BGP Communities

Control your routes with BGP Communities

Traffic over the NL-ix Route Server can be managed via BGP communities or the Route Server Configurator (filter.nl-ix.net). Please note that you should make a choice for either the communities or the GUI of the Route Server Configurator. Using both may result in unexpected behaviour. The GUI will not show any communities that are set manually.

BGP communities:

With BGP communities you can control which routes sent to the Route Servers are announced to other peers. If no community tags are specified, routes are advertised to all peers by default.

Routes are marked with standard communities (16-bit ASNs) or extended communities (16-bit and 32-bit ASNs).

Traffic over the NL-ix Route Server can be managed with the following communities:

Action Communities
Action BGP communities have direct impact on your routing policy. Setting action tags changes the way prefix announcements are handled.

Action Format Standard communities Extended communities
Don't advertise to specific AS 0:peer-as 0:as-number rt:0:as-number
Announce a prefix (only) to a certain peer exchange-as:peer-as exchange-as:peer-as rt:34307:as-number
Do not announce a prefix to any peer* 0:exchange-as 0:34307 rt:0:34307
Announce a prefix to all peers exchange-as:exchange-as 34307:34307 rt:34307:34307
NO_EXPORT** Well-known 65535:65281
NO_ADVERTISE** Well-known 65535:65282
GRACEFUL_SHUTDOWN*** Well-known 65535:0

* Only one of standard or extended BGP communities has to be applied
** Prefixes marked with this community are not redistributed to Route Server peers
*** Route Server selects another instance of prefix. If none available this one goes to peers. Requires them to match on community as well

Prepending
Prepending makes the route you advertise over the Route Server less attractive. Other routes (like your IP-transit upstream) may be preferred

Action Standard Communities Extended communities
Prepend 1 time to all peers 65001:0
Prepend 1 time to as number 65001:as-number rt:65001:as-number
Prepend 2 times to all peers 65002:0
Prepend 2 times to as number 65002:as-number rt:65002:as-number
Prepend 3 times to all peers 65003:0
Prepend 3 times to as number 65003:as-number rt:65003:as-number

Actions per region

Action Standard Communities
Do not advertise to peers connected in the Netherlands 34307:65031
Do not advertise to peers connected in Belgium 34307:65032
Do not advertise to peers connected in France 34307:65033
Do not advertise to peers connected in the United Kingdom 34307:65044
Do not advertise to peers connected in Denmark 34307:65045
Do not advertise to peers connected in Germany 34307:65049
Do not advertise to peers connected in Luxemburg 34307:65352

Informational Communities
Informational BGP communities pass on information about how and where a route was learned. The marks are assigned by the Route Servers. Each prefix received from Route Servers is marked with various communities.

Informational Standard communities
Learned in Netherlands 65000:65031
Learned in Belgium 65000:65032
Learned in France 65000:65033
Learned in United Kingdom 65000:65044
Learned in Denmark 65000:65045
Learned in Germany 65000:65049
Learned in Luxemburg 65000:65352