Network Topologies

What do you mean by Network Topology?

Network topology is the arrangement of nodes. The topology of the network, and the relative locations of the source and destination of traffic flows on the network, determine the optimum path for each flow and the extent to which redundant options for routing exist in the event of a failure. There are two ways of defining network geometry: the physical topology and the logical (or signal) topology.

What is Physical Topology?

The actual layout of the computers, cables and other network devices which is connected physically.

What is Logical Topology?

The way in which the network appears to the devices that use it, or the way devices are communicating with each other.

What is Bus Topology?

It Uses a trunk or backbone to which all the computers on the network connect. Systems connect to this backbone using T connectors or taps. Coaxial cablings (10Base-2, 10Base5) were popular options years ago.

Advantages:

Cheap and easy to implement.

Require less cable.

Does not use any specialized network equipment.

Disadvantages:

Network disruption when computers are added or removed.

A break in the cable will prevent all systems from accessing the network.

Difficult to troubleshoot.

What is Ring Topology?

Logical ring means to say that data travels in circular fashion from one computer to another on the network. Ex - FDDI, SONET or Token Ring. Ring networks are most commonly wired in a star configuration. Token Ring has multi-station access unit (MSAU), equivalent to hub or switch. MSAU performs the token circulation internally.

Advantages:

Ring networks are moderately easy to Install.

Cable faults are easily located, making troubleshooting easier.

Disadvantages:

A single break in the cable can disrupt the entire network.

Expansion to the network can cause network disruption.

What is Star Topology?

All computers/devices connect to a central device called hub or switch. Each device requires a single cable point-to-point connection between the device and hub. It is implemented most widely.

Advantages:

Easy to troubleshoot and isolate problems.

Cable failure affects only a single user.

Easily expanded without disruption.

Disadvantages:

Requires more cable to the network

More difficult to implement

A central connecting device allows for a single point of failure

What is Mesh Topology?

Each computer connects to every other. High level of redundancy. This topology is used rarely. In this topology wiring is very complicated and cabling cost is high. Troubleshooting a failed cable is tricky. A variation hybrid mesh can create point to point connection between specific network devices, often seen in WAN implementation.

Advantages:

The network can be expanded without disruption to current uses.

Provides redundant paths between devices.

Disadvantages:

Complicated implementation.

Requires more cable than the other LAN topologies.

 

What is Wireless Networking?

It does not require physical cabling, particularly useful for remote access for laptop users. Eliminate cable faults and cable breaks and signal interference and security issue.

Advantages:

Network can be expanded without disruption to current users.

Allows for wireless remote access.

Disadvantages:

Limited speed in comparison to other network topologies.

Potential security issues associated with wireless transmissions.

What is FDDI?

Fiber Distributed Data Interface (FDDI) standard was developed by American National Standards Institute (ANSI). Dual ring technology for fault tolerance and it has speed of 100Mbps or higher. Media: fiber optic cable, > 2 kilometers. Also possible use copper wire as Copper Distributed Data Interface (CDDI). Access method is token-passing access method.