Dealing with multi-generational 802.11

Enterprises are just ramping up with 802.11b/g-based Wi-Fi deployments. Relatively speaking, they have hardly touched 802.11a, which offers additional channels for design flexibility and interference avoidance in the 5-GHz range. 802.11a sees the most action today in the backhaul component of Wi-Fi mesh networks.

With another, faster Wi-Fi standard en route – 802.11n – should you simply bypass 802.11a? The answer depends on how broadly you are using your Wi-Fi network and for what applications.

As you likely know, 802.11n promises to bring at least 100Mbps theoretical maximum bandwidth to wireless LANs by making use of multiple input/multiple output (MIMO) smart antennas. But because standards-based products aren’t due out yet for another year, one integrator advises that enterprises simply ignore 802.11n for now and proceed with meeting their needs using what’s available.

Jeff Nelson, vice president of wireless operations at integrator NetVersant Solutions in Houston, says that moving to 802.11n “will be a rip-and-replace effort” in terms of installing a whole new access point (AP) infrastructure.

That’s true, if you require the performance benefits of 802.11n ubiquitously throughout your campus. However, note that 802.11n APs can be added incrementally to your existing 802.11a/b/g networks; IEEE 802.11n draft specifications require that 802.11n be backward-compatible with these networks. And 802.11n vendors claim that mixing and matching 802.11a/b/g networks with 802.11n will provide up to a 50 percent performance benefit. So you could feasibly come out ahead by introducing 802.11n as you need new APs and, through attrition, replacing outdated ones.

But if your WLAN is for casual use or for low-bandwidth traffic, you might be inclined to wait. One company that expects to go this route is United Parcel Service (UPS).

“We’ll likely leapfrog 802.11a and go straight to 802.11n,” says John Killeen, director of global network systems at the Atlanta-based worldwide delivery company. UPS runs a 15,000-AP 802.11b WLAN that stretches across 2000 sites, according to Killeen.

The reason? For now, most of the data that UPS transmits over its WLAN relates to the company’s global scanning system for package tracking.

“The data consist primarily of 18-character bar codes, which do not require a lot of bandwidth,” Killeen explains.