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 XR Config mode.
mpls ip-ttl-propagate disable [forwarded | local]
Syntax Description
disable |
Disables the propagation of IP TTL to and from the MPLS header for both forwarded and local packets. |
forwarded |
(Optional) Disables the propagation of IP TTL to and from the MPLS headed for only the forwarded packets. This prevents the traceroute command from displaying the MPLS-enabled nodes beyond the device under the configuration. |
local |
(Optional) Disables the propagation of IP TTL to the MPLS header for only locally generated packets. This prevents the traceroute command from displaying the MPLS-enabled nodes beyond the device under the configuration. |
Command Default
Enabled
Command Modes
Command History
Release |
Modification |
---|---|
Release 5.0.0 |
This command was introduced. |
Usage Guidelines
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
Task ID |
Operations |
---|---|
mpls-te |
read, write |
mpls-ldp |
read, write |
Examples
The following example shows how to disable IP TTL propagation:
RP/0/RP0/CPU0:router(config)# mpls ip-ttl-propagate disable
The following example shows how to disable IP TTL propagation for forwarded MPLS packets:
RP/0/RP0/CPU0:router(config)# mpls ip-ttl-propagate disable forwarded
The following example shows how to disable IP TTL propagation for locally generated MPLS packets:
RP/0/RP0/CPU0:router(config)# mpls ip-ttl-propagate disable local