What is BGP Routing within an Autonomous System?

Answer - B.

BGP may be used for routing within an autonomous system.

In this application it is referred to as Interior Border Gateway Protocol, Internal BGP, or iBGP.

In contrast, the Internet application of the protocol may be referred to as Exterior Border Gateway Protocol, External BGP, or eBGP.

For more information on the Border gateway protocol please see the below link:

When BGP (Border Gateway Protocol) is used for routing within an autonomous system (AS), it is typically referred to as iBGP (Internal BGP). Therefore, the correct answer is B.

iBGP is used for distributing routing information between BGP routers within the same AS. It is used to ensure that all routers within the AS have the same view of the network topology and can make consistent routing decisions. iBGP sessions are typically established between routers that are not directly connected, but are still within the same AS. This is done by using TCP connections between the routers.

pBGP (Private BGP) is a term that is sometimes used to describe the use of BGP within a private network. It is not a standard term and is not typically used to describe BGP within an AS.

eBGP (External BGP) is used to distribute routing information between different ASes. When two ASes are connected, they use eBGP to exchange routing information between them. This is done by using TCP connections between the routers.

sBGP (Secure BGP) is a security extension to BGP that is used to provide authentication and integrity for BGP messages. It is not used to describe BGP within an AS.