On Thu, 11 Sep 2008 10:25:01 PDT, Jo Rhett said:
I don't agree with this statement. I hear this a lot, and it's not really true. Being multihomed doesn't mean that your source addresses are likely to be random. (or would be valid if they were)
A significant portion of our customers, and *all* of the biggest paying ones, are multihomed. And they might have a lot of different ranges, but we know what the ranges are and filter on those.
The problem isn't your customers, it's *their* customers who also multihome to somebody you peer with at 3 other locations. AS1312 talks to AS7066, which talks to AS1239, and we talk to AS40220, which talks to Level3 and AboveNet. Now - for each of your routers, what interfaces *can* or *can't* see legitimate packets from us? Does your answer change if something at MATP burps and loses its Lambdarail connection? *That* is the use case that makes it difficult-to-impossible for the 'top 5' to do anything resembling strict BCP38.