mpls te p2mp-te leaf switch-delay

Function

The mpls te p2mp-te leaf switch-delay command sets a leaf CR-LSP switchover hold-off time and deletion hold-off time for P2MP TE make-before-break (MBB) mechanism.

The undo mpls te p2mp-te leaf switch-delay command restores the default configuration.

By default, the leaf CR-LSP switchover hold-off time and deletion hold-off time are the same as those configured using the mpls te switch-delay command.

Format

mpls te p2mp-te leaf switch-delay switch-time delete-delay delete-time

undo mpls te p2mp-te leaf switch-delay

Parameters

Parameter	Description	Value
switch-time	Sets a hold-off time after which traffic is switched from the primary sub-LSP to the Modified sub-LSP.	The value is fixed at 0, in ms.
delete-delay delete-time	Sets a hold-off time for deleting the primary sub-LSP after traffic has been switched to the Modified sub-LSP.	The value is fixed at 0, in ms.

Parameter

Description

Value

switch-time

Sets a hold-off time after which traffic is switched from the primary sub-LSP to the Modified sub-LSP.

The value is fixed at 0, in ms.

delete-delay delete-time

Sets a hold-off time for deleting the primary sub-LSP after traffic has been switched to the Modified sub-LSP.

The value is fixed at 0, in ms.

Views

MPLS view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
mpls-te	write

Usage Guidelines

Usage Scenario

MPLS P2MP TE uses an MBB mechanism by default. If MPLS P2MP TE tunnel attributes (such as the bandwidth or path) change, a new leaf CR-LSP (also called Modified sub-LSP) with new attributes must be established before the original leaf CR-LSP (also called primary sub-LSP) is torn down to prevent data loss and additional bandwidth consumption during traffic switching. By default, the primary sub-LSP is deleted only after a specified hold-off time elapses. Before the hold-off time elapses, both the primary sub-LSP and Modified sub-LSP carry traffic. If the egress cannot receive traffic only from one sub-LSP, two copies of traffic exist. To prevent two copies of traffic, run the mpls te p2mp-te leaf switch-delay command to set both the switchover hold-off time and deletion hold-off time to 0. Traffic is then immediately switched to the Modified sub-LSP, and the primary sub-LSP is immediately deleted.

Prerequisites

MPLS TE has been enabled globally using the mpls te command.

Precautions

The mpls te switch-delay command is a global configuration, but the mpls te p2mp-te leaf switch-delay command is not a global configuration. If the mpls te p2mp-te leaf switch-delay command is run, this command configuration takes effect, irrespective of whether the mpls te switch-delay command is run. If the mpls te p2mp-te leaf switch-delay command is not run, the mpls te switch-delay command configuration takes effect.

After the

mpls te p2mp-te leaf switch-delay command is run, traffic may be interrupted if an ingress is idle but the egress is busy. In this situation, either of the following may occur:

The Modified sub-LSP has been ready on the ingress and the primary sub-LSP has been deleted, but the Modified sub-LSP is not ready on the egress. If this occurs, when the ingress switches traffic to the Modified sub-LSP, traffic is temporarily interrupted.
The primary sub-LSP has been deleted, but the Modified sub-LSP failure message cannot be immediately sent to the ingress. If this occurs, traffic is temporarily interrupted.

Example

# Set both the leaf CR-LSP switchover hold-off time and deletion hold-off time to 0 ms for MPLS P2MP TE MBB.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] mpls te
[*HUAWEI-mpls] mpls te p2mp-te leaf switch-delay 0 delete-delay 0