Cable vs. DSL

I lovesummer. I love backyard barbecues, the laughter of friends gathered around thegrill.

And, nowand then, I love a good fight, like one that erupted the other day. Two buddies-- one from the local cable company and the other from the telephone company --dropped by for an outdoor lunch. I can't remember exactly which one asked mewhether I had a 24x7 connection to the Internet in my house yet, but I clearlyrecall what they said when I told them, "No, what would yourecommend?"

The cableguy piped up first. He said "Get a cable modem, that's the only sensibleoption. For a flat $40 per month, we can give you terrific Internetperformance."

As thecable guy bragged on and on about cable data service, I noticed the telephoneguy's eyes narrow and mouth curl downward. When the cable guy finished hispitch, the telephone rep broke in with a few comments of his own. "Yeah,sure, I'd trust a cable TV company for reliable Internet access," he said,then went on to explain how the phone company could sell me a reliable andsecure DSL service that would do pretty much the same thing.

They dronedon and on, and when they finally left, they left me with a decision to make. Idecided to make it based on facts rather than rhetoric.

When acable TV company offers household users access to the Internet, they do it bycreating a virtual Ethernet LAN that loops through the homes and connects backto an Internet router at the cable company. As with Ethernet, the homes thatshare this virtual LAN also share its bandwidth. So, the phone company guy isright: a person's cable connection performance will vary based on the virtualEthernet's simultaneous usage by others. By the same token, its theoreticallypossible that cable modem users on the same virtual LAN can scavenge eachother's Internet traffic, like a high-tech version of eavesdropping on anold-style telephone party line.

A DSL, bycomparison, is a private physical circuit from the telephone company to aperson's home or office, and the user of such a circuit shares neitherbandwidth nor traffic, which is the basis for the phone company's claims ofbetter performance, reliability, and security.

So, whichis better? Which should you buy? After picking through the rhetoric, a fewfacts emerge.

Telephonecompany claims about cable Internet access performance and security aregrounded in fact. However, in general, cable performance can peak much higherthan DSL, and provides better sustained performance. And, unlike DSL, cableInternet access performance isn't affected by distance from the providercompany.

Likewise,there is truth in the telco argument that cable access is less secure. At thesame time, however, we should all remember that a permanent connection to theInternet, whether through DSL or cable, subjects a home PC to wily hackers allover the world.

Unfortunately,for most of us, the argument is still moot. Less than half of the homes in theUS have access to either, and fewer than 25 percent have the luxury of a choicebetween them. For those of us lucky enough to have the choice, there is abottom line: the two services are basically equivalent, with a roughly equalnumber of consumer complaints on both sides. Like my friends around thebarbecue, get your cable and phone companies to beat each other up for you,then decide based on price. And, whichever service you pick, get yourself apersonal firewall software package to go with it. --Al Cini is a senior consultant with Computer Methods Corp. (Marlton,N.J.) specializing in systems and network integration. Contact him at

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