Route Server

Route servers provide multilateral peering between members IXP environment. Unlike the standard BGP peering, where everyone has to establish a BGP connection with each, the establishment of BGP Route Server allows the IXP members a service where is possible to retrieve all networks in IXP with only one connection. 

Below is an overview how the Route Server work in CIX.

rs-web.png

Meaning of BGP Community for Route Servers

BGP Community

Meaning for RS

0:ASN

do not send toward BGP neighbor with ASN

0:51702

do not send to anyone

51702:51702

send everyone

51702:ASN

send toward BGP neighbor with ASN

BGP communities for 32-bit AS numbers

To use BGP communities with 32-bit AS numbers, set ASN values as listed in the following table:

BGP Communities for 32-bit AS numbers

Member

AS number

Community

Sedmi odjel d.o.o.

198785

65002

Altus IT 199244 65003
Avalon 201563 65004
Databox 206575 65005

All advertised networks must be marked with some of the BGP community shown above.

If route is not marked by any of these community, than the route will not be advertised to other members.

If route is marked with more communities, some of which are contradictory then apply the following rules:

- the first it takes into account the more specific community (51702:ASN, 0:ASN), provided that the advantage has community that allows for route to be advertised (51702:ASN)

- then it takes into account the general community (51702:51702, 0:51702), provided that the advantage has community that allows for route to be advertised (51702:51702)

Example:

CIX AS: 51702

AS peer1: 65222
AS peer2: 65333
AS peer3: 65444

 { 51702:51702 0:51702}

- route marked like this will be advertised toward every AS in CIX

 { 0:51702 51702:65333}

- route marked like this will be advertised only toward AS 65333

 { 51702:51702 0:65333}

- route marked like this will be advertised to everyone except AS 65333

 { 51702:51702 0:51702 51702:65222 0:65222 0:65444}

-route marked like this will be advertised to everyone except AS 65444

 { 0:51702 51702:65222 0:65222 51702:65333 0:65444}

- route marked like this will be advertised only toward AS 65222 and AS 65333

BLACKHOLE

  • BLACKHOLE routes must be marked with community 65535:666.
  • Size of BLACKHOLE route can range from /16 to /32.
  • CIX members have to allow /25 - /32 routes marked with BLACKHOLE community to pass trough their input filters 
  • CIX members may advertise BLACKHOLE routes only from the range of their own address space!
  • It is possible to blackhole routes only to certain BGP neighbors respecting the rules described earlier on this page.

Example:

CIX AS: 51702
AS peer1: 65222
AS peer2: 65333

{ 65535:666 51702:51702} 

-  route marked like this will be advertised toward every AS in CIX

{ 65535:666 } 

- route marked like this will not be sent to anyone

{ 65535:666 51702:65222 51702:65333} 

- route marked like this will be advertised only toward AS 65222 and AS 65333

CIX members that use direct peerings for route exchanging can also use the blackholing service.
Networks or hosts that they want to protect should be announced in a way that nexthop address is set to 185.1.87.3.

Configuration examples

Cisco Example

Juniper Example