Configuring preferences for BGP routes
Routing protocols each have a default preference. If they find multiple routes destined for the same network, the route found by the routing protocol with the highest preference is selected as the optimal route.
You can use the preference command to modify preferences for EBGP, IBGP, and local BGP routes, or reference a routing policy to set a preference for matching routes. For routes not matching the routing policy, the default preference applies.
If a device has an EBGP route and a local BGP route to reach the same destination, it does not select the EBGP route because the EBGP route has a lower preference than the local BGP route by default. You can use the network short-cut command to configure the EBGP route as a shortcut route that has the same preference as the local BGP route. The EBGP route will more likely become the optimal route.
To configure preferences for BGP routes (IPv4):
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter BGP view or BGP-VPN instance view. |
| N/A |
3. Enter BGP IPv4 unicast address family view or BGP-VPN IPv4 unicast address family view. | address-family ipv4 [ unicast ] | N/A |
4. Configure preferences for EBGP, IBGP, and local BGP routes. | preference { external-preference internal-preference local-preference | route-policy route-policy-name } | The default preferences for EBGP, IBGP, and local BGP routes are 255, 255, and 130. |
5. Configure an EBGP route as a shortcut route. | network ip-address [ mask | mask-length ] short-cut | By default, an EBGP route has a preference of 255. |
To configure preferences for BGP routes (IPv6):
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter BGP view or BGP-VPN instance view. |
| N/A |
3. Enter BGP IPv6 unicast address family view or BGP-VPN IPv6 unicast address family view. | address-family ipv6 [ unicast ] | N/A |
4. Configure preferences for EBGP, IBGP, and local BGP routes. | preference { external-preference internal-preference local-preference | route-policy route-policy-name } | The default preferences for EBGP, IBGP, and local BGP routes are 255, 255, and 130. |
5. Configure an EBGP route as a shortcut route. | network ipv6-address prefix-length short-cut | By default, an EBGP route has a preference of 255. |