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| --- This message came from the IEEE 802.11 Task Group M Technical Reflector ---
Dear TGm folks, In the September meeting there was a discussion of the likely exhaustion of Element ID space, and a clear sentiment to be proactive in resolving the issue. TGai has just asked the ANA for 14 of the remaining ~20 Element IDs, so we need to consider a possible extension mechanism urgently. In my mind the requirements of any extension are: (most important first) 1.
To be parseable by existing parsers 2.
To support an effectively unlimited number of Element IDs. For this purpose 2**16 might be “unlimited”. 3.
To minimise added overhead 4.
To permit longer elements I don’t see how we can satisfy 1. and 4. simultaneously, but brighter minds may find a solution. (OK, I can see a complex solution, but not a simple one). I suggest, as a starting point to stimulate discussion, the following structures: Structure A: - 8 bit extension, 8 bit length Octet 1: Element ID = 254 Octet 2: Length (1-255), including Octet 3 Octet 3: Element ID Extension 0-255 Octets 4 to Length+3: Body Structure B: - 16 bit extension, 8 bit length Octet 1: Element ID = 255 Octet 2: Length (2-255), including Octets 3 and 4 Octets 3-4: Element ID Extension 0-65535, less one escape Octets 5 to Length+3: Body Regarding lengths greater than 255, we already have a fragmentation scheme in TGai. I don’t see an obvious scheme that doesn’t need “compatibility element header mid-ambles” of some kind. The complexity of such a scheme is similar to the fragmentation scheme of TGai, so there is little benefit to inventing it. I suggest we have an email thread. If there is a consensus emerging, I suggest those folks get together in a submission to TGmc for the November session. Best Regards, Adrian P STEPHENS Tel: +44 (1793) 404825 (office) Tel: +1 (408) 2397485 (mobile, USA) ---------------------------------------------- IF YOU WISH to be Removed from this reflector, PLEASE DO NOT send your request to this CLOSED reflector. We use this valuable tool to communicate on the issues at hand. SELF SERVICE OPTION: Point your Browser to - http://listserv.ieee.org/cgi-bin/wa?SUBED1=STDS-802-11-TGM and then amend your subscription on the form provided. If you require removal from the reflector press the LEAVE button. Further information can be found at: http://www.ieee802.org/11/Email_Subscribe.html _______________________________________________________________________________ |