tunnel select-seq

Function

The tunnel select-seq command specifies the priority sequence of the tunnels taking part in load balancing.

The undo tunnel select-seq load-balance-number command restores the default setting.

By default, only LDP LSPs, BGP LSP or static LSPs are selected and no load balancing is performed.

Format

tunnel select-seq { gre | lsp | cr-lsp } ^* load-balance-number load-balance-number

undo tunnel select-seq

Parameters

Parameter	Description	Value
gre	Specifies a GRE tunnel. NOTE: This parameter is not supported in this version.	-
lsp	Specifies the LDP LSPs, BGP LSP or static LSPs. NOTE: S5731-S, S5731S-S, S6730-S, and S6730S-S do not support this parameter.	-
cr-lsp	Specifies the CR-LSP tunnel. NOTE: S5731-S, S5731S-S, S6730-S, and S6730S-S do not support this parameter.	-
load-balance-number	Specifies the number of tunnels taking part in load balancing.	The value is an integer that ranges from 1 to 6.

Views

Tunnel policy view

Default Level

2: Configuration level

Usage Guidelines

Usage Scenario

By default, a VPN instance uses LSPs for service transmission on the backbone network. To use other types of tunnels or configure load balancing for service transmission of the VPN instance, you need to apply a tunnel policy to the VPN instance.

Precautions

A tunnel policy determines the selection of proper tunnels for VPN services. There are two types of tunnel policies.

Tunnel type prioritizing policy: Such a policy specifies the sequence in which different types of tunnels are selected. The tunnel select-seq command is used to configure a tunnel type prioritizing policy.
Tunnel binding policy: Such a policy binds a tunnel to a VPN for service transmission. The tunnel binding command is used to configure a tunnel binding policy.

If the tunnel select-seq command is run, the VPN instance preferably selects the tunnel type with the highest priority according to the specified sequence. For example, after the tunnel select-seq cr-lsp lsp load-balance-number 2 command is run in the tunnel policy view, the VPN instance will select CR-LSPs to transmit services on the backbone network.

If two or more CR-LSPs are available on the network, the VPN instance randomly selects two of them for service transmission.
If no CR-LSP or only one CR-LSP is available on the network, the VPN instance selects LSPs as substitutes with the existing CR-LSP for service transmission.
If the number of tunnels used by the VPN instance is reduced to 1, the VPN instance uses the tunnel policy to re-select tunnels.

If lsp is specified in the command, three types of LSPs can serve as candidate tunnels: LDP LSP, BGP LSP, and static LSP. The priority sequence of these LSPs taking part in load balancing is LDP LSP > BGP LSP > static LSP. For example, if the tunnel select-seq lsp cr-lsp load-balance-number 3 command is configured for the tunnel policy:

If three or more LDP LSPs are available on the network, the VPN instance randomly selects three of them for service transmission.
If less than three LDP LSPs are available on the network, the VPN instance selects BGP LSPs as substitutes to ensure that three LSPs work in load balancing mode to transmit services.
If the total number of LDP and BGP LSPs available on the network is less than 3, the VPN instance selects static LSPs as substitutes to ensure that three LSPs work in load balancing mode to transmit services.

After the tunnel select-seq command is executed, apply the configured tunnel policy to the VPN instance so that the VPN instance can select tunnels based on the tunnel policy and have its services load-balanced across tunnels.

The load balancing mode configured using the tunnel select-seq command in a tunnel policy takes effect only for L3VPN.

Example

# Configure a tunnel policy that only LDP LSPs, BGP LSP or static LSPs can be used and no load balancing is performed.

<HUAWEI> system-view
[HUAWEI] tunnel-policy l2
[HUAWEI-tunnel-policy-l2] tunnel select-seq lsp load-balance-number 1