On 25 feb 2008, at 9:14, Paul Wall wrote:
I don't know how large Pakistani Telecom is, but it I bet its not large enough that PCCW should be allowing it to advertise anything.
I think you're failing to take into account how multihoming generally works. The real fallacy here is that PCCW/BTN refuses to prefix-list filter their customers, as evidenced by this and past leaks. If something productive can come from today's outage, it would be PCCW beginning to do their part as responsible Internet citizens, given (excuse the pun) "peer" pressure.
Well, if they had problems like this in the past, then I wouldn't trust them to get it right. Which means that it's probably a good idea if EVERYONE starts filtering what they allow in their tables from PCCW. Obviously that makes it very hard for PCCW to start announcing new prefixes, but I can't muster up much sympathy for that. So basically, rather than generate routing registry filters for the entire world, generate routing registry filters for known careless ASes. This number should be small enough that this is somewhat doable. (Although better tools for generating the filters would help, I tried generating filters from the RIPE db a few times but I couldn't figure it out using available tools and I didn't have the time to write my own.)