When a link flaps, an mpls ldp session will also flap. Which feature minimizes traffic loss and
provides faster convergence after the link is re-established?
A.
BFD
B.
MPLS LDP IGP SYNC
C.
graceful restart
D.
LDP session protection
E.
LDP nonstop routing
Explanation:
http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/fssespro.html#wp1027177
MPLS LDP Session Protection maintains LDP bindings when a link fails. MPLS LDP sessions are protected through the use of LDP Hello messages.
MPLS LDP Session Protection uses LDP Targeted Hellos to protect LDP sessions.
An LDP session that exists between two routers is called an LDP Link Hello Adjacency. When MPLS LDP Session Protection is enabled, an LDP Targeted Hello Adjacency is also established for the LDP session. If the link between the two routers fails, the LDP Link Adjacency also fails. However, if the LDP peer is still reachable through IP, the LDP session stays up, because the LDP Targeted Hello Adjacency still exists between the routers. When the directly connected link recovers, the session does not need to be reestablished, and LDP bindings for prefixes do not need to be relearned.