350-401 Question 498
Single answerA network engineer is troubleshooting an MPLS network where traffic is not being forwarded correctly between two routers. After inspecting the network, they determine that one of the Label Switching Routers (LSRs) is not propagating labels to its neighbors. Which MPLS component is most likely misconfigured or failing in this scenario?
- A
Label Distribution Protocol (LDP)
- B
Traffic Engineering (TE) Tunnel
- C
Label Switched Path (LSP)
- D
Forwarding Information Base (FIB)
Show answer and explanation
Correct answer: A
Explanation
In MPLS networks, the Label Distribution Protocol (LDP) is critical for exchanging label information between routers. If LDP is not functioning correctly, labels will not be propagated, causing issues with traffic forwarding. The other options, while relevant to MPLS operations, are not directly responsible for label distribution.
- A. Correct.
Label Distribution Protocol (LDP) is responsible for distributing labels between LSRs. If LDP is misconfigured or failing, labels will not be exchanged properly, leading to issues with label switching.
- B. Incorrect.
Traffic Engineering (TE) Tunnel is used to optimize traffic flows in an MPLS network. While it can affect routing, it is not directly responsible for label propagation.
- C. Incorrect.
Label Switched Path (LSP) is the path that traffic follows in an MPLS network. However, an LSP cannot be established without proper label distribution, which is handled by LDP.
- D. Incorrect.
Forwarding Information Base (FIB) is used by routers to make forwarding decisions. While it is important for routing, it does not handle label propagation in MPLS networks.