I think we need to be extremely careful with deleting features that are in current use in industry.
The main point of this feature is for the planned/managed network to assist non-AP STAs in roaming. And to furthermore indicate when they are leaving said area. Think stadium or shopping mall or office building where transitions between
BSS’s are designed as best as possible to a specific RSSI and absence of coverage when leaving the ESS/ESA.
There is no implied guarantee of “no coverage holes”, as such a guarantee is pretty much impossible with the randomness of RF propagation. I’m not clear on the background of the comment, but if the issue is with “ensure blanket coverage”,
you could change the wording to “…the ESS is deployed to provide coverage to the best of our ability over the ESA…”.
Or is the issue with ESA? This I don’t understand since in 802.11-2020 we have “extended service area (ESA): The area within which members of an extended service set (ESS) can communicate. An ESA is larger than or equal to a basic service
area (BSA) and might involve several basic service sets (BSSs) in overlapping, disjointed, or both configurations.” Even in the definition of ESA, they use the term “disjointed”, so no guarantee of perfect coverage.
As such, I think the original wording covers the intent of feature clearly enough.
Regards,
Eldad
From: Mark Rison <m.rison@xxxxxxxxxxx>
Sent: Tuesday, March 15, 2022 1:59 AM
To: mark.hamilton2152@xxxxxxxxx; STDS-802-11-TGM@xxxxxxxxxxxxxxxxx; Perahia, Eldad <eldad.perahia@xxxxxxx>
Subject: RE: [STDS-802-11-TGM] CID 2315 re-consideration - was [Pull requests for today's motions]
> I believe Mark R is trying to get to the idea there are no physical area gaps between the BSAs. 1) I’m not sure how to say that (other than some term like convex hull – although I’ve never heard convex hull applied to shapes, only to
points); and 2) I’m not convinced that we have a consensus understanding that the ESA was meant to imply such “non-disconnected” coverage area.
> I’m inclined to stick with just deleting this concept. I know Mark R disagrees.
[I'm not a mathmo, so I may well be using "convex hull" incorrectly.
An alternative could be "The combination of the BSAs is topologically
equivalent to a sphere, i.e. no holes."]
The problem is that if you delete "Planned ESS" then the remaining fields
in the (ESS Report) element are reserved, and hence there's no point
having the element at all.
I think the intent was that if you're in a "Planned ESS" then you
can find out when you're about to walk out of the ESS (because the
Edge Of ESS subfield is set). This doesn't work so well, in general,
if there are "holes" in the ESS coverage.
I suppose you could argue that it's OK if there a "holes" as long
as all the BSSes that are not completely surrounded by other BSSes of
the same ESS advertise they're at the edge. In that case maybe the
rules would be something like:
The Planned ESS subfield indicates whether the BSS is part of an ESS that is planned with several BSSs in
an overlapping configuration. This subfield is set to 1 to indicate that the ESS is deployed to ensure
that a STA can move from any BSS in the ESS to any other BSS in the ESS while remaining in the
BSA of at least one BSS in the ESS at all times. Otherwise, this subfield is set to 0 and the Edge Of ESS
and Recommended BSS Transition RSSI Threshold Within ESS subfields are reserved.
The Edge Of ESS subfield indicates whether the BSS is at the edge of the ESS. This subfield is set to 0 to
indicate the BSS is not at the edge of the ESS, i.e. that the BSA overlaps with the BSA of another BSS of
the ESS in every direction. Otherwise, this subfield is set to 1.
? That gets rid of the term "ESA" too.
I vaguely recall that Eldad presented this (although searching Mentor
doesn't support this recollection), so maybe he can help.
Thanks,
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: Mark Hamilton <mark.hamilton2152@xxxxxxxxx>
Sent: Monday, 14 March 2022 21:10
To: STDS-802-11-TGM@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-11-TGM] CID 2315 re-consideration - was [Pull requests for today's motions]
--- This message came from the IEEE 802.11 Task Group M Technical Reflector ---
Stephen,
I think it is a tautology that the ESS covers the area that is the union of the BSAs. I would not want to say that (again), and confuse anybody that it wasn’t already the case.
I believe Mark R is trying to get to the idea there are no physical area gaps between the BSAs. 1) I’m not sure how to say that (other than some term like convex hull – although I’ve never heard convex hull applied to shapes, only to points);
and 2) I’m not convinced that we have a consensus understanding that the ESA was meant to imply such “non-disconnected” coverage area.
I’m inclined to stick with just deleting this concept. I know Mark R disagrees.
Mark
From: Stephen McCann <mccann.stephen@xxxxxxxxx>
Sent: Monday, March 14, 2022 3:05 PM
To: STDS-802-11-TGM@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-11-TGM] CID 2315 re-consideration - was [Pull requests for today's motions]
--- This message came from the IEEE 802.11 Task Group M Technical Reflector ---
Mark,
thanks for your work on this CID 2315:
CID 2315 in MAC-AL: I don't think this is correct. I think the point of "ESA" (albeit perhaps not clear) is that if you have Planned ESS set then you know there are no "dead spots" within the area covered by the ESS (i.e. topologically there are no holes). Maybe the wording should be closer to "This subfield is set to 1 to indicate that the ESS is deployed to ensure that there is coverage over the entire area bounded by the convex hull of the BSAs of the BSSes in the ESS"
I think your revised wording is ok, but I would prefer not to introduce "convex hull" as a new topological term into the specification. I think alternative wording could be "This subfield is set to 1 to indicate that the ESS is deployed
to ensure that there is coverage over the entire area bounded by the BSAs of the BSSes in the ESS".
Do you have any further comments? Thanks
Kind regards
Stephen
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