Verifying LDP Sessions

Purpose

Verify that a TCP-based LDP session has been established between all LDP neighbors. Also, verify that the modified keepalive value is active.

Action

From the CLI, enter the show ldp session detail command.

Address: 10.0.9.7, State: Operational, Connection: Open, Hold time: 28
  Session ID: 10.0.3.5:0--10.0.9.7:0
  Next keepalive in 3 seconds
  Passive, Maximum PDU: 4096, Hold time: 30, Neighbor count: 1
  Keepalive interval: 10, Connect retry interval: 1
  Local - Restart: disabled, Helper mode: enabled
  Remote - Restart: disabled, Helper mode: disabled
  Local maximum recovery time: 240000 msec
  Next-hop addresses received:
    10.0.8.10
    10.0.2.17

What it Means

The output shows the detailed information, including session IDs, keepalive interval, and next-hop addresses, for each established LDP session. Verify the following information:

• Each LDP neighbor address has an entry, listed by loopback address.
• The state for each session is Operational, and the connection for each session is Open. A state of Nonexistent or a connection of Closed indicates a problem with one of the following:
  • LDP configuration
  • Passage of traffic between the two Services Routers
  • Physical link between the two routers
• For Keepalive interval, the appropriate value, 10, appears.

Related Topics

For a complete description of show ldp session detail output, see the JUNOS Routing Protocols and Policies Command Reference.