Fundamentals of LAN and WAN

8/8/2019 Fundamentals of LAN and WAN

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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-


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-


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

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Fundamentals of LAN and WAN