A router is configured to perform MPLS LDP graceful restart. Which three steps are included when the RP sends an LDP initialization to a neighbor to establish an LDP session? (Choose three)

Question

Options

• AReconnect Timeout field
• BLearn from Neighbor (N) flag, set to 1
• CGraceful restart capability in OPEN message
• DRecovery Time field
• ELearn from Network (L) flag, set to 1
• FType-9 LSA

• A
  82% (27)
• B
  6% (2)
• C
  9% (3)
• F
  3% (1)

Explanation

LDP Graceful Restart (GR) allows an LDP session to survive a control-plane restart without disrupting the MPLS forwarding plane. When establishing an LDP session with GR capability, the OPEN message includes a Fault Tolerant (FT) Session TLV containing: (A) Reconnect Timeout - the time the restarting router's neighbor will wait for it to reconnect after a failure; (D) Recovery Time - the time the restarting router needs to recover its MPLS forwarding state; and (E) the Learn from Network (L) flag set to 1 - indicating the restarting router will relearn label bindings from the network rather than from a checkpoint. The 'N' flag (choice B) is the 'Learn from Neighbor' flag and is a different field. Type-9 LSA (choice F) is an OSPF concept unrelated to LDP.

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