Q49MPLS and Segment Routing
Refer to the exhibit. With which router is LDP session-protection capability enabled on IOSXRV-1, while session hold-up is not active?
← → navigate · a answer
Community votes
Discussion · 7
B 3
Selected Answer: B
Session Protection = Targeted LDP Session ... only 192.168.0.5 doesn't have one active, so answer id B.
2
Correct answer should be D.
When the LDP session between two directly connected LSRs is protected, a targeted LDP session is built between the two LSRs. When the directly connected link does go down between the two LSRs, the targeted LDP session is kept up as long as an alternative path exists between the two LSRs. The LDP link adjacency is removed when the link goes down, but the targeted adjacency keeps the LDP session up. When the link comes back up, the LSR does not need to re-establish the LDP session; therefore, the convergence is better.
B 2
Selected Answer: B
B seems right
1
Thanks so much for your full and clear explanation!
1
Why D instead of C?
1
the explanation is correct, however, there is no difference between D and C and so either both have to be correct or neither. This is not a multi answer question, therefore, it can be neither.... also the question is asking for which is the hold up not active. The only differing session is that of B.
1
I'm afraid you're probably giving the exam question writer too much credit. This particular exam is absolutely riddled with these kinds of mistakes and ambiguities. .5 in this example has session protection configured but does not have an active session, hence the "N" in the far right-hand column. Either the question is worded wrong or there are indeed two incorrect answers.