Enabling LDP-IGP Synchronization

LDP-IGP synchronization needs to be enabled on interfaces on both ends of the link between the node where a primary LSP and a backup LSP diverge from each other and its LDP peer on the primary LSP. LDP-IGP synchronization is enabled either on an interface or in an IGP process.

Context

LDP-IGP synchronization can be configured on a specific interface or on interfaces within a specific IGP process:

LDP-IGP synchronization can be enabled on specified interfaces when only a few interfaces need to support this function.
LDP-IGP synchronization can be enabled on all interfaces in the IGP process. If LDP is enabled on all IGP-enabled interfaces on the same node, this method is recommended.

Configure one of the preceding modes as needed.

Procedure

Enable LDP-IGP synchronization in the interface view.
If OSPF is used, perform the following steps on the interfaces on both ends of the link between the node where the primary LSP and the backup LSP diverge from each other and its LDP peer on the primary LSP:
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. Run ospf ldp-sync
  LDP-IGP synchronization is enabled on the protected interface.
  
  To enable LDP-OSPF synchronization on a multi-area adjacency interface, run the ospf ldp-sync multi-area area-id command.
4. Run commit
  The configuration is committed.
If IS-IS is used, perform the following steps on the interfaces on both ends of the link between the node on which the primary LSP and the backup LSP diverge from each other and its LDP peer on the primary LSP:
1. Run system-view
  The system view is displayed.
2. Run interface interface-type interface-number
  The interface view is displayed.
3. Run isis enable process-id
  IS-IS is enabled.
4. Run isis ldp-sync
  LDP-IS-IS synchronization is enabled on the protected interface.
5. Run commit
  The configuration is committed.
  
  Before configuring both LDP-IGP synchronization and the LDP GTSM function on an interface, set the maximum number of valid hops permitted by the GTSM to the number of actual hops (a value greater than 1) because an LDP session must be established over an indirect link. If the maximum number of valid hops permitted by the GTSM is set to 1, no LDP session can be established. As a result, a route convergence failure occurs or LDP-IGP synchronization cannot take effect.
Enable LDP-IGP synchronization in an IGP process.
If OSPF is used, perform the following steps on the node on which the primary LSP and the backup LSP diverge from each other and its LDP peer on the primary LSP:
1. Run system-view
  The system view is displayed.
2. Run ospf [ process-id ]
  A specified OSPF process is started and the OSPF view is displayed.
  
  process-id specifies an OSPF process. If process-id is not specified, the default OSPF process ID is 1. Run the ospf [ process-id | vpn-instance vpn-instance-name ] ^* command to associate an OSPF process with a VPN instance and run OSPF in the VPN instance. If a VPN instance is specified, the OSPF process belongs to the specified VPN instance. If no VPN instance is specified, the OSPF process belongs to a public network instance.
3. Run area area-id
  The OSPF area view is displayed.
4. Run ldp-sync enable
  LDP-IGP synchronization is enabled.
5. Run commit
  The configuration is committed.
If IS-IS is used, perform the following steps on the node where the primary LSP and the backup LSP diverge from each other and its LDP peer on the primary LSP:
1. Run system-view
  The system view is displayed.
2. Run isis [ process-id ]
  A specified IS-IS process is started, and the IS-IS view is displayed.
  
  process-id specifies an IS-IS process. If process-id is not specified, the default IS-IS process ID is 1. Run the isis [ process-id ] [ vpn-instance vpn-instance-name ] command to associate an IS-IS process with a VPN instance.
3. Run ldp-sync enable
  LDP-IS-IS synchronization is enabled.
4. Run commit
  The configuration is committed.