Under the Desktop: Sussing Broadband’s Dynamic Leader

David Morgenstern

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Following a short run of bad luck during its ramp up phase — brief only when compared with continental drift — broadband Internet access is finally making its way to previously neglected neighborhoods. Depending on the access technology, you could face a choice of the more common dynamic and the more expensive static IP addresses. For content creators, is there any practical difference or advantage between the two?

I’m somewhat ashamed to admit that the genesis of this column was a small bit of eavesdropping. At an antique show one weekend, I overheard a couple of attendees discussing broadband services. One was looking forward to the arrival of a cable modem in the household. But instead of congratulating his buddy on the forthcoming performance boost, the other guy replied that his DSL’s static address was “better.” Suddenly, we had a broadband winner and loser.

So, did Mr. Static Address have it right, or was he just trying to one-up his companion?

Running the Numbers
Underneath all the multimillion-dollar branding, the Internet is actually just a bunch of numbers. After all, that’s how computers talk to one another.

Each computer on the Internet has a unique number, called an IP address (Internet Protocol), that’s in a format of four sets of numbers divided by dots. Most of that number is assigned by your ISP. You can find your current address in your TCP/IP settings (TCP/IP control panel in Mac OS, and in the Network control panel in both Mac OS X and Windows).

At first, this IP address was fixed, or static, entered manually into the settings for each Internet-connected computer or device. However, the current IP numbering scheme has been showing its age for a while — it’s 20 or so years old — and there’s not enough unique numbers for the growing audience of Web users and the new types of Internet devices.

One answer to this shortage has been the Dynamic Host Configuration Protocol, a way of temporarily assigning an address to a computer or router. This scheme is used by both cable and DSL modems as well as network servers within an enterprise.

With DHCP, your ISP stores a list of numbers and doles out a dynamic address that is valid for a specified length of time or a session. When the period for a particular address expires, your computer automatically requests another address. The new address could be the same as the previously supplied address, then again, it could be different. It’s potluck.

A short digression: Another technology developed by Internet companies to extend the supply of addresses is called Network Address Translation (NAT). It sits in a router and translates one address into a group of synthetic addresses for all the other devices and computers on a network. For example, my DSL router takes the dynamic address supplied by the ISP and then generates a bunch of fake addresses for all the computers on my Ethernet network. To the outside world, however, the devices have a single address. More than you ever might want to know about NAT is at How Stuff Works.

The Internet Engineering Task Force has developed an address fix that’s due in a couple of years called IPv6, or IP Version 6. The protocol used today is Version 4 — go figure what happened to Version 5. IPv6 uses a longer address format that will greatly expand the number of available static addresses, hopefully providing enough numbers for all our Web-savvy cell phones and toasters.

Dollars and Sense
Appearing to following the law of supply and demand, an Internet package with static addresses costs more than those with dynamic addresses, although the price difference has declined over the past year or so.

For example, the basic (dynamic addressing) home DSL service from SBC/Pacific Bell costs about $50 a month, whereas, the company’s enhanced package (with 5 static addresses) runs $65. So what’s the benefit of that extra $15 a month?

There’s really no advantage between the two addressing schemes for the everyday Internet user — unless you want to run some kind of Internet server yourself. As you can imagine, a static address provides a reliable and steady target for links, rather than the moving target of a dynamic address. This could be a Web server, or some other useful Internet application such as an FTP server for big files. For those of you now running Unix, such as Mac OS X, a static address can also allow you to control your machine remotely via telnet services.

Still, most content creators simply take advantage of services offered by their ISPs, such as site hosting and email, instead of managing a server themselves.

So you can save a few bucks if somehow you’re paying for an enhanced DSL package and are not using it for a task that needs it.

But was this the end of the story?

Static Cling?
At the same time, I wondered if a static address could hold some advantage in stability over a dynamic address. It’s certainly more straightforward an approach than the complicated dynamic method. Perhaps the process of verifying and connecting to a static address was more robust than that for the dynamic address? Could an addressing change provide some relief to my DSL service’s infrequent but annoying connection problems?

No such luck, responded Bill Woodcock, noted network architect at Zocolo, a Berkeley, Calif. Internet services provider. He said there was no difference for reliability for us end users between the dynamic and static schemes. There were plenty of other things that can bring grief to a broadband connection, he added.

However, Woodcock mentioned that the additional cost for static address held an advantage for the DSL service provider. “One way or another they’re going to get you to pay.”

He said that DSL’s roll-out costs have been great and providers are trying any “nickel-and-dime way to get closer to the break-even point.”

In addition, there’s no technical reason why cable ISPs couldn’t offer a static address option like their DSL competitors. According to industry analysts, this restriction is due cable’s network architecture, which can suffer degraded performance with increased traffic. Static addresses would bring local web servers and the potential for additional two-way traffic — a bad thing in the view of the provider.

So the guy at the show giving his buddy a hard time had it wrong about the Internet’s addressing schemes. The medieval sage Ibn Gabirol supplied some wisdom about this know-it-all’s attitude: “It is easier to tolerate a whole fool than a half-fool — that is a fool who tries to act clever.”

A static address isn’t necessarily “better” for all users, only different and a bit more expensive. At the same time, a static address isn’t just “better” when it comes to servers — it’s an absolute necessity.