3Com Switch 8807, Configuration Manual

Page: 376 / 883

376 C
HAPTER
33: BGP C
ONFIGURATION
After you use the reset bgp dampening command, the command will release
the suppression of suppressed routes.
Configuring BGP
Preference
Three types of routes may be involved in BGP: routes learned from external peers
(EBGP), routes learned from internal peers (IBGP) and local-originated routes. You
can set preference values for the three types of route.
Perform the following configuration in BGP view.
The ebgp - value , ibgp - value and local - value arguments are in the range of 1 to
256. By default, the first two is 256 and the last one is 130.
Configuring BGP Timer After a BGP connection is established between two peers, they send Keepalive
message to each other periodically. If a router receives no Keepalive message or
any other type of packet within the set connection holdtime, the router regards
the BGP connection has been interrupted and quits the BGP connection.
When a router establishes a BGP connection with a peer, the router will compare
their holdtime values and uses the smaller time as the negotiated holdtime. If the
negotiation result is 0, the router will not send Keepalive message and will not
detect whether the holdtime expires.
Perform the following configuration in BGP view.
By default, the interval of sending keepalive is 60 seconds. The holdtime value is
180 seconds.
The reasonable maximum interval of sending Keepalive is one third of the
holdtime value. The interval of sending Keepalive cannot be less than 1 second. As
a result, if the holdtime is not 0 seconds, the minimum holdtime value is 3
seconds.
Configuring the Local
Preference
When BGP select routes, it will select the route of the highest local preference.
Perform the following configuration in BGP view.
Table 376 Clear route dampening information
Operation Command
Clear route dampening information reset bgp dampening [ network - address [ mask ] ]
Table 377 Configure BGP preference
Operation Command
Configure BGP preference preference ebgp - value ibgp - value local - value
Restore the default preference undo preference
Table 378 Configure BGP timers
Operation Command
Configure BGP timers timer keep-alive keepalive - interval hold holdtime - interval
Restore the default timer value undo timer