network topologies final final

8/2/2019 Network Topologies Final Final

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NetworkTopologies

BY-ADIL REHMAN BHAT


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Terminology

Networking consists of computers, wiring, and otherdevices, such as hubs, switches, and routers thatmake up the network infrastructure.

Topology (from the Greek word topos meaningplace) is a description of any kind of locality in termsof its layout.

There are two ways to describe a network topology.

1. Physical topology2. Logical Topology


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Client a computer that allows a user to logonto the network and take advantages of theresources on the network.

Server Much more powerful computer thatprovides centralized administration of thenetwork and serves up the resources thatare available on the network.

Terminology


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Client/Server

Client/Server networkoperating systems allowthe network to centralizefunctions andapplications in one ormore file servers

Advantages

Centralized

Scalable

Flexible

Interoperable

Accessible

Disadvantages

Maintenance

Expense

Dependence


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Peer to Peer

Each computer actsboth as a client andserver.

Advantages

Less expense

Easy setup

Decentralized

Disadvantages

Security

Decentralized


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Standard PhysicalTopologies

Star

Ring

Mesh

Bus2223


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Bus Topology

Characterized by a main trunk or backbone line withnetworked computers attached at intervals along thetrunk line.

Passive topology

Typically use coaxial cable hooked to each computerusing a T-connector.


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Bus Topology cont.

Coaxial Cable Connectors


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Star Topology

Computers on the network connect to acentralized connectivity device,usually a hub or a switch.


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Ring Topology

Connects the LAN computersone after the other on the

wire in a physical circle. Moves info on the wire in one

direction, considered anactive topology.


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Mesh Topology

All nodes are directly connected with allother nodes.

Best choice when fault tolerance isrequired.

Very difficult to setup and maintain.


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Standard LogicalTopologies

The way in which data accesses themedium (cable) and transmits packets.

There are only two: Ring and Bus


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Logical Topology: Ring

In the ring logical topology only one node can sendinformation across the network at any giventime. This is done by way of a token.

Each terminal receives this special packet, and if ithas data to send, it will do so.

Once it has sent the data, it passes the token tothe next station.

Used for very fast networks No collisions

Susceptible to faults


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Logical Topology: Bus

Each time a node on a network has datafor another node the sending nodebroadcasts to the entire network.

Stations can always transmit.

Less susceptible to breaks.

Collisions (two stations transmitting at once) have to bedealt with.


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Selecting a Topology

Needs:Do you need very high speeds?

Will you be moving really large files?

Maintenance:

Do you want something (relatively) painless?

Cost:

Are you on a budget?

Do you want replacement parts easily accessible?

Geography:How far is it between stations?Will you be relocating stations often?


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Thank you!

Questions?

network topologies final final

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