Slightly old news, but it looks like Cogent depeered ESnet last week:
Current traceroutes indicate that ESnet is reaching Cogent via 6939_1299.
In other news, automatically dropping interconnects at around the time of your HQ's close of business while your peering co-ordinator is on vacation seems to be the new gold standard.
Nick
I suppose the moral of the story is: "never single-home to Cogent"
From nanog-bounces+bonomi=mail.r-bonomi.com@nanog.org Sun Jun 19 01:46:06 2011
Date: Sat, 18 Jun 2011 23:44:28 -0700
Subject: Re: Cogent depeers ESnet
From: "George B." <georgeb@gmail.com>
To: Nick Hilliard <nick@foobar.org>
Cc: "nanog@nanog.org" <nanog@nanog.org>> Slightly old news, but it looks like Cogent depeered ESnet last week:
>
>>
>> http://www.es.net/news-and-publications/esnet-news/2011/important-statu
>> s-announcement-regarding-cogent-connectivity/
>
> Current traceroutes indicate that ESnet is reaching Cogent via
> 6939_1299.
>
> In other news, automatically dropping interconnects at around the time
> of your HQ's close of business while your peering co-ordinator is on
> vacation seems to be the new gold standard.
>
> NickI suppose the moral of the story is: "never single-home to Cogent"
Anybody got draft language for a SLA clause that requires routing 'at least
one hop _past_ the provider's network edge' for every AS visible at major
public peering points and/or LookingGlass sites?
<*EVIL* grin>
This is relevant to my interests. I'd love to sneak this into an RFP.
-cjp
*every* ASN? Oh my. 
I would qualify that a bit to say "every ASN available at every
peering point at which the provider appears". So if the provider
appears at an Equinix peering point, there is no excuse for not
providing connectivity to every other ASN also at that same peering
point by some means. Cogent seems to want to play a game where they
not only don't want to peer directly with a number of networks, they
also don't want to use any transit to reach those with which it
doesn't peer, forcing the other side to use transit to reach them.
Interesting gamble but probably not providing the intended result. It
just ends up selling transit to the competition as people multi-home
instead of being single-homed to Cogent.
Cogent probably is the single largest seller of competitors' services.
Many people are interested in things like end-to-end performance, or global connectivity. However, one must be careful how such an SLA is written. No network wants to guarantee performance or even simple connectivity to gear they do not own / control. (Well, almost no one. I know at least one company that does, but they don't sell "transit" per-se.)
Put another way, how do you write this such that my competitor cannot cause me to go bankrupt with SLA credits?
Some simple things spring to mind, such as: "Do substantially all prefixes appear in the table handed to BGP customers?" (Lawyers can fight over "substantially all". 
But is that really enough? Having a prefix in the table means nothing, if the path is over a cable modem in Sri Lanka. And the reverse, my prefixes appearing in other networks' tables, is under the control of my competitors.
I'm not saying it is impossible. I'm saying be careful.
Likely economic pressure is more productive, i.e. vote with your wallet. Unfortunately, on the Internet, we have a history of doing the opposite. When Sprint literally disconnected from some parts of the 'Net with ACL 112, people intentionally bought from Sprint to ensure they could reach the entire Internet. When InternetMCI couldn't connect to an exchange without packet loss to save its life, people intentionally bought from InternetMCI to avoid the congestion. Etc., etc. What did we think these networks would do when we literally paid them for their faults?
Worse, if there is a network who will not peer, and a network who will, most people buy from the non-peering network. The result of this is more networks want to close down peering, fewer want to open it up. Seems counter-productive to me, and trivially easy to fix. For instance, make peering a requirement of transit purchases. Of course, there would be other requirements (still need to run a good network, 24/7 NOC, fair pricing, yadda, yadda), but it uses financial incentives to promote the activities we want, not the opposite.
Perhaps it is time we stopped enabling - rewarding! - the very networks & behaviors most of want to change?
From georgeb@gmail.com Sun Jun 19 17:48:31 2011
Date: Sun, 19 Jun 2011 15:48:32 -0700
Subject: Re: Cogent depeers ESnet
From: "George B." <georgeb@gmail.com>
To: Valdis.Kletnieks@vt.edu
Cc: Robert Bonomi <bonomi@mail.r-bonomi.com>, nanog@nanog.org>
>> Anybody got draft language for a SLA clause that requires routing 'at
>> least one hop _past_ the provider's network edge' for every AS visible
>> at major public peering points and/or LookingGlass sites?
>
> *every* ASN? Oh my.
No, not an *unqualified* "every ASN".
Merely every one that is 'publicly visible' at any 'signficiant' point on
the network. <*GRIN*>
I would qualify that a bit to say "every ASN available at every peering
point at which the provider appears".
I wrote it the way I did, because I expressly did not want that loophole.
If a provider claims they provide 'complete' Internet acess, the idea is
to require _complete_ access.
The moral is multihome. It gets real old hearing people whine that they're losing $XXX,XXX.XX per hour, minute, whatever, when their internet access fails...but they spend some tiny fraction (like 1% or a lot less) of that per month on a single internet connection. If your business depends on internet connectivity, and that much $ is at stake, you're stupid if you don't have some redundancy. Nothing works all the time forever.
I can't consider Cogent even a redundant link, since I need two other
upstreams to reach the Internet redundantly.
-cjp
internet connectivity, and that much $ is at stake, you're stupid if you don't have some redundancy. Nothing works all the time forever.
I can't consider Cogent even a redundant link, since I need two other
upstreams to reach the Internet redundantly.-cjp
Well, they aren't someone you can take a default route from (either
ipv4 or ipv6), that's for sure. So yeah, could use them if taking
full routes.
