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Internet Partitioning - Cogent vs Level 3?
slashmicah asks: "Internet partitioning and Tier 1 ISPs are something most people don't know much about (myself included). Today, however, some Slashdot readers might have run into some issues involving these two topics. Cogent Communications and Level 3, both Tier 1 ISPs, are apparently having some 'undisclosed' disagreements, causing an Internet partition by turning-off or deactivating their peering point. Cogent Co. has released a statement explaining their side of the problem, however they have no mention of when the problem will be fixed, or when they will sort it out. This partitioning is a problem because any [single-homed] computers that are connected through Cogent Co, can not connect to [single-homed] computers connected through Level 3. Having spent all day sorting out this problem, I ask Slashdot: Isn't there a better way that the issue of peering can be handled/regulated? If not, does the future hold a scenario in which the Internet is split into several separate networks, only to be connected at the whims of large corporations?"
"Recently, certain peers have been disconnected from their direct connection to the Level 3 IP network. Some disconnected peers may elect to block access to certain IP addresses as a result of the disconnection. If a peer elects not to restore connectivity to the Level 3 network through alternative means, customers seeking continued access to the Level 3 network should make alternate arrangements."
They're saying Cogent is intentionally not advertising routes to them via other providers, presumably because they're upset about not having a peering agreement in place. Anyone affected by this presumably needs to harass Cogent.
http://ws.arin.net/whois?queryinput=AS174
First, I think that Level-3 is within it's legal rights in terms of dealing with Cogent, but is probably in trouble with it's customers. I am a customer of Level-3 and of Cogent (in the same facility). When I buy IP transit from Level-3, I am not buying "part of the internet". This peering issue places 45+ Million IP addresses out of reach of the Level-3 network (and vice versa). Level-3 did not notify me that they were making this type of change. There is nothing on Level-3's website that even implies that everything is not hunky dory. If you buy a Level-3 line today, will they disclose to you that you are not connecting to the entire internet. I know I am being a little niave here, but not disclosing such a large change of policy is unconscionable.
Second, it is dishonest for Level-3 to blame Cogent for this exclusively. Level-3 had a peering arrangement with Cogent for a long time. If you look at Level-3's interconnection policy page:
http://www.level3.com/1511.html
It still looks like Cogent and Level-3 could peer under these terms. It was Level-3 that pulled the plug, not Cogent.
What is really annoying is that this is only traffic from Level-3 to Cogent, not to other parts of the internet. Level-3 wants money for Cogent customers to connect to Level-3's network but does not understand that this is a two-way connection and that Cogent's customers and Level-3's customer both benefit from this equally.
Up until this point, I was very happy with Level-3. They run an excellent network and I pay top-dollar to be on it. This blatent disregard for the impact on their customers is a diservice to their customers, to their reputation, and only begs for regulation.
The short version goes something like this:
.. well .. you get what happened today (I'm making an educated guess here based on what I know of the two carriers involved). A decides that spending 30 grand a month for what is a very lopsided bandwidth agreement is no longer economically feasible or reasonable. They go to B and say 'look, we're not doing this anymore, we're basically paying a hell of a lot of money every month for you to send a ton of traffic to us, and we don't send much of anything to you. You can either pay for all (or some larger portion of) the circuits, pony up some $$ per megabit, or we'll just cut it off at the stub and be done.'
Provider A and Provider B peer, be it public or private, normally they do this in several places and alternate who pays for the circuit, etc. Now, under normal circumstances, they both push enough traffic from one to the other to justify this mutual payment plan. However, in some cases, you find that B is either intentionally dumping traffic into A thinking A won't notice, or A discovers that its sending so little traffic to B in comparison to the amount B is sending to A that its not worth the continued cost.
When the first sort of thing happens, it usually gets resolved -REALLY- quick, that sort of behavior is not tolerated and will result in B getting de-peered by A (and potentially others once the abusive behavior is discovered and known) exceptionally quick unless B can show that it wasn't done knowingly or intentionally.
When the second instance happens
Based on Cogent's 'oh poor us' post from this morning, I'm leaning towards them having given L3 the finger when L3 said 'look, this isn't equitable, we're going to have to re-arrange the money'.
YMMV of course, but I'm betting I'm not terribly far off.
As a cogent customer, it's *really* not their fault, IMHO. I gather L3 pulled the same stunt with XO last week.
Yeah, Level 3 is really out of line in my opinion. It's not that they shut down the peering link. That wouldn't be that big of a deal. The traffic would just flow through other providers on less efficient routes. It's not as though every single backbone carrier peers with every other. But I just checked my BGP sessions, and Level 3 is not advertising the Cogent route at all. And you know for a fact that Level 3 is receiving the Cogent route from many of it's other peers. But it appears that they are intentionally filtering out the Cogent route. Which is pretty much not playing by the rules. It's one thing to shut down a peering agreement. It's something else entirely to refuse to accept that route from any of your other peers.
Anyone want to explain for those of us that don't get it?
What they are essentially saying is: "We haven't done anything. We haven't made any changes on our side" Level 3 have terminated their connection to Cogent "Without cause". Now, that's probably legal speak on Cogent's side for we haven't got the letter in triplicate yet telling us what the reason is. Or otherwise whoever put up the notification about it doesn't know.
Now, Cogent may have tried to change the peering arrangement, or Level 3 may have too, one side probably didn't agree, or otherwise an agreement ran out and the switch got flipped. This has happened previously with Cogent in their peering arrangement with AOL.
What Cogent are trying to do is get business from Level 3 customers because Level 3 stopped the connection. Cogent is offering them connections to the Cogent network (And subsequently Cogent's customers) for a year with no fee on the amount of data they put through. That connection itself they will obviously have to pay for, but the customer can connect into (presumably) the closest of any of 1000 points across North America and Europe.
Now some people are already connected to both Cogent and Level 3. These people won't have any problems as they will be able to go direct into either ISP. These people would probably have never have used the interconnect between Cogent and Level 3 either, unless one of their connections into either Cogent or Level 3 went down.
I understand this is still rather technical, for a simpler version, take a look through the document that I linked to.
Curiosity was framed; ignorance killed the cat. -- Author unknown
The Internet is a power law network, meaning there are some very well-connected routers out there that a lot of the end-to-end transfers through the Internet go through. These are typically the peering points, owned by Tier 1 ISPs. It's not inconceiveable that if two ISPs don't peer with each other anymore, at some level a partition is created.
When Paul Baran had the task of designing a network that could withstand a nuclear attack, he envisioned a "distributed network". By today's lingo, it's a mesh network where each router is connected to approximately the same number of other routers. But now that routing infrastructure is driven commercially, with tit-for-tat contracts between Tier 1 ISPs, we ended up with what he said was a "decentralized network" -- that is, power law. Not what Paul Baran had in mind. If the underlying topology were his distributed network, you wouldn't be reading this story.
You can read his paper here. The Internet could withstand one nuclear attack. Several well-placed nuclear attacks? That's debatable...
- shadowmatter
Level 3 is not advertising the Cogent route at all.
I'd bet L3's argument is that they will not provide transit across their AS to Cogent. It's a play that's been made several times before. The first time I know of it being done was in 1995 when Sean Doran pulled this at the CIX-W router, preferring to take commercial traffic via NSFNET or Sprint reseller service. Not only didn't it work, but it caused some immediate political backlash as Sean's action (presumably made without his boss's approval, who was the chairman of the CIX board and took some political grief for Sean's latest stunt) caused several state's to literally drop off the map.
If my memory's right, I think this got pulled again around 1998 timeframe on Exodus by someone like Genuity (I may be wrong about the culprit), only for the higher ups at the culprit to discover they couldn't see half of the world's worthwhile websites and search engines. Much of this was in the transit battle - e.g. if you had consumers, you felt your eyeballs were the value of the Internet and all other ISPs should pay you to get to your consumers, while if you were a content provider, you had the stuff all those consumers were paying their ISP to get to and someone had better pay you for that content.
What can you do about it? Let your ISP know you're not paying them for 80% of the Internet. When UUNET considered pulling this stunt around 1997, I worked for a small software shop that had a couple bonded UUNET T1's and we let them know we were going to drop them the moment they were only selling partial Internet. Then follow through if they do (UUNET backed off). Bilateral agreements are weird things in the world of settlement-free IP exchange, so unless you want a settlement-driven Internet (which will have unusual effects you might not want, like driving a per-packet pricing model), just expect this occasionally and drop those who don't play well with others. When L3 drops customer base, even the Denver boys will figure out their customers aren't happy.
*scoove*
I worked there and its a deathmarch shop for IT and network people; they treat their peopel like crap, and leaving there was the best thing I ever did.
The arrogance of Jim Crowe [workign on his 7th manion and 8th large layoff at Level 3] and Kevin O'Hara (President, CEO) is only matched by the jailbird Bernie Ebbers. They only reason they have yet to decalre bankruptcy and liquidate thier debt (and clear away their bad business model with a fresh debt-free start) is that all their Omaha cronies have tied up money in the company stock, which would be flushed.
That they would resort to stunts like this against companies that undermine their pricing is not surprising. Level 3 have amassed BILLIONS in debt that they cannot service at current pricing levels, while Cogent and other more nimble competitors can sustain operations and drain Level3 into bankruptcy. So Level 3 execs do what arrogant desperate people do: lash out.
Level 3 is playing the "Sampson" card - if they cant make people price it their way, they will take the internet down with them.
And they did this trying to kill XO and now Cogent. Watch for more until they finally admit their business model is a failed one, and they declare bankruptcy, wipe the debt, and then begin to price lower and rake in the profits that their debt service is now eating.
I work for Time Warner Cable and we use Level 3. I can't talk about the details of what's going on but the notes on the ticket opened for this issue and the conference call/bridge have covered alot. Alot of people in high up positions are working for find us a work around until a solution can be found. Level 3 is still routing traffic TO Cogent but they are not routing it back at this time. I was working on this issue all night. My suprise to come home and find it on Slashdot. I sure hope they can come to some kind of agreement soon (contract was terminated at 5:30am 10/5/05) but from what's been said thus far it's not looking like it's going to be a quick fix.