What two statements are correct in this scenario?

You are a network operator who wants to add a second ISP connection and remove the default route to the existing ISP You decide to deploy the BGP protocol in the network.

What two statements are correct in this scenario? (Choose two.)
A . IBGP updates the next-hop attribute to ensure reachability within an AS.
B . IBGP peers advertise routes received from EBGP peers to other IBGP peers.
C . IBGP peers advertise routes received from IBGP peers to other IBGP peers.
D . EBGP peers advertise routes received from IBGP peers to other EBGP peers.

View Answer

Answer: AB

Explanation:

A is correct because IBGP updates the next-hop attribute to ensure reachability within an AS. This is because the next-hop attribute is the IP address of the router that advertises the route to a BGP peer. If the next-hop attribute is not changed by IBGP, it would be the IP address of an external router, which may not be reachable by all routers within the AS. Therefore, IBGP updates the next-hop attribute to the IP address of the router that received the route from an EBGP peer1.

B is correct because IBGP peers advertise routes received from EBGP peers to other IBGP peers. This is because BGP follows the rule of advertising only the best route to a destination, and EBGP routes have a higher preference than IBGP routes. Therefore, IBGP peers advertise routes learned from an EBGP peer to all BGP peers, including both EBGP and IBGP peers1.