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NETWORKING TOPOLOGY

Presented to: Madam Mah-e-

bushraPresented by: Shafiq-ur-rehmanRoll no: 04 BS (Hons) 7th

semester Session (2010-2014) 

The Islamia University of Bahawalpur

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Networking Topology

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ContentNetworking Topology 05

Physical topology 08

Smart art graphic 09

Ring topology 10

Diagram of Ring topology 11

Advantages/disadvantages 12

Bus Topology 13

Diagram of Bus Topology 14

Advantages of Bus topology 15

Disadvantages of Bus Topology 16

Star Topology 17

Diagram of Star topology 18

Advantages/Disadvantages of Star topology 19

Tree topology 20

Mesh Topology 21

Diagram of Mesh Topology 22

Advantages/Disadvantages of Mesh Topology 23

Logical Topology 24

Two types of logical Topology 25

Reference 26

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AN INTRODUCTION TO NETWORKING TOPOLOGY

Network topology is the study of the arrangement or mapping of the elements (links, nodes, etc.) of a network, especially the physical (real) and logical (virtual) interconnections between nodes A local area network (LAN) is one example of a network that exhibits both a physical topology and a logical topology.

Any particular network topology is determined only by the graphical mapping of the configuration of physical and/or logical connections between nodes. LAN Network Topology is, therefore, technically a part of graph theory.

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NETWORKING TOPOLOGY

Networking Topology: The way in

which the connections are made is called the topology of the network.

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The structure of the network is divided into the physical topology and the logical topology.

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PHYSICAL TOPOLOGY

refers to the configuration of the cables, computers, and other peripherals.

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Topologies Ring

Bus

Star

Tree

Mesh

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RING TOPOLOGY

Diagram Description: Devices are connected from one to another

to form a ring shape. Each host is connected to the next and the

last node is connected to the first. A data token1 is used to grant permission for

each computer to communicate.

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Advantages: Easy to install and wire. Because every computer is given equal access to

the token, no one computer can monopolize the network.

Disadvantages: Requires more cable than a bus topology. If one computer fails it can affect the whole

network. It is difficult to identify the problem if the entire

network shuts down.

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BUS TOPOLOGY

Diagram

The bus topology is often used when a network installation is small, simple, or temporary.

Description: All hosts are connected to the backbone

cable in a linear fashion.

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Advantages of the Bus There are several advantages to a bus topology: The bus is simple, reliable in very small networks,

easy to use, and easy to understand. The bus requires the least amount of cable to

connect the computers together and is therefore less expensive than other cabling arrangements.

It is easy to extend a bus. Two cables can be joined into one longer cable with a BNC barrel connector, making a longer cable and allowing more computers to join the network.

A repeater can also be used to extend a bus; a repeater boosts the signal and allows it to travel a longer distance.

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Disadvantages of the Bus A bus topology is commonly subject to the following

disadvantages: Heavy network traffic can slow a bus considerably. Because any

computer can transmit at any time, and computers on most bus networks do not coordinate with each other to reserve times to transmit, a bus network with a lot of computers can spend a lot of its bandwidth (capacity for transmitting information) with the computers interrupting each other instead of communicating. The problem only gets worse as more computers are added to the network.

Each barrel connector weakens the electrical signal, and too many may prevent the signal from being correctly received all along the bus.

It is difficult to troubleshoot a bus. A cable break or malfunctioning computer anywhere between two computers can cause them not to be able to communicate with each other. A cable break or loose connector will also cause reflections and bring down the whole network, causing all network activity to stop.

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STAR TOPOLOGY Diagram In a star topology, all the cables run from the computers to a

central location, where they are all connected by a device called a hub.

Stars are used in concentrated networks, where the endpoints are directly reachable from a central location; when network expansion is expected; and when the greater reliability of a star topology is needed.

Description: All hosts are connected to a single point of concentration. Usually uses a hub3 or switch4 as a center node. Range limits are about 100 meters from the hub Data on a star network passes through the hub or concentrator

before continuing to its destination.

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Advantages: It is easy to modify and add new computers to a star

network without disturbing the rest of the network. If one node or workstation (beside the middle node) goes

down, the rest of the network will still be functional. The center of a star network is a good place to figure out

where the network faults are located. You can use several cable types in the same network if

the hub you have can handle multiple cable types. Disadvantages: Requires more cable than a bus topology. If the middle node goes down , then the entire network

goes down. It is more expensive than because all cables must be

connected to one central point.

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TREE TOPOLOGY

Tree topology is a combination of Bus and Star topology.

This particular type of network topology is based on

a hierarchy of nodes. The highest level of any tree network

consists of a single, 'root' node, this node connected either

a single (or, more commonly, multiple) node(s) in the level

below by (a) point-to-point link(s). These lower level nodes are also connected to a single or multiple nodes in the next level down. Tree networks are not constrained to any number of levels, but as tree networks are a variant of the bus network topology, they are prone to crippling network failures should a connection in a higher level of nodes fail/suffer damage. Each node in the network has a specific, fixed number of nodes connected to it at the next lower level in the hierarchy, this number referred to as the 'branching factor' of the tree. This tree has individual peripheral nodes.

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MESH

Diagram

The mesh topology is distinguished by having redundant links between devices. A true mesh configuration has a link between each device in the network. As you can imagine, this gets unmanageable beyond a very small number of devices. Most mesh topology networks are not true mesh networks.

Description: Each host is connected to all the other hosts.

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Advantages: Increased reliability since there are multiple paths

for each node to take. Increased speed since shortcuts have been

created by add more cables/links. Disadvantages: The cost of cabling all the hosts together is

expensive and time consuming.

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LOGICAL TOPOLOGY

refers to the method for passing information between workstations.

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TWO TYPES OF LOGICAL TOPOLOGIES:

Broadcast - This type of logical topology works on a first come, first serve basis.  The first in line gets to be the first to be sent.  Each host sends its data to all other hosts.  The Ethernet is a good example of a broadcast logical topology.

Token Passing - This type of logical topology controls access by passing a token1.  Each host can only send data when it has the token1.

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REFERENCE

1) Cisco Networking Academy Program CCNA 1 and 2 Lab Companion, Revised Third Edition.  Cisco Press, 2005.  ISBN:  158731498.

2) Computer in business P.62-65

3) Network Topology:  http://www.theapaws.net/network_topology.htm

4) The Home PC:  http://thehomepc.com/networks/topology.htm

5) http://www.sis.pitt.edu/~icucart/networking_basics/networking_topology.html

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