Command Reference Guide

94 ● ttl expiration 3Com Router 5000 Family and Router 6000 Family
Command Reference
ttl expiration
Purpose Use the ttl expiration command to configure the router to forward ICMP
responses by local IP routing when the MPLS TTL expires.
Use the undo ttl expiration command to disable the function.
Use the undo mpls command to clear all the configurations related to the ttl
expiration
command.
Syntax ttl expiration pop
undo ttl expiration pop
Parameters None
Default For a one-tier MPLS packet with TTL expired, its ICMP response is forwarded by local
IP routing by default.
Example Send back an ICMP packet along the LSP if the TTL of an MPLS packet expires.
[3Com -mpls] undo ttl expiration pop
View This command can be used in the following views:
■ MPLS view
Description You are recommended to configure the undo ttl expiration command on the
ASBRs or the SPEs on an HoVPN network. This ensures that you can get the correct
forwarding path of the public-network routers when tracerting to another device on
the VPN.
Related Command ttl propagate