Scotty! I need more Bandwidth!

By Vince "TC" Cavasin

Okay. It’s unlikely Captain Kirk has a bandwidth problem in a universe where people’s particles are routinely beamed down to strange planets (which happen to have atmospheres identical to Earth’s) and even the narliest looking space creatures speak perfect English. But damn it Mr. Scott, we webheads here on Earth could sure use more bandwidth; and it looks like we’re finally going to get it.

What’s bandwidth? Well, basically it’s the size of your pipe—the conceptual pipe, that is, that delivers data to your computer. Bandwidth is the rate at which data flows over a wire; generally it’s measured in kilobits per second (kbps) or Megabits per second (Mbps) (a bit is simply the smallest unit of data that’s relevant to a computer). In the context of the internet, the bandwidth bottleneck is generally your computer’s modem and the phone line that links it to your Internet Service Provider (ISP).

This bottleneck becomes an issue when you try to send or receive any decent size (say, greater than 50k) file over the internet—like when you’re downloading a graphics-intensive webpage, or a monstrous Powerpoint presentation attached to email. Analog modems are pretty much limited by physics to 56kbps, and most of us are lucky to get actual connection speeds of 28kbps due to the quality of the phone lines; at this speed, a 1.5 Megabyte Powerpoint presentation takes about 7 minutes to download. And if you’ve ever tried to download an application like Netscape, you know that 1.5 Megabytes is relatively trivial.

ISDN, which stands for Integrated Subscriber Digital Network, can provide some relief: it gives 128 kbps, but since it’s a pure digital protocol, it requires a specially-installed phone line. ISDN prices have come down a lot recently, but still can’t compare with POTS (Plain Old Telephone Service); in Austin, installation totals around $300, and the monthly fee is $52.

A better solution than ISDN is ADSL: Asynchronous Digital Subscriber Line. ADSL provides up to 1.5 Mbps over POTS—there’s no need for a new phone line, even though it too uses a digital signal. Of course, "Asynchronous" means that upload and download speeds are not the same; the 1.5 Mbps is the downstream rate, but that’s the direction in which you need the most bandwidth—for example, when pulling down files from the internet. The upstream speed is 64 kbps—plenty for sending the few control signals (mouse clicks, etc) needed when surfing the net.

ADSL availability is currently very limited, and when you can get it, it’s expensive; in Austin, one of only a handful of American cities where this new technology is available, ADSL installation fees total around $800, and monthly fees are around $150.

But the good news is that late last month a huge group of companies—including most of the baby bells, Intel, GE, and even the mighty Microsoft—agreed on an ADSL standard. This means that ADSL availability should skyrocket this year, and prices for both modems and service should tumble. With Compaq talking about building ADSL modems into future PCs, chances are we’ll all be surfing the net at warp speed before long; International Data Corporation is estimating 2.5 Million ADSL connections by 2001.

Another bottleneck-slayer that’s on the horizon for the internet is IP Multicasting. This relatively new technology doesn’t provide a bigger bandwidth pipe itself; it just makes more efficient use of the bandwidth that’s available.

Currently, the internet uses unicasting—if you want to send the same message to 1000 people, you send each person their own copy, for a total of 1000 copies. If this doesn’t seem like a big deal, remember the pipe analogy: if the internet is plumbing, and data is water moving through it, 1000 gallons takes a lot more pipe than one gallon to travel an equivalent distance.

Multicasting allows you to send a single copy that only gets replicated when absolutely necessary (i.e. when it comes to a fork in the physical path it’s taking over the internet). This greatly reduces the burden on the bandwidth available, and allows everyone’s traffic to travel faster.

I know what you’re thinking: come on, you green-blooded, pointy-eared devil, tell me what this has to do with business! Settle down, Bones. Given the internet’s explosive growth, it’s in every business’s best interest to make the most efficient use possible of the bandwidth that’s available; multicasting helps with that.

But the coolest development, especially for home surfers and small businesses that need to get hooked up to the ‘net cheaply, is ADSL. Within a couple years, the bandwidth it provides will enable internet-based real-time video conferencing, 3D interactive web pages, and even video on demand, all for not much more than your current phone bill.