Access Point Tiff Simmers
Engineers from Airespace Inc., Cisco Systems Inc. (Nasdaq: CSCO), and NTT DoCoMo Inc. (NYSE: DCM) have presented the Internet Engineering Task Force (IETF) with a memo proposing a standard protocol for controlling 802.11 "lightweight" or "thin" access points via a wireless LAN switch.
Following the trend towards wireless LAN switching that is happening in the industry, the authors are proposing a "standardized, interoperable" lightweight access point protocol (LWAPP) that can "radically simplify the deployment and management of wireless networks."
Fat. Thin. Dumb. Smart. Lightweight. Herbaceous? The lexicon of terms used to describe access points just seems to keep growing and growing. But this isn't just one of those semantic conceits that tend to twist the white cotton-blend panties of tech geeks.
The issue of whether its better to install cheap access points with less intelligence (and use a really smart 802.11 switch to manage them) or make expensive ones that can manage themselves is absolutely fundamental to the 802.11 LAN market. And some analysts see standardization of a lightweight protocol as one of the keys to the success of the WLAN switching market, because -- in theory -- a standard would ensure that this new class of access points will work in a heterogeneous environment and not simply as part of a single-vendor system.
The vendors' memo cites three goals:
- Reducing the amount of code that is actually processed at the access point, so that these devices purely handle the wireless access side of the equation.
- Centralizing at a switch level: "The bridging, forwarding and policy enforcement functions for a WLAN, to apply the capabilities of network processing silicon to the WLAN, as it has already been applied to wired LANs."
- "Providing a generic encapsulation and transport mechanism, the protocol may be applied to other access protocols in the future."
Prodan says that, for instance, voice and data traffic has to be prioritized at the access point if services such as voice over IP (VOIP) are to be enabled on wireless LAN networks (see Is 802.11 Ready for VOIP?). "Adding a protocol on top of an access point is not going to do that." In other words, the access point will need at least some smarts -- if not a mensa-grade IQ.
The IETF is not the only industry body working on standardizing the way in which these "dumb" access points communicate with the network, which means things could get jolly complicated before the whole issue is sorted out. The Institute of Electrical and Electronics Engineers Inc. (IEEE) is also working on a document laying out "recommended practice for inter access point protocol" -- a.k.a. 802.11f (see IEEE Plots Speedier WLAN). The latest status report from that group can be found here.
There is some common ground between the two efforts. Bob O'Hara, director of systems engineering at Airespace, is one of the authors of the IETF memo and also one of the chairs of the 802.11f group.
Historical footnote: The meta issue of whether network intelligence should be centralized in the middle (in a switch or hub) or pushed out to the devices that sit at the edge of the network is as old as the LAN market itself. In the early 90s 3Com Corp. (Nasdaq: COMS) took a bet that enterprises would want to distribute management intelligence (and other bits 'n' pieces, like quality of service) out in the PC, via its fancy shmancy adapter cards. Meanwhile, other companies (like Bay Networks) took the opposite tack. 3Com lost (really lost) and ended up with little more than an ugly concrete ballpark to its name.
— Dan Jones, Senior Editor, Unstrung