History

• In the old ARPANET, routing was static

• As the ARPANET grew, the routing became more dynamic, but with all routers sharing a single protocol

• As the Internet became the “network of networks” routing was separated into interior and exterior domains

• • Each AS could determine the IGP that suited it best
  • A standard EGP was used between AS’s

• Today

• • RIP and OSPF are the most widely used IGP’s
  • IS-IS is another IGP that is generally available
  • EGP was the first EGP (confused?) but has been replaced with BGP (which is now in version 4)