Basic MPLS LDP Configuration
ip cef mpls ldp router-id Loopback0 [force] mpls label protocol ldp
224.0.0.2 group IP multicast address. The UDP port used for LDP is 646.
LDP Discovery
LDP discovery timers manipulation
mpls ldp discovery {hello {holdtime | interval } seconds
The default value for holdtime
is 15 seconds for link Hello messages, and the default value for interval
is 5 seconds.
If the two LDP peers have different LDP Hold times configured, the smaller of the two values is used as the Hold time for that LDP discovery source.
Cisco IOS might overwrite the configured LDP Hello interval. It will choose a smaller LDP Hello interval than configured so that it can send at least three LDP Hellos before the Hold time expires. (At least nine Hellos are sent in the case of a targeted LDP session)