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FundamentalsOf
LAN and WAN
Chapter 4
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Understand what is Ethernet LAN
Identify types of Ethernet LAN
Understand Ethernet addressingDefine broadcast and collision domains
Identify cable types
Explain Ethernet UTP Cabling
Understand basic concepts of WAN
Chapter Objectives
At the end of this Chapter you will be able to:
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Ethernet Networking
Ethernet is a contention media access method that allows all hosts
on a network to share the same bandwidth of a link. Ethernet is
popular because its readily scalable, meaning that its
comparatively easy to integrate new technologies, such as Fast
Ethernet and Gigabit Ethernet, into an existing network
infrastructure. Its also relatively simple to implement in the first
place, and with it, troubleshooting is reasonably straightforward.
Ethernet uses both Data Link and Physical layer specifications.
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S ome Ethernet S pecifications
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Media Access
Ethernet networking uses Ca rrier Sense Multiple Access withCo llisi o n Detecti o n ( C SMA/ C D), a protocol that helps devices
share the bandwidth evenly without having two devices transmit at
the same time on the network medium. C SM A/CD was created to
overcome the problem of those collisions that occur when packetsare transmitted simultaneously from different nodes.
Basically, the C SM A/CD algorithm can be summarized as follows:
A device that wants to send a frame waits until the LAN is silentin
other words, no frames are currently being sentbefore attempting
to send an electrical signal.
If a collision still occurs, the devices that caused the collision wait a
random amount of time and then try again.
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Ethernet at the Data Link Layer
Ethernet at the Data Link layer is responsible for Ethernet add ressing , commonly referred to as hardware addressing or M AC
addressing.
Vendor ID Adaptor ID
Ethernet Addressing S cheme
Ethernet Addressing
24 bits 24 bits
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Broadcast Domain
A broadcast domain is a logical division of a computer network in
which all nodes can reach each other by broadcast at the data link
layer.
In terms of current popular technologies: Any computer connected to
the same Ethernet Repeater or S witch is a member of the same
broadcast domain. Further, any computer connected to the same set
of inter-connected switches/repeaters is a member of the samebroadcast domain.
Broadcast Domain & Collision Domain
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Collision Domain
A Collision domain is a logical network S egment where data
packets can "collide" with one another for being sent on a shared
medium, in particular in the Ethernet networking protocol. This is an
Ethernet term used to describe a network scenario wherein one
particular device sends a packet on a network segment, forcing
every other device on that same segment to pay attention to it.
Collisions decrease network efficiency; if two devices transmit
simultaneously, a collision occurs, and both devices must retransmit
at a later time.
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Ethernet at the Physical Layer
Ethernet Physical layer S pecifications
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10B ase2 10M bps , baseband technology , up to 185 meters in
length:
It is known as thinnet and can support up to 30 workstations on a
single segment.10B ase 5 10M bps , baseband technology , up to 500 meters in
length
It is known as thicknet . It uses a physical and logical bus with AUI
connectors. Up to 2,500 meters with repeaters and 1,024 users for allsegments.
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10B aseT 10M bps using category 3 UTP wiring
Unlike with the 10Base2 and 10Base5 networks, each device must
connect into a hub or switch, and you can have only one host per
segment or wire
Here are the expanded IEEE Ethernet 802.3 standards:
100B aseTX (IEEE 802.3u): EIA/TIA category 5, 6, or 7 UTP two-pair
wiring. One user per segment; up to 100 meters long. It uses an
RJ45 connector with a physical star topology and a logical bus.100B aseFX (IEEE 802.3u): Uses fiber cabling 62.5/125-micron
multimode fiber. Point-to-point topology; up to 412 meters long. It
uses an S T or S C connector, which are media interface connectors.
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Conti
1000B aseCX (IEEE 802.3z): Copper twisted-pair called twinax (a
balanced coaxial pair) that can only run up to 25 meters.
1000B aseT (IEEE 802.3ab): Category 5, four-pair UTP wiring up to
100 meters long.
1000B aseSX (IEEE 802.3z): MM F using 62.5- and 50-micron core;
uses an 850 nanometer laser and can go up to 220 meters with
62.5-micron, 550 meters with 50-micron.
1000B aseLX ( IEEE 802.3z):S
ingle-mode fiber that uses a 9-microncore and 1300 nanometer laser and can go from 3 kilometers up to
10 kilometers.
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Ethernet Cabling
Introduction
Three types of Ethernet cables are available:
S traight-through cable
Crossover cable
Rolled cable
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Straight-Through Cable
The straight-through cable is used to connect
Host to switch or hub
Router to switch or hub
Notice that only pins 1, 2, 3, and 6 are used. Just connect 1 to 1, 2
to 2 , 3 to 3 , and 6 to 6
S traight-through Ethernet cable
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Crossover Cable
The crossover cable can be used to connect
S witch to switch
Hub to hub
Host to host
Hub to switch
Router direct to host
Notice that instead of connecting 1 to 1, 2 to 2, and so on, here we
connect pins 1 to 3 and 2 to 6 on each side of the cable.
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R olled Cable
Although r o lle d c ab le isnt used to connect any Ethernet
connections together, you can use a rolled Ethernet cable to
connect a host to a router console serial communication (com) port.
Rolled Ethernet Cable
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H ow to Make an Ethernet Cable
R equirementsBulk Ethernet Cable ( RJ -45)
Bulk RJ 45 Crimpable Connectors
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RJ -45 Crimping tool
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Standard , Straight-Through Wiring ( Both Ends Are the Same )
RJ 45 Pin # Wire Color (T568 A)Wire Diagram
(T568 A)
10B ase-TSignal
100B ase-TXSignal
1 White/Green Transmit+2 Green Transmit-
3 White/Orange Receive+
4 Blue Unused
5 White/Blue Unused6 Orange Receive-
7 White/Brown Unused
8 Brown Unused
S tandard S traight-through Wiring
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Straight-Through Cable Pin out for T 568 A
RJ 45 Pin # Wire Color (T568B)Wire Diagram
(T568B)
10B ase-T Signal100B ase-TX
Signal
1 White/Orange Transmit+2 Orange Transmit-
3 White/Green Receive+
4 Blue Unused
5 White/Blue Unused6 Green Receive-
7 White/Brown Unused
8 Brown Unused
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Straight-Through Cable Pin out for T 568B
RJ 45 Pin # Wire Color (T568B)Wire Diagram
(T568B)
10B ase-T Signal100B ase-TX
Signal
1 White/Orange Transmit+2 Orange Transmit-
3 White/Green Receive+
4 Blue Unused
5 White/Blue Unused6 Green Receive-
7 White/Brown Unused
8 Brown Unused
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Basics of WAN
What is WAN?
Wide Area Network (WAN) is a Computer network that covers a
broad area (i.e., any network whose communications links cross
metropolitan, regional, or national boundaries). Or, a network that
uses routers and public Communication Links.
Conceptual View of Point-to-Point Leased Line
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The several options available for WAN connectivity are:
Option Description Advantages DisadvantagesBandwidthrange
Sampleprotocolsused
Leased line
Point-to-Pointconnection betweentwo computers or
Local Area Networks(LANs)
M ost secure ExpensivePPP , HDLC ,S DLC, HNAS
Circuitswitching
A dedicated circuitpath is created
between end points.Best example isdialup connections
LessExpensive
CallS etup
28 Kb/s -144 Kb/s PPP , IS DN
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Packet switching
Devices transportpackets via a sharedsingle point-to-point or point-to-multipoint link
across a carrier internetwork. Variablelength packets aretransmitted over Permanent VirtualCircuits (PVC ) or S
witched VirtualCircuits (S VC)
S hared mediaacross link
X.25 Frame-Relay
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Cell relay
S imilar to packetswitching, butuses fixedlength cellsinstead of variable lengthpackets. Data isdivided intofixed-length cellsand thentransportedacross virtualcircuits
best for simultaneous useof Voice and data
Overhead can beconsiderable AT
M
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WAN Cabling Standards
S erial Cabling Options
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TH ANK YOU