load-balance unequal-cost weight

Function

The load-balance unequal-cost weight command sets a weight for a link before unequal cost multiple path (UCMP) is carried out among links.

The undo load-balance unequal-cost weight command restores the default weight for a link.

By default, the UCMP weight of each link is 0 after UCMP is enabled globally.

Format

load-balance unequal-cost weight weight

undo load-balance unequal-cost weight

Parameters

Parameter	Description	Value
weight	Specifies a weight for a link. A link transmits traffic based on the configured UCMP weight.	The value is an integer that ranges from 1 to 64.

Parameter

Description

Value

weight

Specifies a weight for a link. A link transmits traffic based on the configured UCMP weight.

The value is an integer that ranges from 1 to 64.

Views

Tunnel interface view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
mpls-te	write

Usage Guidelines

Usage Scenario

On an existing MPLS network, devices in the core area support TE, and devices in other areas use LDP. LDP over TE applies and allows a TE tunnel to function as a hop on an entire LDP LSP. On MPLS VPNs where LDP is widely used, LDP over TE is used to prevent VPN traffic congestion on some nodes. If multiple tunnels on a transit node have the same downstream node, load balancing can be configured on the transit node. This allows each link to carry traffic based on the proportion of the specific weight to the total weight.

Prerequisites

The load-balance unequal-cost enable command has been run to enable UCMP globally before any UCMP-associated commands are used.

Configuration Impact

The load-balance unequal-cost weight command takes effect 10 minutes after being run.

Precautions

Note the following issues when configuring UCMP weights:

If only some links are configured with weights, the system carries out load balancing based on bandwidth, the configured weights do not take effect. If some links are not assigned bandwidth resources, ECMP is performed.
If all links are configured with weights, UCMP is carried out among links. Each link carries traffic based on a specified percent calculated using the following formula:
Traffic percent on a specified link = 64 x (Weight of a specified link/Sum of weights).
As the sum of weights may not be divisible, the traffic volume of each link may deviate from the calculated result but the sum of weights remains 64.

Example

# Set the weight of a link to 12 on Tunnel 10.

<HUAWEI> system-view
[~HUAWEI] mpls
[*HUAWEI-mpls] mpls te
[*HUAWEI-mpls] quit
[*HUAWEI] load-balance unequal-cost enable
[*HUAWEI] interface Tunnel 10
[*HUAWEI-Tunnel10] tunnel-protocol mpls te
[*HUAWEI-Tunnel10] load-balance unequal-cost weight 12