H3C S3610-28P Operation Manual page 495

Operation Manual – IPv4 Routing
H3C S3610&S5510 Series Ethernet Switches
Figure 5-12 BGP route dampening
III. Peer group
A peer group is a collection of peers with the same attributes. When a peer joins the
peer group, the peer obtains the same configuration as the peer group. If configuration
of the peer group is changed, configuration of group members is also changed.
There are many peers in a large BGP network. Some of these peers may be configured
with identical commands. The peer group feature simplifies configuration of this kind.
When a peer is added into a peer group, the peer enjoys the same route update policy
as the peer group to improve route distribution efficiency.
Caution:
If an option is configured both for a peer and for the peer group, the latest configuration
takes effect.
IV. Community
A peer group makes peers in it enjoy the same policy, while a community makes a
group of BGP routers in several ASs enjoy the same policy. Community is a path
attribute and advertised between BGP peers, without being limited by AS.
A BGP router can modify the community attribute for a route before sending it to other
peers.
5-14
Chapter 5 BGP Configuration