HP MSR2000/3000/4000 Router Series MPLS Configuration Guide

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MPLS BFD establishes a BFD session between the ingress and egress of the tunnel to be inspected, adds
the label associated with the tunnel into a BFD control packet at the ingress, sends the packet to the
egress node over the tunnel, and determines the tunnel status according to the BFD control packet
returned by the egress. When BFD detects a connectivity failure, it triggers the pre-configured action,
such as FRR or path protection switching, to ensure uninterrupted traffic forwarding.
A BFD session for LSP or MPLS TE tunnel connectivity verification can be established in one of the
following modes:
• Static mode—You manually specify the local and remote discriminators through command lines to
establish the BFD session.
• Dynamic mode—The system automatically runs MPLS ping to negotiate the discriminators to
establish the BFD session.
In static mode, the egress node returns a BFD control packet to the ingress node through the reverse
tunnel. If no reverse tunnel exists, the ingress node cannot receive the BFD control packet, resulting in a
verification failure.
In dynamic mode, the egress node returns a BFD control packet to the ingress node through the reverse
tunnel. If no reverse tunnel exists, the egress mode returns a BFD packet through IP routing.
Use the static mode to test the connectivity of a pair of LSPs or MPLS TE tunnels in opposite directions (one
from local to remote, and the other from remote to local) between two devices. Use the dynamic mode to
test the connectivity of one LSP or MPLS TE tunnel from the local device to the remote device.
Protocols and standards
RFC 4379, Detecting Multi-Protocol Label Switched (MPLS) Data Plane Failures
Configuring MPLS OAM for LSP tunnels
To verify LSP connectivity, you can use the ping mpls ipv4 command or the tracert mpls ipv4 command
to manually trigger LSP connectivity verification, or configure periodic MPLS traceroute or MPLS BFD to
verify LSP connectivity.
Configuring MPLS ping for LSPs
Perform the following task in any view:
Task Command
Use MPLS ping to verify MPLS LSP connectivity
for an IPv4 prefix.
ping mpls [ -a source-ip | -c count | -exp exp-value | -h
ttl-value | -m wait-time | -r reply-mode | -rtos tos-value | -s
packet-size | -t time-out | -v ] * ipv4 dest-addr mask-length
[ destination start-address [ end-address
[ address-increment ] ] ]
Configuring MPLS traceroute for LSPs
Perform the following task in any view: