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Re: [STDS-802-11-TGBE] about A3 reused for ML address(672R2)



Hi Jay, 
You are just misunderstanding the SP. 
The SP didn't say that the A3 field is set to the MLD MAC address. It said that the SA field is set to the MLD MAC address. 

An AP MLD that broadcasts the group addressed MPDU received from a non-AP MLD with which it has done multi-link setup shall set the SA field of the broadcast group addressed MPDU to the MLD MAC address of the non-AP MLD. 
A non-AP MLD filters out the group addressed MPDU with the SA field set to the MLD MAC address of the non-AP MLD. 

You made an issue with a wrong example. In your example, the 4-address format contains the SA in the A4 field. If needed, the SP said that the A4 field is set to the MLD MAC address.   

>> BTW, I understand the A3 used to indicate DA in SPEC, not SA, could you double confirm it?

This is wrong. The content of the A3 field is varied depending on the MSDU type and the UL/DL. When an AP sends a group-address frame, the A3 field is set to the SA field. 


Regards, 
Yongho 

2020년 8월 31일 (월) 오후 9:19, Yang, Zhijie (NSB - CN/Shanghai) <zhijie.yang@xxxxxxxxxxxxxxx>님이 작성:

Hi Mark,

 

WDS is a typical 4-address format, we could use the concept of 4-address link to replace the WDS concept because you mentioned that it’s removed from the SPEC.

 

I believe the following graph is still alive in current SPEC, and 4-address format is defined in Multi-AP SPEC and extensively used in easy-mesh product.

 

A lot of chipset follows Multi-AP SPEC and use the 4-address format to set up backhaul link between APs in easy-mesh topology.

 

For instance, IPQ8174 and BCM43684 use such 4-address format to set up easy-mesh network.  I don’t know why QCA and BRCM support this intention. It will be harmful to their own product. It’s better we could find a better solution which is not harmful to current SPEC and products.

 

Therefore, I hope the group reconsider this SP.

 

A screenshot of a cell phone

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Thanks

 

Best Regards

 

Jay Yang

 

From: mark.hamilton2152@xxxxxxxxx <mark.hamilton2152@xxxxxxxxx>
Sent: 2020831 23:16
To: Yang, Zhijie (NSB - CN/Shanghai) <zhijie.yang@xxxxxxxxxxxxxxx>; STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: RE: [STDS-802-11-TGBE] about A3 reused for ML address(672R2)

 

Jay,

 

I believe WDS was removed from 802.11 in 2016.

 

However, there are other uses of “four address format”.  In particular, for mesh (does 11be anticipate being used for mesh, I haven’t seen much (if any) discussion about how these concepts map to mesh structures) and for GLK (11ak).  It would be good to make sure the four-address frame format is considered in these addressing discussions.

 

All that said, I think the intent of the proposal, as I understood it, was to effectively say that where in the current spec we have the AP’s address/BSSID, for these frame types that field would contain the MLD MAC address, rather than an affiliated AP’s MAC address.  If we apply that consistently, I think it probably works.

 

Mark

 

From: Yang, Zhijie (NSB - CN/Shanghai) <zhijie.yang@xxxxxxxxxxxxxxx>
Sent: Saturday, August 29, 2020 9:20 AM
To: STDS-802-11-TGBE@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-11-TGBE] about A3 reused for ML address(672R2)

 

Hi Yongho, Arbi,

 

I see you propose to reuse A3 for ML address on Group addressed frame, and individual mgmt. frame. I think it still need more discussion before we make such decision, see my explanation below.

 

@Yongho Seok,  As you know, WDS uses 4-address to indicate the RA/TA/DA/SA, and RA is not equal to DA, TA is not equal to SA as well.

I’m afraid your SP will cause WDS link not works although it is passed. That’s why I said it will bring other issues in the meeting.

BTW, I understand the A3 used to indicate DA in SPEC, not SA, could you double confirm it?

 

 

I make the following example to illustrate  this:

 

AP1 (WIFI MAC: 72:11:22:33:00:88)and AP2 (MAC: 6a:47:d0:2f:e1:db)set up WDS link, and then we set up two sessions in higher layer, and DA can be used to distinguish the two session. AP1 sends these group addressed pkts to AP2. (We Convert grouped address pkt to unicast pkt in this case, so it’s shown with unicast RA). The sniffer log graph shown as below:

In this case, it’s not correct to reuse A3 for ML MAC address.

 

A screenshot of a cell phone

Description automatically generated

 

 

A close up of text on a black background

Description automatically generated

 

@Abhishek Patil, I don’t have the enough time to check individual mgmt. frame,  could you help double confirm it?  I understand only data frame use 4-MAC address for WDS link, but not very sure on this.

 

Thanks

 

Best Regards

 

Jay Yang

 


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