Bgp Route Selection - Extreme Networks ExtremeWare XOS Guide Manual

BGP Features
Configuring Route Flap Dampening
BGP route flap dampening can be enabled on a per BGP peer session basis, for a BGP peer group, or for
a set of routes, using a route map.
To enable route flap dampening over BGP peer sessions, use the following command:
configure bgp neighbor [all | <remoteaddr>] {address-family [ipv4-unicast |
ipv4-multicast]} dampening {{half-life <half-life-minutes> {reuse-limit
<reuse-limit-number> suppress-limit <suppress-limit-number> max-suppress
<max-suppress-minutes>} | policy-filter [<policy-name> | none]}
To enable route flap dampening for a BGP peer group, use the following command:
configure bgp peer-group <peer-group-name> {address-family [ipv4-unicast |
ipv4-multicast]} dampening {{half-life <half-life-minutes> {reuse-limit
<reuse-limit-number> supress-limit <suppress-limit-number> max-suppress
<max-suppress-minutes>}} | policy-filter [<policy-name> | none]}
You can supply the dampening parameters directly through the CLI command, or use the command to
associate a policy that contains the desired parameters.
Disabling Route Flap Dampening
To disable route flap dampening for a BGP neighbor (disabling the dampening will also delete all the
configured dampening parameters), use the following command:
configure bgp neighbor [<remoteaddr> | all] {address-family [ipv4-unicast |
ipv4-multicast]} no-dampening
To disable route flap dampening for a BGP peer group, use the following command:
configure bgp peer-group <peer-group-name> no-dampening
Viewing the Route Flap Dampening Configuration
To view the configured values of the route flap dampening parameters for a BGP neighbor, use the
following command:
show bgp neighbor <remoteaddr> {address-family [ipv4-unicast | ipv4-multicast]}
[accepted-routes | flap-statistics | received-routes | rejected-routes |
suppressed-routes | transmitted-routes] {detail} [all | as-path <path-expression> |
community [no-advertise | no-export | no-export-subconfed | number <community_num> |
<AS_Num>:<Num> ] | network <ip_addr>/<mask_len> ]
To view the configured values of the route flap dampening parameters for a BGP peer group, use the
following command:
show bgp peer-group {detail | <peer-group-name> {detail}}

BGP Route Selection

BGP will select routes based on the following precedence (from highest to lowest):
• higher weight
• higher local preference
ExtremeWare XOS 10.1 Concepts Guide 213