300-410 Question 162
Single answerA network engineer is configuring MPLS in their network. The engineer observes that Label Switched Paths (LSPs) are not being established between Label Switching Routers (LSRs). Upon further investigation, it is discovered that the routers are not exchanging labels. Which MPLS component is most likely misconfigured or not enabled, causing this issue?
- A
Label Distribution Protocol (LDP)
- B
Border Gateway Protocol (BGP)
- C
Forwarding Equivalence Class (FEC)
- D
Open Shortest Path First (OSPF)
Show answer and explanation
Correct answer: A
Explanation
Label Distribution Protocol (LDP) is critical for establishing MPLS Label Switched Paths (LSPs) as it handles the exchange of labels between Label Switching Routers (LSRs). If LDP is not configured or operational, LSRs cannot share label information, resulting in the failure of LSP establishment.
- A. Correct.
Label Distribution Protocol (LDP) is responsible for exchanging labels between MPLS routers. If LDP is not enabled or misconfigured, LSPs cannot be established.
- B. Incorrect.
Border Gateway Protocol (BGP) is used for routing between autonomous systems and does not directly handle label exchange in MPLS.
- C. Incorrect.
Forwarding Equivalence Class (FEC) defines how traffic is categorized for label assignment, but it does not handle the label exchange process between routers.
- D. Incorrect.
Open Shortest Path First (OSPF) is a routing protocol used for IP routing and does not directly manage MPLS label distribution.