How High-speed Dial-up Works

High-speed dial-up allows your machine to establish a connection with your ISP in a fraction of the time it takes with standard dial-up.

High-speed Dial-up: Acceleration Servers

The standard software handshake goes something like this:

Your machine: Hello, my name is Sparky. ISP Server: Hello, Sparky. Your machine: I am John's computer. ISP Server: John who? Your machine: John Smith. ISP Server: I know 32,422 John Smiths. Your machine: He is one of your customers. ISP Server: Does he have an account number? Your machine: Yes. ISP Server: What is that number? Your machine: 5546743897 ISP Server: Ah, yes. OK, go ahead, 5546743897. You have access.

This is a simplified explanation, of course, but you can get the idea of the back-and-forths that need to occur in the handshake protocol before information can be sent or received. High-speed dial-up providers have cut down on this back-and-forth by creating a system that allows the conversing machines to remember responses to questions. This makes for a much shorter conversation:

Your machine: Hello, my name is Sparky. ISP Server: Ah, hello, Sparky. Aren't you John Smith's machine. Your machine: Yes, his account number is 5546743897. ISP Server: Go ahead, 5546743897. You have access.

This shorter handshake equals much faster connection times. The increase in speed varies by machine, but in some cases it can reduce the handshake by up to 50 percent. What might take 45 seconds with a "normal" dial-up service becomes maybe a 30-second process with a high-speed service.

When you search for a Web page on the Internet, your request is routed though your ISP to the Web. After making a series of stops along the way at machines that help find the page you're looking for, your machine is connected to the computer that serves the Web page you requested. Once this connection is established, data can flow freely from the Web server to your computer. Once the information leaves the Web server and hits your dial-up connection, that's where the bottleneck begins in the typical Internet transaction.

But high-speed dial-up providers have come up with some pretty clever ways to open up that bottleneck. By loading special software into a server, they turn it into what they call an acceleration server. And by sandwiching the acceleration server into the chain between your dial-up connection and the Web, they can speed up the process considerably.

When you search for a Web page using high-speed dial-up, your request is sent from the dial-up modem in your computer to the ISP's acceleration server. Now the acceleration server is requesting and serving pages on your behalf. The acceleration server uses a broadband connection to quickly search the Internet for the server that hosts the page you're looking for. Once it finds that server, the two machines start talking and exchanging the information you need. Your ISP's acceleration server takes that information and sends it to your machine.

How High-speed Dial-up Works

The high-speed dial-up data path

Acceleration servers speed up the dial-up data transfer using several techniques:

  • Compression
  • Filtering
  • Caching

Next, we'll go over how these acceleration servers drop the pedal on your dial-up.