 Typical phone-line modem |
It is and it isn't. As always, the connection speed of dial-up is limited by the bandwidth of phone lines; but at the same time, the average file size for Web content is getting larger and larger. More people are using broadband connections that can handle a bigger load, so Web sites feel more comfortable bulking up their pages. It takes a lot time to squeeze all of that data through a dial-up connection.
New technology offers a solution to the slow-down that doesn't necessitate broadband. Services like NetZero and EarthLink are now offering "high-speed dial-up." According to ads for these services, you can get connection speeds that are five times faster than traditional dial-up service.
So how is this possible? In this article, HowStuffWorks examines what it takes to speed up your dial-up. First let's address what we know you're all wondering, "What is that unusual noise the modem makes when it's making a connection?"
A Very Special Handshake
When you think of dial-up Internet service, the first thing that probably comes to mind is the strange sort of "R2-D2 in a blender" type chirping that the modem makes as it connects. This song is called the handshake protocol, and it is the first thing that bogs down the speed of dial-up Internet.
The handshake protocol, as the name implies, begins the conversation that allows data to be sent to and from your computer using the Internet. There are actually two separate handshakes that occur in this process. The first half is the modem initializing the Internet connection. We'll call that the modem handshake. The second part is the software handshake. That deals with authenticating the user's access to the ISP (Internet Service Provider). When your computer is chirping away, it is introducing itself to your ISP. High-speed dial-up providers can't do anything about the modem handshake, but they can speed up the software handshake. The standard software handshake goes something like this:
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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:
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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.
 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. |
In the next sections, we'll learn what happens to accelerate dial-up after your machine and the ISP have established a connection.
