Routing Protocols for Public Autonomous Systems

B.

The correct answer is BGP (Border Gateway Protocol).

BGP is an inter-autonomous system routing protocol, which means it is used to exchange route information between different autonomous systems (AS) on the Internet. An autonomous system is a network or a group of networks that are managed as a single entity and have a common routing policy.

BGP is a path-vector protocol that operates by exchanging information about network prefixes and the paths used to reach them. BGP routers maintain a table of all known routes to other ASes and use this information to make routing decisions.

OSPF (Open Shortest Path First) is a link-state routing protocol that is typically used within an autonomous system to exchange routing information. OSPF routers maintain a database of all network links in the AS and use this information to calculate the shortest path to each destination.

EIGRP (Enhanced Interior Gateway Routing Protocol) is a proprietary Cisco routing protocol that is also used within an autonomous system to exchange routing information. EIGRP routers use a combination of distance-vector and link-state algorithms to determine the best path to a destination.

RIP (Routing Information Protocol) is a distance-vector protocol that is used to exchange routing information within a single autonomous system. RIP routers maintain a table of all known routes and periodically broadcast updates to neighboring routers.

In summary, BGP is the routing protocol used to exchange route information between public autonomous systems on the Internet.