350-401 Question 497
Single answerA network engineer is configuring MPLS in a service provider network. They want to ensure that routers can exchange label information to establish Label Switched Paths (LSPs). Which protocol must be enabled on the routers for this functionality?
- A
LDP
- B
OSPF
- C
BGP
- D
RSVP
Show answer and explanation
Correct answer: A
Explanation
In an MPLS environment, LDP (Label Distribution Protocol) is the default protocol used to exchange label bindings between Label Switch Routers (LSRs). This allows the routers to build and maintain Label Switched Paths (LSPs), which are critical for packet forwarding in an MPLS network.
- A. Correct.
LDP (Label Distribution Protocol) is specifically designed for exchanging label information between routers in an MPLS network, enabling the establishment of LSPs.
- B. Incorrect.
OSPF is a routing protocol used for exchanging IP routing information, but it does not handle MPLS label distribution.
- C. Incorrect.
BGP is primarily used for inter-domain routing and does not natively handle MPLS label distribution unless extended with MPLS-specific capabilities like MP-BGP.
- D. Incorrect.
RSVP (Resource Reservation Protocol) is used for signaling and reserving resources in certain MPLS-TE (Traffic Engineering) scenarios but is not the default protocol for label distribution.