Net Neutrality and the Core Network

Reading a tweet on Shamus Young’s site, I was directed to this youtube video by Vi Hart on Net Neutrality. And, in watching it, there are a few misconceptions in it that make sense from the perspective of someone who isn’t in a major ISP — meaning, the people who buy the hardware and maintain it to get all of that traffic from one place to another — but when you know what’s happening behind the scenes you can see that it isn’t quite right. Since I work in telecommunications myself — not at an ISP but at a company that supplies the ISPs, particularly in software that manages all of the equipment that you need to get traffic from one place to another — I thought I’d try to explain some of the things behind the scenes that I can do without, well, putting my job in jeopardy. Note that I don’t plan to say that major ISPs absolutely aren’t playing games in order to make more money, just to point out things that make the analysis and analogy misleading, and reasons why even ISPs that are playing things completely straight won’t like strict Net Neutrality.

The main analogy in the video is of a delivery company, delivering books. It starts by setting it up so that you have a person who is asking for delivery of books from two different companies, where one is from a chain bookstore and one is from a small bookstore. The chain bookstore ships a lot more things through them than the small bookstore, and at some point the delivery company says that the chain bookstore is shipping too much stuff so they’ll have to delay their deliveries while they still ship the book from the small bookstore — even if they’re going to the same person. It is then suggested that they just buy more delivery trucks, but this doesn’t appease them, and the company asks for more money from the chain bookstore instead, which is presented as being completely and totally unreasonable since, after all, isn’t it the case that the person buying more stuff or people buying more stuff brings them more business? Then why would they want more money on top of that?

And then it gets into all sorts of stuff about the FCC that I don’t know much about. But to explain how this ends up being misleading, I first want to talk about where the complaint is. The video talks about main roads and stuff like that, but it mainly talks about driveways, which would be the last bit of fibre from the main line to your house. It also talks about ISPs simply being able to run more cable (which is why this is limited to major ISPs that do lay cable as opposed to those that simply use the existing infrastructure) to solve the problem. All of this misses the point that the complaint is not about the edge of the network — ie the part directly attached to you — but is instead about the core of the network, which is what ships massive amounts of data between cities, across countries, and around the world.

So, let’s start there. Imagine that you have 100 units of bandwidth available for any application that wants to get its data to your customers. This bandwidth has to be shared amongst all applications, and if I understand Net Neutrality properly the idea is that all applications should, ideally, be treated the same. So, let’s say that we have 10 applications that want to use that bandwidth. Ideally, we’d want all of them to use 10 units each, because then the line is used to its full capacity and everyone still gets what they need when they need it. In practice, pretty much all applications will be “bursty” in some way, busier at some times than at others (and, of course, there won’t just be 10, but let’s live with that simplification for now). But that’s an ideal breakdown.

Now, imagine that one particular application starts getting more popular or bandwidth intensive, and so starts using more than its 10 units on a regular basis. Let’s say that it starts using 30 units. This is maintainable as long as everyone else isn’t using their 10 units, their bursts are at low-usage times, or the data isn’t critically time sensitive and so it can wait for a while if everything is busy. So, for example, E-mails and texts tend to be easily scalable this way because if they start putting out too much bandwidth and things get full, all that happens is that they get delayed for a few minutes or hours until things clear out, and most of the time few will really notice. Of course, separating out these cases immediately breaks strict Net Neutrality; we have to introduce the notion of priorities to know what traffic can be delayed for a bit and what has to be sent right now.

Which leads us to Netflix. Video and voice are incredibly high priority in a network, because for them to be useful you need to make sure that the next segment of video — a packet in IP — makes it there with a minimum of delay, at least relative to the last one you sent. If not, you get stuttering and a huge decrease in the quality of the service (in terms of the video, it gets “slow”), Voice, however, is fairly small, especially with all of the data compression that has been used for it over the past few decades (which is the main reason why TDM and ATM networks tended to find T1 level bandwidth acceptable for phone calls, with OC3 level required for their core, both of which as far as I can tell are very small today). Video, however, uses a lot of bandwidth, and it’s bandwidth that has to get there as quickly as possible and cannot be delayed without greatly affecting service.

So, going back to the example above, we have one application that can take up 30 to 50 units of our bandwidth — or possibly even more — and is also of the highest priority, so it will bump out everything else. Thus, what this risks — to return to the delivery truck analogy — that the chain bookstore will fill up all of the trucks so that the small bookstore simply can’t get their books delivered, and since this is in the core and not on the edge that would be true even if they were delivering to the same person. (Part of this is because at the core itself no one really knows where it’s going to end up, and since it’s servicing all customers and is trying to move between cities at times there’s no real sense in trying to figure out who the end user is. You’re trying to get the data to London at that point, not 123 Baker Street). And this is obviously not a good thing.

Now, the comment is that this is increasing the business for the ISP, so why can’t they analogously simply buy more trucks? In this specific case, why can’t they lay more cable? Well, in general, laying cable’s not that easy, but even then it’s not just about laying cable. The biggest part of the expansion is buying all of the switching equipment that figures out all of the important things like how to get the data to London and what traffic has to be sent now and what can wait. This equipment is not cheap, and each of these switches can only handle a certain amount of traffic itself before you need a new one. So there’s a significant amount of capital that you have to expend to expand the network, and to do that you have to believe that that expenditure will make you more money.

But wait, doesn’t the Netflix explosion make the ISPs more money? Well, not necessarily. For many if not most people, their ISP plans budget them get a certain rate of speed and a certain bandwidth and a certain usage in a month. While video uses up a ton of bandwidth, most of the time that’s in the rate they’re supposed to get … and if it isn’t, then at the edge they themselves are slowed down and the problem is solved for them. So most of their existing customers are already paying for enough bandwidth to watch videos, if they use all or most of it, and so won’t actually pay the ISP anymore unless they go on a splurge and have a limited plan … and if they notice this, then they’ll cut back once they hit their limit. That doesn’t stop people from all deciding to watch a great Netflix video all at the same time and flooding the core, and the ISP gets no more money from that than they are already getting. And the intermittent “Use it heavily until we hit our limit and then drop it” makes the expenditure worse because they might end up with an infrastructure that they need for two weeks out of a month and that doesn’t get used for the other two weeks … and they still didn’t get paid anymore for having it.

Thus, the idea of charging high-priority, high-bandwidth applications — again, video in general but Netflix in particular, perhaps — a fee to support an additional infrastructure in the core to get those applications the priority they need without screwing over everyone else. A gatekeeper at your driveway — as the video talked about when it talked about the fastlane — wouldn’t make sense because at that point they already have one. I don’t claim that ISPs aren’t putting one there, and I’d agree that that isn’t sane. What they can do is allocate out of their existing bandwidth a fastlane in the core, which would have a similar effect to the gatekeeper at the door but would ensure that the high-priority, high-bandwidth applications get what they need (as long as they pay for it), that other applications get what they need, and that they can tell when they need to add more infrastructure (ie either the smaller applications are still getting crowded out by themselves, or that those who are paying for the fastlane need more bandwidth to get the service that they’re paying for), all inside a structure where they actually do get more money the more these services come on-line. But to the end user, all they’d notice is that the site was getting slow or stuttery, which looks exactly the same as if there was a gatekeeper at the edge (or the driveway).

Look, I’m as cynical about big business as the next guy. I’m not here to praise nor bury the major ISPs. My goal here was to show the impact that services and applications like Netflix can have on a network, to show why maybe treating them differently isn’t so radical a notion after all. I mean, they would indeed want to be treated differently themselves because of how their traffic has to get there right away while E-mails and file transfers don’t, and so it’s also reasonable for ISPs to say that that — and the large bandwidth requirements — give them specific problems that they want to be able to resolve by treating them differently. At the end of the day, I’m not advocating for or against Net Neutrality or the ISPs “fastlane” ideas, but am instead just pointing out a technological issue from the other side that might have an impact on the discussion.