(Optional) Configuring a Policy for Triggering LDP LSP Establishment
Context
After MPLS LDP is enabled, LSPs are automatically established. If no policy is configured, an increasing number of LSPs are established, wasting resources.
Configure the lsp-trigger command on the ingress and egress nodes to trigger LSP setup based on routes. This setting controls the number of LSPs and saves network resources.
The lsp-trigger command can be configured in the MPLS view and MPLS-LDP-IPv4 view. If the lsp-trigger command is configured in both the MPLS view and MPLS-LDP-IPv4 view, the lsp-trigger command in the MPLS-LDP-IPv4 view takes effect.
Configure the propagate mapping command on the transit node to allow LDP to use routes matching specified conditions to establish transit LSPs. For the routes that do not match specified conditions, the local device does not send Label Mapping messages to the upstream device, which reduces the number of LSPs and saves network resources.
The propagate mapping command can be configured in the MPLS-LDP view and MPLS-LDP-IPv4 view. If the propagate mapping command is configured in both the MPLS-LDP view and MPLS-LDP-IPv4 view, the latest configuration takes effect.
By default, the lsp-trigger command is used. If policies cannot be configured on the ingress and egress nodes, configure the propagate mapping command.
Procedure
- Perform the following steps on the ingress and egress nodes:
Configuration in the MPLS view:
- Run the following commands as required.
Run lsp-trigger { all | host | ip-prefix ip-prefix-name | none }
A policy for triggering LSP establishment based on static and IGP routes is configured.
By default, the policy is host. This policy allows LDP to use 32-bit host-address routes ( except 32-bit host-address of interfaces ) to establish LSPs.
LSPs can be established using exactly matching routes on LSRs. For example, an exactly matching host route to an IP address with a 32-bit mask of a loopback interface can be used to trigger LSP establishment.
Run lsp-trigger bgp-label-route [ ip-prefix ip-prefix-name ] [ not-only-host ]
A policy for triggering LSP establishment based on labeled public network BGP routes is configured.
By default, LDP does not allocate labels to labeled BGP routes on the public network.
Configuration in the MPLS-LDP-IPv4 view:
- Run lsp-trigger { all | host | ip-prefix ip-prefix-name | none }
A policy for triggering LSP establishment based on static and IGP routes is configured.
By default, the policy is host. This policy allows LDP to use 32-bit host-address routes (except 32-bit host-address of interfaces) to establish LSPs.
LSPs can be established using exactly matching routes on LSRs. For example, an exactly matching host route to an IP address with a 32-bit mask of a loopback interface can be used to trigger LSP establishment.
- Run the following commands as required.
- Perform the following steps on the transit nodes:
