You can create BGP community lists so that you can configure route maps based on community lists.

Community lists are user-defined lists of community attribute values. These lists can be used for matching or manipulating the communities attribute in BGP update messages.

Both the BGP Communities attribute (RFC 1997) and the BGP Large Communities attribute (RFC 8092) are supported. The BGP Communities attribute is a 32-bit value split into two 16-bit values. The BGP Large Communities attribute has 3 components, each 4 octets in length.

In route maps we can match on or set the BGP Communities or Large Communities attribute. Using this feature, network operators can implement network policy based on the BGP communities attribute.

Procedure

  1. With admin privileges, log in to NSX Manager.
  2. Select Networking > Tier-0 Gateways.
  3. To edit a tier-0 gateway, click the menu icon (three dots) and select Edit.
  4. Click Routing.
  5. Click Set next to Community List.
  6. Click Add Community List.
  7. Enter a name for the community list.
  8. Specify a list of communities. For a regular community, use the aa:nn format, for example, 300:500. For a large community, use the format aa:bb:cc, for example, 11:22:33. Note that the list cannot have both regular communities and large communities. It must contain only regular communities, or only large communities.
    In addition, you can select one or more of the following regular communities. Note that they cannot be added if the list contains large communinities.
    • NO_EXPORT_SUBCONFED - Do not advertise to EBGP peers.
    • NO_ADVERTISE - Do not advertise to any peer.
    • NO_EXPORT - Do not advertise outside BGP confederation
  9. Click Save.