Date: Sat, 29 Sep 2001 21:09:49 +0100 (BST) From: Stephen J. Wilcox <steve@opaltelecom.co.uk>
[1] Providers SHOULD filter/aggregate downstream routes, unless
Two different subjects? Filter definitely, you want to ensure quality and sanity. But aggregate... hmm, dont think that'll work with commerical people. A customer multihomes and you aggregate whilst a.n.other doesnt.. a.n.other gets all the traffic and you become the secondary provider and let a.n.other get all the new business as primary!
Punch holes in aggs for multihoming, same as now. Maybe I should clarify... I was referring to splitting netblocks for the purpose of tuning traffic.
[2] Want to tune inbound traffic? Fine... advertise those longer prefixes to your upstreams/peers. But don't make the rest of the Internet suffer. Communities good. Extra routes bad.
but people dont advertise long prefixes in order to simply make use of two providers for the sake of it, they do it in order to
IGP-into-BGP causes this, and is hardly for preferring traffic from one upstream.
create their own unique routing policies which by definition needs to be internet-wide
Tag a single netblock with a community or MED. Don't split it into two longer prefixes. Of course, that might require inter-AS cooperation.
i would envisage all kinds of problems too where the aggregating upstream accepts your specific routes via another isp by mistake and then your transit traffic ends up going all round the place.. you'd be advertising /24s to peers and all but one transit, with primary transit aggregating up to /16 or whatever, feels bad..
Hmmmm. So I have customer X, who also connects to backbone B. They advert several blocks, which I agg to 192.168.0.0/19. B does not agg the blocks... but I'd also agg what I hear from B, into the same /19. No problem here. Or perhaps a hack... match ^[0-9]*_ and prefer it over longer prefixes. i.e., if you can get there directly, it's better than going through another AS. Your point definitely merits thought... but I'm not sure that it's insurmountable. Eddy --------------------------------------------------------------------------- Brotsman & Dreger, Inc. - EverQuick Internet Division Phone: +1 (316) 794-8922 Wichita/(Inter)national Phone: +1 (785) 865-5885 Lawrence --------------------------------------------------------------------------- Date: Mon, 21 May 2001 11:23:58 +0000 (GMT) From: A Trap <blacklist@brics.com> To: blacklist@brics.com Subject: Please ignore this portion of my mail signature. These last few lines are a trap for address-harvesting spambots. Do NOT send mail to <blacklist@brics.com>, or you are likely to be blocked.