Details of the BGP communities supported by the burble.dn42 network.
|( 64511 : 0 < x < 21 )||Max latency|
|( 64511 : 20 < x < 30 )||Min bandwidth|
|( 64511 : 30 < x < 35 )||Min encryption|
|( 64511 : 40 < x < 54 )||Route Origin|
The following well known communities are implemented.
|( 65535 : 65281 )||No Export||Prefix should not be exported outside of AS4242422601|
|( 65535 : 65282 )||No Advertise||Prefix should not be exported to any peers|
|( 65535 : 65283 )||Local-AS||Prefix should not be exported outside of region|
|( 4242422601 : 120 : host code )||Route learned on this host|
|( 4242422601 : 130 : 1 )||Route is a direct peer|
|( 4242422601 : 140 : DN42 region )||Route learned in this DN42 region|
In a large network like burble.dn42 it can take some time for route updates to be distributed and for the network to settle following changes. This can be particularly noticeable when routes are deleted as it can create a cascade of ghost updates, each with an increasing internal path length as the route removal spreads across the network.
To protect against ghost routes, a community is used to track how many internal hops a route has. In a fully meshed network like burble.dn42, a genuine route should never have more than two internal hops, so an export filter is used to prevent distribution of longer paths.
|( 4242422601 : 100 : 1 )||Added on first internal re-distribution|
|( 4242422601 : 100 : 2 )||Added on second re-distribution and prevents further re-distribution within burble.dn42|
The ( 4242422601 : 100 : x ) communities are not exported to peers.