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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