# Configuring LDP-IGP Synchronization

MPLS data packets can be discarded in a network when the network IGP is operational on a link for which LDP is not fully operational, because there is no coupling between the LDP operational state and the IGP. When LDP is not fully operational, LDP is considered to not be synchronized with the IGP.

To configure LDP-IGP synchronization:

1. Specify whether LDP is synchronized with the IGP on the current interface or all interfaces.
   - Synchronize LDP with the IGP on the current interface:
     host1(config)#interface atm 2/0 host1(config-if)#mpls ldp isis sync
   - Synchronize LDP with the IGP on all interfaces in the IGP router context:
     host1(config)#router ospf 1 host1(config-router)#mpls ldp ospf sync
2. Specify how long the IGP waits to synchronize with LDP.
   host1(config)#mpls ldp igp sync holddown 15

#### Related Topics

- Basic MPLS Configuration Tasks
- Additional LDP Configuration Tasks
- mpls ldp igp sync holddown
- mpls ldp sync