Being an early adopter of technology means you sometimes pick the losers. Somewhere in my basement is my Betamax VCR, and somewhere behind that is my 56K-Flex modem. Remember those? They were an early standard in 56K modems that competed with X2 before the V90 standard came out and made both of them obsolete. When these two standards first emerged, internet service providers would offer 56K dial-up connections but often only supported one and not the other. Eventually modem companies released firmware upgrades to bring their customers to V90, but these upgrades sometimes didn’t work properly and frequently were more technical than the average user could deal with.
We are now about to see a similar standards battle emerge in the area of wireless networking. The 802.11g and 802.11a standards both promise wireless networking at speeds up to 54 megabits per second (Mbps). These standards will be a significant evolution over the current 802.11b standard, which tops out at 11 Mbps.
Many factors will motivate schools to adopt wireless networking technology, including the need to provide connectivity to local area networks (LANs) and the internet for students with their own laptops or personal digital assistants. Many schools already have invested in mobile laptop labs with wireless access points. Others have deployed wireless networks throughout their campuses. In most cases, these networks are based on the de facto 802.11b standard, which has grown in popularity since its approval in 1999. Now, however, school leaders who want to get into wireless networking or expand their current wireless LAN have to make choices that could impact both functionality in the present and expandability in the future.
Like the difference in modem standards, compatibility will be the critical factor in the success or failure of these different wireless LAN standards. To the end-userthe guy who spends the money and drives the marketmodulation methods, frequencies, and power efficiencies are distant seconds to questions like “Will it work with what I have?” or “Will it work with what I want to buy five years from now?”
The first of these questions is easy enough to answer, because the standards are, for the most part, already defined. The 802.11g standard was designed specifically to be compatible with 802.11b. This means 802.11b network cards will work with 802.11g access points. Both standards use the 2.4 gigahertz (GHz) range of the spectrum, and although they use different methods of placing the data into a radio wave, these modulation methods are designed to be compatible with one another.
This is not the case with 802.11a. Although it uses the same modulation method as .11g, it is designed to operate in the 5 GHz range of the spectrum, thus making it incompatible with both .11b and .11g. That’s not to say you can’t operate a .11a and a .11b network in tandem, however. Because they use different slices of the spectrum, there should be no interference problems in putting both types of access points right next to each other. In fact, Intel’s latest 802.11a wireless access point comes with an optional dual-mode expansion module that allows you to run both .11a and .11b standards from the same access point.
When doing this, however, you should realize that the effective range of a .11b access point is significantly greater than that of a .11a access point, and you may need to add additional .11a access points to your network to effectively cover an area with 54 Mbps access. You should also realize that the actual speed achieved through the access point will decrease as you move away from it, and it might be necessary to have a second site survey done to ensure that your coverage is adequate for the type of throughput you will need.
The second question is obviously the more difficult to answer, and it’s also the more critical one. It involves a bit of crystal ball gazing, and the crystal ball says different things depending on whom you talk to. Some say that .11g is just a blip on the radar screen and soon will disappear because .11a’s use of the 5 GHz range insulates network traffic from the already overcrowded 2.4 GHz space. The fact that the .11g standard has yet to be finalized, and .11a products are already in the sales channels, will make .11g a relic before it even gets to market.
Still other people caution that the backward compatibility to .11b and the fact that the .11a standard is presently only approved for use in the United States will give .11g the foothold it needs to become the new standard.
In any case, school leaders should look at their current and future needs and make decisions based on these needs, rather than trying to guess the direction the market is going to head. If you’ve already invested significantly in .11b technology and there is no pressing need for high-bandwidth access for applications such as streaming video, then most experts seem to agree that you should stay at 11 Mbps until a clearer migration path emerges. The .11b standard isn’t going anywhere fast, and it has enough of an installed base that whatever standard emerges will have to account for existing installations of .11b. If faster speeds are required in specific locations now, the 802.11a devices that offer dual-mode expansion modules will allow you to leverage your investment while experimenting with the newer and faster speeds.
If you’re installing new wireless LANs, you face a more difficult choice. It is often the high-bandwidth applications that make such a project attractive to donors, and most people don’t like the idea of installing a wireless LAN that will operate at a tenth of the speed of their wired 100 Mbps LAN. They are afraid that users will notice a significant speed difference and become frustrated.
A complete deployment of either the .11a or the .11g standard could be somewhat risky and expensive. With access points in the $300 to $500 range and PC cards in the $200 to $300 range, most schools can ill afford to redo an entire campus-wide wireless LAN in three or four years when a de facto standard emerges. Fortunately, unlike the X2 versus Flex standards battle in 56K modems, schools will have complete control over the workstation device as well as the network access point. You won’t be dependent on a service provider to support one standard or the other, so if you choose to purchase equipment that does not become the de facto standard in three years, you would still be okay. Furthermore, because the standards do not overlap in frequency, you could migrate to the other standard one piece at a time while supporting the previous standard by leaving old equipment in place.
A less risky approach for schools looking to get into wireless networking would be to wait at least another year before deploying a wholesale solution and to focus on one or two buildings using either the .11a or the .11g standard. Because .11g won’t even be available until later this year, schools looking to put something in place immediately will have to use .11a.
Regardless of what standard you choose to implement right now, you should discuss the issue of an upgrade path. Many manufacturers offer a buy-back option when users want to upgrade equipment. Other vendors will promise a firmware upgrade to their equipment to bring it into compliance with a new standard. In any case, be sure that you understand the upgrade path for the equipment that you choose and that you are comfortable with it. With some luck and planning, you can avoid investing in another Betamax.