You are logged in to an MX80 and issue the command "show route protocol bgp" You see that you have received the route 10.0.4/24 from two different peers.
One peer is an external peer and the other is an internal peer. The route received from the internal peer is active.
By the rules of BGP preference, what would cause the internal path for this prefix to be preferred over the external one?
Click on the arrows to vote for the correct answer
A. B. C. D.B
BGP (Border Gateway Protocol) is a routing protocol that is used to exchange routing information between different Autonomous Systems (AS). In BGP, there are several factors that determine which path should be selected as the best path for a specific prefix. These factors are called BGP attributes, and the selection process is called BGP route selection process.
In this scenario, you have received the same prefix (10.0.4/24) from two different peers, one external and one internal. When multiple paths exist for the same prefix, BGP uses the following criteria in order to select the best path:
Now, let's analyze each of the answers given in the question:
A. Internally learned prefix is preferred over an externally learned prefix - This statement is partially true. BGP does prefer internal paths over external paths, but it is not the first criterion in the BGP route selection process.
B. The local-preference value of the internally learned prefix is higher than the externally learned peer - This answer is correct. Local preference is the first criterion that BGP uses to select the best path when multiple paths exist for the same prefix. The local preference value is an attribute that is set locally and is used to indicate the preferred path for a prefix. By default, the local preference value is 100, but it can be modified by the network administrator.
C. The peer ID of the internally learned prefix is lower than that of the externally learned peer - Peer ID is not a BGP attribute that is used in the route selection process. Therefore, this answer is incorrect.
D. The internally learned prefix has a shorter cluster length - Cluster length is not a BGP attribute that is used in the route selection process. Therefore, this answer is incorrect.
In conclusion, the correct answer to the question is B. The local-preference value of the internally learned prefix is higher than the externally learned peer.