Routing Algorithms in Computer Networks

Routing Algorithms in Computer Networks

Routing Algorithms: 

 

Routing algorithms is using for  preparing the routing information table.
  • Non-Adaptive Routing Algorithm
  • Adaptive Routing Algorithm
Non-Adaptive Routing Algorithm
Non-adaptive routing algorithm is based on initial permanent information.The information in the routing information table (RIT) cannot accommodate changes in the network.
Example: Static Algorithm
 
Adaptive Routing Algorithm: 
This accommodates changes in the network that is the information in the routing information table (RIT) can be updated dynamically.
  • Centralized Routing Algorithm
  • Isolated Routing Algorithms
  • Distributed Routing Algorithm 

 

Centralized Routing Algorithm:

Here the routing information table (RIT) is prepared by the Routing Control Center (RCC).The routing information table (RIT) is prepared based on global knowledge.

Disadvantages of Centralized Routing Algorithm :
  • Heavy traffic near Routing Control Center (RCC)

  • Inconsistency in Routing information Table (RIT)

  • If RCC fails, updates in RIT is not possible

Status information from all routers coming continuously to RCC and updates in RIT is sending to all routers from RCC, thus there is heavy traffic near RCC. The Updates from RCC reaches soon to routers near to RCC and later to others.,hence there is inconsistency in RIT.

Isolated Routing Algorithms


In Isolated Routing Algorithms each router prepares it’s Routing Information table (RIT)  based on local knowledge.The following are isolated routing algorithms.

  • Hot Potato

  • Backward Learning

  • Flooding

  • In Hot Potato the router forward the incoming packet to the less traffic route.

  • In Backward Learning the router makes entries in RIT based on the information from the incoming packets.

  • In Flooding the router forwards the incoming packet to all other route except the incoming route.

Disadvantages of Flooding : Vast number of duplicate packets.

 

Distributed Routing Algorithm

Each router based on the local and global knowledge prepares RIT.
  • Link state routing Algorithm