3Com Switch 8800 Configuration Guide Chapter 31 MBGP Multicast Extension Configuration
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31.2.5 Configuring Local Preference
Different local preference can be configured as a reference of the MBGP route
selection. When an MBGP router gets routes with the same destination but different
next hops through different neighbors, it will choose the route with the highest local
preference.
The configuration works both in unicast and multicast.
For the details of this configuration, refer to “BGP Configuration” of the Routing Protocol
part of this manual.
31.2.6 Configuring MBGP Timer
After a router establishes MBGP connection with a peer, it sends Keepalive messages
to the peer periodically to check for the smooth connection. If the router does not
receive a single Keepalive message or any other kind of message from the peer within
the defined connection Holdtime, it will think the MBGP connection broken and exit, and
will process the routing information received through this connection as appropriate.
Therefore, the Keepalive message sending interval and MBGP connection Holdtime
are two parameters of great importance in MBGP mechanism.
The configuration works both in unicast and multicast.
For the details of this configuration, refer to “BGP Configuration” of the Routing Protocol
part of this manual.
31.2.7 Configuring MBGP Peer (Group)
The use of MBGP peer groups is to simplify configuration. When configuring MBGP
peers, you can create and configure a peer group in BGP view, and then add the peers
into the group, since all peers in a group have the same configuration with the group.
Then, enable this peer group in IPv4 multicast sub-address family view and add peers
to this peer group to create MBGP peers and an MBGP peer group. In conclusion, to
create MBGP peers/peer groups, you must configure them successfully in BGP view
first.
Caution:
Configure the peer group under the guide of technical support engineers.

I. Creating a peer group with members

To configure a MBGP peer (group), configure a peer group in BGP view and add peers
to this peer group. For details, refer to “BGP Configuration” in the Routing Protocol part.