Route Serves Policy Control

The Balcan-IX Route Servers have built in filters that allow participants to maintain their peering policies.

  1. BGP Announcement Filtering

The following filtering mechanism that can be used to filter BGP announcements:

Incoming Prefixes Filtering

We do not monitor or control which prefixes participants announce to each other. If participants wish to filter out more specifics, they may do it on their own router.

Outgoing Prefixes Filtering among Route-Server participants: Control of Re-distribution

The participants can control which peer / AS receives which BGP announcements they send to the route servers. The following BGP Communities are supported:

1.1.                  Do not announce

Action BGP Standard Community (RFC 1997)
Redistribute to all (default) 24745:24745
Do not redistribute 0:24745
Redistribute to $PEERAS 24745:$PEER-AS
(in combination with 0:24745)
Do not Redistribute to $PEERAS 0:$PEER-AS

*Where:

Term Description
$PEERAS ASN of an regular  member of the exchange
$PEERIX ASN of an regular  partner IX member of the  Balcan-IX exchange

1.2.                  NO-EXPORT  /NO-ADVERTISE well known

Action BGP Standard Community (RFC 1997)
NO-EXPORT 65535:65281
NO-ADVERTISE 65535:65282
Send NO-EXPORT  to all PEERAS 63034:65281
Send NO-ADVERTISE to all PEERAS 63034:65282

In case two or more BGP (extended) Communities are contradicting the community with the lowest evaluation order wins.

Evaluation order Community
1 NO-EXPORT (65535:65281)
NO-ADVERTISE (65535:65282)
2 0:$PEER-AS
3 24745:$PEER-AS
4 0:24745
5 24745:24745

1.3.                  Usage example

Example 1

BGP announcements marked with the following communities are only re-distributed to AS64501 and AS64502:

  • (0:24745)
  • (24745:64501)
  • (24745:64502)

Example 2

BGP announcements marked with the following communities are re-distributed to all peers / ASNs except AS64501 and AS64502:

  • (0:64501)
  • (0:64502)
  • (24745:24745)

  1. Transparency

All BGP Communities that not mach  (*:24745 ) or (24745:*) are not touched by the route servers and transparently re-distributed. Routes with no community at all are distributed to all peers.