Pardon the top post. Marco, we do these things in the real world generally because we have to, not because we don't know any better. IX participants come in all kinds of flavors, and some have to turn some really weird BGP knobs to ensure everything works. I very much appreciate your position -- clean, optimal standards are a great goal -- but real world operability is the true MUST HAVE of a standard. David > On Jun 1, 2016, at 7:12 AM, Marco Marzetti <marco@xxxxxxxxxxx> wrote: > >> On 2016-06-01 13:17, Nick Hilliard wrote: >> Marco Marzetti wrote: >>> I agree with you that you can run a route server and insert your ASn in >>> the path, but i think that is a lack of common sense which brings only >>> contraries and no benefits. >>> About RFC2119: It says that "SHOULD NOT" implies a valid reason to >>> accept a behavior, but i can't find any. >> I agree that it is not a clever thing to do. The valid reason to accept >> the behaviour is that it works in practice: some IXPs have done this in >> production, in many cases for years. >> There is a secondary reason: some rs client bgp stacks don't support the >> option to accept an AS path from the RS where the leftmost entry on the >> AS path != peeras. >> These are not "good" reasons in the sense that they mandate behaviour >> which is suboptimal, but they are valid reasons. >> Nick > > Nick, > > I think that we should define a standard that addresses and corrects those non-clever behaviors rather than embrace them. > > My point is: even if they work in the real world, they do because of the workarounds that other people put in place and they bring no benefits. > > Regards > > -- > Marco >