[STDS-802-11-TGBE] 答复: [STDS-802-11-TGBE] Discussion on ESS Report eleme

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Hi Atsushi,

If we strictly stick to the current text as shown in below, it should be my understanding.

The Planned ESS subfield indicates whether the BSS is part of an ESS that is planned with several BSSs (not APs) in

an overlapping configuration. This subfield is set to 1 to indicate that the ESS is deployed to ensure blanket

coverage over the Extended Service Area (ESA). 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 (not the AP) is at the edge of the ESS. This subfield is set to 1 to

indicate the BSS is at the edge of the ESS. Otherwise, this subfield is set to 0.

Regards

Guogang Huang

发件人: SHIRAKAWA Atsushi [mailto:shirakawa.atsushi@xxxxxxxxxxx]
发送时间: 2022年5月11日 11:46
收件人: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
主题: Re: [STDS-802-11-TGBE] Discussion on ESS Report element

Hi Guogang

My consideration towards “Planned ESS” is similar as what Thomas mentioned below

I believe the original intent of the Planned ESS subfield definition “ESS that is planned with several BSSs” was to describe a network comprising multiple physical APs in different locations - not simply a single physical AP operating multiple bands.

I mean ESS Report element would not help STA to roam from AP1’s band to AP2’s band.. In the case a STA is capable of operation on only AP1’s band, the STA cannot roam to AP2’s band. So I thought the STA check ESS Report element from AP1 and know whether it is at Edge of ESS of AP1’s band.

I’m not sure it might be deployment dependent issue and both you and me may be right, need any other opinion.

Atsushi

From: huangguogang <huangguogang1@xxxxxxxxxx>
Sent: Tuesday, May 10, 2022 3:34 PM
To: 白川淳/研究員 <shirakawa.atsushi@xxxxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: 答复: [STDS-802-11-TGBE] Discussion on ESS Report element

Hi SHIRAKAWA,

I don’t why co-located AP 1 and AP 2 shall have the same value for Edge of ESS. Do you have the text to support you?

According to the following text, we can see the Edge of ESS subfield is used for roaming. Hence, it is set based on the AP’s coverage. Even for collocated AP 1 and AP 2, if they have different coverages, the Edge Of ESS subfield can be set to the different value.

Regards

Guogang Huang

发件人: SHIRAKAWA Atsushi [mailto:shirakawa.atsushi@xxxxxxxxxxx]
发送时间: 2022年5月9日 16:33
收件人: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
主题: Re: [STDS-802-11-TGBE] Discussion on ESS Report element

Hi Guogang

Is it correct that your drawing indicates Edge of ESS for AP1 = 0 even though Edge of ESS for AP2 = 1 ?

I thought co-located AP 1 and AP2 have same value for Edge of ESS.

If those have different value as you drew

a non-AP STA operating on AP1’s band has different Edge from another non-AP STA operating on AP2’s band,

and the latter have no Edge, it seems weird for me.

If my assumption is correct

a non-AP STA just check existing 11ax Edge of ESS

and new Edge of ESS For MLDs is not required.

From: huangguogang <000017b1384624cd-dmarc-request@xxxxxxxxxxxxxxxxx>
Sent: Saturday, May 7, 2022 11:50 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-11-TGBE] 答复: [STDS-802-11-TGBE] Discussion on ESS Report element

Hi Thomas,

Thanks for your discussion. The Planned ESS for MLDs subfield can tell the associated non-AP MLD whether there is neighboring AP/AP MLD to which it can transition base on the recommended RSSI threshold.

For the Edge Of ESS for MLDs subfield, If we consider that some non-AP MLD cannot support some band, then it will not probe the info on that link. In this case, the non-AP MLD doesn’t need to probe all links of the AP MLD. That’s why I add this subfield.

Regards

Guogang Huang

发件人: Thomas Derham [mailto:thomas.derham@xxxxxxxxxxxx]
发送时间: 2022年5月4日 2:25
收件人: huangguogang <huangguogang1@xxxxxxxxxx>
抄送: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
主题: Re: [STDS-802-11-TGBE] Discussion on ESS Report element

Because the Planned ESS subfield shall be always set to 1 for the legacy STA if the AP MLD has more than one affiliated AP.

Not clear to me why that is a problem… Effectively it just means that the Edge of ESS and Recommended … RSSI Thresholds fields are actually defined (not reserved).

The value of Edge Of ESS For MLDs subfield = the value of the Edge Of ESS subfield of affiliated AP 1∨ the value of the Edge Of ESS subfield of affiliated AP 2∨…∨the value of the Edge Of ESS subfield of affiliated AP n

I’m not sure this complexity is really necessary. If the non-AP MLD is using multiple links, it can derive this value from the existing ESS Reports on each link, without defining new fields.

Thanks

Thomas

On Apr 29, 2022 at 12:28:26 AM, huangguogang <000017b1384624cd-dmarc-request@xxxxxxxxxxxxxxxxx> wrote:

Hi all,

I initiate this thread to discussion 1931r4. I would like to explain the setting of these subfields in the ESS Report element by using two examples.

Since all APs affiliated with the same AP MLD have the same SSID and belong to the same ESS, the existing Planned ESS subfield and Edge Of ESS subfield cannot be used to assist the roaming for the non-AP MLD. Because the Planned ESS subfield shall be always set to 1 for the legacy STA if the AP MLD has more than one affiliated AP.

In the following, I will give two examples to explain the setting of these subfields. In scenario 1, since there is no neighboring AP or AP MLD, the Planned Of ESS For MLDs subfield is set to 0. But for a legacy STA, since it can initiate a BSS transition between AP 1 and AP 2, the Planned Of ESS subfield is set to 1.

Scenario 1: Single AP MLD

In scenario 2, since a non-AP MLD can initiate a BSS transition among AP MLD 1, AP MLD 2 and AP 3, the Planned Of ESS For MLDs subfield is set to 1.

Scenario 2 with non-co-located multiple APs or AP MLDs belonging to the same ESS

When there is at least one affiliated AP that sets the Edge Of ESS subfield to 1, then the Edge of ESS For MLDs shall be set to 1, which can be expressed as the following formula:

The value of Edge Of ESS For MLDs subfield = the value of the Edge Of ESS subfield of affiliated AP 1∨ the value of the Edge Of ESS subfield of affiliated AP 2∨…∨the value of the Edge Of ESS subfield of affiliated AP n

Please reply with your comments.

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