3Com Switch 7750 Configuration Guide Guide

Adjusting and Optimizing a BGP Network 349
implementations, BGP supports the route-refresh function. With route-refresh
function enabled on all the BGP routers, if BGP routing policy changes, the local
router sends refresh messages to its peers. And the peers receiving the message in
turn send their routing information to the local router. In this way, you can apply
new routing policies and have the routing table dynamically updated seamlessly.
To apply a new routing policy in a network containing routers that do not support
the route-refresh function, you need first to save all the route updates locally by
using the peer keep-all-routes command, and then use the refresh bgp
command to reset the BGP connections manually. This method can also refresh
BGP routing tables and apply a new routing policy seamlessly.
4 BGP authentication
BGP uses TCP as the transport layer protocol. To improve the security of BGP
connections, you can specify to perform MD5 authentication when a TCP
connection is established. Note that the MD5 authentication of BGP does not
authenticate the BGP packets. It only configures the MD5 authentication
password for TCP connection, and the authentication is performed by TCP. If
authentication fails, the TCP connection cannot be established.
Configuration
Prerequisites
You need to perform the following configuration before adjusting the BGP clock.
■ Enable basic BGP functions
Before configuring BGP clock and authentication, make sure the following
information is available.
■ Value of BGP timer
■ Interval for sending the update packets
■ MD5 authentication password
Adjusting and
Optimizing a BGP
Network
Table 283 Adjust and optimize a BGP network
Operation Command Description
Enter system view system-view -
Enable BGP, and enter BGP view bgp as-number
Required
By default, BGP is
disabled.
Configure BGP timer
Configure the
Keepalive time
and Holdtime
of BGP.
timer keepalive
keepalive-interval hold
holdtime-interval
Optional
By default, the keepalive
time is 60 seconds, and
holdtime is 180 seconds.
The priority of the timer
configured by the timer
command is lower than
that of the timer
configured by the peer
time command.
Configure the
Keepalive time
and holdtime
of a specified
peer/peer
group.
peer { group-name |
ip-address } timer
keepalive
keepalive-interval hold
holdtime-interval