Configuring the BGP additional path feature
By default, BGP advertises only one optimal route. When the optimal route fails, traffic forwarding will be interrupted until route convergence completes.
The BGP additional path (Add-Path) feature enables BGP to advertise multiple routes with the same prefix and different next hops to a peer or peer group. When the optimal route fails, the suboptimal route becomes the optimal route, which shortens the traffic interruption time.
You can enable the BGP additional path sending, receiving, or both sending and receiving capabilities on a BGP peer. For two BGP peers to successfully negotiate the additional path capabilities, make sure one end has the sending capability and the other end has the receiving capability.
For more information about the BGP additional path configuration commands, see BGP commands in Layer 3—IP Routing Command Reference.
To configure the BGP additional path feature:
Step | Command | Remarks | |
|---|---|---|---|
1. Enter system view. | system-view | N/A | |
2. Enter BGP VPNv4 address family view or BGP-VPN VPNv4 address family view. |
| N/A | |
3. Configure the BGP additional path capabilities. | peer { group-name | ipv4-address [ mask-length ] } additional-paths { receive | send } * | By default, no BGP additional path capabilities are configured. | |
4. Set the maximum number of Add-Path optimal routes that can be advertised to a peer or peer group. | peer { group-name | ipv4-address [ mask-length ] } advertise additional-paths best number | By default, a maximum of one Add-Path optimal route can be advertised to a peer or peer group. | |
5. Set the maximum total number of Add-Path optimal routes that can be advertised to all peers. | additional-paths select-best best-number | By default, a maximum of one Add-Path optimal route can be advertised to all peers. This command is not supported in BGP-VPN VPNv4 address family view. | |