Nokia Network Voyager, Reference Manual

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6
Configuring Routing
288 Voyager Reference Guide
Communities
BGP communities allow you to group a set of IP addresses and apply routing
decisions based on the identity of the group or community.
To implement this feature, you need to map a set of communities to certain
BGP local preference values. Then you can apply a uniform BGP
configuration to the community as a whole as opposed to each router within
the community. The routers in the community can capture routes that match
their community values.
Using community attributes, you can configure your BGP speaker to set,
append, or modify the community of a route that controls which routing
information is accepted, preferred, or distributed to other neighbors. The
following table displays some special community attributes that a BGP
speaker can apply.
Refer to the communities documents (RFCs 1997 and 1998 as of this writing)
for further details.
Community Attribute Description
NO_EXPORT (0xFFFFFF01) Is not advertised outside a BGP
confederation boundary. A stand-
alone autonomous system that is not
part of a confederation should be
considered a confederation itself.
NO_ADVERTISE (0xFFFFFF02) Is not advertised to other BGP
peers.
NO_EXPORT_SUBCONFED(0xFFFFFF03) Is not advertised to external BGP
peers. This includes peers in other
members’ autonomous systems
inside a BGP confederation.