Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) — Question 209

A network engineer is configuring a newly installed PE router at the regional gateway location. The new PE router must use MPLS core routing protocols with the existing P router, and LDP sessions between the two routers must be protected to provide faster MPLS convergence. Which configuration must the engineer perform on the network so that LDP sessions are established?

Answer options

• A. Enable RSVP-TE FRR on the LDP interface to protect the LDP session between routers.
• B. Enable communication over TCP port 646 T-LDP hello messages.
• C. Set the LDP session protection timer on each router to the same value.
• D. Enable LDP session protection on either one of the routers, which allows them to autonegotiate.

Correct answer: C

Explanation

The correct answer is C because setting the LDP session protection timer to the same value on both routers ensures that they can maintain a consistent session. Option A is incorrect as RSVP-TE FRR is not specifically related to LDP session establishment. Option B is not relevant to session protection, and option D, while it describes an auto-negotiation feature, does not guarantee that the session protection timers will match, which is essential for successful LDP session establishment.