Which of these is an example of an Exterior Gateway Protocol?

The Border Gateway Protocol (BGP) is considered an Exterior Gateway Protocol (EGP) because it is specifically designed to manage how packets are routed across different autonomous systems (ASes) on the internet. Unlike interior gateway protocols (IGPs) that operate within a single autonomous system, BGP facilitates the exchange of routing information and policy decisions between different networks, making it essential for inter-domain routing.

BGP uses a path vector mechanism, allowing it to maintain the paths that data packets take through the network. This protocol is widely used for internet routing and has become the standard for exchanging routing information between various organizations and service providers. Its capability to handle complex routing decisions and policies across diverse networks underscores its role as an EGP, distinguishing it from protocols that manage internal routing within a singular network environment.