Configuring preferences for bgp routes – H3C Technologies H3C S5560 Series Switches User Manual
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Step Command
Remarks
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.
ip vpn-instance
vpn-instance-name
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.
Specify a preferred value for
routes received from a peer or
peer group.
peer { group-name | ipv6-address
[ prefix-length ] } preferred-value
value
The default preferred value is 0.
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.
•
Enter BGP view:
bgp as-number
•
Enter BGP-VPN instance view:
a.
bgp as-number
b.
ip vpn-instance
vpn-instance-name
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.