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Level 3 Peering Changes Causing Headaches
Roadrunner, Cogent users unable to hit major sites
by Karl Bode 04:18PM Wednesday Oct 05 2005
Both Roadrunner and Cogent users are complaining about a level 3 decision to turn off public peering with Cogent, likely because of an ongoing peering and contract spat. As a result, many broadband users can't hit websites such as Photo Bucket or The Drudge Report. Customers who call in for support are being told that the network partners are working on a resolution, but aren't given an ETA.

Some additional information is available on the NANOG newsgroup, where Cogent is blaming Level3, and Level3 is blaming Cogent. The official statement from Cogent:
"As of 5:30 am EDT, October 5th, Level(3) terminated peering with Cogent without cause (as permitted under its peering agreement with Cogent) even though both Cogent and Level(3) remained in full compliance with the previously existing interconnection agreement. Cogent has left the peering circuits open in the hope that Level(3) will change its mind and allow traffic to be exchanged between our networks. We are extending a special offering to single homed Level 3 customers.

Cogent will offer any Level 3 customer, who is single homed to the Level 3 network on the date of this notice, one year of full Internet transit free of charge at the same bandwidth currently being supplied by Level 3. Cogent will provide this connectivity in over 1,000 locations throughout North America and Europe.
However a large number of users heap the blame for the cutoff squarely in the lap of Cogent, who has a bit of a sketchy history when it comes to peering arrangements. One of our users hits it cleanly on the head.

177 comments .. click to read

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Jim Lippard

2 recommendations

reply to JoeShmoMe

Re: Did anyone not see this comming?

"The fact remains though that Level3 shutdown all traffic to AS174, Cogent. If a hacker had gone in and did such you can guarantee they would be looking at jail time.

To shut down part of the Internet should have major reprecussions and I hope Level3 suffers for it. This is a major impact to US Businesses."

Level 3 shut down the free peering connection to Cogent, after over a month's notice. Cogent is still trying to route all Level 3 traffic over that free peering connection, instead of routing it over a link to an IP transit provider that has reachability to Level 3. Cogent has such IP transit provider links, on which they are filtering Level 3's routes. If Cogent removes those filters, their customers will be able to reach Level 3, but Cogent's expenses will go up because that's a connection they have to pay for.


2 recommendations

reply to insomniac84
said by "insomniac84" :
Maybe cogent should start hosting high traffic webpages cheaply. That should turn around their deficit.
Actually, that's a very astute observation. My observation is that there seems to be a fairly direct analog between money (trade) and bandwidth (trade). So in essence, there is a "trade deficit" (of bandwidth) going on here, and the other parties have decided to institute an embargo (of bandwidth, not of trade). In the history of nations, such things have precedent - but it's very interesting to see that analogy extended to major ISPs/carriers and bandwidth. I guess bandwidth is truely the currency of the "new information economy".

If that is true, then in a sense, the US (with poorer home broadband options than say, Korea or Japen) is a "poor" nation compared to other nations which offer higher bandwidth. You could say that the bandwidth-per-capita is higher in those other countries than in ours.

An interesting metric to be sure, but I think it's accurate. Bandwidth allows you to do things, and more bandwidth allows you to do things that you weren't previously capable of doing - just like money.

If you live below the poverty line (1Mbit/sec broadband being roughly that line), then there are certain online activities that you cannot even contemplate using. But if you have mega-bandwidth (think Internet2, the playground of the "bandwidth-rich elite"), then they are able to experience online activities that most of us can only dream of. (Live multi-screen video-wall projection rooms, for distance-learning application, for example. To think nothing of how that could revolutionize "listening" to music videos and MTV.)

It's also interesting to hear about the WiFi free internet (bandwidth) being talked about deployed in SanFran - essentially, it's "bandwidth welfare", of a sort, but information-connectedness is now starting to be an essential and crucial component of modern living. The Internet has replaced both phone and television for many people.

It's time to start understanding bandwidth for what it truely is - the currency in trade of the new information economy. Bandwidth is power.

I know your IP address
Foothill Ranch, CA

2 recommendations

reply to gamepro100

Re: Not Cogent's Fault...

said by gamepro100:

I really don't see how this is cogent's fault.
That's because you don't understand how the internet works: let's have a little lesson in peering.

There are two broad arrangements - peering and transit - (with plenty of variants), but they don't look anything like each other.

Transit is paying an ISP to deliver your traffic to some other place on the internet, and they take responsibility for getting it there. They carry over their own links, and eventually hand off to some other party if necessary. You pay for all traffic you give them, and they don't care who you're sending it to.

Peering is the non-settled ("free") exchanging of traffic to mutual customers only, and it normally is only negotiated between rough equals. Little guys will peer with anybody, but the big guys are very hard to peer with. You have to do a certain amount of traffic with them (hundreds of megabits per second), have certain in-vs-out ratios, and often require geographic diversity.

Everybody wants to peer, and it's been observed that peering requests often turn into sales calls offering to sell transit. If you've ever been a (paid) transit customer, you'll never be considered for (free) peering.

Peering arrangements exchange traffic only for mutual customers: two ISPs plug their routers into each other, advertise routes of their own customers, and send traffic to the other guy's customres. Peering traffic should not generally leave either of the two networks - it's strictly internal stuff.

But if I'm sneaky, I'll send other traffic to Level(3) too, making them figure out how to deliver it to other networks of non-customers. This way I get not only the benfit of peering with Level(3), by making them deliver to non-customers, I'm effectively stealing their transit.

This is absolutely against peering agreements (aka "contracts"), and NANOG is full of rumors that Cogent was doing just that, and has done it before. It doesn't take that much netflow analysis to figure out that a peer is sending you traffic they shouldn't, and I'd imagine there are procedures for asking a peer to cut it out.

From what I understand, it all revolves around whether Cogent was doing this or not. They certainly seem to qualify for peering on the usual terms - geographic diversity, volume of traffic - so it's a matter of whether they were getting transit on the sly.

Transit at their kinds of volumes is very expensive (even though the cost/mb drops), and it's no surprise that a bottom-of-the-barrel ISP like Cogent might want to engage in this kind of thing.

If Cogent was doing this - stealing transit - then L3 was absolutely right to cut them off. If they weren't doing this, then maybe Level(3) is trying to bully a peer into becoming a transit customer. I just don't know which is which, but we're all entitled to our suspicions.

Stephen J. Friedl • Unix Wizard • Microsoft Security MVP • Tustin, California USA • my web site


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reply to Chris3Duncan

Re: Peering points cost $$$$ ...

said by Chris3Duncan :

Can anyone give a list of big name hosts that are with cogent? It would be good from a customer service perspective to show clients its not a hosting providers problem rather their ISP / upstream
Anybody who gets bandwidth solely from Cogent is not marking himself as one who really cares much about connectivity or reliability.
Stephen J. Friedl • Unix Wizard • Microsoft Security MVP • Tustin, California USA • my web site


Richland, WA

1 edit

2 recommendations

Did anyone not see this comming?

Peering is the very basis of the Internet. Peering works because big ISPs (AT&T, Level3, UUnet, Sprint, etc) have to exchange traffic, and on average they end up trading equal amounts of bandwidth. AT&T takes on traffic from Sprint's network in about the same amount that Sprint takes on traffic from AT&Ts network. Thus everyone's happy.

Cogent has a long history of peering issues. Because Cogent is "cheap" bandwidth, they end up sending a lot more traffic onto other's networks and take less traffic off other's networks. It just the nature of their customers (1000mbit unmetered for just a few grand a month).

So it makes sense that Level3 wants Cogent to pay for the level of bandwidth "mis-match" so to say. But Cogent has all these peering agreements that really screw the other Tier-1 ISPs over. This was bound to happen sooner or later.