(Optional) Setting the Hold-down Timer Value

Context

On a device that has LDP-IGP synchronization enabled, if the active physical link recovers, an IGP enters the Hold-down state, and a Hold-down timer starts. Before the Hold-down timer expires, the IGP delays establishing an IGP neighbor relationship until an LDP session is established over the active link so that the LDP session over and IGP route for the active link can become available simultaneously.

If IS-IS is used, you can set the value of the Hold-down timer on a specified interface or set the value of the Hold-down timer for all IS-IS interfaces in the IS-IS view.

If different Hold-down values on an interface and in an IS-IS process are set, the setting on the interface takes effect.

Procedure

If OSPF is used as an IGP, perform the following steps:
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. (Optional) On an Ethernet interface, run undo portswitch
  The interface is switched to Layer 3 mode.
  
  By default, an Ethernet interface works in Layer 2 mode.
  
  Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
4. Run ospf timer ldp-sync hold-down value
  The interval during which OSPF waits for an LDP session to be established is set.
  
  By default, the Hold-down timer value is 10 seconds.
If IS-IS is used as an IGP, perform the following steps:
Set the Hold-down timer on a specified IS-IS interface.
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. (Optional) On an Ethernet interface, run undo portswitch
  The interface is switched to Layer 3 mode.
  
  By default, an Ethernet interface works in Layer 2 mode.
  
  Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support switching between Layer 2 and Layer 3 modes.
4. Run isis timer ldp-sync hold-down value
  The interval during which IS-IS waits for an LDP session to be established is set.
  
  By default, the Hold-down timer value is 10 seconds.
Set the Hold-down timer on all IS-IS interfaces in a specified IS-IS process.
1. Run system-view
  The system view is displayed.
2. Run isis [ process-id ]
  The IS-IS process view is displayed.
3. Run timer ldp-sync hold-down value
  The Hold-down timer is set, which enables all IS-IS interfaces within an IS-IS process to delay establishing IS-IS neighbor relationships until LDP sessions are established.
  
  By default, the Hold-down timer value is 10 seconds.