(Optional) Configuring the MPLS TTL Processing Mode
Context
MPLS TTL processing modes
In MPLS applications, the MPLS backbone network needs to be shielded to ensure network security. The MPLS Pipe mode on the ingress node is recommended for private network packets. To reflect the path where packets pass, use the MPLS Uniform mode on the ingress node.
Path where ICMP response packets are transmitted
By default, when the received MPLS packet contains only one label, the LSR directly sends an ICMP response packet to the sender using an IP route. When the received MPLS packet contains multiple labels, the LSR sends an ICMP response packet to the sender along an LSP.
However, MPLS packets received by the devices may contain only one label in some cases. The devices have no IP routes to the sender, so they forward the ICMP response packets along an LSP.
Procedure
- Configuring the MPLS TTL processing mode.For the CE6870EI and CE6875EI, run the following commands.
Run system-view
The system view is displayed.
Run mpls mode { short-pipe [ ttl ttlvalue exp expvalue ] | uniform }
The MPLS TTL processing mode is configured.
By default, the MPLS TTL processing mode is Uniform.
Run commit
The configuration is committed.
For non-CE6870EI and non-CE6875EI, run the following commands.Run system-view
The system view is displayed.
Run mpls
The MPLS view is displayed.
Run mpls ldp ttl-mode { pipe | uniform }
The mode for MPLS LDP to process TTLs in packets is configured.
By default, MPLS LDP processes TTLs in packets in uniform mode.
Run quit
The system view is displayed.
Run commit
The configuration is committed.
- Configuring the path where ICMP response packets are transmitted
