An interior gateway protocol (IGP) or interior routing protocol is a type of routing protocol used for exchanging routing table information between gateways (commonly routers) within an autonomous system (for example, a system of corporate local area networks).
Specific examples of IGPs include Open Shortest Path First (OSPF), Routing Information Protocol (RIP), Intermediate System to Intermediate System (IS-IS) and Enhanced Interior Gateway Routing Protocol (EIGRP).
[2] By contrast, exterior gateway protocols are used to exchange routing information between autonomous systems and rely on IGPs to resolve routes within an autonomous system.
Examples of distance-vector routing protocols: Examples of link-state routing protocols: Advanced distance vector routing protocols have both the features of distance vector routing protocols and link-state routing protocols.
One example is Enhanced Interior Gateway Routing Protocol (EIGRP).