MPLS LDP-IGP synchronization
MPLS LDP-IGP synchronization provides a means to synchronize LDP and IGPs to minimize MPLS packet loss.
MPLS LDP-IGP synchronization also provides the following benefits:
- Provides a means to disable LDP-IGP synchronization on interfaces that you do not want enabled
- Allows you to globally enable LDP-IGP synchronization on each interface associated with an IGP Open Shortest Path First (OSPF)
MPLS LDP-IGP synchronization may be enabled on an interface. LDP determines convergence (receipt of all labels) for a link through one of two methods:
- Receive Label silence mechanism
- End Of Lib mechanism (RFC 5919)
The following figure provides an example of LDP-IGP synchronization.
When the LDP peer is not reachable, the IGP establishes the adjacency to enable the LDP session to be established. When an IGP adjacency is established on a link but LDP-IGP Synchronization is not yet achieved or is lost, the IGP advertises the maximum metric (max-metric) on the link.
- Affects IPv4 metrics only
Configuring MPLS LDP-IGP synchronization
Configuring MPLS LDP-IGP includes the following tasks:
∙ Configuring MPLS LDP-IGP synchronization with OSPF interfaces (required)
∙ Selectively disabling MPLS LDP-IGP synchronization from some OSPF interfaces (optional)
∙ Verifying MPLS LDP-IGP synchronization with OSPF (optional)