On 03/08, Christopher Morrow wrote: > On Tue, Mar 8, 2022 at 2:36 PM Sriram, Kotikalapudi (Fed) > <[email protected]> wrote: > > > This question has relevance to the ASPA method for route leak detection. > > > > Is it possible that an ISP AS A peers with a customer AS C via a > > non-transparent IXP AS B? > > IOW, the AS path in routes propagated by the ISP A for customer C's > > prefixes looks like this: A B C. > > I.e., can the AS of a non-transparent IXP/RS appear in an AS path in the > > middle between an ISP and its customer? > > > > > it seems unlikely to me that an ISP would pick up a 'customer' (someone > that pays them to transport packets) at an IXP fabric. > Might it happen? sure? is it messy? yes! > I know of several transit providers that will allow customers to use an IXP as a kind of virtual access circuit (which itself is a poor idea), but I would be *very* surprised if any of them allow RS peerings to be the control plane interconnection (intentionally, at least).
If the underlying question is "should the ASPA path validation algorithm have a corner case that accommodates this?", that is a very, very firm "no" from me! Cheers, Ben
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