Bandwidth is NEVER Unlimited!

There has been quite a bit of ink in the newspapers and magazines about how the "flat rate price for unlimited bandwidth" on the Internet is not long for this world. There is just one problem with this claim: there is no such thing as unlimited bandwidth.

The impression that such claims are trying to leave is that a flat price model for Internet service is as unworkable as an "all you can eat" deal at a restaurant. In practice, there are always limits.

The Real Limits

Users of the Internet are limited at any given instant by a variety of things: the speed of their computer (hardly much of a concern these days), the quality of their software (of deep and abiding concern - how often does your system crash?), how quickly the user can read, but most often, they are limited by the bandwidth of their link to the Internet.

The most common access method to the Internet these days is by modem; what follows is a table of modem modulation standards and the bandwidth you get out of them under ideal conditions (i.e. the phone line has no noise on it):

Standardbits per sec
CCITT V.329,600
CCITT V.32bis14,400
CCITT V.3428,800
CCITT V.34bis33,600
ITU V.9056,000/33,600(asymmetric down/up)
ISDN B (DS0)64,000
ISDN B * 2128,000

For contrast, Ethernet moves data at ten million bits per second (bps). The CCITT changed names recently to the ITU-TSS. It is an international telephony standards organization, under the United Nations.

The new "56K" modems are only 56,000 bps in one direction - toward the subscriber, and they must be supported by the Internet service provider you use. You can't get 56K between two of the consumer 56K modems, because one end is required to be all-digital (e.g. ISDN). In the user to user situation, they'll revert to V.34bis (33,600 bps).

ISDN, a symmetric bandwidth, digital telephony system, is not yet in wide use because the Telephone Companies (and their regulators) refuse to price it competitively (let alone price it in relation to its cost against normal analog phone service - i.e. at a lower price).

If your modem also does compression (and the vast majority do, these days - there are standards for that too), you might get as much as a 50% increase in throughput if you're moving lots of text, at the cost of some latency (i.e. trading bandwidth for time - it takes time for the modems to compress and decompress the data). However, typical throughput increases from compression in modems is more likely to be between 10 and 30%.

So, when someone connects up to their Internet Service Provider using a typical analog modem, the best they're going to be able to push or pull under ideal circumstances is 50,000 bps. This is not unlimited.

In fact, as the amount of bandwidth purchased moves up, so does the (flat) price for it, which is as it should be: you buy more, you pay more. Just check the prices for ISDN service as compared to slower modem connections - it costs more for ISDN Internet service. Or T1 (1.544 megabits per second) versus ISDN - it costs more for T1. No one is getting the free ride implied by the phrase "unlimited bandwidth."

What this is Really About

What the large Internet Service Providers are really complaining about is that they can't charge you by usage, which is typically much more lucrative than a flat price for a given bandwidth - if you need any proof of that, go look at Telephone Company profits - they charge by the minute for your voice calls.

They're also complaining at the same time about their own inability to grow their networks fast enough to accomodate the demand for Internet service (the voice telephone market is growing at 7% a year, and the data market is growing 400% per year right now, so they want to raise the prices of data services to both stem demand and reap windfall economic profits), and that the ever-changing mix of network applications (i.e. mixture of uses of the Internet) keeps blowing out their assumptions about how much bandwidth the "average" user will actually use (a key component to network backbone engineering and management).

Finally, the big players are trying to cut the little guys (who are often the lowest overhead and thus offer service at the deepest discont) out of the game, by pricing connections that are "for resale" higher than the market - the "unlimited user bandwidth" shibboleth is part of the patter to get the mark to accept this con game. It's also partly a game of "chicken" - who is "big," who is "small," and therefore who gets to charge whom (and how much) for service.

So, when you read that large backbone providers of Internet Service (e.g. UUNET, MCI, SPRINT) complain that users have "unlimited bandwidth" at a flat rate price, call them on their lie.

There is no such thing as unlimited bandwidth!

Erik Fair <>
March 15, 1998