outbound peer split-horizon (MPLS-LDP-VPN instance view)

Function

The outbound peer split-horizon command enables LDP split horizon to restrain an LSR from distributing labels to a specified downstream LDP peer.

The undo outbound peer split-horizon command disables LDP split horizon.

By default, LDP split horizon is disabled. An LSR distributes labels to both upstream and downstream LDP peers.

Format

outbound peer all split-horizon

undo outbound peer all split-horizon

Parameters

Parameter	Description	Value
all	Restrains an LSR from distributing labels to all downstream LDP peers.	-

Parameter

Description

Value

all

Restrains an LSR from distributing labels to all downstream LDP peers.

Views

MPLS-LDP-VPN instance view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
mpls-ldp	write

Usage Guidelines

Usage Scenario

An LSR usually distributes labels to both upstream and downstream LDP peers, speeding up LDP LSP convergence. On DSLAMs with low performance deployed on an MPLS network, LDP distributes labels to all LDP peers, which leads to the establishment of a large number of LSPs and exposes a heavy burden on the DSLAMs. To help reduce the number of LSPs and save memory, run the outbound peer all split-horizon command on LSRs to configure split horizon.

Prerequisites

MPLS LDP has been enabled globally using the mpls ldp command in the system view.

Configuration Impact

After the outbound peer split-horizon command is run, either of the following situations occurs:

If LDP sessions have been established, the local LSR withdraws labels distributed to a specified or all downstream LDP peers.
If LDP sessions are being established, the local LSR does not distribute labels to a specified or all downstream LDP peers.

Precautions

The all parameter takes preference over the peer-id parameter. For example, the outbound peer all split-horizon and then outbound peer 2.2.2.2 split-horizon commands are run, the outbound peer all split-horizon command can be saved in the configuration file and take effect, not the outbound peer 2.2.2.2 split-horizon command.

Example

# Configure split horizon on an LSR to restrain the LSR from distributing labels to all downstream LDP peers.

<HUAWEI> system-view
[~HUAWEI] mpls
[~HUAWEI-mpls] quit
[~HUAWEI] mpls ldp vpn-instance vpn1
[~HUAWEI-mpls-ldp-vpn-instance-vpn1] outbound peer all split-horizon