agenda 1. quiz 2. homework 3. atm 4. sonet/sdh/otn 5. network devices
TRANSCRIPT
Agenda
1. QUIZ 2. HOMEWORK 3. ATM 4. SONET/SDH/OTN 5. NETWORK DEVICES
Pre-amble
To Fromaddr addr
Data Pad Check sum
Bits:7 1 2/6 2/6 2 0 - 1500 0 - 46 4
Start of framedelimiter
Length ofdata field
(Ethernet Frame)
(IP Header)
32 bits
Version IHL Type of service Total length
Identification Fragment offset
Time to live Protocol Header checksum
Source address
Destination address
Options (0 or more words)
DF
MF
(TCP Header)
32 bits
Source port Destination port
Sequence number
Acknowledgement number
Window size
Urgent pointer
Options (0 or more 32 bit words)
Checksum
Data (optional)
TCPheaderlength
URG
ACK
PSH
RST
SYN
FIN
Homework
19-1, 19-3, 19-6, 19-73, 19-82
20-1, 20-6, 20-13, 20-55
21-2, 21-51
Chapter 19
ATM
Figure 19-1
Multiplexing Using Different Packet Sizes
• We have packets as large as 65,545 bytes sharing systems with systems with packets having fewer than 200 bytes• What does the size of X do to A?
Figure 19-2
Multiplexing Using Cells
Cell network overcomes delay problems by using the cell as the basic unit of data exchange, so X becomes X, Y & Z (smaller fixed size blocks).
Figure 19-3
ATM Multiplexing
• Note: Multiplexer output is sequential like token ring
• Call it TDM or CDM?
Figure 19-4
Architecture of an ATM Network Showing User-Network & Network-Network Interface Points
What is the difference?
Figure 19-5
Transmission Path, Virtual Paths, and Virtual Circuits
Virtual Circuit means• Part or all of the paths are the same?• All cells follow the same route for a message or transmission?
Figure 19-6
Example of VPs and VCs
8 end points using 4 virtual circuits
Figure 19-7
Virtual Path & Virtual Circuit Connection Identifiers
Figure 19-8
Virtual Connection Identifiers in UNIs and NNIs
Why does NNI have more Virtual Path Indicator bits?
Figure 19-9
An ATM Cell(One Size Fits All)
Figure 19-10
SVCSetup
Same as X.25& Frame Relay?
What about PVC?
Figure 19-11
Routing with a VP Switch
Virtual Path Switch uses only Virtual path identifiers (like IP table?)
Figure 19-12
A Conceptual View of a VP Switch
Virtual path identifiers change but virtual circuit identifiers don’t.
Figure 19-13
Routing with a VPC Switch(Combining VP & VC Switches)
Figure 19-14
A Conceptual View of a VPC Switch
What does this add to the VP switch? It uses VCIs too & not just VPIs.
Figure 19-15
Crossbar Switch
Figure 19-16Knockout Switch
• Uses distributors & queues to direct cells to different queues at the output.• With n inputs & n outputs you need n2 crosspoints. So?
Figure 19-17 A Banyan Switch
• Multi stage with microswitches at each stage• For n inputs & n outputs you have log2(n) stages & n/2 microswitches• What probability of cell collision?
2
n
Figure 19-19
Batcher-Banyan Switch
Buffer?
Overcomes Banyan by sorting incoming cells by their final destination
Figure 19-20
ATM Layers
Figure 19-21
ATM Layers in End-Point Devices and Switches
Note: Switches use only two bottom layers
Data Types & Sub-layer Functions
Data Types• Constant bit rate (CBR) has no delays & good for real time• Variable bit rate (VBR) at some burst level • Connection oriented packet data like X.25 & TCP• Connectionless packet data like most IP
Sub-layers• Convergence divides the bit stream into 47 byte segments• SAR adds a one byte header so 48 bytes goes to ATM layer
Figure 19-22
AAL Types
Figure 19-23
AAL1
Note: CSI used for signaling while SC for error & flow control
Figure 19-24
AAL2
Note: IT says where in message & LI points to how much padding
Figure 19-25AAL3/4
Figure 19-26
AAL5
What happened to all the control complexity?
Figure 19-27
ATM Layer
Routing, traffic management, switching & multiplexing
Figure 19-28ATM Header
Figure 19-29
Payload Type (PT) Fields
Figure 19-30
Service Classes
Figure 19-31
Service Classes and Capacity of Network
Figure 19-32
QoS
Sustained Cell RatePeak Cell RateMinimum Cell RateCell Variation Delay
Cell Loss RatioCell Transfer DelayCell Delay VariationCell Error Rate
How about a term paper on the value of each of these?
Figure 19-33ATM WAN
Are these routers or gateways?
Figure 19-34
Ethernet Switch and ATM Switch
• Connectionless vs. connection oriententation• Physical address vs. virtual connection identifiers• Broadcast vs.
Figure 19-35
Local Area Network Emulation (LANE) Approach
What do Broadcast/Unknown server & LANE clients add? Connectionless Service
Lane Clients (LEC), Lane Servers (LES), and Broadcast/Unknown Server (BUS)
Chapter 20
SONET/SDH
Figure 20-1
The SONET System Using Synchronous Transport Signal Multiplexers
Figure 20-2
An Example of a SONET Network
Regenerators regenerate & change some header information. So?
Figure 20-3SONET Layers
PL: end-to-end, LL: mux-to-mux, SL: neighbors; like OSI?
Figure 20-4
Device-Layer Relationship in SONET
Figure 20-5
Data Encapsulation in SONET
Note the pretty overhead additions.
Figure 20-6
STS-1 Frame
Is this structure or throughput?
Figure 20-7
STS-1 Frame Overhead(showing SynchronousPayload Envelope)
Figure 20-8
STS-1 Frame Section Overhead
Figure 20-9
STS-1 Frame Line Overhead
Figure 20-10
Payload Pointers
ID location of payload when it is someplace other than the beginning
Figure 20-11
STS-1 Frame Path Overhead
Figure 20-12
Virtual Tributaries
VTs for multiple sources?
Figure 20-13
VT Types
Figure 20-14
STS-n
Figure 20-15
STS Multiplexing
Figure 20-16
ATM in an STS-3 Envelope
• With STS-3 (155.520 Mbps) entire payload can be used for cell transport• 260 octets can carry close to 5 cells (5 X 53 = 265 bytes)• Recall STS-1 is 51.84 Mbps
Broadband’s Future: Optical Networking
• Background:– Over 100 standards are currently on the drafting
table– Networkers should no longer need to purchase
monthly or yearly for one-time capacity– Networks may not be structurally sound:
• Ethernet/IP mentality eschews complex networks
• SONET-voice & security worlds argue for multi-layered networks with all the complexity and protection that implies.
Broadband’s Future: Optical Networking
• Same old conflict:– The SONET successor is the Optical Transport
Network (OTN) which could work across an Automatic Switched Optical Network (ASON)
– The IP-centric approach uses Generalized Multiprotocol Label Switching (GMPLS)
Broadband’s Future: Optical Networking
• SONET’s disadvantages:– Bandwidth efficiency is a problem at higher
capacities. More overhead is required.– It’s a single wavelength solution (so far)– It’s ignorant of the underlying infrastructure
• Providers are left to manage two layers:– The SONET network with its point to point Wavelength
Division Multiplex network
– The layer-2 or layer-3 networks that might be transported across the SONET network.
• SONET’s advantage: It’s circuit switched.
IP to WDM Choices
RPRPHY
10GigELAN PHY
10GigEWAN PHY
GigEPHY
GFP
RPRMAC
Ethernet MAC HDLC ATM
SONET/SDH
Interface for OTN, G.709
Optical fiber/OTN (WDM)
IPIEEE 802.2 LLC IEEE 802.2 LLC PPP AAL 5
POS
WDM, WWDM, DWDM
IP to WDM Choices
• Acronyms:– RPR = Resilient Packet Ring, IEEE 802.17– HDLC = High-level Data Link Control– POS = Packet over SONET/SDH– GFP = Generic Framing Procedure (ANSI T1 X1
driven standard)– OTN = Optical Transport Network– WDM = Wavelength Division Multiplexing– WWDM = Wide WDM– DWDM = Dense WDM
Optical Networking Approaches
• Overlay Model: Maintaining two discrete networks: A layer-1 optical network and a client network. Users access the underlying optical network through User Network Interfaces (UNIs). Devices in the optical network rely on Network-to-Network Interfaces (NNIs).
• Peer-to-peer Model: A single network, equipment at the networks edge decides how bandwidth is allocated at the network core.
Overlay Approach: ITU Plan
– Divide connections into three components (like SONET):
• The path (the logical connection between stations) called optical channels, to provide end-to-end networking.
• The line (the underlying physical link) called optical multiplex sections, to underpin the channels; but these are expanded to have multiple wavelengths when SONET has one.
• The sections (the individual copper or fiber spans that terminate at the amplifiers or regenerators) called the optical transmission section to define the physical interface that details the optical parameters such as frequency (wavelength), power level, signal-to-noise ratio, etc.
– Include a SONET-like hierarchy called the Optical Transport Hierarchy
Chapter 21
Networking and
Internetworking Devices
Figure 21-1
Connecting Devices
Figure 21-2
Connecting Devices and the OSI Model
Figure 21-3
A Repeater in the OSI Model
Figure 21-6
A Bridge in the OSI Model
Figure 21-10
A Router in the OSI Model
Figure 21-12
A Gateway in the OSI Model
Figure 21-16
Switch
Figure 21-17
Example of an Internet
Figure 21-18 The Concept of Distance Vector Routing
Figure 21-24
Concept of Link State Routing
Figure 21-27
Flooding of A’s LSP