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I remember sitting in the IEEE Task Group E (TGe) meetings during discussions on adding HCCA (more PCF than DCF) in coordinating access for QOS. The draft 802.11e standard (which is what WMM is based on) is more for classifying priority of data applications than assuring delivery.

At that time, I said to myself "Oh, oh, not another one of the 'optional' standard" These are not only confusing for implementers and purchasers of technology but also have a bad track record. (remember 802.11 FH?, PCF?)

A few years later (in 2005/2006), I was surprised to see that the Wi-Fi Alliance was going to certify products that were 802.11e HCCA based? This was to be called WMM-SA (Scheduled Access).

The current certification is called WMM (or WMM baseline) which is based on EDCA (not HCCA)

So, we are in 2007. I'm writing an article for a large magazine and I'm looking for HCCA products? Are there any!? Is there any HCCA champions out there?

Some of the CWNP exams require you to understand PCF, contention free periods etc but I've always maintained that the CWNP exams should be based on shipping products not theory mechanisms that never really see the light of day.

... Jonn Martell, PMP, CWNE, CWNT jonn@martell.ca

Jonn,
HCCA died almost a year ago. Here is an article.

http://www.wirelessnetdesignline.com/showArticle.jhtml?articleID=190500201

Check out page three. RIP HCCA; September 2005 - May 2006.

I have to give props to my WiFi brother Ben Miller who predicted that HCCA would die. His prediction is in the CWNT forums if you can access that.

[quote="GTHill"]
HCCA died almost a year ago. Here is an article.
http://www.wirelessnetdesignline.com/showArticle.jhtml?articleID=190500201
Check out page three. RIP HCCA; September 2005 - May 2006.

...quote]

That gets my vote for the industry's best kept secret! Technically HCCA isn't dead because it's part of IEEE 802.11e, but on the practical sense, it is if the industry (represented by the Wi-Fi Alliance) isn't supported it.

Even folks that follow WLANs very closely didn't see that article and the WiFi Alliance has nothing on their site to validate the claim (although I don't doubt it for a second). There's not a lot of references about the death of WMM-SA out there.

HCCA (and PCF) works for an clean RF environment but how many of these are there? I'd love to argue why WMM-SA (HCCA interop) died but I'm not surprised. Interesting that WMM will include some components of it though. Admission Control being the main one...

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Jonn Martell, Martell Consulting, jonn@martell.net, www.martell.net
PMP, CWNT, CWNE, CWNA, Wireless#, CWSP, CWAP