3Com Switch 8800 Configuration Guide
Chapter 21 BGP Configuration
21-19
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.
21.2.11 Configuring BGP Timer
After you established BGP connections between routers, a router sends Keepalive
packets to the peer periodically. Otherwise, the routers regard the BGP connections are
interrupted. If the router receives no Keepalive packets or any other types of packets
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 the peer, the router will compare their
holdtime and regard the smaller time as the negotiated holdtime. If the negotiation
result is 0, the router does not send Keepalive packets and detect whether the holdtime
exceeds.
Perform the following configuration in BGP view.
Table 21-31
Configure BGP timers
Operation
Command
Configure BGP timers
timer keep-alive
keepalive
-
interval
hold
holdtime
-
interval
Restore the default timer value
undo timer
By default, the interval of sending keepalive packet is 60 seconds. The interval of
sending holdtime packet is 180 seconds.
The reasonable maximum interval of sending Keepalive packets is one third of the
interval of sending holdtime packet. The interval of sending Keepalive packets cannot
be less than 1 second. As a result, if the holdtime is not 0 second, the minimum
holdtime is 3 seconds.
21.2.12 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 21-32
Configure the local preference
Operation
Command
Configure the local preference
default local-preference
value
Restore the default local preference
undo default local-preference
The local preference is transmitted only when the IBGP peers exchange the update
packets and it will not be transmitted beyond the local AS.