Configuring MPLS LDP-IGP synchronization and hold time globally

MPLS LDP-IGP synchronization is disabled by default. You can globally enable MPLS LDP-IGP synchronization with IS-IS and OSPF and configure the hold time setting.

1. In privileged EXEC mode, enter global configuration mode.
   

   device# configure terminal

2. Enable OSPF and enter OSPF router configuration mode.
   

   device(config)# router ospf

3. Configure LDP-IGP synchronization.
   

   device(config-router-ospf-vrf-default-vrf)# ldp-sync 

4. Set the hold time to advertise the maximum IP metric while waiting for an update from LDP.
   

   device(config-router-ospf-vrf-default-vrf)# ldp-sync hold-down 100
   

   In this example, the global hold time is set to 100 seconds. The default setting is 30. The range is from 1 through 65535.
5. Enter global configuration mode.
   

   device(config-router-ospf-vrf-default-vrf)# exit

6. Enter IS-IS router configuration mode.
   

   device(config)# router isis

7. Enable IPv4 address-family configuration mode.
   

   device(config-isis-router)# address-family ipv4 unicast

8. Configure the generation and acceptance of new-style TLVs.
   

   device(config-router-isis-ipv4u)# metric-style wide

   On IS-IS, wide metric-style is required.
9. Configure LDP-IGP synchronization.
   

   device(config-router-isis-ipv4u)# ldp-sync

10. Set the hold time to advertise the maximum IP metric while waiting for an update from LDP.
    

    device(config-router-isis-ipv4u)# ldp-sync hold-down 100

    In this example, the global hold time is set to 100 seconds. The range is from 1 through 65535.
11. Verify the LDP-IGP synchronization configuration with OSPF.
    

    device# show ip ospf
    OSPF Version                 Version 2
    Router Id                    10.1.1.2
    ASBR Status                  No
    ABR Status	No	(0) Redistribute Ext Routes from
    Initial SPF schedule delay   0         (msecs) 
    Minimum hold time for SPFs   0         (msecs) 
    Maximum hold time for SPFs   0         (msecs) 
    External LSA Counter         0
    External LSA Checksum Sum    00000000
    Originate New LSA Counter    9
    Rx New LSA Counter           6
    External LSA Limit           174762
    Database Overflow Interval   0
    Database Overflow State :	NOT OVERFLOWED 
    RFC 1583 Compatibility :	Enabled
    Slow neighbor Flap-Action :  Disabled,  timer 300
    Nonstop Routing:             Disabled
    Graceful Restart:            Disabled,  timer 120
    Graceful Restart Helper:     Enabled
    LDP-SYNC: Globally enabled, Hold-down time 100 sec
    

    In this example, the LDP-SYNC fields displays the enabling of LDP-IGP synchronization and the hold-down time.
12. Verify the LDP-IGP synchronization configuration with IS-IS.
    

    device# show running config router isis
     net 11.0010.0100.1002.00 
     log adjacency
     address-family ipv4 unicast 
     ldp-sync
      metric-style wide
      ldp-sync
      ldp-sync hold-down 100 
     redistribute connected level-1 
     redistribute static
     exit-address-family
    
     address-family ipv6 unicast 
     ldp-sync
      multi-topology transition 
     exit-address-family
    
    end
    

Example

The following example shows the previous steps to configure to globally enable MPLS LDP-IGP synchronization with OSPF and IS-IS.

device(config)# router ospf
device(config-router-ospf-vrf-default-vrf)# ldp-sync
device(config-router-ospf-vrf-default-vrf)# ldp-sync hold-down 100
device(config-router-ospf-vrf-default-vrf)# exit
device(config)# router isis
device(config-router-isis)# address-family ipv4 unicast
device(config-router-isis-ipv4u)# metric-style wide
device(config-router-isis-ipv4u)# ldp-sync
device(config-router-isis-ipv4u)# ldp-sync hold-down 100