flow-label (VSI-LDP-PW view)

Function

The flow-label command enables flow-label-based load balancing for an L2VPN PW.

The undo flow-label command disables flow-label-based load balancing of an L2VPN PW.

The flow-label disable command disables flow-label-based load balancing of an L2VPN PW.

The undo flow-label disable command restores flow-label-based load balancing of an L2VPN PW.

By default, a PW has the same flow-label-based load balancing capability as the VSI to which it belongs.

Format

flow-label { { both | send | receive } [ static ] | disable }

undo flow-label { { both | send | receive } [ static ] | disable }

undo flow-label

Parameters

Parameter	Description	Value
both	Indicates both the send and receive capabilities of flow-label-based load balancing for the local device.	-
send	Indicates the send capability of flow-label-based load balancing for the local device.	-
receive	Indicates the receive capability of flow-label-based load balancing for the local device.	-
static	Statically configures flow-label-based load balancing.	-

Views

VSI-LDP-PW view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
l2vpn	write

Usage Guidelines

Usage Scenario

When multiple links exist between P devices, configure flow-label-based load balancing to improve L2VPN traffic forwarding efficiency. After flow-label-based load balancing is enabled on a PE, the PE adds different labels for different L2VPN data flows to distinguish them. After a P device receives a data packet carrying a flow label, it selects a forwarding path based on the flow label in the data packet.

To enable flow-label-based load balancing for a specific L2VPN PW, run the flow-label command.

Note that:

If flow-label-based load balancing is configured for both a VSI and a PW in this VSI, the configuration of the PW takes precedence.
If the undo flow-label command is run in the VSI-LDP-PW view, only the flow-label-based load balancing capability that has been configured using the flow-label command in the VSI-LDP-PW view is disabled.
If the flow-label command has been run for a VSI but not for a PW, you can run the flow-label disable command in the VSI-LDP-PW view to disable flow-label-based load balancing of the PW. If the PW needs the flow-label-based load balancing capability again, you can run the undo flow-label disable command to restore flow-label-based load balancing.

Prerequisites

MPLS L2VPN has been enabled.

Precautions

When configuring flow label-based load balancing for an L2VPN, note the following:

Flow label-based load balancing can be successfully configured only when the send and receive parameters configured on both ends of the PW match.
The receive parameter is configured on the local PE, and the send parameter is configured on the remote PE.
The send parameter is configured on the local PE, and the receive parameter is configured on the remote PE.
Flow label-based load balancing is enabled in both the send and receive directions on the local and remote ends.
If the static flow label-based load balancing configuration does not match on both ends, the device discards packets carrying flow labels, causing packet loss.
The configuration of flow label-based load balancing triggers PW renegotiation. As a result, the service transiently goes down and then up again.

Example

# Disable flow-label-based load balancing for a PW.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] quit
[*HUAWEI] mpls l2vpn
[*HUAWEI-l2vpn] quit
[*HUAWEI] vsi 1 static
[*HUAWEI-vsi-1] pwsignal ldp
[*HUAWEI-vsi-1-ldp] vsi-id 10
[*HUAWEI-vsi-1-ldp] peer 2.2.2.2 encapsulation vlan
[*HUAWEI-vsi-1-ldp] peer 2.2.2.2 pw p1
[*HUAWEI-vsi-1-ldp-pw-p1] flow-label disable

# Enable flow-label-based load balancing for a PW.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] quit
[*HUAWEI] mpls l2vpn
[*HUAWEI-l2vpn] quit
[*HUAWEI] vsi 1 static
[*HUAWEI-vsi-1] pwsignal ldp
[*HUAWEI-vsi-1-ldp] vsi-id 10
[*HUAWEI-vsi-1-ldp] peer 2.2.2.2 encapsulation vlan
[*HUAWEI-vsi-1-ldp] peer 2.2.2.2 pw p1
[*HUAWEI-vsi-1-ldp-pw-p1] flow-label both