H3C Technologies H3C S12500 Series Switches - Manual (Page 237)

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shortcut command to configure an EBGP route as a shortcut route that has the same preference as a local
route. The EBGP route is then more likely to become the optimal route.
To configure preferences for BGP routes:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter BGP view or BGP-VPN
instance view.
• Enter BGP view:
bgp as-number
• Enter BGP-VPN instance view:
a. bgp as-number
b. ipv4-family vpn-instance
vpn-instance-name
Use either method.
3. Configure preferences for
external, internal, local BGP
routes.
preference { external-preference
internal-preference
local-preference | route-policy
route-policy-name }
Optional.
The default preferences of external,
internal, and local BGP routes are
255, 255, and 130.
4. Increase the preference of a
received EBGP route. network ip-address [ mask |
mask-length ] short-cut
Optional.
By default, an EBGP route received
has a preference of 255.
Configure the default local preference
The local preference is used to determine the best route for traffic leaving the local AS. When a BGP
router obtains from several IBGP peers multiple routes to the same destination but with different next hops,
it considers the route with the highest local preference as the best route.
This task allows you to specify the default local preference for routes sent to IBGP peers.
To specify the default local preference:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter BGP view or BGP-VPN
instance view.
• Enter BGP view:
bgp as-number
• Enter BGP-VPN instance view:
a. bgp as-number
b. ipv4-family vpn-instance
vpn-instance-name
Use either method.
3. Configure the default local
preference.
default local-preference value
Optional.
100 by default.
Configuring the MED attribute
MED is used to determine the best route for traffic going into an AS. When a BGP router obtains from
EBGP peers multiple routes to the same destination but with different next hops, it considers the route with
the smallest MED value as the best route if other conditions are the same.