nanog mailing list archives
Re: Cogent input
From: Stephen Kratzer <kratzers () pa net>
Date: Thu, 11 Jun 2009 10:33:25 -0400
We've only recently started using Cogent transit, but it's been stable since its introduction 6 months ago. Turn-up was a bit rocky since we never received engineering details, and engineering was atypical in that two eBGP sessions were established, one just to advertise loopbacks, and another for the actual feed. The biggest issue we have with them is that they don't allow deaggregation. If you've been allocated a prefix of length yy, they'll accept only x.x.x.x/yy, not x.x.x.x/yy le 24. Yes, sometimes deaggregation is necessary or desirable even if only temporarily. And, they have no plans to support IPv6. "Cogent's official stance on IPv6 is that we will deploy IPv6 when it becomes a commercial necessity. We have tested IPv6 and we have our plan for rolling it out, but there are no commercial drivers to spend money to upgrade a network to IPv6 for no real return on investment." Stephen Kratzer Network Engineer CTI Networks, Inc. On Thursday 11 June 2009 09:46:45 Justin Shore wrote:
I'm in search of some information about Cogent, it's past, present and future. I've heard bits and pieces about Cogent's past over the years but by no means have I actively been keeping up. I'm aware of some (regular?) depeering issues. The NANOG archives have given me some additional insight into that (recurring?) problem. The reasoning behind the depeering events is a bit fuzzy though. I would be interested in people's opinion on whether or not they should be consider for upstream service based on this particular issue. Are there any reasonable mitigation measures available to Cogent downstreams if (when?) Cogent were to be depeered again? My understanding is that at least on previous depeering occasion, the depeering partner simply null-routed all prefixes being received via Cogent, creating a blackhole essentially. I also recall reading that this meant that prefixes being advertised and received by the depeering partner from other peers would still end up in the blackhole. The only solution I would see to this problem would be to shut down the BGP session with Cogent and rely on a 2nd upstream. Are there any other possible steps for mitigation in a depeering event? I also know that their bandwidth is extremely cheap. This of course creates an issue for technical folks when trying to justify other upstream options that cost significantly more but also don't have a damaging history of getting depeered. Does Cogent still have an issue with depeering? Are there any reasonable mitigation measures or should a downstream customer do any thing in particular to ready themselves for a depeering event? Does their low cost outweigh the risks? What are the specific risks? Thanks Justin
Current thread:
- Cogent input Justin Shore (Jun 11)
- RE: Cogent input Paul Stewart (Jun 11)
- Re: Cogent input Andrew Mulholland (Jun 11)
- Message not available
- Re: Cogent input Mike Tancsa (Jun 11)
- Re: Cogent input Marshall Eubanks (Jun 11)
- Re: Cogent input Andrew Mulholland (Jun 11)
- Re: Cogent input Bret Clark (Jun 11)
- RE: Cogent input Zak Thompson (Jun 11)
- Re: Cogent input Chuck Anderson (Jun 11)
- RE: Cogent input Paul Stewart (Jun 11)
- Re: Cogent input seph (Jun 11)
- Re: Cogent input Stephen Kratzer (Jun 11)
- Re: Cogent input manolo (Jun 11)
- Re: Cogent input Steve Bertrand (Jun 11)
- Re: Cogent input Bret Clark (Jun 11)
- Re: Cogent input Stephen Kratzer (Jun 11)
- Re: Cogent input Bret Clark (Jun 11)
- Re: Cogent input Stephen Kratzer (Jun 11)
- Re: Cogent input Bret Clark (Jun 11)
- Re: Cogent input Raymond Dijkxhoorn (Jun 11)
- Re: Cogent input Dave Israel (Jun 11)