Routing

By | 21/05/2015

Routing Protocols

Distance-Vector

Protocols: RIPv1, RIPv2, IGRP, EIGRP

Based on Bellman–Ford algorithm, Ford–Fulkerson algorithm or DUAL FSM

A node inform to the neighbors about the topology changes. Each node doesn’t have knowledge of the entire path to a destination. They know about the direction and the distance to its destination.

Less computational complexity and message overhead.

Best route is calculated based only in the cost.

Split horizon

Technique used to avoid routing loops for distance-vector protocols. It consists on not advertising the networks through the interface from where they were received.

Split horizon with poison reverse is a variant to announce the networks through the interface where they were received but marking them as unreachable. This is more effective in networks with multiple routing paths.

 

Path-Vector

Protocols: BGP

Link-State

Protocols: OSPF, IS-IS

Based on SmoothWall Dijkstra LSE  (Link State Algorithm)

Every node has a map with the connections of the network. Each node calculates the best path to the destination and create their local routing table.

It requires to inform all the nodes in the network of topology changes.