----- Original Message -----
From: "Saku Ytti" <saku@ytti.fi>
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 jra@baylink.com 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