Network Topologies

INTRODUCTION

Network Topology is the arrangement of the various elements of a communication network.There are  two ways of defining network geometry:The physical topology and the logical topology.The physical topology of a network is the actual geometric layout of workstation.

There are several common physical topologies,

• Bus network.
• Ring network.
• Tree network.
• Star network.
• Mesh network.

1.Bus Network Topology.

        A Bus network topology is a network setup in which each computer and network device are connected to a single cable or backbone.Bus networks are well known for their nodes being located in a shape of a bus.

      There are two types of bus network topologies,one of which is a"Linear bus" one.This type of network topology is the one where all of the nodes of the entire network are connected to one common transmission with only two endpoints.In this type of bus topology all of the data transmitted between nodes is transmitted over this common medium and it is able to be received by all nodes at the same time.

       Another type of bus network is called "Distributed bus". This type of network topology is the one where all of the network nodes are connected to one common transmission medium and it has more than two endpoints which are created by adding the branches to the main section of the transmission medium.

Advantages of Bus Topology.

1. It is easy to set-up.
2. Cost very less.
3. Mostly used in small networks,good for LAN.
4. Cable length required for this topology is the least compared to other networks. 

Disadvantages of Bus Topology.

1. Maintenance costs can get higher with time.
2. Efficiency is reduces.
3. Limitation on central cable length and number of nodes that can be connected.
4. Not suitable for networks with heavy traffic. 

 

2.Ring Network Topology

        A Ring network is a network topology in which each node connects to exactly two other nodes,forming a single continuous path way for signals through each node - a ring.Each data packet is sent around the ring until it reaches it's final destination.Ring topologies are used in both local area network and wide area network setups.

Advantages of Ring Topology.

1. Additional components do not affect the performance of network.
2. No need network server to control the connectivity between workstation.
3. Each computer has equal access to resources.
4. It's performance is better than the bus topology.

Disadvantages of Ring Topology.

1. Slower than the star topology.
2. If one workstation goes down,the entire network gets affected.
3. Network cards are expensive as compared to Ethernet cards and hubs.

3.Tree Network Topology

        A tree network is a combination of two or more star networks connection together.Each star network is a local area network in which there is a central computer or server to which all the workstation nodes are directly connected.

In computer networks a tree topology is also known as a star bus topology.In a tree topology there can be only one connection between any two connected nodes.Because any two nodes can have only one mutual connection tree topology form a natural parent-child hierarchy.

Advantages of Tree Topology.

1. Easier maintenance and fault finding.
2. Scalable as leaf nodes can accommodate more nodes in the hierarchical chain.
3. Error detection and correction is easy.
4. If one segment is damaged ,other segments are not affected.

Disadvantages of Tree Topology.

1. Huge cabling is needed.
2. A lot of maintenance is needed .
3. Backbone forms the point of failure. 

4.Star Network Topology

         Star network topology is one of the most common Computer network topology.A star topology for a local area network in which all nodes are individually connected to a central connection point like a hub or a switch.It is an implementation of a spoke-hub distribution paradigm in computer networks.

Advantages of Star Topology.

• Centralized management.It helps in monitoring the network.
• Easy to add another computer to the network.
• Breakdown of one node doesn't affected to the other components.

Disadvantages of Star Topology.

• The central hub is a single point of failure for the network.
• The use of hub ,a router or a switch as central device increases the cost.

 

5.Mesh Network Topology

      A Mesh network is a network topology in which each node relays data for the network.All mesh nodes cooperate  in the distribution of data in the network.It can be applied to both wired and wireless networks.It is a local area network or virtual LAN that employs one of two decentralized connection arrangements:full mesh topology or partial mesh topology.In full mesh topology each network node is connected to those others ,but others are only only connected to those nodes with which they exchange the most data.

Advantages of Mesh Topology.

• Data can be transmitted from different devices simultaneously.
• Even if one of the components fails there is always an alternative present.
• Expansion can be done without disrupting others nodes.

Disadvantages of Mesh Topology.

• Overall cost of this network is high.
• Setup and maintenance are difficult.