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

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.
> 
> 
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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