Juniper JUNOSE 11.2.X BGP AND MPLS User Manual

Figure 51: TTL Processing on Incoming MPLS Packets
TTL Processing on Outgoing MPLS Packets
The flow chart on Figure 52 on page 226 illustrates TTL processing on outgoing MPLS
packets.
Rules for Processing on an LSR
On an LSR—where an MPLS packet is label-switched after processing on the line
module—the TTL value in the swapped-to label is decremented by 1 from the incoming
TTL value when the swapped-to label is not implicit-null. When the swapped-to label
is implicit-null (for example, in a PHP configuration), the inner or exposed header's TTL
is either left unchanged (when the forwarded option for the mpls ip propagate-ttl
Copyright © 2010, Juniper Networks, Inc.224
JunosE 11.2.x BGP and MPLS Configuration Guide

Juniper JUNOSE 11.2.X BGP AND MPLS Specifications

General

Brand	Juniper
Model	JUNOSE 11.2.X BGP AND MPLS
Category	Software
Language	English