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Hello Mark, Please read my reply in line. Thanks, Lin From: Mark Rison [mailto:m.rison@xxxxxxxxxxx]
Hello Lin, > DiffServ solutions are designed to improve the network QoS performance in general. Right, but unless there is enforcement/metering then everyone will just claim that their traffic is top-priority. [L] When the optional feature is implemented, the STAs shall follow the standard to determine its priority based on the specified criteria in the DILS element.
> When the optional feature of DILS is implemented, high priority STAs can have better chance to associate with the AP with shorter delays. But conversely low-priority STAs will have a lower chance of associating. As a STA, why would I take the chance, rather than just use non-DILS mechanisms which don't risk deprioritising me?
[L] This is not a new question and we have extensively discussed this issue in TGai in the last couple of years. Basically DILS can improve the association performance of high priority STAs but not necessarily sacrifice the delay performance
of low priority STAs. We have shown some simulation results of DiffServ performance with contention based CSMA/CA MAC that a differentiated coordination can help improve the performance of all STAs in the network in the bursty channel access case in previous
meetings [back in 2012]. If every STA likes to greedily take the chance for channel access, all STAs may suffer from overly delay, which could be larger than the delay of low priority STAs using differentiated channel access, due to the contention nature of
CSMA/CA. Again, DiffServ is a networking solution that requires the coordination of both AP and STAs. Even part of STAs follow the DILS mechanism while some others ignore it, the bursty channel access can still be alleviated and delay performance
can be improved. > This is the motivation of the non-AP STA to use DILS.
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: Lin Cai [mailto:Lin.Cai@xxxxxxxxxx]
Hello, DiffServ solutions are designed to improve the network QoS performance in general. When the optional feature of DILS is implemented, high priority STAs can have better chance to associate with the AP with shorter
delays. This is the motivation of the non-AP STA to use DILS. Best regards, Lin From: Mark Rison [mailto:m.rison@xxxxxxxxxxx]
Hello, I have a concern about the resolution for CID 4841. The comment was: What is the incentive for a non-AP STA to use DILS? The resolution was: Rejected. DILS is used to improve the link setup performance in pre-association stage by differentiating STAs with different priorities. The incentive for non-AP
STA is similar to that of EDCA which is used for associated STAs. However, DILS is optional, while EDCA is mandatory (for QoS STAs), so the analogy does not work. Hence DILS will only be used if it provides a benefit -- what is the benefit for a given STA (as opposed to the BSS)? Why would a STA choose to set dot11DILSActivated to true? 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:
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