Configuring Basic Detection Functions

This section describes how to configure proper MPLS OAM parameters on both ends of an associated bidirectional LSP for network loads.

Context

Associated bidirectional LSPs are classified into the following types:
  • Dynamic associated bidirectional LSP
  • Static associated bidirectional LSP

A forward RSVP-TE LSP and a reverse RSVP-TE LSP between two nodes are established. Each LSP is bound to the ingress of its reverse LSP. The two LSPs then form a dynamic associated bidirectional LSP. If two static unidirectional CR-LSPs are deployed, the CR-LSPs can form a static associated bidirectional LSP. The associated bidirectional LSP is used to prevent traffic congestion. If a fault occurs on one end, the other end is notified of the fault so that both ends trigger traffic switchovers, preventing service interruptions.

A node functions as both the ingress and egress for an associated bidirectional LSP. Perform the following steps on both ends:

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run mpls

    The MPLS view is displayed.

  3. Run mpls oam

    MPLS OAM is globally enabled.

  4. Run quit

    Return to the system view.

  5. Run either of the following commands:

    • If a reverse tunnel is not specified, run the mpls oam ingress tunnel tunnel-number [ type { cv | ffd frequency ffd-fre } ] [ backward-lsp share ] [ compatibility-mode { ptn-mode | router-mode } ] [ bdi-frequency { detect-freq | per-second } ] [ exp exp-value ] command to configure MPLS OAM parameters for the ingress.

    • If a reverse tunnel is specified, run the mpls oam ingress tunnel tunnel-number [ type { cv | ffd frequency ffd-fre } ] [ backward-lsp { lsp-name lsp-name | lsr-id rev-ingress-lsr-id tunnel-id rev-tunnel-id | share } ] [ compatibility-mode { ptn-mode | router-mode } ] [ bdi-frequency { detect-freq | per-second } ] [ exp exp-value ] command to configure MPLS OAM parameters for the ingress.

    • If the source end of a static LSP is configured to work in shared mode, a TTSI must be configured on the destination end. If a TTSI is not configured on the destination end, BDI packets cannot be received.
    • It is recommended that a reverse LSP be configured to allow OAM for the ingress OAM to check BDI packets.

  6. Run mpls oam ingress enable { tunnel tunnel-number }

    OAM is enabled on the ingress.

  7. Run either of the following commands:

    • To enable OAM auto protocol extension, run the mpls oam egress { lsp-name lsp-name | lsr-id ingress-lsr-id tunnel-id tunnel-id } auto-protocol [ overtime over-time ] [ backward-lsp { tunnel tunnel-id | tunnel-name } [ private | share ] ] [ bdi-frequency { detect-freq | per-second } ] command.

    • To configure OAM parameters when OAM auto protocol extension is disabled on the egress, run the mpls oam egress { lsp-name lsp-name | lsr-id ingress-lsr-id tunnel-id tunnel-id } [ type { cv | ffd frequency { 3 | 10 | 20 | 50 | 100 | 200 | 500 } } ] [ backward-lsp { tunnel-type tunnel-number | tunnel-name } [ share | private ] ] [ bdi-frequency bdi-frep-value ] command.

    • If OAM auto protocol extension is enabled and in Step 7, Step 8 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.
    • It is recommended that a reverse LSP be configured to allow OAM on the egress to send BDI packets.

  8. (Optional) Run mpls oam egress enable { lsp-name lsp-name | lsr-id ingress-lsr-id tunnel-id tunnel-id }

    OAM is enabled on the egress.

  9. (Optional) Run mpls oam ingress loss-measure oam-packet loss-ratio{ threshold1 threshold1-value | threshold2 threshold2-value } * tunnel tunnel-number

    The packet loss alarm threshold on the ingress is set.

  10. (Optional) Run mpls oam ingress lost-measure single-ended proactive[ exp exp-value ] tunnel interface-number

    The single-ended packet loss measurement is enabled on the ingress.

  11. (Optional) Run mpls oam egress loss-measure oam-packet loss-ratio{ threshold1 threshold1-value | threshold2 threshold2-value } * { lsp-name lsp-name | lsr-id lsr-id tunnel-id tunnel-id }

    The packet loss alarm threshold is set on the egress.

  12. (Optional) Run mpls oam ingress delay-measure two-way proactive[ exp exp-value | packet-size packet-size-value | [ padding-value { 0 | 1 } ] ] * { tunnel-type tunnel-number | tunnel-name }

    The two-way delay measurement is enabled on the ingress.

  13. 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:
  1. Run the shutdown command on the service interface of the receive end to disable services.
  2. Run the mpls oam egress command on the transmit end to modify frequency ffd-fre.
  3. 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 ingress enable command on the transmit end to disable FFD. Then, reconfigure FFD.
Parent Topic: Configuring MPLS OAM for an Associated Bidirectional LSP
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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