BGP community propagation
By default, when BGP communities are configured in a BGP router, these communities are shared with neighboring BGP routers using the neighbor send-community command. The communities by default, are not further propogated to BGP neighbors downstream unless this command is present in each BGP router along the way. This behavior can be further refined using one of the keywords for this command:
neighbor send-community [standard | extended | both]
- standard - only standard communities will be sent
- extended - only extended communities will be sent
- both - both standard and extended communities will be sent
For more information about BGP community types, take a look at BGP community types