Re: [Idr] Last Call: <draft-ietf-idr-ix-bgp-route-server-10.txt> (Internet Exchange BGP Route Server) to Proposed Standard

> On May 25, 2016, at 6:11 AM, Marco Marzetti <marco@lamehost.it> wrote:
> 
> On 2016-05-25 00:43, The IESG wrote:
>> The IESG has received a request from the Inter-Domain Routing WG (idr) to
>> consider the following document:
>> - 'Internet Exchange BGP Route Server'
>>  <draft-ietf-idr-ix-bgp-route-server-10.txt> as Proposed Standard
>> The IESG plans to make a decision in the next few weeks, and solicits
>> final comments on this action. Please send substantive comments to the
>> ietf@ietf.org mailing lists by 2016-06-07. Exceptionally, comments may be
>> sent to iesg@ietf.org instead. In either case, please retain the
>> beginning of the Subject line to allow automated sorting.
>> Abstract
>>   This document outlines a specification for multilateral
>>   interconnections at Internet exchange points (IXPs).  Multilateral
>>   interconnection is a method of exchanging routing information between
>>   three or more external BGP speakers using a single intermediate
>>   broker system, referred to as a route server.  Route servers are
>>   typically used on shared access media networks, such as Internet
>>   exchange points (IXPs), to facilitate simplified interconnection
>>   between multiple Internet routers.
>> The file can be obtained via
>> https://datatracker.ietf.org/doc/draft-ietf-idr-ix-bgp-route-server/
>> IESG discussion can be tracked via
>> https://datatracker.ietf.org/doc/draft-ietf-idr-ix-bgp-route-server/ballot/
>> No IPR declarations have been submitted directly on this I-D.
>> _______________________________________________
>> Idr mailing list
>> Idr@ietf.org
>> https://www.ietf.org/mailman/listinfo/idr
> 
> All,
> 
> Beside i agree on the most part of this draft i would like to underline how bullet 2.2.2 breaks the the nature of BGP itself.
> 
> The exact part i am referring to is:
> """
> As a route server does not participate in the process of forwarding
>   data between client routers, and because modification of the AS_PATH
>   attribute could affect route server client BGP Decision Process, the
>   route server SHOULD NOT prepend its own AS number to the AS_PATH
>   segment nor modify the AS_PATH segment in any other way.
> """
> 
> I firmly think that it really has to state "MUST NOT" instead of "SHOULD NOT".
> 
> From a route-server client point of view that breaks the natural BGP best selection process and forces you to purely rely on LOCAL_PREFERENCE which in turns breaks your traffic engineering because it forces you to prefer/not-prefer the prefixes learned over the route server in place of those learned, for instance, over a private session or another IXP.
> 
> Regards
> 
> -- 
> Marco
> 
> 
Marco,

There are some IXP route servers that prepend their AS number to the AS_PATH, according to some things I’ve read, such as this Akamai presentation <http://peeringforum.bknix.co.th/2016/docs/Bob%20Lau%20(Akamai).pdf>.  My guess is the use of “SHOULD NOT” here reflects that this is not a recommended procedure.

Since your concerns about traffic engineering are operational in nature, perhaps you could address them via draft-ietf-grow-ix-bgp-route-server-operations.

Incidentally, idnits turned up an outdated reference: a later version (-15) exists of
draft-ietf-idr-add-paths-13.

—gregbo