Configuring a Device to Be Able to Recurse Non-labeled Public BGP Routes to LSPs

By default, non-labeled public BGP routes can recurse to outbound interfaces and next hops, but not to LSPs. You can configure the system to be able to recurse non-labeled public BGP routes to LSPs.

Usage Scenario

If an Internet user uses a carrier network that performs IP forwarding to access the Internet, core carrier devices on the forwarding path need to learn many Internet routes. This imposes a heavy load on core carrier devices and affects their performance. To solve this problem, configure the corresponding access device to be able to recurse non-labeled public BGP routes to LSPs, so that packets can be forwarded over a tunnel. This configuration frees core carrier devices from learning Internet routes, saving their routing table entries and CPU resources.

Pre-configuration Tasks

Before configuring the device to be able to recurse non-labeled public BGP routes to LSPs, complete the following tasks:

Configure the routing protocol or static routes.
Establish an MPLS LSP, BGP LSP, or MPLS local IfNet tunnel.
Configure an IP prefix list, tunnel selector or tunnel policy to allow only desired non-labeled public BGP routes to recurse to the LSP.

Procedure

Configure the device to be able to recurse non-labeled public BGP routes and static routes to LSPs.
1. Run system-view
  
  The system view is displayed.
2. Run route recursive-lookup tunnel [ ip-prefix ip-prefix-name ] [ tunnel-policy policy-name ]
  
  The system is configured to be able to recurse non-labeled public BGP routes and static routes to LSPs for MPLS forwarding.
  This configuration recurses non-labeled public BGP routes and static routes to the following tunnels:
  - LDP LSP: Non-labeled public BGP routes and static routes can recurse to LDP LSPs, supporting the bearer of unicast and multicast services.
  - BGP LSP: Non-labeled public BGP routes and static routes can recurse to BGP LSPs, supporting the bearer of unicast services but not multicast services.
  - Unlabeled public BGP routes and static routes can recurse to SR LSPs, which can be used to carry unicast services but not multicast services.
  - MPLS local IfNet tunnel: Only non-labeled public BGP routes can recurse to MPLS local IfNet tunnels, supporting the bearer of unicast and multicast services.
  If neither ip-prefix ip-prefix-name or tunnel-policy policy-name is specified, all static routes and non-labeled public BGP routes preferentially recurse to LSPs.
3. Run commit
  
  The configuration is committed.
Configure the device to be able to recurse static routes to LSPs.
1. Run system-view
  
  The system view is displayed.
2. Run ip route-static recursive-lookup tunnel [ ip-prefix ip-prefix-name ] [ tunnel-policy policy-name ]
  
  The system is configured to be able to recurse static routes to LSPs for MPLS forwarding.
3. Run commit
  
  The configuration is committed.
Configure the device to be able to recurse non-labeled public BGP routes to LSPs.
1. Run system-view
  
  The system view is displayed.
2. Run bgp { as-number-plain | as-number-dot }
  
  The BGP view is displayed.
3. Run unicast-route recursive-lookup tunnel [ tunnel-selector tunnel-selector-name ]
  
  The system is configured to be able to recurse non-labeled public BGP routes to LSPs for MPLS forwarding.
4. Run commit
  
  The configuration is committed.
The ip route-static recursive-lookup tunnel and unicast-route recursive-lookup tunnel commands are mutually exclusive with the route recursive-lookup tunnel command. The ip route-static recursive-lookup tunnel and unicast-route recursive-lookup tunnel commands are not mutually exclusive.

Example

After configuring the system to be able to recurse non-labeled public BGP routes to LSPs, run the display bgp routing-table network command to view route recursion information.