No Thin AP Protocol for Now

By Eric Griffith

March 03, 2004

LWAPP, the proposed protocol for thin access points, has 'expired' but in its place comes a working group that will first define switch architecture before it even considers addressing a protocol.

Just when you get comfortable with an acronym, the industry replaces it with a new one.

In this instance, the acronym is LWAPP, short for the Light Weight Access Point Protocol set forth by wireless LAN switch companies as the future for their products to communicate with "thin" or "light" (some call them "dumb") access points (APs). Thin APs require that all the smarts reside on the switch.

A LWAPP standard was proposed to the Internet Engineering Task Force (IETF) months ago, but this week Wi-Fi Planet learned that the draft of LWAPP has expired. Replacing it is CAPWAP -- the Control and Provisioning of Wireless Access Points.

Alan Cohen, vice president of marketing at Airespace, a WLAN switch vendor that was one of the main LWAPP backers, calls CAPWAP the "official renaming" for LWAPP.

However, CAPWAP isn't a replacement protocol -- at least, not yet.

CAPWAP is the name of the Working Group within the IETF that will eventually handle what LWAPP was meant to. CAPWAP was proposed as a "Birds of a Feather" (BoF) within the IETF last year. BoF is what the group calls the start of any new effort. Not all are approved to become a Working Group (WG), but CAPWAP was.

According to Michelle McLean, director of product marketing for switch maker Trapeze Networks, "CAPWAP's current charter is to define the WLAN architecture; it defines the topology. Its current charter doesn't include any work on protocol development. All it does is say where devices sit and what they call them. It doesn't define how they communicate."

This architecture work will reportedly take about six months. When that's finished, it's assumed the CAPWAP WG will seek another charter with the IETF to do protocol work. This won't hit products until 2005.

Aruba Networks communications director David Callisch says the "CAPWAP group has mandated that all references to LWAPP, or any existing protocol, be removed from the current working group documents."

Aruba has been a holdout on supporting LWAPP, along with heavy-hitter Cisco, but Callisch says "Aruba will support any protocol that is agreed upon within the IETF."

He points out that CAPWAP is getting input from more organizations than LWAPP did. Companies with personnel in the Working Group include Trapeze, Lucent, Avaya, Intel, Airespace, Nokia, Chantry and Panasonic. The original LWAPP specification was proposed to the IETF by Airespace and Japanese wireless operator NTT DoCoMo.

With LWAPP going-going-gone, that means companies will continue to use their own proprietary communications protocols for the time being. For example, products like D-Link's recently announced LWAPP access points will only work directly with Airespace switches (they are working with Airespace as a partner). Other Airespace partners include NEC, Alcatel and Nortel.

"We all have our own version of 'LWAPP,'" says McLean, "but they have to be proprietary." If and when CAPWAP has defined a protocol (probably in about a year), products will likely be upgradeable with simple firmware changes.

Switches and thin APs are considered a potential major growth area for Wi-Fi networks this year. Synergy Research Group says "2003 was characterized by renewed enterprise adoption of Wi-Fi technology," mostly in vertical markets. The research firm started tracking available sales figures on switches and thin APs in the final quarter of last year, and the nascent market was already reaching $22 million. They decline to forecast on the market until they've got a year of data, but do say the enterprise market will be "fueled by sales of new class products including Wireless Switches/Controllers and 'Light' Access Points."

Originally published on .

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