mpls te cspf (Tunnel interface view)

Function

The mpls te cspf disjoint command enables the disjoint algorithm.

The undo mpls te cspf disjoint command disables the disjoint algorithm.

This command varies in transport and router modes. For detailed differences, see Differences Between Commands in Transport and Router Modes. This topic describes the command configuration in router mode.

By default, the disjoint algorithm is disabled.

Format

mpls te cspf { disable | disjoint }

undo mpls te cspf { disable | disjoint }

Parameters

Parameter Description Value
disable

Setting up LSPs without CSPF.

-

disjoint

Calculate fully disjoint path for main and hot-standby.

-

Views

Tunnel interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name Operations
mpls-te write

Usage Guidelines

Usage Scenario

Most IP RANs use ring topologies and have the access ring separated from the aggregation ring. To improve the end-to-end and inter-ring LSP reliability, IPRAN carriers require isolated primary and hot-standby LSPs. The CSPF algorithm does not meet this reliability requirement because CSPF is a metric-based path computing algorithm that may compute two intersecting LSPs.

Specifying explicit paths can resolve this problem. However, this method does not adapt to topology changes.

Now you can run the mpls te cspf disjoint command to enable isolated LSP computation. After this command is run, the device uses both the disjoint and CSPF algorithms to compute isolated primary and hot-standby LSPs.

Prerequisites

Before executing this command, you need to meet the following conditions:

  • The mpls te cspf command has been run in the MPLS view to enable the CSPF algorithm.
  • The CR-LSP hot-standby feature has been enabled and the primary and hot-standby LSPs have the same bandwidth constraint.

Configuration Impact

After you run this command, the device does not allow you to configure the following features:

  • Explicit path
  • Hop limit property

    After you enable the disjoint algorithm, the SRLG feature, if configured, becomes ineffective.

Precautions

The mpls te cspf disjoint command configuration takes effect in new LSP computation tasks, but does not on existing LSPs.

When an affinity is configured, the disjoint algorithm takes effect only when affinities of the primary and backup LSPs are the same or no affinities are configured for the primary and backup LSPs.

Example

# Enable the disjoint algorithm on Tunnel 10.
<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] mpls te
[*HUAWEI-mpls] mpls te cspf
[*HUAWEI-mpls] mpls rsvp-te
[*HUAWEI-mpls] quit
[*HUAWEI] interface Tunnel 10
[*HUAWEI-Tunnel10] tunnel-protocol mpls te
[*HUAWEI-Tunnel10] mpls te backup hot-standby
[*HUAWEI-Tunnel10] mpls te cspf disjoint
Copyright © Huawei Technologies Co., Ltd.
Copyright © Huawei Technologies Co., Ltd.
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