The bestroute nexthop-resolved ip command enables labeled BGP IPv4 unicast routes, Virtual Private Network version 4 (VPNv4) routes or Virtual Private Network version 6 (VPNv6) routes to be available in route selection only when their next hops are iterated to IP addresses.
The bestroute nexthop-resolved tunnel command enables labeled BGP IPv4 unicast routes, VPNv4 routes or VPNv6 routes to be available in route selection only when their next hops are iterated to Label Switched Paths (LSPs).
The undo bestroute nexthop-resolved command restores the default setting.
By default, labeled BGP IPv4 routes, VPNv4 routes or VPNv6 routes participate in route selection only when their next hops are iterated to IP addresses.
| Parameter | Description | Value |
|---|---|---|
ip |
Enables labeled routes to be available in route selection only when their next hops are iterated to IP addresses. |
- |
tunnel |
Enables labeled routes to be available in route selection only when their next hops are iterated to LSPs. |
- |
Usage Scenario
In Route Reflector (RR) networking where the next hop of a labeled BGP IPv4 route is changed or non-RR networking, BGP needs to check whether there is an LSP destined for the next hop. If the LSP is not found, BGP needs to establish an LSP in advance. If the default setting is adopted, a labeled BGP IPv4 unicast route may be selected prior to LSP establishment. As a result, services are incorrectly switched before LSP establishment and service stability is affected. The bestroute nexthop-resolved tunnel command can be run to allow route selection only after the labeled BGP IPv4 route is iterated to an LSP. This ensures service stability.
By default, a VPNv4 route or VPNv6 routes can participate in route selection if its next hop is iterated to an IP address. The system adds the optimal VPNv4 route or VPNv6 route to the forwarding table for traffic forwarding. However, traffic cannot be forwarded over the route if the route is not iterated to an LSP. In this situation, run the bestroute nexthop-resolved tunnel command to enable VPNv4 routes or VPNv6 routes to be available in route selection only when their next hops are iterated to LSPs to ensure uninterrupted traffic forwarding.
Configuration Impact
The bestroute nexthop-resolved ip and bestroute nexthop-resolved tunnel commands are mutually exclusive.