Question: Within our organization, I'm responsible for determining the best technology for our home-based workers. Currently, I'm evaluating cable modems and DSL [Digital Subscriber Line]. Any thoughts on which way to go?
Laura: Right off the bat, I'll tell you that I prefer DSL to cable modems. I'm really into guaranteed bandwidth, and DSL can deliver on that guarantee while cable is simply not able. Despite the bandwidth guarantees of DSL, there is no clear top performer between these two technologies.
For example, Keynote recently carried out tests of DSL and cable performance. Keynote used a fixed set of Web pages as a benchmark and discovered that Pacific Bell's DSL system took an average of 3.55 seconds to download a page between 5 p.m. and 11 p.m., and 4.30 seconds during the day. The cable modem system took an average of 3.97 seconds to download during the evening hours, and 3.68 seconds during the day. Of course, these numbers are not etched in stone, as performance will vary based on your environment.
The real drawback to DSL is its limited availability. Despite how cool the technology is and how much I want it, it's not available in my area. I hear it's on its way, but I've been hearing that for some time. Also I have heard that DSL implementation can be burdensome. Technicians install DSL by splitting the phone line into two channels -- one for voice and one for data. In addition, you need an adapter installed and your home PC configured. Though this sounds straightforward, I've heard a few horror stories.
In the meantime, you won't see me purchasing cable. In addition to the the lack of guaranteed bandwidth, cable is inherently less secure than DSL because of its shared lines. For the consumer market, this shortcoming may not be a big deal, but for businesses security is a concern.
Finally, you need to consider cost. I haven't seen a recent breakdown of cost, but traditionally DSL has been more expensive than cable. I hear you can receive both types of services for about $60 per month. You need to research the options available in all of the geographic areas you wish to support. Your research may show that you really don't have an alternative at this time.
Brooks: I agree with Laura that DSL is superior to cable modem technology, but my reasoning on the matter is somewhat different. My fundamental problem with cable modems is that cable is a shared media. This has a few implications. First, the more people using cable modems on a given segment of cable, the slower the performance. Second, depending on your needs, you can get DSL speeds that far exceed cable modem speeds, especially the upstream capacity.
When it comes to DSL, I wouldn't recommend trying to run it on your existing copper phone lines. Numerous people I've talked with have complained that doing so affects the sound of the phone line, sometimes adding a shrill, annoying tone. It's better to run a separate pair of lines into the house; it's not that much more expensive and it generally seems to be more trouble-free. What's more, you may want to consider getting an actual DSL router and small Ethernet hub rather than putting the DSL adapter right into your users' home PCs -- that way you'll be ready to support IP phones or other network-attached devices your telecommuting users may need.
Neither technology, by the way, should be looked at as an alternative to T1 lines for mission-critical applications. Both cable modems and DSL lines have more frequent outages, and the outages tend to last longer. Plus, you're just one of the masses and your provider probably won't take the outage as seriously as a phone company takes a downed T1. Not that phone companies are notorious for their customer service, but compared to cable companies .