Network Topologies in Computer Network

 

The term Network Topology defines the Geographic, Physical, or logical arrangement of computer and networking devices.

The pattern of the interconnection of nodes on a network is called the topology.

FACTORS for choosing a Topology of a network are:-

• Cost: which offers minimum installation cost based on the network under consideration.
• Flexibility: Can offer easy move of existing nodes and adding new ones.
• Reliability: Offers least failure.

BUS TOPOLOGY-:

• It consists of one continuous length of cable (trunk) that is shared by all the nodes in the network.
• It has a terminating resistor (terminator) at each end that absorbs the signal when it reaches the end of the line.

Advantage -:

1. Easy to connect a computer.
2. Requires less cable length.
3. Failure of one node does not affect the network functioning. 

Disadvantage -:

1. The entire network shuts down if there is a break in the main cable.
2. Terminators are required at both ends.
3. Difficult to identify the problem.
4. Nodes must be intelligent.

RING TOPOLOGY -:

• Each node has two neighboring nodes.
• Data packet is received from one neighboring and is transmitted to the next.
• Data travels in one direction in the ring-like structure.

Advantage -:

1. Short cable length
2. The possibility of collision is minimum

Disadvantages -:

1. One node causes network failure
2. It is very difficult to diagnose faults
3. Network reconfiguration is difficult.

STAR TOPOLOGY -:

• Each node connected directly to a central network hub or concentrator.
• Data passes through the hub or concentrator before continuing.
• The hub or concentrator manages and controls all functions of the network.

Advantage -:

1. Easy to install.
2. No disruptions to the network when connecting or removing devices.
3. Easy to detect faults and to remove parts.

Disadvantage -:

1. Requires more cable length than a BUS/RING topology.
2. If the hub or concentrator fails, the nodes attached are disabled.
3. More expensive than linear bus topologies because of the cost of the concentrators.

MESH TOPOLOGY -:

• Each node is connected to another Node.

Advantage -:

1. It is robust.
2. Provides security and privacy.
3. The fault is diagnosed easily.

Disadvantage -:

1. The cost to implement is higher than other network topologies.
2. Installation and configuration are difficult.

TREE TOPOLOGY -:

• A tree topology combines characteristics of linear BUS and STAR topologies.
• Inverted tree-like structure.
• It consists of groups of star-configured workstations connected to a linear bus backbone cable.

Advantage -:

1. Point-to-point wiring for individual segments
2. It is highly flexible
3. Centralized monitoring 

Disadvantage -:

1. If the backbone line breaks, the entire segment goes down.
2. It is difficult to configure the network if there is a single point of failure.
3. More wire is required than other topologies.

HYBRID TECHNOLOGY -:

• A hybrid topology is an integration of two or more different topologies to form a resultant topology.