Configuring Basic Detection Functions

This section describes how to configure proper MPLS OAM parameters on both ends of a static bidirectional co-routed LSP for network loads.

Context

A static bidirectional co-routed LSP is similar to two LSPs in opposite directions. A static bidirectional co-routed LSP, however, is only one LSP. It is mapped to two forwarding entries for traffic in opposite directions and goes Up only when both forwarding entries are available. If the LSP is Down in one direction, the LSP is in the Down state. The two forwarding entries are associated with each other. When the IP forwarding capability is unavailable, any intermediate node can send back a response packet along the original path.

A node functions as both the ingress and egress for a static bidirectional co-routed LSP. Perform the following steps on both ends:

Procedure

Run system-view
The system view is displayed.
Run mpls
The MPLS view is displayed.
Run mpls oam
MPLS OAM is globally enabled.
Run quit
Return to the system view.
Run mpls-oam
The MPLS-OAM view is displayed.
Run mpls oam bidirectional-tunnel { tunnelName | tunnelType tunnelNum } type { cv | ffd frequency { 3 | 10 | 20 | 50 | 100 | 200 | 500 } } [ auto-protocol [ overtime overtime-value ] ] [ compatibility-mode compati-mode-val ] [ bdi-frequency bdi-frep-value ] [ exp exp-value ]
MPLS OAM is configured for a static bidirectional co-routed LSP.
- The same compatibility mode must be set to ensure interworking between different products.
- When OAM auto protocol extension is enabled, the compatibility-mode parameter must be set to the same value on the local and peer devices.
- If OAM auto protocol extension is enabled and the shared reverse tunnel is specified in Step 6, Step 7 does not need to be performed. After receiving the first CV or FFD packet, the egress automatically records OAM parameters, such as the detection packet type and interval at which detection packets are sent. The egress then uses these parameters to monitor link connectivity.
(Optional) Run mpls oam bidirectional-tunnel enable { send | receive } { tunnel tunnel-number }
MPLS OAM is enabled for the static bidirectional co-routed LSP.

To prevent detection errors, specify send and then receive when enabling MPLS OAM, or specify receive and then send when disabling MPLS OAM.
(Optional) Run mpls oam bidirectional-tunnel loss-measure oam-packet loss-ratio threshold1 threshold1-value threshold2 threshold2-value {tunnel-type tunnel-number |tunnel-name}
The packet loss alarm threshold of OAM packets is set.
(Optional) Run mpls oam bidirectional-tunnel lost-measure single-ended proactive [ exp exp-value ] { tunnel-type tunnel-number | tunnel-name }
The single-ended packet loss measurement of the bidirectional LSP is enabled.
(Optional) Run mpls oam bidirectional-tunnel delay-measure two-way proactive [ exp expvalue | packet-size packet-SizeValue [ padding-value { 0 | 1 } ] ] ^* { tunnelType tunnelNum |tunnelName }
The proactive two-way delay measurement of the bidirectional LSP is enabled.
Run commit
The configuration is committed.

Exception Handling

If the transmit end has FFD configured and the receive end has auto-protocol configured, the receive end receives FFD packets at the interval that the transmit end sends packets. After the following operations are performed, an unknown alarm is automatically reported and cannot be cleared:

Run the shutdown command on the service interface of the receive end to disable services.
Run the mpls oam bidirectional-tunnel command on the transmit end to modify frequency ffd-fre.
Run the undo shutdown command on the service interface of the receive end to enable services. Then, the receive end will receive FFD packets at an interval different from the locally recorded one.

In this situation, run the undo mpls oam bidirectional-tunnel enable command on the transmit end to disable FFD. Then, reconfigure FFD.