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Behind the Cogent-Sprint Depeering
An anonymous reader brings an update to Sprint's depeering with Cogent, which we discussed a few days back — namely, Sprint's side of the story. According to them, no free peering contract had ever existed, Cogent refused to pay the bills to exchange traffic, and after a year Sprint gave Cogent 30 days notice of their intent to disconnect. During this 30-day period, when one or two connections (out of ten) per week were shut down, Cogent made no alternate arrangements to alleviate the impact on their customers — but they had a press release ready when Sprint snipped the final wire. It will be interesting to see how Cogent responds.
First it's not just single homed connections that suffer, due to cost many multihomed systems have such a large weighting to Cogent that they won't use the other connection unless the physical route to Cogent is down (I know that's stupid but it's the real world). Also the peering contracts Cogent has with their other peers might not allow for transit traffic and further those contracts are probably enforced through ACL's that would drop the traffic into the bit bucket anyways.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Cogent press release: "Sprint [severed its Internet connection to Cogent] in violation of a contractual obligation to exchange traffic with Cogent on a settlement free peering basis."
FACT: At no time did Sprint and Cogent enter into a contract for settlement free peering. In 2006, Sprint and Cogent formed a commercial trial agreement that ended in September 2007. Cogent was unable to satisfy the agreed-upon traffic exchange criteria within the trial agreement, yet refused to pay Sprint or disconnect from Sprint's network.
If what Sprint says is true, Cogent has just dug itself a hole and not just in the court room.
Either there was a settlement free peering contract in place, or there wasn't.
Cogent can spin all it wants, but they aren't actually supposed to lie in a press release.
Cogent's press release would definitely constitute a material statement, which means they could be hearing from the SEC for lying to the public and investors.
[Fuck Beta]
o0t!
My lay understanding of the situatin is that, once routing tables are changed to reflect the new topography, most everything goes back to normal
My just as lay understanding is that that would be the case were Sprint not actively filtering routes from Cogent.
In other words, assuming I understand the situation right, Sprint are taking active measures to make sure that routes that originate in the Cogent network never reach Sprint's customers.
Cogent could have, at any time during this depeering, allowed the sprint bound traffic to route through one of their other peering points. This would have allowed their customers, including yourself, to continue to reach the entire internet even though it may have been slightly slower. It's the beauty of the internet, they could have easily routed the traffic elsewhere but they CHOSE to route sprint to a blackhole route.
http://internetpulse.net/ .. Are they connected again? The traffic is flowing.
-- these are only opinions and they might not be mine.
I think you mean the other way around; Cogent filtered AS1239 paths, blamed Sprint, and offered Sprint customers free circuits. Cogent customers were still visible via XO through Sprint during this mess, but Cogent filtered the traffic.
Uh, because Sprint gave them a free trial then they refused to pay for over a year after they were notified they did not meet free peering requirements? How long can you not pay your bills before you get cut off?
Sprint did not cut off their customers; I am a Sprint customer who gets a full BGP table. I could still see Cogent and their customers through XO, but Cogent was dropping return traffic into a black hole.
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Settlement free peering usually means both parties exchange roughly equal amounts of data. If it's lopsided one way or the other, then they wouldn't qualify in the traditional sense.
this is my sig
As others have noted Sprint was routing Cogent traffic through XO, but Cogent was blackholing the return traffic. Had they updated their BGP the return traffic would have flowed and the end customers would have been unaffected.
This is not accurate.
When you peer with another network, it goes like this:
1) you only exchange routes for your customers.
2) Your routes should not be visible to the peer through any other transit or peering connections.
So if Sprint and Cogent were just exchanging routes and the peer session was removed, Cogent and Sprint no longer see each other. For them to see each other again to happen, one of them would have to pay someone else for the transit.
Sprint is not going to pay for transit. Cogent doesn't want to, or apparently, they don't even want to to do settlement based peering.
Regulation might be ok if it opened the tier 1 peering to more networks. Forcing large networks to peer with much smaller network is shifting the cost of transporting that traffic long distances to the larger network.
Equal size networks setting up connections in multiple locations should have the same benefit and cost to both networks.
The summary misses a key point: Sprint has restored its connection to Cogent, meaning the two companies can pursue their lawsuit and grievances without using customers as bargaining chips.
It's common for many smaller ISPs (around here, at least) to start out with a Cogent link until they're large enough to be able to afford being multi-homed. And some of the smaller ISPs offer excellent service, despite being single-homed.
Of course, most of these companies DO throw other providers into the mix as soon as they have enough traffic to be able to make a sufficiently large commit to the second provider to not get charged through the nose per-megabit. But everybody has gotta start somewhere, right?
I was lucky throughout this. As a consumer, my ISP is multihomed, having a Cogent link, but also numerous others. There were no connectivity issues there. As a server admin, my host is single-homed with Cogent. They have some other peering going on, but not for transit.
Of course, I don't care if my server host is single-homed; similar to my ISP example above, they provide quite good service at dirt-cheap prices (and it's a non-critical server). They're an example of a company not large enough to be able to justify going multihomed, although I know it's in the cards eventually.
Not to mention that they knew the depeering was imminent, and apparently did not attempt to inform their customers.
Please stand clear of the doors, por favor mantenganse alejado de las puertas
Multihoming doesn't fix the problem. It does double your costs.
For example, I know one site that was multi-homed. They had Sprint and a regional provider. The regional provider was de-peered by Cogent about a year ago, and the regional provider only buys transit from Sprint (they peer with many other networks).
Guess what, he couldn't reach the University he just executed a major contract with -- they are single-homed through Cogent.
And what do end users do? Multihome?
It may help people to think of it on a personal level: So suppose you and I are neighbors. I have a nice business class cable connection, you have a nice business class DSL connection. Now turns out we do a lot of traffic between each other, which doesn't go particularly fast since it goes over the net but also since it turns out our connections are routed very differently and have a lot if hops to get to each other. So being geeks, we decide to fix this by peering our networks. We connect up a Cat-5 connection between our houses and set up routers to handle things. What's more, we share each other's net. So traffic goes out the connection based on who's got the shortest route. Also if one connection goes out, we use the other one exclusively till it comes back up.
Now we don't charge each other for this service. We both pay our own costs. I pay for my line, you pay for yours and so on. Hence we are peers. The reason we do this is we both benefit equally form the relationship.
Ok so then another neighbor finds out about this. He's on dialup and would like something better. We say sure you can join our network, but you have to pay. Why? Well he isn't providing us any value. He's just going to cancel his dialup and use our network. That's great, but he's got to help with the costs. Also, he doesn't have anything we want, we aren't going to be accessing his files, so there is no peer situation. We sell him access.
In the case of Cogent it would be like a 4th neighbor. He asks to peer. He says he's got a wireless connection to a great provider, plus lots of stuff we'd want. So we decide to let him on as a peer. However, it turns out to be false. His link is slow and high latency, so we end up just using ours. Further he just uses our connections, since they are better for everything. Finally, we find little data from him we want. So we tell him "Know what? You can pay us to stay on our network, but we aren't letting you peer because we don't get anything out of it."
The idea of peering is just that: You connect to your peers, you equals. Those networks that have data you want, and you have data they want. Since it is an equal agreement, both sides bear their own costs. In unequal agreements, like you purchasing a connection from your ISP, then you have to pay.
There were no routes between Sprint and Cogent, which means anyone who only reached Cogent via Sprint and vice versa (including anyone who was single-homed to either) could not reach the other. IIRC, it was about 210 ASes on one side, 270 ASes on the other.
You've officially missed the point of the settlement-free peering trial. As mentioned in TFA, it is only beneficial to both parties in a settlement-free peering agreement if the amount of traffic passed between the two networks is almost equal.
After 3 months, the traffic from Cogent wasn't as much as Cogent claimed it would be, and Sprint opted not to continue with the creation of a real settlement-free peering contract.
Nobody pulled out of anything, Cogent claimed their network passed more traffic than it really did and Sprint had no motivation to let them leech for free.
This isn't about Sprint charging Cogent for the 3-month trial; it's about Cogent freeloading for nearly a year AFTER the trial expired despite repeated warnings of a disconnection.
It's what your network does, over all. A datacentre still pays for all their bandwidth. It isn't a situation of "consumers pay, providers don't." What it comes down to is if it is more advantageous to trade with someone, rather than both of you going through a third party. Remember you can peer on any level. My neighborhood peering thing could be a reality, if people wanted to do so. As a practical matter I work for a university and we do peer with some institutions.
Basically it's a situation of how much data you need to get to and from network X, and how much it costs you and them to do so. If you are both going through another company, especially if you both have to pay that company, it may be in your best interests to peer your networks. However peering isn't free, you are paying for equipment and space and rights of way and such so that you can hook your networks together. So this is only worth it if the sharing is on equal ground. If it turns out that it isn't, well then maybe one side needs to pay.
Part of the equality thing isn't just direction of traffic, it is destination. If we peer our connections, as in my example, and 95% of the traffic you get from me is stuff on my network, well that's a useful peer to me. I cut down on my traffic to other networks, and you do the same. However if 95% of the traffic is in fact destined for other networks, then you are leeching off me, and should be paying. It isn't a useful peer if what you are doing is using that link just to get to other places. That just loads down my other links.
So that's how it works. The big networks peer with each other because they all have a lot of traffic that needs to flow to each other. It would be silly for AT&T to send all traffic for Sprint through Level 3, rather they just connect themselves and do it direct. The same thing can be true of smaller peers. Company A and Company B realize they do a lot of traffic, and thus setup a little peer network so they aren't loading up their Internet connections. However that only works when it is an equal share situation. If Sprint were to use AT&T's links mainly to contact other networks (especially large networks), AT&T would want to start charging for the links. Same deal if Company B jsut starts using the link to use Company A's bandwidth.
That would be the case with most normal isp's but Cogent purchased enough ISP's in the last few years to now be considered Tier 1. They do not purchase bandwidth from anyone. If I remember correctly they purchased Verio giving them the peering agreement with AOL/TW. They do not block the traffic to the sprint network, they just don't have any transit agreements in place. (they peer with every other Tier 1 provider) Having a transit agreement in place would make them Tier 2 and they would probably have Tier 1 providers disconnecting from them left and right. (because it wouldn't affect their customers, traffic would re-route to the transit provider)
The Tier 1 providers hate them because they brought the price of bandwidth down so low that the market had to follow.
Its just a way for the PHB's tp assign a metric to a connection.
If my customers want to see stuff on your network more then your clients want to see stuff on mine.
It's not an ego issue, it's about maintaining Tier1 status. As soon as you enter into a transit agreement or are paying someone for peering, you are not a Tier1 backbone provider. Sprint is the big dog here, and Cogent is just trying to push people around.
/toph