Which technology does not support SR-MPLS?

The correct answer is B. LDP. LDP (Label Distribution Protocol) does not support SR-MPLS because LDP is a competing label distribution mechanism - SR-MPLS was actually designed to replace LDP, not extend it. LDP distributes labels hop-by-hop through its own signaling protocol and has no concept of Segment…

MPLS and VPN Technologies

Question

Options

AIS-IS
BLDP
COSPF
DBGP

How the community answered

(34 responses)

A
18% (6)
B
71% (24)
C
9% (3)
D
3% (1)

Explanation

LDP (Label Distribution Protocol) does not support SR-MPLS because LDP is a competing label distribution mechanism - SR-MPLS was actually designed to replace LDP, not extend it. LDP distributes labels hop-by-hop through its own signaling protocol and has no concept of Segment Routing SIDs.

The distractors are wrong because IS-IS (A), OSPF (C), and BGP (D) are all control plane protocols that have been extended with SR-specific TLVs/attributes to flood or advertise Prefix-SIDs and Adjacency-SIDs: IS-IS and OSPF use new sub-TLVs in their LSPs/LSAs, while BGP uses the Prefix-SID attribute (RFC 8669) and BGP-LS to carry SR topology information.

Memory tip: "LDP and SR-MPLS are rivals, not teammates." LDP = Legacy Distribution Protocol - SR-MPLS was built specifically to modernize and replace it, so LDP has no role in the SR world.

Topics

#SR-MPLS#LDP#IGP Integration#Label Distribution

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