Which TWO statements accurately describe MPLS LDP label distribution and autoconfiguration? (Choose two.)
Trap 1: LDP allocates labels for all prefixes in the IGP routing table by…
Incorrect. LDP does not allocate labels for all IGP prefixes by default; it allocates labels for routes in the FIB, and some routes (e.g., BGP) are not labeled by default.
Trap 2: LDP sessions are always established using the physical interface IP…
Incorrect. LDP sessions are commonly established using loopback addresses to ensure stability, not necessarily physical interface IP addresses.
Trap 3: LDP label allocation is per interface by default.
Incorrect. LDP label allocation is per prefix, not per interface, by default.
- A
LDP can be configured to allocate labels only for specific prefixes using label filtering.
Correct. LDP label filtering allows selective label allocation for specific prefixes, providing control over label distribution.
- B
LDP uses hello messages sent to multicast address 224.0.0.2.
Correct. LDP hello messages are sent to multicast address 224.0.0.2 for link-local neighbor discovery, which is a fundamental part of LDP autoconfiguration.
- C
LDP allocates labels for all prefixes in the IGP routing table by default.
Why wrong: Incorrect. LDP does not allocate labels for all IGP prefixes by default; it allocates labels for routes in the FIB, and some routes (e.g., BGP) are not labeled by default.
- D
LDP sessions are always established using the physical interface IP address.
Why wrong: Incorrect. LDP sessions are commonly established using loopback addresses to ensure stability, not necessarily physical interface IP addresses.
- E
LDP label allocation is per interface by default.
Why wrong: Incorrect. LDP label allocation is per prefix, not per interface, by default.