Specifications

mpls ip propagate-ttl
MP-174
Cisco IOS Multiprotocol Label Switching Command Reference
January 2010
mpls ip propagate-ttl
To control the generation of the time-to-live (TTL) field in the Multiprotocol Label Switching (MPLS)
header when labels are first added to an IP packet, use the mpls ip propagate-ttl co
mmand in global
configuration mode. To use a fixed TTL value (255) for the first label of the IP packet, use the no form
of this command.
mpls ip propagate-ttl
no m
pls ip propagate-ttl [forwarded | local]
Syntax Description
Defaults This command is enabled. The TTL field is copied from the IP header. A tra
ceroute command shows
all of the hops in the network.
Command Modes Global configuration
Command History
Usage Guidelines By default, the mpl
s ip propagate-ttl command is enabled and the IP TTL value is copied to the MPLS
TTL field during label imposition. To disable TTL propagation for all packets, use the no mpls ip
propagate-ttl command. To disable TTL propagation for only forwarded packets, use the no mpls ip
propagate forwarded command. Disabling TTL propagation of forwarded packets allows the structure
of the MPLS network to be hidden from customers, but not the provider.
This feature supports the IETF draft document I
CMP Extensions for Multiprotocol Label Switching,
draft-ietf-mpls-label-icmp-01.txt. The document can be accessed at the following URL:
http://www2.ietf.org/internet-drafts/draft-ietf-mpls-label-icmp-01.txt
forwarded (Optional) Prevents the tr
aceroute command from showing the hops for
forwarded packets.
local (Optional) Prevents the tr
aceroute command from showing the hops only
for local packets.
Release Modification
12.1(3)T This command was introduced.
12.1(5)T The keywords fo
rwarded and local were added to this command.
12.2(33)SRA This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX This command is supported in the Cisco IOS Release 12.2SX train. Support
i
n a specific 12.2SX release of this train depends on your feature set,
platform, and platform hardware.