Routing Protocols Basics

IGP – Interior Gateway Protocol
EGP – Exterior Gateway Protocol
BGP – Border Gateway Protocol
RIP – Routing Information Protocol
IGRP – Interior Gateway Routing Protocol
OSPF – Open Shortest Path First (Click this link for more details on OSPF)
ISIS – Intermediate System to Intermediate System
EIGRP – Enhanced Interior Gateway Routing Protocol

Routing protocol :

Routing protocol specifies how router communicate with each other and distribute information that enable them to select the route for traffic flow. Routing protocol are configured on routers with a purpose of exchanging routing information. 

Static Routing Protocol : 

Static routing are manually configured by Network administrator by adding fixed entries in to routing tables. It is also known as non-adaptive routing since it doesn't change routing table unless the network administrator modifies it manually. This protocol does not uses complex algorithm for routing but it definitely provides high security compared to dynamic routing protocols.

Dynamic Routing Protocol :

Dynamic routing is when routing protocols is used to figure out best path for traffic flow. Its an adaptable routing protocol as it has ability to update routing table whenever there is change in topology or network, these modification in routing table are done with help of protocols like OSPF, ISIS, BGP, etc.This routing protocol uses complex algorithm but does not provide very high security like static routing protocol.

When the network/topology changes,it sends message to router for ensuring that changes are recalculated and are send for updating routing tables.

Default Routing Protocol :

This is the routing method where all routers are configured to send all packets towards a single router. However, its usually combined with static protocol or dynamic protocol. These protocols are mostly used in small networks or for network with single entry and exit points.