Wireless LAN architectures continue to morph

The latest debate over ectomorphic vs. endomorphic access points (AP) got pretty loud at the recent NetWorld+Interop 2003 trade show in a panel session called “Wireless in the Wiring Closet.” According to many vendors, thin is in; that is, putting network services (security, management, quality of service, addressing) in a collapsed backbone device, usually called a switch, and running bare-bones 802.11 radios in the ceiling.

But maybe the “thin” AP arguments have confused the issue for customers. Most vendors of thin APs insist that they are more manageable. But it seems the argument really has more to do with investment protection than with manageability. You can manage devices centrally whether they are smart or dumb. But the bigger question is whether the processors in ceiling-mounted devices are adequate to support new services until your investment has depreciated.

This issue has more to do with vendors’ ability to predict the future in their product planning than with you getting centralized management features.

There has been extreme pressure on vendors to drop prices and drive installations in so-called “carpeted” (mainstream) business environments. So vendors have to face a dilemma: If they put an abundance of processing power and memory into their devices as investment protection for customers, the cost goes up. However, if they go to add new capabilities, and the CPU/memory of the existing APs is inadequate, someone must manually touch each AP to upgrade it.  So your lowered upfront capital expense turns out to be a short-lived benefit.

This is the biggest driver behind vendors making “smart” switches and “dumb” APs.

Note, however, that if the existing AP CPU and memory can indeed accommodate new services, you do not have to manually make changes. Virtually all enterprise-class wireless LAN vendors enable remote upgrades.

In a couple of years, the Wi-Fi Alliance will require Advanced Encryption Standard-based encryption, which most vendors acknowledge will require a hardware upgrade. Symbol points out that it’s easier to make CPU/memory upgrades to a handful of smart WLAN switches than to scores of ceiling-mounted APs. Cisco, a maker of fat APs, says its APs use an accelerator card for encryption so that CPU/memory is not an issue.

Any self-respecting vendor is working hard at giving you all sorts of clever centralized manageability functions. In the case of vendors with endomorphic (fat) APs, find out what kind of assurance they can provide that your APs will last several years without your having to fiddle with them up in the ceiling.