Network Topologies

What’s in the WorkshDefine Network Topology

hShow models of the three major types.

hList advantages and disadvantages.

hVocabulary

hSummary

Topology is:

the physical layout of the local area network(LAN)

How the network is put together!

Topology - Physical arrangement of network nodes and media within an enterprise networking structure.

Types of TopologiesTypes of Topologies

i1. Bus 1. Bus

i2. Star2. Star

i3. Ring3. Ring

The Bus LayoutThe Bus Layout

This is the physical layout for This is the physical layout for a typical bus network.a typical bus network.

A bus topology uses one long cable, called the A bus topology uses one long cable, called the backbone. Short cables, called drop cables, can backbone. Short cables, called drop cables, can be attached to the backbone using t- connectors. be attached to the backbone using t- connectors. The backbone is terminated at both ends.The backbone is terminated at both ends.

Think of a bus as a small one street town (the bus) Each Think of a bus as a small one street town (the bus) Each person has a driveway (the drop). They (the data) can person has a driveway (the drop). They (the data) can drive from house to house(the NIC card).drive from house to house(the NIC card).

Ethernet StarEthernet Star

Think of an airline.Think of an airline.Anytime you (the data) go across the country you have to Anytime you (the data) go across the country you have to travel to destination hubs such as Phoenix, Dallas, or travel to destination hubs such as Phoenix, Dallas, or Chicago (network hubs or switches) before you get to Chicago (network hubs or switches) before you get to your destination.your destination.

Star topologies use a central device with drop cables Star topologies use a central device with drop cables extending in all directions. It uses point to point extending in all directions. It uses point to point links from a central connecting device called a hub.links from a central connecting device called a hub.

RingRing TopologyTopology

Ring TopologyRing TopologyToken passing - Access method by which network devices access the physical medium in an orderly fashion based on possession of a small frame called a token.

Imagine you (data) are at Yosemite Valley Imagine you (data) are at Yosemite Valley and the only way you may go to another and the only way you may go to another site (workstation) is to hop on the tour site (workstation) is to hop on the tour trolley (token). When you get off other trolley (token). When you get off other people(data) hope on the token. The road people(data) hope on the token. The road (network media) only loops the valley.(network media) only loops the valley.

SourceSource

DestinationDestination

A free token is A free token is routed around the routed around the ring. As it passes ring. As it passes around the ring, it around the ring, it polls devices on the polls devices on the network to see if network to see if they want to transmit they want to transmit data.data.

Advantages and DisadvantagesAdvantages and DisadvantagesBus TopologyBus Topology

AdvantagesAdvantages DisadvantagesDisadvantages

Low cost to createLow cost to create High management costHigh management cost

Less media usedLess media used Difficult to troubleshootDifficult to troubleshoot

One goes down, One goes down, doesn’t affect rest.doesn’t affect rest.

All units affected by All units affected by media failure.media failure.

Advantages and DisadvantagesAdvantages and DisadvantagesStar TopologyStar Topology

Easy to configureEasy to configure

Easy to troubleshootEasy to troubleshoot

One goes down it One goes down it doesn’t affect rest.doesn’t affect rest.

AdvantagesAdvantages DisadvantagesDisadvantagesmore costlymore costlyuses more mediauses more mediaIf hub fails, entire If hub fails, entire network failsnetwork fails

Hub can become Hub can become bottleneckedbottlenecked

AdvantagesAdvantages DisadvantagesDisadvantages

Advantages and DisadvantagesAdvantages and Disadvantages

Cable faults easily Cable faults easily identified.identified.

It can span longer It can span longer distances. Each host distances. Each host repeats and amplifies repeats and amplifies

signal.signal.

More difficult to install More difficult to install

media failure on a media failure on a single unidirectional single unidirectional loop cause complete loop cause complete

network failurenetwork failure

COSTCOST

Ring TopologyRing Topology

Less CollisionsLess Collisions

VocabularyVocabulary

Algorithm - Well-defined rule or process for arriving at a solution to a problem. In networking, algorithms arecommonly used to determine the best route for traffic from a particular source to a particular destination

Bus - Common physical signal path composed of wires or other media across which signals can be sent from one partof a computer to another. Sometimes called highway.

Backoff - The retransmission delay enforced when a collision occurs.

Collision - In Ethernet, the result of two nodes transmitting simultaneously. The frames from each device impact andare damaged when they meet on the physical media.

Collision domain - In Ethernet, the network area within which frames that have collided are propagated. Repeaters andhubs propagate collisions; LAN switches, bridges and routers do not.Terminator - Device that provides electrical resistance at the end of a transmission line to absorb signals on the line,thereby keeping them from bouncing back and being received again by network stations.

Token passing - Access method by which network devices access the physical medium in an orderly fashion based onpossession of a small frame called a token.

Topology - Physical arrangement of network nodes and media within an enterprise networking structure.

Checking for UnderstandingChecking for UnderstandingTopology - Physical arrangement of network nodes and media within an enterprise networking structure.

There are three basic Topologies

Bus

Star

Token Ring

Each topology has it’s own advantages and disadvantages. You need to design your network according strengths and weaknesses of each.

NETWORK PROTOCOLS

Network Protocol: the “language” that computers use to communicate over a network.

NETWORK PROTOCOLS

TCP/IP Transmission Control Protocol / Internet

Protocol Most common protocol in use Oldest protocol in use Each device has its own network ID

number (209.231.13.42)

NETWORK PROTOCOLS

AppleTalk Can work over LocalTalk or Ethernet Some complain that it’s “chatty” Used since 1984 with Macs Can be used with Windows

NETWORK PROTOCOLS

NetBUI Original Windows networking protocol Macs can’t use it Not as stable or cross platform as

TCP/IP

NETWORK PROTOCOLS

IPX Novell Protocol Can be used with DOS, Windows, and

Macs Used to be most popular protocol before

Windows NT.

Peer-To-Peer

Any modern computer can share its files over the network

Much slower than Server Should only be used with 1 other

computer at a time

Client-Server

Typical network setup Server can serve files, printing jobs,

email, web pages, etc.