Talkback on my wireless standards article in September's CONTROL

Walt, I just finished your article and want to raise a couple of points: 1) You said "The other piece of good news is that there is a standard: IEEE 802.15.4 or Zigbee, which uses the mesh network topology." Sort of. IEEE 802.15.4 and ZigBee are NOT the same thing. All ZigBee uses 15.4 but to use 15.4 you do not have to use ZigBee. Companies like Millennial Net, Sensicast, and Dust Networks all have 15.4 products available that are not based on ZigBee. Why? Well, I am attaching an ARC report on ZigBee in industrial applications that you are welcome to read (and quote if you wish) but please do not to forward it to anybody else (our clients pay for these reports...). It goes into these points in more detail. 2) You also said "Unlike other industrial standards, the eventual industrial wireless standard must achieve total interoperability with the existing IEEE series of wireless standards, including WiFi, WiMax and others. That is going to be necessary because of the growing interpenetration of the plant-floor space and the enterprise, where the IEEE standards are ubiquitous." You should take care to distinguish between (RF) coexistence and interoperability. They are 2 different things. The first is a MUST have, and the 2nd is a nice-to-have. Coexistence is paramount because many if not all of these different types of networks will be operating within factories and plants...along with UHF RFID readers which also use the same radio frequencies to read tags. You get the picture. Harry Forbes Senior Analyst ARC Advisory Group You are right, Harry, I elided past the difference between 15.4 and Zigbee. The existence of these highly proprietary 15.4 implementations is likely to present a serious barrier to adoption of any industrial wireless standard. I don't agree with your second point, though. I am aware of the distinction between _coexistence_ and interoperability. Zigbee, for example, is aiming at _coexistence_ and calling it _interoperability_. I believe that any industrial wireless standard (SP100) will need to require both. There is the issue of use transparency that will either facilitate or retard adoption rates-- and true interoperability with all the existing 802.11 stuff, and all the nascent 802.15.4 stuff will clearly be a very high level of use transparency. Thanks for the paper. I'm reading it now... What do the REST of you think? Walt