NTAC Peering Working Group

[John Hess <>]

BGP Community Controls for TR/CPS Participants

   (DRAFT - for review by NTAC Peering and Routing WG)

All:

During the April 20th NTAC Peering and Routing WG call, an inquiry was  
made regarding support within the consolidated TR/CPS network for BGP  
communities to allow traffic control by participants.   The legacy  
Internet2 CPS network (AS11537) supports a set of BGP communities  
which allow connectors to control their traffic to/from CPS peer  
networks; the legacy TransitRail network (AS11164) supports a similar  
set of BGP communities to provide the same functionality.

To ease the transition of connections to the consolidated TR/CPS  
network the communities of both the legacy TransitRail and CPS  
networks are supported on links to AS11164 as described below.


The group of communities for selective prepending and no-export are:
Community        Description
65000:<ASN>    Do not advertise at all to the peer ASN
65001:<ASN>    Prepend once toward peer ASN
65002:<ASN>    Prepend twice toward peer ASN
65003:<ASN>    Prepend thrice toward peer ASN
65009:<ASN>    Allow advertisement toward peer ASN if otherwise  
excluded by more general community control
    and/or
65500x:<ASN>  Variants of the above communities (to be deprecated *)


The following community can be used to blackhole traffic to more  
specific netblocks (up to /32):
Community       Description
11164:53666    Rewrite next hop to discard traffic
    and/or
11537:911        (to be deprecated *)


The following communities can be used to alter relative preference  
within the consolidated TR/CPS network (AS11164):
Community       Description
11164:51240    Set preference of learned route Above standard local  
preference value for Participant
    and/or
11537:260        (to be deprecated *)
--
11164:51200    Set preference of learned route Below standard local  
preference value for Participant
    and/or
11537:140        (to be deprecated *)
--
These additional communities are available to alter relative  
preference.  Though available, these communities are rarely used and  
can take substantial care to appreciate the outcome from using them:
11164:51080     Set preference of learned route Below standard local  
preference value for Settlement Free Peers
11164:51050     Set preference of learned route Below standard local  
preference value for any Transit Providers (no Transit Providers exist  
to-date)


Additionally, these communities can be used to alter the announcement  
profile of your routes:
Community        Description
11164:52400     Do not export to North American peers (all TR/CPS  
peers to-date)
11164:52401     Prepend once to North American peers
11164:52402     Prepend twice to North American peers
11164:52403     Prepend thrice to North American peers
11164:52300     Do not export to Extended Peers
--
Related communities for future use, but which are in-active in the  
network, at present:
11164:52200     Do not export to transit
11164:52201     Prepend once to transit
11164:52202     Prepend twice to transit
11164:52203     Prepend thrice to transit
11164:52500     Do not export via peer-links in Asia-Pac
11164:52501     Prepend once via peer-links in Asia-Pac
11164:52502     Prepend twice via peer-links in Asia-Pac
11164:52503     Prepend thrice via peer-links in Asia-Pac
11164:52600     Do not export via peer-links in Europe
11164:52601     Prepend once via peer-links in Europe
11164:52602     Prepend twice via peer-links in Europe
11164:52603     Prepend thrice via peer-links in Europe


*  The indicated BGP communities will be supported through the period  
of integration of the legacy TR and CPS networks: their use will be  
deprecated within the consolidated TR/CPS network after the  
integration is complete.   These changes will not affect the set of  
communities available to connectors within the Internet2 (R&E) network:
    <http://noc.net.internet2.edu/i2network/maps--documentation/documentation/bgp-communities.html#Internet2%20BGP%20Communities 
>


Please let us know if you have questions, 
<mailto:>

thanks,

john

john hess 
<>
phone:      714 220-3469