flow-label

Function

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

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

By default, flow-label-based load balancing of L2VPN VSIs is disabled.

Format

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

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

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-BGP 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 one from the other. 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. This processing implements load balancing.

To enable flow-label-based load balancing for all PWs in a VSI, run the flow-label command in the VSI-LDP view.

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 the receive and send directions on both 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

# Enable flow-label-based load balancing for BGP VPLS.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] quit
[*HUAWEI] mpls l2vpn
[*HUAWEI-l2vpn] quit
[*HUAWEI] vsi 1
[*HUAWEI-vsi-1] pwsignal bgp
[*HUAWEI-vsi-1-bgp] flow-label both