Configuring Bgp Community - H3C LS-3100-52P-OVS-H3 Operation Manual

Configure an eBGP peer group
If peers in an eBGP group belong to the same external AS, the eBGP peer group is a pure eBGP peer
group; if not, it is a mixed eBGP peer group.
There are two approaches for configuring an eBGP peer group:
Create the eBGP peer group, specify its AS number, and add peers into it.
Create the eBGP peer group, and add a created peer into it or add a peer with the AS number
specified
Follow these steps to configure an eBGP peer group using the first approach:
To do...
Enter system view
Enter BGP view
Create an eBGP peer group
Specify the AS number for the
group
Add a peer into the group
Follow these steps to configure an eBGP peer group using the second approach:
To do...
Enter system view
Enter BGP view
Create an eBGP peer group
Add a peer into the group
Configuring BGP community can also help simplify routing policy management, and a community has a
much larger management scope than a peer group by controlling routing policies of multiple BGP
routers.
To guarantee the connectivity between iBGP peers, you need to make them fully meshed. But it
becomes unpractical when there are large numbers of iBGP peers. Configuring route reflectors or
confederation can solve it. In a large-scale AS, both of them can be used.

Configuring BGP Community

A BGP community is a group of destinations with the same characteristics. It has no geographical
boundaries and is independent of ASs.
You can configure a route policy to define which destinations belong to a BGP community and then
advertise the community attribute to a peer/peer group.
You can apply a route policy to filter routes advertised to/received from a peer/peer group according to
the community attribute. This way helps simplify policy configuration and management.
For how to configure a route policy, refer to Route Policy Configuration in the IP Routing Volume.
Follow these steps to configure BGP community:
Use the command...
system-view
bgp as-number
group group-name external
peer group-name as-number as-number
peer ip-address group group-name
Use the command...
system-view
bgp as-number
group group-name external
peer ip-address group group-name
[ as-number as-number ]
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