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?
A. Enable communication over TCP port 646 for T-LDP hello messages.
B. Enable RSVP-TE FRR on the LDP interface to protect the LDP session between routers.
C. Enable LDP session protection on either one of the routers, which allows them to auto negotiate.
D. Set the LDP session protection timer on each router to the same value.
Explanation:
To establish LDP sessions between the PE and P routers, you need to enable communication over TCP port 646 for T-LDP hello messages.
T-LDP (Targeted LDP) uses TCP port 646 for session establishment.
Example configuration:
interface GigabitEthernet0/0
mpls ldp discovery targeted-hello accept
Reference: Implementing and Operating Cisco Service Provider Network Core Technologies (SPCOR) v1.0 course material.
