Difference Between Interior Gateway Protocol (IGP) and Exterior Gateway Protocol (EGP)?

When I first heard about Interior Gateway Protocol (IGP) and Exterior Gateway Protocol (EGP), I was just like, “what on bits and bytes are these?” If you are new to networks and you suddenly heard these on your first day, you might ignore the meaning and also the importance. However, you don’t have to memorize the meaning because you will know it by heart as days go by.

So what are IGP and EGP?

IGP is composed of routing protocols that are used within the autonomous system while EGP is used between different autonomous system. IGP usually runs within the LAN while EGP mostly used in WAN. EGP is the protocol run by ISPs to connect to customer’s edge device and protocol used by the internet. It is used to interconnect different autonomous system.

Interior Gateway Protocols:

1. Routing Information Protocol (RIP)
2. Open Shortest Path First (OSPF)
3. Enhanced Interior Gateway Routing Protocol (EIGRP)
4. Intermediate System to Intermediate System (IS-IS)

Exterior Gateway Protocol:

1. Border Gateway Protocol (BGP)

Believe me, if you missed it, you’ll get to know it on the other day.