Right - but IMO route leaking can happen both in the Internet or in customer <- via IXP -> content provider interconnects.
And in the latter case - especially for those with open peering policy - often going via RS. After all this is how route servers are mainly used today :) So both sides will be peering to IXP RS while IXP RS will (in most cases) not appear in the AS_PATH. Kind regards, R. On Tue, Mar 8, 2022 at 9:26 PM Christopher Morrow < christopher.mor...@gmail.com> wrote: > > > On Tue, Mar 8, 2022 at 3:15 PM Robert Raszuk <rob...@raszuk.net> wrote: > >> Well I think the answer is - it depends. >> >> First IXP fabric can be used as pure L3 share LAN or can be used (and it >> is often the case) as a p2p emulated VLAN over such L3 shared LAN. >> >> Now if this is L3 shared LAN still customer and ISP may peer directly and >> no third party traffic would be accepted at either end. >> >> If we talk about emulating L2 IXP fabric becomes just an emulated circuit >> and from the perspective of routing it a p2p interface. >> >> Sure the other aspects of the IXP quality, port monitoring, >> oversubscription etc... always will apply but there are ways to mitigate or >> handle those in real IXPs. >> >> > I don't dispute your content here, except that Sriram's question was about > seeing 'customer routes via the RS'... which I think would obviate the > emulation examples you provided. > (well in a bunch of cases it would, you COULD hook up some tomfoolery to > get this to work, but... that sounds complex and prone to disaster) > > >> Best, >> R. >> >> >> >> >> >> >> >> >> On Tue, Mar 8, 2022 at 9:05 PM Christopher Morrow < >> christopher.mor...@gmail.com> wrote: >> >>> >>> >>> On Tue, Mar 8, 2022 at 2:36 PM Sriram, Kotikalapudi (Fed) >>> <kotikalapudi.sriram=40nist....@dmarc.ietf.org> 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! >>> >>> 1) that's probably a shared port >>> 2) there are other folk feeding routes and packets into the mix >>> 3) how many came through the 'customer' port (which you can't really >>> know easily) vs other participants on the ix >>> 4) what capacity planning could the 'customer' do here? (none, basically >>> with respect to the remote ISP port) >>> >>> Your question might work also as: >>> "ISP A has a customer C on a direct link in location Y. >>> ISP A is present at IXP-Z, so is customer C, though they do not >>> bilaterally peer (not do they interconnect at the IXP). >>> ISP A can still see Customer C's routes through the IXP-Z Route >>> Server." >>> >>> that seems plausible, but not a desired outcome for the ISP :) since >>> they will be unlikely to collect pesos for the traffic >>> which MAY pass across that interconnect. >>> >>> _______________________________________________ >>> GROW mailing list >>> GROW@ietf.org >>> https://www.ietf.org/mailman/listinfo/grow >>> >>
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