Everthing You Wanted To know About TCP/IP, But Were Afriad To Ask

by David G. Propson

TCP/IP: Five of the most familiar, least understood letters around today. Anyone who’s ever done some casual fiddling with a modem or an Internet connection has probably stumbled across them, registered their importance, dropped the keyboard, and fled. Normal humans fear acronyms; techies, however, love them.

These particular five letters stand for, respectively, Transfer Control Protocol and Internet Protocol. Doesn’t make things a whole lot clearer, does it? Techies have their own language, and it’s just as hard to learn as Russian or Ancient Greek. Usually it requires immersion.

TCP and IP can be translated as the technology that underpins every bit of data sent through the Internet.


Just as techies have their own language, so do computers. In fact, they have all sorts of them ­ dialects are as common in cyberspace as in the real world. What we’re interested in here aren’t programming languages or file formats, but what are called protocols.

Protocols are an essential part of the language computers use to swap data with one another. Remember C-3PO, from the Star Wars movies? He was a protocol droid, designed to translate messages from one language to another ­ with a British accent of course. Like the British, protocols are concerned not so much with what you say but how you say it, that all the pieces are in the right order, and all the grammar is correct.


TCP/IP was created back in the 1970s to solve a simple problem: The Arpanet, which in the past had been mostly a system of interconnected supercomputers, was now connecting more small, local networks. Each of these sent data in different ways, so that one might not be able to talk to another. In response to the problem, two techie heroes named Vint Cerf and Bob Kahn created a new way of packaging information so that any network could receive it. TCP/IP was soon adopted as a standard, and turned the Babel of the Arpanet into a world where all networks could communicate ­ it’s what really made the Internet, the Internet.

Before a message is sent through the Internet, it’s chopped up into many discrete packets and each is sent individually to the destination. This is done so that each can be routed along its own path, and ­ Cisco willing ­ each can get there faster than if they followed, single-file, along the same path. With TCP, the sending computer can create electronic envelopes that the receiving one will know how to piece together. Meanwhile, IP stamps an address on each packet, so they can be routed through to where they need to go.


Problems on the Internet occur when certain packets don’t reach their destination or take too long to get there. It’s just as if you were driving past a roadside neon “Eat at Joe’s” sign that had half its letters burnt out, and thus seemed to have an entirely different meaning ­ “Eat Joe.” TCP/IP protocols help identify when something has gone wrong.

Very often, when e-mail or other files being sent through the Internet absolutely fail to reach their destination, it’s because some of the packets have been lost along the way. Thanks to TCP, the receiving computer can tell something’s missing, and so refuses to deliver the rest of the message. Instead, it waits a little while to see if the missing packet eventually shows up.

Anytime information is sent that needs to be processed immediately ­ live audio or video, for instance ­ that luxury doesn’t exist. Packet loss can cause breaks and choppiness in online video and audio, and vendors who sell these services still struggle to overcome the problem. That’s why audio and video on the Web is still primitive, largely because the Internet really wasn’t designed to deliver it. But then again, the story of innovation on the Internet has been one of people figuring out how to use it to do things for which it was never intended.

Small Business Computing Staff
Small Business Computing Staff
Small Business Computing addresses the technology needs of small businesses, which are defined as businesses with fewer than 500 employees and/or less than $7 million in annual sales.

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