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