Computer Knowledge: About Network Topology's in Computers for Competitive Exams

Network Topology's ( Mesh, Star and Tree Topology's)

Mesh Topology: 
It is also known as completely interconnected topology. In mesh topology, every node has a dedicated point to point link to every other node. It provides a bi-directional link between each possible node. This type of network topology contains at least two nodes with two or more paths between them. Mesh topology is robust because the failure of any one computer does not bring down the entire network.

Advantages of Mesh Topology are:

• Excellent for long distance networking.
• Communication possible through the alternate route, if one path is busy.

Disadvantage of Mesh Topology are:

• Long wire or cable length, hence increase in the cost of installation and maintenance.

Star Topology:
In this network topology, the peripheral nodes are connected to a central node, which rebroadcasts all transmissions received from any peripheral node to all peripheral nodes across the network, including the originating node.If the central hub fails, then whole network fails. The protocols used in star topology are Ethernet, Token Ring and Local Talk. A star network can be expanded by placing another star hub.

Advantages of Star Topology are:

• Installation of star topology is very easy as all the nodes are directly connected to the central node or server.
• Easy to detect faults and remove it.
• Failure of single system will not bring down the entire network.
• Allows several types of cables in same network.

Disadvantages of Star Topology are:

• Requires more cable length than bus topology.
• If hub or server fails, the entire network will be disabled.
• Difficult to expand, as the new node has to connect all the way to central node.

Tree Topology: 
This is a network topology in which nodes are arranged as a tree. The function of the central node in this topology may be distributed. A tree topology is an extension and variation of star topology. Its basic structure is like an inverted tree, where the root acts as a server. It allows more devices to be attached to a single hub.

Advantages of Tree Topology are:

• The tree topology simulates hierarchical flow of data. So, it is suitable for applications where hierarchical flow of data and control is required.
• We can easily extend the network.

Disadvantages of Tree Topology are:

• Long cable are required.
• There are dependencies on the root node.
• If the central hub fails, the entire system breaks down.

Computer Knowledge: Network Topology's for Competitive Exams

Network Topology's ( Bus - Ring)

Network Topology: The term "Topology" refers to the way a network is laid out, either physically or logically. Topology can be referred as the geometric arrangement of a computer system. Each computer system in a topology is known as node. Network topology is determined only by the configuration of connections between nodes. In a fully connected network with n nodes, there are n(n-1)/2 direct links.

Bus Topology:

A bus topology is such that there is a single line to which all nodes connected. It is usually used when a network installation is small, simple or temporary. In bus topology, all the network components are connected with a same (single) line. Ethernet is commonly well protocol in networks connected by bus topology.

Advantages of Bus topology are:

• All the nodes are connected directly, so very short cable length is required.
• The architecture is very simple and linear.
• Bus topology can be extended easily on either sides.
• The cabling cost of bus topology is less and requires the least amount of cable to connect computers.

Disadvantages of Bus topology are:

• Diagnosis of fault is difficult. It is difficult to find the problem, if any of the node is facing problem in data communication.
• In case of any fault in data transmission, fault isolation is very difficult. We have check the entire network to find the fault.
• Becomes slow which increase in number of nodes.
• The entire network shuts down if there is an error occurs in the main cable.

Ring or Circular Topology

Ring topology is used in high-performance network where large band with is necessary. The protocols used to implement ring topology are Token Ring and Fibre Distributed Data Interface (FDDI). In ring topology, data is transmitted in form of Token over a network. After passing through each node, the data returns to the sending node.

Advantages of ring or circular topology are:

• Short cable length is required.
• Suitable for optical fibre as the data flow in one direction.

Disadvantages of ring or circular topology are;

• In ring topology, each node is connected in a circular way, with its two neighbouring nodes, so when there is transmission problem anywhere in the network, entire network stops functioning.
• Fault diagnosis is very difficult in a network formed using ring topology.
• In ring topology, every node has exactly two branches connected to it, the ring is broken and cannot work if one of the nodes on the ring fails.
• Failure of single computer affects the whole network.
• Adding or removing the computer disturbs whole network activity.

Note:- We will discuss remaining Three Topology's in coming posts. Happy Reading.....