MPLS Forwarding Commands on Cisco IOS XR Software
mpls ip-ttl-propagate
MPR-154
Cisco IOS XR Multiprotocol Label Switching Command Reference
mpls ip-ttl-propagate
To configure the behavior controlling the propagation of the IP Time-To-Live (TTL) field to and from
the MPLS header, use the mpls ip-ttl-propagate command in global configuration mode. To return to
the default behavior, use the no form of this command.
mpls ip-ttl-propagate disable
no mpls ip-ttl-propagate
Syntax Description
Defaults Enabled
Command Modes Global configuration
Command History
Usage Guidelines To use this command, you must be in a user group associated with a task group that includes the proper
task IDs. For detailed information about user groups and task IDs, see the Configuring AAA Services on
Cisco IOS XR Software module of the Cisco IOS XR System Security Configuration Guide.
By default, the IP TTL is propagated to the MPLS header when IP packets enter the MPLS domain.
Within the MPLS domain, the MPLS TTL is decremented at each MPLS hop. When an MPLS
encapsulated IP packet exits the MPLS domain, the MPLS TTL is propagated to the IP header. When
propagation is disabled, the MPLS TTL is set to 255 during the label imposition phase and the IP TTL
is not altered.
Task ID
Examples The following example shows how to disable IP TTL propagation:
RP/0/RP0/CPU0:router(config)# mpls ip-ttl-propagate disable
disable Stops the propagation of IP TTL to and from the MPLS header.
Release Modification
Release 2.0 This command was introduced on the Cisco CRS-1.
Release 3.0 No modification.
Release 3.2 This command was supported on the Cisco XR 12000 Series Router.
Release 3.3.0 No modification.
Task ID Operations
mpls-te, mpls-ldp read, write, read, write
