nanog mailing list archives
Re: Level 3 BGP Advertisements
From: Jon Lewis <jlewis () lewis org>
Date: Wed, 29 Aug 2012 15:48:00 -0400 (EDT)
On Wed, 29 Aug 2012, Nick Olsen wrote:
Anyways, I've always thought that was standard practice. And its never been a problem. Until we brought up peering with level 3..
No...I'd call that global table pollution. In general, there's no reason you should announce your CIDRs and all their /24 subnets.
I noticed that while the /24's made it out to the world. The larger counterparts (2 /21's and a /20) did not. So, I start sniffing around. Find that I do indeed see the prefixes in Level 3's looking glass but they aren't handing it off to peers. So, Naturally, I land on this being some kind of prefix filtering issue and open a ticket with Level 3. They tell me this is standard practice. And If I want to see the /20 or /21's make it out to the rest of the world, I need to stop sending the /24's. Does this sound normal?
No. I announce to Level3 our IP space and 2 subnets of each CIDR (i.e. /17 + 2 /18 subnets of that /17, etc.), but I use community tags (and other tricks) to mark the more specifics as advertise to [certain] L3 customers only, and let the less specifics out to the world. The only problems I've had with this have been when L3 peers have become customers, and one L3 customer doing something odd (never did find out what) that caused them to effectively null route our space until I kept them from seeing the more specifics (creative abuse of loop detection).
Level3's prefix filter for your session should be built based on IRR data. If it's not doing what you want, you probably haven't setup the IRR data properly.
---------------------------------------------------------------------- Jon Lewis, MCP :) | I route Senior Network Engineer | therefore you are Atlantic Net | _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
Current thread:
- Level 3 BGP Advertisements Nick Olsen (Aug 29)
- Re: Level 3 BGP Advertisements Andy Davidson (Aug 29)
- Re: Level 3 BGP Advertisements Berry Mobley (Aug 29)
- Re: Level 3 BGP Advertisements Jon Lewis (Aug 29)
- Re: Level 3 BGP Advertisements Randy (Aug 29)
- RE: Level 3 BGP Advertisements Hale, William C (Aug 29)
- Re: Level 3 BGP Advertisements William Herrin (Aug 29)
- $10k per BGP prefix? (was Re: Level 3 BGP Advertisements) Jay Ashworth (Aug 29)
- Re: $10k per BGP prefix? (was Re: Level 3 BGP Advertisements) Peter Kristolaitis (Aug 29)
- Re: $10k per BGP prefix? (was Re: Level 3 BGP Advertisements) William Herrin (Aug 29)
- RE: Level 3 BGP Advertisements STARNES, CURTIS (Aug 29)
- Re: Level 3 BGP Advertisements Grzegorz Janoszka (Aug 29)
- Re: Level 3 BGP Advertisements james machado (Aug 29)
- RE: Level 3 BGP Advertisements John van Oppen (Aug 29)
- $10k per BGP prefix? (was Re: Level 3 BGP Advertisements) Jay Ashworth (Aug 29)
- Re: Level 3 BGP Advertisements Andy Davidson (Aug 29)