The bestroute nexthop-resolved command configures the condition of the route selection of labeled BGP IPv4 routes, VPNv4 routes, or VPNv6 routes for next hop iteration.
The undo bestroute nexthop-resolved command restores the default configuration.
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.
Product |
Support |
|---|---|
S5720-EI, S5720-HI, S5730-HI, S5731-S, S5731S-S, S5731-H, S5731S-H, S5732-H, S6720-EI, S6720-HI, S6720S-EI, S6730S-H, and S6730-H |
Supported |
S2720-EI, S5720I-SI, S5720-LI, S5735-L, S5735S-L, S5735S-L-M, S5720S-LI, S5720S-SI, S5720-SI, S5735-S, S5735S-S, S5735-S-I, S5730S-EI, S5730-SI, S6720-LI, S6720S-LI, S6720-SI, S6720S-SI, S6730-S, and S6730S-S |
Not supported |
| Parameter | Description | Value |
|---|---|---|
ip |
Allows labeled routes that are iterated to IP addresses to participate in route selection. |
- |
tunnel |
Allows labeled routes that are iterated to MPLS tunnels to participate in route selection. |
- |
BGP view, BGP-IPv4 unicast address family view, BGP-VPNv4 address family view, BGP-VPNv6 address family view
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.
Precautions
The bestroute nexthop-resolved ip and bestroute nexthop-resolved tunnel commands are mutually exclusive.
# In the BGP VPNv4 view, configure BGP VPNv4 routes that are iterated to LSP tunnels to participate in route selection.
<HUAWEI> system-view
[HUAWEI] bgp 100
[HUAWEI-bgp] ipv4-family vpnv4
[HUAWEI-bgp-af-vpnv4] bestroute nexthop-resolved tunnel
# In the BGP VPNv6 view, configure BGP VPNv6 routes that are iterated to LSP tunnels to participate in route selection.
<HUAWEI> system-view
[HUAWEI] bgp 100
[HUAWEI-bgp] ipv6-family vpnv6
[HUAWEI-bgp-af-vpnv6] bestroute nexthop-resolved tunnel