----- Original Message ----- > From: "Saku Ytti" <[email protected]>
> On (2013-03-28 13:07 -0400), Jay Ashworth wrote: > > > The edge carrier's *upstream* is not going to know that it's reasonable > > for their customer -- the end-site's carrier -- to be originating traffic > > with those source addresses, and if they ingress filter based on the > > prefixes they route down to that carrier, they'll drop that > > traffic... > > Question is, is it reasonable to expect customer to know what networks > they have. If by "customer" you mean the same thing I do: an end user who sources and sinks packets, which is fed by some Internet Access Provider... then my answer is the same thing it was before: "No, but it doesn't matter, because we're talking about ingress filters on the carrier which provides them with public address space, and *it* *does* know which network they've been given." > If yes, then you can ask them to create route objects and then you can > BGP > prefix-filter and ACL on them. I do both, and it has never been > problem to > my customers (enterprises, CDNs, eyeballs). You are at least 30,000 feet higher than the conversation I'm having. BGP-speaking end sites are a whole different matter, and sufficiently smaller in number (2-5 orders of magnitude, depending on what you sell) that they're not really pertinent here. > But if your customer has many other transit customer it can quickly become > less practical. I'm sure for many/most customers of tier1 it would not > be reasonable expects to keep such list up-to-date. Correct, and this was the substance of my question. > You can't do it at top-level nor it's not practical to hope that some > day BCP38 is done in reasonably many last-mile port. I don't know that that's true, actually; unicast-rpf does, as I understand it, most of the work, and is in most of the current firmware. > But there are only 6000 non-stubby networks, if you do it at network > before stubby network, it's entirely practical and maintainable, provided > we'd want to do it. Your assertion is the thing for which I'm requesting support in this query. Cheers, -- jra -- Jay R. Ashworth Baylink [email protected] Designer The Things I Think RFC 2100 Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DII St Petersburg FL USA #natog +1 727 647 1274
