options

bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet

bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP

Gigabit Ethernet 1 10 Gbps Ethernet

TELCOM 2110 11

ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP

Current Ethernet Options

bullBusbullTransmission from a station broadcast to all stations on the bus

bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time

L 2 Eth t S it h

TELCOM 2110 12

bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time

7

Switch traffic isolationbull switch installation breaks subnet into LAN segments

bull switch filters packetsndash same-LAN-segment frames not usually forwarded

t th LAN tonto other LAN segmentsndash segments become separate collision domains

h b h b hub

switch

collision domain

TELCOM 2110 13

hub hub hub

collision domain collision domain

Typical Physical Topology

Often have a mix of speeds and hubsswitches in LAN

TELCOM 2110 14

8

Ethernet LAN Building Blocks

bull Network Interface Cardndash IO device that interfaces

computer to network ndash Frame transmission and

reception

bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN

bull Hub

TELCOM 2110 15

bull Hubndash Multicast device - broadcasts

frame to all output portsndash Star Configurationndash Data Link Layer

LAN Building Blocks

bull Media Converters ndash Connect different physical media

types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)

bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address

and Forwards valid framesndash Can bridge different speedmedia

networks bull Switch

TELCOM 2110 16

ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash

examines MAC address to determine port to forward frame too

ndash Multiple ports can handle multiple frames at a time

ndash Can do cut through switching in hardware

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

2

Technology Choicesbull Wireless Access Network Design

ndash Physical design is incorporated in the Logical Design ( Power level Technology Frequency etc)

bull Wired Access Network Design Root

ndash the logical layer may be partially separated from the physical design

ndash Technology Choicesndash For circuit switched voice traffic

bull STM ATM ndash constant bit rate service (CBR) MPLS CBR emulation

ndash For packet data trafficbull STM ATM SMDS X25 Frame Relay Token Ring

FIDDI Ethernet cable modem dSL wireless

21

34 5

TELCOM 2110 3

FIDDI Ethernet cable modem dSL wireless technology etc

ndash Choice depends on cost and features neededndash Given technology selection and logical design

bull create physical design (select equipment addressing wiring etc)

6

Technology Choicesbull For Wired Network Packet Data trafficbull Choice depends in part on distances

ndash Connect Pitt branch campuses and labs (Johnstown Bradford etc) to main Pitt (Jo sto ad o d etc ) to a ttcampus computer center ndashbull Options Private Line (DS-1 DS-3 OC-3 etc) Frame Relay

ATM SMDS IPSTM X25 ISDN MPLS based VPN VPLS etc

ndash Connect hostsservers in different locations of a building to campus backbonebull Ethernet Fast Ethernet Gigabit Ethernet etc

bull Need to factor in performance needs and user

TELCOM 2110 4

requirements (eg lease vs buy security etc)bull Consider LAN physical design

ndash Majority of installations today are Ethernet to the desktop ndash growing deployment of WLAN 80211 to the desktop

3

Classical Ethernet

bull IEEE 8023 Standard 1983bull Bus topology LANbull 10 Mbps

CSMACD medium accessbull CSMACD medium access control protocol

bull 10Base5 ndash coax cabling ndash 10 Mbpsndash 50-ohm coaxial cable busndash Maximum segment length 500

meters ndash extend with repeaters

bull 10Base-T cabling (1987)

TELCOM 2110 5

10Base T cabling (1987)ndash Twisted pair maximum length

100 metersndash Star topology (hub at central

point)

Ethernet Frame StructureSending adapter encapsulates IP datagram (or

other network layer protocol packet) in Ethernet frameframe

Preamble

TELCOM 2110 6

bull 7 bytes with pattern 10101010 followed by one byte with pattern 10101011

bull used to synchronize receiver sender clock rates

4

Ethernet Frame Structure

bull Addresses 6 bytesndash if adapter receives frame with matching

destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol

ndash otherwise adapter discards frame

bull Type indicates the higher layer protocol (mostly IP but others may be supported)

TELCOM 2110 7

bull CRC checked at receiver if error is detected the frame is simply dropped

CSMACD (Collision Detection)

CSMACD carrier sensing multiple access with collision dectection

adapter doesnrsquot transmit if it senses that some otherndash adapter doesn t transmit if it senses that some other adapter is transmitting that is carrier sense

ndash transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection

bull collision detection

TELCOM 2110 8

ndash easy in wired LANs measure signal strengths compare transmitted received signals

5

CSMACD collision detection

TELCOM 2110 9

Jam Signal make sure all other transmitters are aware of collision 48 bits

Ethernet CSMACD algorithm

1 Adaptor receives datagram from net layer amp creates frame

4 If adapter detects another transmission while transmitting aborts and

2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits

3 If adapter transmits entire

sends jam signal

5 After aborting adapter enters exponential backoff after the mth

collision adapter chooses a K at random from

TELCOM 2110 10

pframe without detecting another transmission the adapter is done with frame

012hellip2m-1 Adapter waits K512 bit times and returns to Step 2

6

Ethernet Evolution

bull Ethernet Protocol so wide spread that evolution rather than replacement

bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options

bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet

bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP

Gigabit Ethernet 1 10 Gbps Ethernet

TELCOM 2110 11

ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP

Current Ethernet Options

bullBusbullTransmission from a station broadcast to all stations on the bus

bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time

L 2 Eth t S it h

TELCOM 2110 12

bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time

7

Switch traffic isolationbull switch installation breaks subnet into LAN segments

bull switch filters packetsndash same-LAN-segment frames not usually forwarded

t th LAN tonto other LAN segmentsndash segments become separate collision domains

h b h b hub

switch

collision domain

TELCOM 2110 13

hub hub hub

collision domain collision domain

Typical Physical Topology

Often have a mix of speeds and hubsswitches in LAN

TELCOM 2110 14

8

Ethernet LAN Building Blocks

bull Network Interface Cardndash IO device that interfaces

computer to network ndash Frame transmission and

reception

bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN

bull Hub

TELCOM 2110 15

bull Hubndash Multicast device - broadcasts

frame to all output portsndash Star Configurationndash Data Link Layer

LAN Building Blocks

bull Media Converters ndash Connect different physical media

types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)

bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address

and Forwards valid framesndash Can bridge different speedmedia

networks bull Switch

TELCOM 2110 16

ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash

examines MAC address to determine port to forward frame too

ndash Multiple ports can handle multiple frames at a time

ndash Can do cut through switching in hardware

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

3

Classical Ethernet

bull IEEE 8023 Standard 1983bull Bus topology LANbull 10 Mbps

CSMACD medium accessbull CSMACD medium access control protocol

bull 10Base5 ndash coax cabling ndash 10 Mbpsndash 50-ohm coaxial cable busndash Maximum segment length 500

meters ndash extend with repeaters

bull 10Base-T cabling (1987)

TELCOM 2110 5

10Base T cabling (1987)ndash Twisted pair maximum length

100 metersndash Star topology (hub at central

point)

Ethernet Frame StructureSending adapter encapsulates IP datagram (or

other network layer protocol packet) in Ethernet frameframe

Preamble

TELCOM 2110 6

bull 7 bytes with pattern 10101010 followed by one byte with pattern 10101011

bull used to synchronize receiver sender clock rates

4

Ethernet Frame Structure

bull Addresses 6 bytesndash if adapter receives frame with matching

destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol

ndash otherwise adapter discards frame

bull Type indicates the higher layer protocol (mostly IP but others may be supported)

TELCOM 2110 7

bull CRC checked at receiver if error is detected the frame is simply dropped

CSMACD (Collision Detection)

CSMACD carrier sensing multiple access with collision dectection

adapter doesnrsquot transmit if it senses that some otherndash adapter doesn t transmit if it senses that some other adapter is transmitting that is carrier sense

ndash transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection

bull collision detection

TELCOM 2110 8

ndash easy in wired LANs measure signal strengths compare transmitted received signals

5

CSMACD collision detection

TELCOM 2110 9

Jam Signal make sure all other transmitters are aware of collision 48 bits

Ethernet CSMACD algorithm

1 Adaptor receives datagram from net layer amp creates frame

4 If adapter detects another transmission while transmitting aborts and

2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits

3 If adapter transmits entire

sends jam signal

5 After aborting adapter enters exponential backoff after the mth

collision adapter chooses a K at random from

TELCOM 2110 10

pframe without detecting another transmission the adapter is done with frame

012hellip2m-1 Adapter waits K512 bit times and returns to Step 2

6

Ethernet Evolution

bull Ethernet Protocol so wide spread that evolution rather than replacement

bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options

bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet

bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP

Gigabit Ethernet 1 10 Gbps Ethernet

TELCOM 2110 11

ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP

Current Ethernet Options

bullBusbullTransmission from a station broadcast to all stations on the bus

bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time

L 2 Eth t S it h

TELCOM 2110 12

bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time

7

Switch traffic isolationbull switch installation breaks subnet into LAN segments

bull switch filters packetsndash same-LAN-segment frames not usually forwarded

t th LAN tonto other LAN segmentsndash segments become separate collision domains

h b h b hub

switch

collision domain

TELCOM 2110 13

hub hub hub

collision domain collision domain

Typical Physical Topology

Often have a mix of speeds and hubsswitches in LAN

TELCOM 2110 14

8

Ethernet LAN Building Blocks

bull Network Interface Cardndash IO device that interfaces

computer to network ndash Frame transmission and

reception

bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN

bull Hub

TELCOM 2110 15

bull Hubndash Multicast device - broadcasts

frame to all output portsndash Star Configurationndash Data Link Layer

LAN Building Blocks

bull Media Converters ndash Connect different physical media

types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)

bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address

and Forwards valid framesndash Can bridge different speedmedia

networks bull Switch

TELCOM 2110 16

ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash

examines MAC address to determine port to forward frame too

ndash Multiple ports can handle multiple frames at a time

ndash Can do cut through switching in hardware

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

4

Ethernet Frame Structure

bull Addresses 6 bytesndash if adapter receives frame with matching

destination address or with broadcast address (eg ARP packet) it passes data in frame to net-layer protocol

ndash otherwise adapter discards frame

bull Type indicates the higher layer protocol (mostly IP but others may be supported)

TELCOM 2110 7

bull CRC checked at receiver if error is detected the frame is simply dropped

CSMACD (Collision Detection)

CSMACD carrier sensing multiple access with collision dectection

adapter doesnrsquot transmit if it senses that some otherndash adapter doesn t transmit if it senses that some other adapter is transmitting that is carrier sense

ndash transmitting adapter aborts when it senses that another adapter is transmitting that is collision detection

bull collision detection

TELCOM 2110 8

ndash easy in wired LANs measure signal strengths compare transmitted received signals

5

CSMACD collision detection

TELCOM 2110 9

Jam Signal make sure all other transmitters are aware of collision 48 bits

Ethernet CSMACD algorithm

1 Adaptor receives datagram from net layer amp creates frame

4 If adapter detects another transmission while transmitting aborts and

2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits

3 If adapter transmits entire

sends jam signal

5 After aborting adapter enters exponential backoff after the mth

collision adapter chooses a K at random from

TELCOM 2110 10

pframe without detecting another transmission the adapter is done with frame

012hellip2m-1 Adapter waits K512 bit times and returns to Step 2

6

Ethernet Evolution

bull Ethernet Protocol so wide spread that evolution rather than replacement

bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options

bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet

bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP

Gigabit Ethernet 1 10 Gbps Ethernet

TELCOM 2110 11

ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP

Current Ethernet Options

bullBusbullTransmission from a station broadcast to all stations on the bus

bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time

L 2 Eth t S it h

TELCOM 2110 12

bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time

7

Switch traffic isolationbull switch installation breaks subnet into LAN segments

bull switch filters packetsndash same-LAN-segment frames not usually forwarded

t th LAN tonto other LAN segmentsndash segments become separate collision domains

h b h b hub

switch

collision domain

TELCOM 2110 13

hub hub hub

collision domain collision domain

Typical Physical Topology

Often have a mix of speeds and hubsswitches in LAN

TELCOM 2110 14

8

Ethernet LAN Building Blocks

bull Network Interface Cardndash IO device that interfaces

computer to network ndash Frame transmission and

reception

bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN

bull Hub

TELCOM 2110 15

bull Hubndash Multicast device - broadcasts

frame to all output portsndash Star Configurationndash Data Link Layer

LAN Building Blocks

bull Media Converters ndash Connect different physical media

types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)

bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address

and Forwards valid framesndash Can bridge different speedmedia

networks bull Switch

TELCOM 2110 16

ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash

examines MAC address to determine port to forward frame too

ndash Multiple ports can handle multiple frames at a time

ndash Can do cut through switching in hardware

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

5

CSMACD collision detection

TELCOM 2110 9

Jam Signal make sure all other transmitters are aware of collision 48 bits

Ethernet CSMACD algorithm

1 Adaptor receives datagram from net layer amp creates frame

4 If adapter detects another transmission while transmitting aborts and

2 If adapter senses channel idle it starts to transmit frame If it senses channel busy waits until channel idle and then transmits

3 If adapter transmits entire

sends jam signal

5 After aborting adapter enters exponential backoff after the mth

collision adapter chooses a K at random from

TELCOM 2110 10

pframe without detecting another transmission the adapter is done with frame

012hellip2m-1 Adapter waits K512 bit times and returns to Step 2

6

Ethernet Evolution

bull Ethernet Protocol so wide spread that evolution rather than replacement

bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options

bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet

bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP

Gigabit Ethernet 1 10 Gbps Ethernet

TELCOM 2110 11

ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP

Current Ethernet Options

bullBusbullTransmission from a station broadcast to all stations on the bus

bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time

L 2 Eth t S it h

TELCOM 2110 12

bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time

7

Switch traffic isolationbull switch installation breaks subnet into LAN segments

bull switch filters packetsndash same-LAN-segment frames not usually forwarded

t th LAN tonto other LAN segmentsndash segments become separate collision domains

h b h b hub

switch

collision domain

TELCOM 2110 13

hub hub hub

collision domain collision domain

Typical Physical Topology

Often have a mix of speeds and hubsswitches in LAN

TELCOM 2110 14

8

Ethernet LAN Building Blocks

bull Network Interface Cardndash IO device that interfaces

computer to network ndash Frame transmission and

reception

bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN

bull Hub

TELCOM 2110 15

bull Hubndash Multicast device - broadcasts

frame to all output portsndash Star Configurationndash Data Link Layer

LAN Building Blocks

bull Media Converters ndash Connect different physical media

types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)

bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address

and Forwards valid framesndash Can bridge different speedmedia

networks bull Switch

TELCOM 2110 16

ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash

examines MAC address to determine port to forward frame too

ndash Multiple ports can handle multiple frames at a time

ndash Can do cut through switching in hardware

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

6

Ethernet Evolution

bull Ethernet Protocol so wide spread that evolution rather than replacement

bull Multiport Bridges and Switches to increaseMultiport Bridges and Switches to increase throughput and extend configuration options

bull Higher speed versions of Ethernetndash Fast Ethernet 100 Mbps Ethernet

bull Called 100BaseTX bull IEEE 8023u standard in 1995bull Uses Fiber or Cat5 UTP

Gigabit Ethernet 1 10 Gbps Ethernet

TELCOM 2110 11

ndash Gigabit Ethernet 1 10 Gbps Ethernetbull IEEE 8023z standard in 1998bull Full Duplex to build backbones or connect serversbull Fiber cabling and UTP

Current Ethernet Options

bullBusbullTransmission from a station broadcast to all stations on the bus

bullHubTransmission from a station received by centralhub and retransmitted on all outgoing linesOnly one transmission at a time

L 2 Eth t S it h

TELCOM 2110 12

bullLayer 2 Ethernet SwitchIncoming frame switched to one outgoing lineMany transmissions at same time

7

Switch traffic isolationbull switch installation breaks subnet into LAN segments

bull switch filters packetsndash same-LAN-segment frames not usually forwarded

t th LAN tonto other LAN segmentsndash segments become separate collision domains

h b h b hub

switch

collision domain

TELCOM 2110 13

hub hub hub

collision domain collision domain

Typical Physical Topology

Often have a mix of speeds and hubsswitches in LAN

TELCOM 2110 14

8

Ethernet LAN Building Blocks

bull Network Interface Cardndash IO device that interfaces

computer to network ndash Frame transmission and

reception

bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN

bull Hub

TELCOM 2110 15

bull Hubndash Multicast device - broadcasts

frame to all output portsndash Star Configurationndash Data Link Layer

LAN Building Blocks

bull Media Converters ndash Connect different physical media

types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)

bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address

and Forwards valid framesndash Can bridge different speedmedia

networks bull Switch

TELCOM 2110 16

ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash

examines MAC address to determine port to forward frame too

ndash Multiple ports can handle multiple frames at a time

ndash Can do cut through switching in hardware

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

7

Switch traffic isolationbull switch installation breaks subnet into LAN segments

bull switch filters packetsndash same-LAN-segment frames not usually forwarded

t th LAN tonto other LAN segmentsndash segments become separate collision domains

h b h b hub

switch

collision domain

TELCOM 2110 13

hub hub hub

collision domain collision domain

Typical Physical Topology

Often have a mix of speeds and hubsswitches in LAN

TELCOM 2110 14

8

Ethernet LAN Building Blocks

bull Network Interface Cardndash IO device that interfaces

computer to network ndash Frame transmission and

reception

bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN

bull Hub

TELCOM 2110 15

bull Hubndash Multicast device - broadcasts

frame to all output portsndash Star Configurationndash Data Link Layer

LAN Building Blocks

bull Media Converters ndash Connect different physical media

types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)

bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address

and Forwards valid framesndash Can bridge different speedmedia

networks bull Switch

TELCOM 2110 16

ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash

examines MAC address to determine port to forward frame too

ndash Multiple ports can handle multiple frames at a time

ndash Can do cut through switching in hardware

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

8

Ethernet LAN Building Blocks

bull Network Interface Cardndash IO device that interfaces

computer to network ndash Frame transmission and

reception

bull Repeater ndash Physical Layerndash No Address reviewndash Broadcast Devicendash Transparent to end devicesndash Extends range of LAN

bull Hub

TELCOM 2110 15

bull Hubndash Multicast device - broadcasts

frame to all output portsndash Star Configurationndash Data Link Layer

LAN Building Blocks

bull Media Converters ndash Connect different physical media

types together100 Base Tx (UTP) connection tondash 100 Base Tx (UTP) connection to 100 Base Fx (Fiber)

bull Bridgendash Connect different LAN segmentsndash Data Link Layer ndash Stores frame examines MAC address

and Forwards valid framesndash Can bridge different speedmedia

networks bull Switch

TELCOM 2110 16

ndash Star Configurationndash Data Link Layer ndash Layer 2 Switch ndash

examines MAC address to determine port to forward frame too

ndash Multiple ports can handle multiple frames at a time

ndash Can do cut through switching in hardware

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

9

LAN Building Blocks

bull Layer 3 switch or Routerbull Operates at the Network Layer

(layer 3) of OSI Modelndash Uses protocol (IP) to determine

action

bull Used to connect dissimilar LANrsquosndash can covert frame from one type to

another provide security etc

bull Makes a decision to forward or drop a frame

bull Maintains routing tables that list

TELCOM 2110 17

Maintains routing tables that list connected networksndash IP amp MAC address of next relay

station

bull Does not forward broadcast frames (layer 2)

LAN Wiring

Cables are connected to network devices and the computerMost networks use a mixture of cable types

bull Coaxial cable ndash Known as Thin Net or T

base 2 or T-2

bull Twisted-pair cablendash shielded (STP)ndash unshielded (UTP)ndash Five categories of UTP

bull Plenum Cable ndash jackets are made of

nonflammable fluoro-polymers (such as Teflon)

ndash More expensive than non-plenum jackets

bull Non-plenum cable uses less expensive

TELCOM 2110 18

Five categories of UTP

bull Fiber-optic cablendash single-mode ndash multi-mode or graded-

index multi-mode

ndash uses less-expensive material for jackets such as polyethylene (PE) or polyvinylchloride (PVC) which will give off toxic fumes in a fire

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

10

Medium Options for Ethernet

bull Coax - 13ft + 300 per connector

bull UTP category 5 -ndash Plenum - 33ft + 100 per

connector

ndash PVC - 13ft + 100 per connector

bull Multi-mode Fiber - 35ft + 1500 per connector

TELCOM 2110 19

bull Single mode Fiber - 50ft + 1500 per connector

Wiring Standards

bull Large Number of Wiring Standards see httpwwwtiaorg

bull For example TIAEIA-568pndash Commercial Building Telecommunications

Cabling Standardbull Sets specific requirements for cable

ndash Impedancendash Signal Loss or Attenuationndash Termination Requirementsndash Maximum Distancesndash Other factors for correct use of cable and

wire in commercial environment

bull TIAEIA-568A covers 6 areas

TELCOM 2110 20

568 co e s 6 a eas1 Building Entrance2 Equipment Room3 Backbone Cabling4 Telecommunications Closet5 Horizontal Cabling6 Work Area

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

11

BackboneSwitch

bull Need to connect the numerous wires (could be hundreds) to the network

Wiring ClosetPatch Panel

PC

Fiber Patch Panel

Fiber Run

UTP P Panel

Fiber Patch Panel

network

bull Use wiring closetpatch panels to provide an way to connect the wiring bundles to the electronics

L ti

TELCOM 2110 21

Wall Jack

In conduit Wiring

UTP P Panel

Switch

bull Locationndash Accessibility amp Security

ndash Environmental concerns (heatingcooling power)

Taxonomy

bull Thus far have considered wired and wireless greenfield access design

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 22

VPN

greenfield greenfield incremental

Stage

The techniques used to design the network will depend on the classification

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

12

Virtual Networksbull Virtual Network refers to

ldquo A class of service that uses a shared network infrastructure to emulate the characteristics of a private networkrdquo

ndash The virtual network should for all intensive purposes appear to the users as a fully functional physical network (``network within a networkrdquo)

bull Virtual Network Technologyndash Virtual Networks can be implemented at several network layers

in different technologyndash Some technology options

bull WANndash MPLSndash WDM ndash lightpath based VNs

bull MANs

TELCOM 2110 23

bull MANsndash SONET WiMAX VPLS MPLS etc

bull LANsndash Ethernet 80211

bull Overlay Applications (MBONE Overcast etc)bull Tunneling Protocols (GRE + IPSEC PPTP etc

bull Consider one type of access network VN technologyndash Virtual LANs IEEE 8021Q

Virtual LANs (VLANs)

bull VLANsndash Group of devices on one or more physical LANrsquos that are

configured such that they are logically attached to the same wire

ndash May be located on different physical LAN segmentsndash LANrsquos based on LOGICAL instead of PHYSICAL connectionsndash LAN membership defined by network manager

bull VLAN Usendash Separate out users into logical groups of workers regardless

of actual physical location (security and QoS differentiation)ndash Help alleviate traffic congestion without adding more

TELCOM 2110 24

Help alleviate traffic congestion without adding more bandwidth ndash spreads out contention among different uses

ndash Broadcast and multi-cast traffic only goes to members of VLAN

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

13

VLAN Types

bull Basic techniques for providing VLANs 1 Port Based

bull Configured at each switch portbull Configured at each switch port 2 MAC Address Based

ndash Uses the end stations MAC address for VLAN Assignment

3 High Layer Based bull Protocol based

TELCOM 2110 25

ndash Uses protocol to determine VLAN assignment

ndash Dynamic Based ndash A User Profile (stored as a database) determine VLAN

assignment

bull Etc

VLAN Types

bull Port Based VLANsbull Layer 1 approach bull VLAN is a group of physical portsbull Configured at each switch port

bull Port X on Switch A belongs to VLAN 1bull Port Y on Switch B belongs to VLAN 1bull A port may belong to one or more VLANs

TELCOM 2110 26

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

14

VLAN Types

bull Port Based Approach ndash Common approach to control broadcast domainndash Good when traffic mostly local or tofrom enterprise serversndash Also called port switching

TELCOM 2110 27

VLAN Types

bull MAC Address Based VLANs - (Layer 2 approach) bull Network Manager uses the end stations MAC address

for VLAN Assignmentbull Host X MAC belongs to VLAN 1bull Host X MAC belongs to VLAN 1bull Host Y MAC belongs to VLAN 2bull Host Z MAC belongs to VLAN 1

switch

to externalnetwork

router

VLAN ndash defined by

mail server

web server

TELCOM 2110 28

hub hub hub

f yMAC list at switch

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

15

VLAN Typesbull Higher Layer Based VLANs ndash many options

ndash Protocol Based bull VLAN determined by MAC layer protocol field ndash packet based VLANs

bull IP traffic is VLAN 1bull UDP traffic belongs to VLAN 2bull Can add additional fields to VLAN membership (eg IP Source address)bull Service based VLAN ndash all workstations using employee database are on

HR-VLAN etcndash General protocol policy based

TELCOM 2110 29

General protocol policy based bull VLAN membership can be based on a combination of incoming port MAC

address subnet or higher layer info time of day etcndash Dynamic Based

bull A User Profile (stored as a database) determine VLAN assignmentndash When user X logs in the profile says to connect the user to VLAN 1ndash Users belong to a specific VLAN regardless of where they attach to the network - User

can ldquoroamrdquo on the networkndash Broadcast traffic will follow the user

Large Networks

bull How does the network know where to sent the data packets when a VLAN has been put into place across multiple Layer 2 switchesndash Frames can be tagged with the VLAN information by switchesndash Consider example below traffic from right to left

bull First switch adds tag containing VLAN id to all incoming packetsbull Intermediate switches do not recompute the VLAN idbull Last switch removes tags from all outgoing packets

TELCOM 2110 30

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

16

IEEE 8021Q

bull IEEE standard specifying VLAN functionality for 802 Bridged LANs

bull Supports ppndash port based MAC address based and higher layer

VLANS ndash up to 4095 VLANs on a common infrastructurendash Static and dynamic VLAN membershipndash shared media and switched LANsndash VLAN and non VLAN aware bridges

IEEE 802 p priority based VLAN membership

TELCOM 2110 31

ndash IEEE 802p priority based VLAN membershipndash GARP (Generic Attribute Registration Protocol)

bull for configuring VLAN memberships (ie port filtering MAC membership lists etc)

bull propagation of VLAN information

IEEE 8021Q

bull IEEE 8021Q uses VLAN tags across multiple LANsswitchesbull An IEEE 8021Q tagged port is typically used as a VLAN trunk bull Inserts TAG between Source address and Protocol Type fields in

Ethernet Frame and places RIF field in Payload bull Tag consists ofbull Tag consists of

ndash TPID ndash Tag Protocol IDndash User Priorityndash CFI ndash Canonical Frame Format ndash specifies Layer 2 format (Ethernet

FDDI Token Ring)ndash VLAN ID ndash the tag ndash Routing Indication Field

bull Ethernet frames should carry their VLAN ID when traversing a link shared by multiple VLANs

TELCOM 2110 32

y p

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

17

IEEE 8021Q

bull IEEE 8021Q

bull Provide means for

Router

TELCOM 2110 33

campus wide VLANs

Taxonomy

Network DesignSize

Metro AccessWAN

Wired

Size

Wired Wireless

Technology

Stage

TELCOM 2110 34

Incremental greenfield greenfield VPN

Stage

The techniques used to design the network will depend on the classification

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

18

Access Network Incremental Design

bull Basically two types of Access Network Incremental Design

1 UpgradeAugmentationndash Modify existing network in order to improve performanceModify existing network in order to improve performance

features reliability security etc (ie meet set of technical or business objectives)

ndash Basic approach is to identify bottleneck linksndash (ie links with highest utilization)

bull Increase the capacity of bottleneck links or restructure loadndash (ie bandwidth bombing)

2 Expansion

TELCOM 2110 35

pndash Grow existing network to add more hostsusersndash Can view expansion as independent AND problem

connecting to a hubbackbone node on the existing infrastructure

bull Both are imbedded in whatever technology currently using

Incremental AND

to externalmail server

Consider corporate network using 100Mbs Ethernet Congestion on file server link

switch

to externalnetwork

router

Congested link

file server

TELCOM 2110 36

hub hubhub

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

19

Link Aggregation

bull Need to increase capacity of file server linkndash Options Upgrade to 1G link (may require switch

upgrade) or Link Aggregation

bull Link Aggregation ndash Combine several independent links so it looks to the

system like one large connectionndash The idea is to create a ldquological linkrdquo made up of

several normally independent links

TELCOM 2110 37

Link Aggregation

bull Multiple links in parallel as a single logical linkndash For increased capacityndash For redundancy (fault tolerance) If one of the lines

i th t k f il th th li i k th t ffiin the trunk fails the other line can pick up the trafficndash Also known as ``port bundlingrdquo or ``link bundlingrdquo

bull Link aggregation control protocol (LACP) is used to identify and connect physical links between two switches

bull Distribute traffic in bundled links based on

TELCOM 2110 38

Distribute traffic in bundled links based onndash Source andor destination MAC addressndash Source andor destination IP addressndash Source andor destination port numbers

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39

20

Access Network Design

bull Wired Network Designndash One speed one center design

ndash Multi-speed access design

ndash Multi-center design

bull Wireless Network Designndash Point-to-Point Link Design

ndash Last hop WLAN designndash Last hop WLAN design

bull Physical Layer Considerations

bull Virtual and Incremental Design

TELCOM 2110 39