Cogent Becomes Transit-Free

September 25, 2014 Todd Underwood

Cogent (AS174) has established a direct connection to the America Online Transit Data Network (ATDN) (AS1668). This long-awaited connection completes Cogent’s effort to directly connect with every transit-free network in the world and qualifies them, for the first time, as being transit-free.

In one sense, this is an unsurprising event. ATDN has been shrinking its transit network for some time in order to focus on their revenue-producing ad business. AOL/Time Warner has been selling off their European access networks since 2006. At the same time, Cogent has been adding customers and growing and peering. So that these two networks would eventually connect (re-connect) is unsurprising.

But the history between these two organizations is textured and murky. This connection is particularly interesting in part because of this history. It’s also interesting because of how different these two networks are, in almost every respect: history, revenues, business model, culture, brand. I’ll take a look at where Cogent is, the history between Cogent and AOL, and what this all might mean for the Internet.

This is the next major step in the maturation of Cogent as a network and as a business. Last year we wrote about Cogent depeering smaller networks in Europe and referred to it as the early adulthood of the network. If depeering Datahop, Entanet and Telecomplete was Cogent as a teenager, peering with ATDN is Cogent all grown up. At this point, Cogent have graduated university, secured a reasonable job, moved out of their parents’ basement, and rented an apartment downtown. Let’s take a deeper look at what happened, and when it happened, and get some context on the history of these two organizations from people who know it well.

This story goes back to the dark ages of the Internet and a company called PSINet. This isn’t just stupid Internet history from some obnoxious Internet graybeard. It’ll matter in just a second. Trust me. Just go with it. As I was saying before I so rudely interrupted myself, PSINet was one of the first commercial Internet service providers. They had a crazy heyday of growth and acquisition in the late 1990s, but by early 2001 they were in complete disarray and collapsed. Cogent bought what was left (including the Autonomous System Number 174) in 2002.

PSINet had some decent peering. (Learn more about how peering works if you’re fuzzy on any of the details). But if you weren’t involved in the Internet back in those days, you might not know that good peering wasn’t as important then as it is now. According to former AOL Global Peering Manager Dan Golding, PSINet and AOL had peering that went back several years, but in 2000 PSINet chose to terminate this peering, for whatever reason. AOL didn’t take the event too seriously, filing away the letter in a correspondence folder and moving on with their lives. In 2000 AOL wasn’t serious about becoming a transit-free network yet, so peering didn’t matter. Says Golding: “At that point peering was just something nice to have. It didn’t matter that much.”

Fast-forward to 2002. Cogent buys PSINet and independently turns up a new test peering with AOL. According to Golding, the test didn’t go so well. The main problem was ratios. Cogent was just sending AOL way more traffic than AOL was sending Cogent. By 2002, AOL was serious about peering and Cogent didn’t meet the requirements, so the trial was turned down.

Cogent chose to try to bully AOL into peering. According to Golding, at the time Cogent was buying transit from Abovenet (AS6461). There is some debate on this issue from people that I’ve talked who were involved at the time, but routing data from Renesys at the time seem to confirm this. At the time, Cogent was still using AS16631. Back in 2002, we see paths such as:

  • <omitted> 16631 6461 701 22358
  • <omitted>16631 6461 2914 22921
  • <omitted> 20473 16631 6461 1239 11859
  • <omitted> 19406 16631 6461 209 22132
  • <omitted> 13331 16631 6461 1239 14770

These clearly look like Cogent (AS16631) getting transit from Abovenet (AS6461) to get to UUNet (AS701), Verio (AS2914), Sprint (AS1239) and Qwest (AS209). So yes, at Renesys we have routing data going back to 2002. And yes, it’s useful. Since Cogent was buying from Abovenet and AOL was peering with them, there should have been a path between the two. Moreover, AOL was buying transit from Level 3 (AS3356) with whom Cogent had a peering relationship. Despite these two possible paths, the Cogent/AOL depeering incident of 2002 was one of the Internet’s big partitions. It lasted for about a week and eventually turned into national news. Cogent seems to have a knack for getting into these high profile peering disputes that result in a partition of the Internet.

Golding recounts the tale: “[AOL] had transit through Level 3 at the time, but Cogent put communities in so that we would not see their routes through Level 3. Cogent told us that until we turned the peering back up they wouldn’t be reachable. There was nothing technically that we could do other than turn peering back up. The executive decision was made at AOL to not negotiate, and so we didn’t.”

Pretty straightforward and not a lot of love lost there, still. In the end Cogent caved and fixed the routing on their side and the Internet was once again made whole. So the stage is set. Big peering fight. Cogent wants AOL peering, they don’t get it, they break all their toys, they still don’t get it, they give up and go home. And ever since then, Cogent has been keeping at it, working their business plan and plugging away. They do things cheaply, but not necessarily badly. They have steadily grown, bought networks, integrated them, added customers and gotten more and better peering.

But that’s not what I came here to talk to you about. I came to talk about the draft. (Obligatory Alice’s Restaurant reference, without which no long tale would be complete.) No, really, I came to talk about what has happened since then.

As of Tuesday morning, Cogent was still buying a little bit of transit from NTT (AS2914) and only to get to AOL ATDN (AS1668). That all changed at 16:23:28 UTC on Tuesday, 24 June 2008 when the 1668_174 adjacency first appeared. Shortly thereafter we began to see a medium-sized handful (about 10) peering sessions from all over the world select routes on this edge. And we’ve been watching it ever since. This isn’t a leak, it’s not a fluke. It is up, seen by a bunch of people and stable for more than 24 hours now.

Interesting trivia: the first prefix that we see on this edge is 65.205.129.0/24, advertised by HBO Miami (AS36032), and sent to us by one of our peering sessions in the Netherlands across the Amsterdam Internet Exchange. So Cogent’s access customers (a much smaller group than Cogent’s content customers) now have slightly better path to HBO Miami networks than they did previously. That can’t hurt.

This change leaves Cogent, for the first time, with no transit providers. This will negatively impact NTT (AS2914) in Renesys’s Market Intelligence rankings, because they were getting credit for providing Cogent transit to prefixes routed downstream to AOL. They will no longer be getting that credit. The new rankings should begin rolling out roughly at the time I publish this, and will fully phase in over the next month, provided this peering trial succeeds for Cogent. :-) Renesys Market Intelligence customers should go take a look at the rankings (sample global rankings are published for free for non-customers and we leak some other ones sometimes.)

This peering won’t really help Cogent’s Customer Base ranking at all, but it should continue the task of moving their network in the direction they’ve been heading all along: selling from the cheap seats and laughing all the way to the bank.

The post Cogent Becomes Transit-Free appeared first on Dyn Research.

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