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[STDS-802-11-TGBE] CR doc 22/1709 - Requesting feedback on add/delete link procedure

Hi all,

 

I presented CR doc 22/1709r4 during the TGbe Nov plenary session which proposes add/delete link procedures for dynamically adding a link to the ML setup or deleting a link from the ML setup of a non-AP MLD.

 

There were some concerns raised by Ming and Yongho on the proposal. I tried to initiate small group discussions to understand and address their concerns, however due to holidays time, it is hard to find a suitable time slot which works for most.

Hence, I am initiating this discussion on the reflector to hear their concerns and make progress on this CR doc.

 

I would like to briefly summarize below the reasons/benefits for this proposal, to help the group better understand.

  • Add Link - Currently the spec does not define any action for the non-AP MLD to take when a new affiliated AP is added to the AP MLD. If the non-AP MLD wants to add a link to the new AP it is forced to do a re-association, which is very disruptive as it clears all the context on BA, security etc. and interrupts ongoing transmissions on existing links. The add link procedure in 22/1709 proposal a mechanism for seamlessly adding a link to the ML setup of the non-AP MLD without requiring a re-association - it maintains current BA and security context and does not cause any interruption to ongoing transmission on existing links. This is a highly desirable behavior for adding a link to an ML setup.
  • Delete Link – In current spec if a non-AP MLD intends to delete a link from its ML setup, there is no procedure defined for it to do that. It still has to keep using resources for maintaining the link as part of ML setup even if it moves that link to Power save or negotiate a TID-to-link mapping excluding that link. The delete link procedure in 22/1709 allows explicit deletion of a link from the ML setup and frees up resources for both the non-AP MLD and AP MLD and simplifies link management.

 

@Ming – please provide your specific concerns on the add link and delete link procedure. You expressed some concerns on delete link procedure during the call and below are my responses on those. You didn’t express any technical concerns on the add link part, so are you fine with the proposed add link procedure?

  • You mentioned that non-AP MLD can use the power save or negotiate a new T2L mapping for disabling a link from its ML setup. That is possible but that still requires both sides to keep using resources to maintain the disabled link as I mention above. It is desirable to provide an explicit mechanism to remove the link to simplify the link management for both sides.
  • You also mentioned that Advertised T2LM can be used for deleting a link. That feature is defined for disabling a link for the entire AP MLD level and not for deleting a link from the ML setup of a specific non-AP MLD. So, the Advertised T2LM can’t be used for deleting a link from the ML setup of a non-AP MLD.

 

@Yongho – please provide your specific concerns on the add/delete link procedure. The main concern I heard from you is that this is a new feature, and it could impact other parts of the spec and hence should be addressed in UHR timeframe. I think this feature is pretty self-contained and if there is any impact on some other part of the spec, it would be minor clarification, not any big technical change. Please let me know what specific spec impact you are concerned about (if any). BTW, this feature has been discussed in the group previously in 11-21/0534 CR doc, so this is not a new feature being discussed first time. I also understand that at that time the group’s direction was that this feature could be brought back in D2.0, and that’s what we are doing here. So, shouldn’t reject this feature saying that this is a new feature.  

 

Again, I would like to understand your specific concerns and find ways to address those to make progress on this proposal in D2.0 timeframe.

 

Others – please let me know if you have any feedback/comments on the proposal.

 

Thanks,

Binita

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