Which exterior gateway protocol routes traffic between autonomous systems?

Which exterior gateway protocol routes traffic between autonomous systems?

• A. BGP Border Gateway Protocol
• B. IGP Interior Gateway Protocol
• C. NAT Network Address Translation
• D. EGP Exterior Gateway Protocol

Answer: (A)

Exchanging routing information between autonomous systems is handled by exterior gateway protocols. The standard method today is BGP, the Border Gateway Protocol, which is designed to scale across the Internet and to enforce routing policies between different ASes. BGP uses TCP to ensure reliable delivery and carries path information via the AS path attribute to prevent loops, while allowing operators to influence route selection through policies and route attributes. This contrasts with interior gateway protocols, which operate inside a single autonomous system (such as OSPF or EIGRP). NAT is not a routing protocol between ASes; it translates addresses rather than routes between domains. Exterior gateway protocols like EGP existed historically but are not used now, with BGP providing the current inter-domain routing solution.

Exchanging routing information between autonomous systems is handled by exterior gateway protocols. The standard method today is BGP, the Border Gateway Protocol, which is designed to scale across the Internet and to enforce routing policies between different ASes. BGP uses TCP to ensure reliable delivery and carries path information via the AS path attribute to prevent loops, while allowing operators to influence route selection through policies and route attributes. This contrasts with interior gateway protocols, which operate inside a single autonomous system (such as OSPF or EIGRP). NAT is not a routing protocol between ASes; it translates addresses rather than routes between domains. Exterior gateway protocols like EGP existed historically but are not used now, with BGP providing the current inter-domain routing solution.