IGP:

  • Within a single autonomous system
  • Single network administration
  • Unique routing policy
  • Make best use of network resource
  • An IGP (Interior Gateway Protocol) is a protocol for exchanging routing information between gateways (hosts with routers) within an autonomous network (for example, a system of corporate local area networks).
  • IGP’s fall into two categories:
    • Distance Vector Protocols
      • Routing Information Protocol (RIP)
      • Interior Gateway Routing Protocol (IGRP)
    • Link State Protocols
      • Open Shortest Path First (OSPF)
      • Intermediate System to Intermediate System (IS-IS)

EGP:

  • Among different autonomous systems
  • Independent administrative entities
  • Communication between independent network infrastructures
  • Exterior Gateway Protocol (EGP) is a protocol for exchanging routing information between two neighbor gateway hosts (each with its own router) in a network of autonomous systems.
  • EGP is commonly used between hosts on the Internet to exchange routing table information.
  • Examples of an EGP:
    • Border Gateway Protocol (BGP)
    • Exterior Gateway Protocol (Replaced by BGP)