Network Neutrality and Quality of Service


There has been a lot of discussion about "network neutrality" as being a core property of internet service. This discussion includes a number of inter-related concepts, which not every advocate agrees to. In particular, the wikipedia article on the subject identifies:

"* Non-discrimination means that all traffic over the network (typically or exclusively digital packets or bits) is treated the same by the network, including the traffic originating with the network operator. This principle of 'bit parity' means that all bits are treated as 'just bits', and no bit traffic is prioritized over other bits, and none is hampered or disabled.

* Interconnection means that network operators have both a duty of interconnection and a right of interconnection to any other network operator. Networks must be constructed so that there are a reasonable number of accessible interconnect points; that traffic is carried to and from rival networks at reasonable rates; and that the network is built with sufficient excess capacity to accomodate the reasonably foreseeable traffic that may be presented at the head-ends or peering points. Without a right of interconnection, there is no network.

* Access means that any end user can connect to any other end-user. End users may be people, but the term could also mean devices (modems, routers, switches) or even other networks. Access means that a piece of content, say, an email message, has a right to enter the network, and if properly addressed, be received by the other end user, even if said user is on another network. In other words, traffic can begin at any point on the network and be delivered to any other point."

All of these have merits. One could argue that the ideas of access and inter-connection are in a sense constitutional (like Freedom of Speech). However, the idea of non-discrimination can learn from transportation.

"Free" (i.e. untolled) roads in the United States accept any vehicle on a first come-first serve basis, and do not charge any vehicle more for use of the network capacity at a given time (aside from the difference in gas utilization, and some extra taxes from trucks, which are not place or time specific). The consequence is congestion, over-use at peak times at particular places. Users are not paying for the congestion imposed on others. This would be merely wasteful if all users were identical. However users are not identical, some travel is more urgent than other, yet the urgent travel (excepting emergency vehicles) does not get priority.

The high occupancy vehicle lane was the first serious attempt at differentiating travel by value in post-Interstate America. First deployed on Shirley Highway in the Virginia suburbs of Washington, HOV lanes gave priority to high occupancy vehicles (those with multiple passengers) on the theory that cars with 2 or more people had a higher value of time than cars with only 1 person.

However HOV lanes were not terribly efficient, most such lanes had excess capacity. The notion arose in the 1970s (Ward Elliott) to charge non-HOVs for use of that capacity. These High Occupancy Toll lanes are generally parallel to "free" facilities, and allow users to buy their way out of congestion. Users with a high economic value for their trips can now pay to get to their destination faster (just as we can send packages overnight by Federal Express instead of taking a longer time with the post office).

The parallel free roads are no worse for the existance of formerly HOV/now HOT lanes if the alternative were no extra capacity at all. But if that capacity were taken away from the free lanes, some people would pay a premium to jump the queue, while those who don't pay take longer. I discuss this in Chapter 11 of Financing Transportation Networks.

This disruption may be heavily opposed when the packets are people, it depends very much on the assumed base case. However bits don't complain when delayed or routed the long way. So more urgent applications (real-time communication, e.g.) should be able to pay a premium to get a faster (higher quality) service than non-real-time applications. Of course when there are scarce resources, privelaging some traffic (i.e. discriminating for) will discriminate against other traffic. This may be inequitable to some, but economically efficient. We need to balance those two goals.

-- dml


The parallel between info transportation and physical transportation is good. I'd tell you to write it up for Wired, except they are philosophically opposed to your viewpoint. The notion of giving preferential treatment to those who pay more on the Internet is about as popular as the notion of allowing people to buy their way into the HOV lane - either will get you tarred and feathered.

From an economic perspective, clearly a system that allows people to charge for different levels of use will be more efficient in the end. But how does this jibe with the current notion being floated by backbone providers, of charging websites (rather than uses) for preferential treatment? The idea is that eBay and Google would pay Sprint some millions of dollars per year, and get priority for their packets. Any average Joe with a website - or spam, I might add - would creep to 56K speeds. My problem with this is that the money spent, in this case, represents capitalization, not demand. Hence this market will NOT be efficient, except indirectly, in that websites with high-demand content may, sometimes, be able to convert that high demand into capital. In many cases, however - for instance, or - a website can have high demand, yet not be able to pay for high bandwidth itself.

The complaints about HOV/HOT lanes seem to disappear after they are implemented. Though they *do* to some extent favor the rich, allowing people to buy onto underused HOV lanes is not unpopular. Converting existing "free" lanes would get one crucified.

Backbone providers are a nominally competitive industry. They should be able to compete on price and service. It is really interesting, the way it is currently structured the financing is very fuzzy. I pay an ISP (in my case Time-Warner) for bits to my house. Google must also pay to serve bits from their server to the backbone. Then there is some sort of sharing scheme for backbone.

If I want faster bits delievered, I can move from dial-up to DSL to cable modem to TI. I assume Google (or average Joe) could in theory do the same, which would improve the speed of the bits from one end to the backbone.

Why should not the backbone also be able to differentiate when every other stage of the network does?

As a common carrier, it should not be able to prohibit legal traffic (i.e. there should be a "basic service" at some relatively low charge), and senders and receivers should be able to choose backbone providers of choice (just as we choose long distance providers now), which provide the optimal combination of price and service.

Especially for premium services (e.g. iTunes Music Store), Apple should be able to pay a backbone provider for faster delivery, and a backbone provider should be able to offer that service.

I do think there ought to be some separation between content providers and networks, i.e. Verizon as a public utility common carrier network provider with eminent domain privelages should not really be moving its own content.

-- dml

David Levinson

Network Reliability in Practice

Evolving Transportation Networks

Place and Plexus

The Transportation Experience

Access to Destinations

Assessing the Benefits and Costs of Intelligent Transportation Systems

Financing Transportation Networks

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This page contains a single entry by David Levinson published on May 13, 2006 3:48 PM.

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