Re: [STDS-802-11] EPD for OCB in the 5.9 GHz band, or for ICB in any band
--- This message came from the IEEE 802.11 Working Group Reflector ---
Hi,
I recommend that you wait a couple of weeks for P802.11ak_D1.0 as
there are some glitches in the current D.07 and D1.0 will have
complete EPD support mechanisms.
Thanks,
Donald
=============================
Donald E. Eastlake 3rd +1-508-333-2270 (cell)
155 Beaver Street, Milford, MA 01757 USA
d3e3e3@xxxxxxxxx
On Fri, Mar 13, 2015 at 5:27 PM, Hamilton, Mark
<Mark.Hamilton@xxxxxxxxxxxxxxx> wrote:
> --- This message came from the IEEE 802.11 Working Group Reflector ---
>
> Mark,
>
>
>
> The general use of EPD is being added in 11ak via a negotiation method sort
> of along the lines you describe (this will apply to any type of link or any
> band that wants to use it, not just GLK links – its negotiation is
> orthogonal to the negotiation of GLK, that is). I’d recommend you read the
> description in TGak’s draft (since it is about to be put to a mandatory
> letter ballot anyway J), and take technical concerns to TGak.
>
>
>
> Based on the straw poll taken in January, I personally think it is unlikely
> we’ll get any general purpose (any band) EPD mechanism any sooner than 11ak,
> as the full 11ak development cycle allows time for the WG members to study
> and refine the methods to be sure all the compatibility concerns are
> understood and handled.
>
>
>
> In the meantime, my personal opinion is also that 802.11p in 5G9 could
> simply mandate EPD immediately, since that is a greenfield band, and would
> be by definition a “prior agreement” as you mention. I don’t believe there
> are any compatibility problems with this (including if non-802.11p uses
> start to share 5G9), but I do recognize that not everyone is convinced yet.
>
>
>
> So, we either take the 5G9 decision slowly enough to let (at least the
> majority of) everyone have time to think it through, or it gets accomplished
> elsewhere, like IEEE 1609/ITS/etc. I believe the latter is being
> considered, so for now, I think within 802.11 we just let 11ak proceed with
> the development at the normal pace.
>
>
>
> Mark
>
>
>
> From: Mark Rison [mailto:m.rison@xxxxxxxxxxx]
> Sent: Friday, March 13, 2015 1:19 PM
> To: Hamilton, Mark; STDS-802-11@xxxxxxxxxxxxxxxxx; 'dickroy@xxxxxxxxxxxx'
> Subject: RE: EPD for OCB in the 5.9 GHz band, or for ICB in any band
>
>
>
> Hello,
>
>
>
> This discussion seems to have gone quiet, and I'm wondering whether it's
>
> just that it's going on in a place I'm not aware of.
>
>
>
> I think that many/most people would agree that if we could save 6 octets
>
> per MSDU by switching from LPD to EPD, that would in principle be desirable.
>
> The concerns are about backward-compatibility (on the assumption a 5G9
>
> device might have to roam to or otherwise support other bands in some
>
> situations).
>
>
>
> It seems to me that we can use EPD with backward-compatibility as long as
>
> we take some precautions:
>
>
>
> - Have an extended capabilities bit to say "I understand EPD". Do not
>
> use EPD to STAs which don't say they understand it (this means all the
>
> STAs, in the case of group-addressed transmissions by an AP; note that
>
> there would be the complexity that an AP receiving an EPD frame from a
>
> STA which is to be broadcast back would have to convert it to LPD if any
>
> STAs didn't understand EPD)
>
>
>
> - Signal the use of EPD through some mechanism, e.g. use of the remaining
>
> unused Data frame subtype (1101), or if PCF/HCCA needs to be supported,
>
> a triplet or quartet of Extension frame subtypes (depending on whether
>
> the non-+CF subtype remains as a Data frame for simplicity with devices
>
> which don't care about PCF/HCCA). A similar technique can be used for
>
> the "PV1" frames with a compressed MAC header introduced by 11ah (there are
>
> enough reserved Types)
>
>
>
> [I am assuming no-one cares about non-QoS STAs enough anymore to worry
>
> about supporting EPD with them.]
>
>
>
> There are other possibilities, such as these, but they seem more hacky to
> me:
>
>
>
> - Special-case the Ethertypes AA-AA (and maybe also E0-E0 and FF-FF per
>
> Tables P-2 and P-3 in P802.11 REVmc/D4.0), saying that if the MSDU starts
>
> with this it's actually LPD, but otherwise it's EPD (this means that in
>
> the worst case, if Ethertypes AA-AA, E0-E0 and FF-FF had to be supported,
>
> they would have to be used with LPD)
>
>
>
> - Have prior agreement on use of EPD, e.g. specified in a relevant standard
>
> (such as DSRC/ITS/11p or 11ah; but as described above there were concerns
>
> about this approach), or dynamically signalled, e.g. via the Extended
>
> Capabilities element in Management frames exchanged before any Data frames
>
> (such as in (Re)Association Request/Response frames in an infrastructure
> BSS)
>
>
>
> - Find some other MAC header bit to signal use of EPD
>
>
>
> Any thoughts? Think of all those octet sextuples we could save!
>
>
>
> Mark
>
>
>
> --
>
> Mark RISON, Standards Architect, WLAN English/Esperanto/Français
>
> Samsung Cambridge Solution Centre Tel: +44 1223 434600
>
> Innovation Park, Cambridge CB4 0DS Fax: +44 1223 434601
>
> ROYAUME UNI WWW: http://www.samsung.com/uk
>
>
>
> From: *** IEEE stds-802-11 List *** [mailto:STDS-802-11@xxxxxxxx] On Behalf
> Of Hamilton, Mark
> Sent: 14 January 2015 06:07
> To: STDS-802-11@xxxxxxxxxxxxxxxxx
> Subject: [STDS-802-11] Presentation and motion in mid-week plenary - EPD for
> OCB in the 5.9GHz band
>
>
>
> --- This message came from the IEEE 802.11 Working Group Reflector ---
>
> All,
>
>
>
> I have requested that Adrian add this topic to the mid-week plenary agenda:
> EPD (EtherType) format for MSDUs for OCB/ITS communications in the 5.9GHz
> band.
>
>
>
> Material can be found here:
> https://mentor.ieee.org/802.11/dcn/14/11-14-1521-04-000m-epd-for-ieee802-11-5-9ghz-operations.pptx
>
>
>
> I will be asking the WG for a Straw Poll, and likely a Motion, to gauge the
> support for this proposal before requesting it be considered by TGmc.
>
>
>
> Please review the materials ahead of the mid-week plenary, if possible, and
> be prepared to indicate whether you can support the proposal.
>
>
>
> Also, please let me know if you have any questions, of course.
>
>
>
> Mark Hamilton
>
>
>
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