[ no | default ] mpls ip propagate-ttl [ forwarded | local ]
Command introduced before JUNOSe Release 7.1.0.
Controls the value for the TTL field in the MPLS header at the tunnel ingress when a label is assigned to an IP packet. Enabled by default, this command sets the TTL to the TTL value from the IP packet header.
The no version sets the value to 255 to hide the network structure from all traffic, preventing the traceroute command from discovering and displaying LSP hops. The no version changes the TTL processing model from the default uniform model to the pipe model.
The default version reverts to the global default, causing the TTL field to be copied from the IP packet header and enabling the traceroute command to show all the hops in the network.