BGP communities

Route-server BGP communities for ERA-IX.

Large BGP Communities

BGP communities in general provide an in-band mechanism to provide additional information along with routes announced through BGP. This information can be used for administrative but also technical purposes, such as route-filtering, prepending and preferring.
For our members various BGP communities have been implemented to provide members with additional functionality over 'plain' BGP. All communities are of the 'large' type, allowing to transport information for/about both 16 and 32 bit ASNs.

Informational Communities (Set by ERA-IX)

These following communities are set by ERA-IX to 'tag' information onto routes. They can be used to perform your own filtering when the route-servers are configured in tagging mode.

IRR Route Filtering
  • 206221:2:1 IRR valid, Route valid according to IRR.
  • 206221:2:2 IRR invalid, Route invalid according to IRR.
RPKI Route Origin Validation
  • 206221:3:1 RPKI valid, Matching ROA found and valid.
  • 206221:3:2 RPKI not found, No matching ROA could be found.
  • 206221:3:3 RPKI invalid, Matching ROA found and invalid.

Filtering Communities (Set by member)

The filtering communities can be utilized by members to enforce peering policy. The filtering communities can be set to alter where your route is going to be exported to.

  • 206221:0:x Do not announce to member x, Selective de-peer ASN.
  • 0:x Do not announce to member x (legacy), Selective de-peer ASN.
  • 206221:0:0 Do not announce to any member, De-peer all ASNs.
  • 206221:1:x Announce to member x (override 206221:0:0), Override de-peer all ASNs for ASN.

ERA-IX advocates for open peering and exchanging of routes. However, when more advanced policy is desired, our communities will help to achieve this.
For example: A selective/restrictive peering policy can be enforced on the ERA-IX route-servers by setting the 206221:0:0 community along with the 206221:1:x for all member ASNs which should receive the route.
For legacy purposes we also allow selective de-peering through standard communities, these communities are only able to affect routes exported to 16-bit ASNs.

Prepending Communities (Set by member)

Prepending communities can be used to selectively prepend routes. Allowing members to alter the flow of traffic from remote networks.

  • 206221:101:x Prepend once to member ASN x.
  • 206221:102:x Prepend twice ot member ASN x.
  • 206221:103:x Prepend thrice to member ASN x.

These communities only affect routes exported by the ERA-IX route-servers, direct bilateral peering sessions will be unaffected by setting the prepending communities.