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Joint meeting with 802.1AVB

Joint meeting with 802.1AVB. Date: 2009-07-16. Authors:. Proposed Agenda. What is the worst case delay when streaming under different conditions over a 802.11 link? Is there a mechanism specified in 802.11 to propagate the worst case delay under current conditions, to upper layers?

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Joint meeting with 802.1AVB

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  1. Joint meeting with 802.1AVB Date: 2009-07-16 Authors: Ganesh Venkatesan, Intel Corporation

  2. Proposed Agenda What is the worst case delay when streaming under different conditions over a 802.11 link? Is there a mechanism specified in 802.11 to propagate the worst case delay under current conditions, to upper layers? 802.11 TSPEC mapping to 802.1Qav TSPEC How are QoS errors fed back from the 802.11 MAC? SRP over 802.11 – need for relaying stream information (09/403r0) – list choices, pros/cons of each for discussion jointly Status Update on 802.11aa Status Update on 802.11v Goals for the November 2009 joint meeting Slide 2 Ganesh Venkatesan, Intel Corporation

  3. Worst Case delays over a 802.11 link What is the worst case delay when streaming under different conditions? Good conditions: 1msec, Moderate – 8 msec and Heavy congestion - 800 msec Delay depends on Subset of options used Channel conditions Power Save options used Slide 3 Ganesh Venkatesan, Intel Corporation

  4. Mechanisms Are there mechanisms specified in 802.11 to propagate the worst case delay under current conditions, to upper layers? QoS APs report BSS Access Category Access Delay (7.3.2.44) Average medium access delay as seen by a QoS AP in transmitting a frame belonging to an AC QoS non-AP STAs do not report this value Discussion Topic(s): Is BSS Access Category Access Delay the right metric? If so, do we need a triggering mechanism? What other data makes the most sense? Is there a 802.11k/v measurement we could use to deduce this data? Do we need additional mechanisms defined? Slide 4 Ganesh Venkatesan, Intel Corporation

  5. TSPEC mapping 802.11 TSPEC mapping to 802.1Qav TSPEC 802.11 QoS mechanisms: EDCA-AC HCCA Jointly fill-in this table Then fill in the TSPEC template Slide 5 Ganesh Venkatesan, Intel Corporation

  6. TSPEC Element TSPEC Body format RED indicates required parameters used in Admission Control TSPEC Value returned by AP if Admission Accepted (Admission Control) TS Info Field TSPEC Element 801.D User Priority Up Down Bi 1=APSD 0-7 WMM 8-15 HCCA Access Policy EDCA, HCCA Note: Often TID 0-7 = UP * Reproduced from https://mentor.ieee.org/802.11/dcn/08/11-08-1214-02-00aa-11e-tutorial.ppt Graham Smith, DSP Group

  7. TSPECs for HCCA (WMM-SA) The basic QoS requirements such as jitter, latency, bandwidth etc are defined by the TSPEC • ‘Standard’ TSPECs exist for: • Voice • Multi-Media (Video) • Audio STAs send information on their TC and TSPEC, this allows HC to allocate the TXOPs and calculate QoS requirements (jitter, latency, bandwidth, etc.) Graham Smith, DSP Group

  8. 802.11 TSPEC (EDCA-AC) for SR Class-A Ganesh Venkatesan, Intel Corporation

  9. 802.11 TSPEC (EDCA-AC) for SR Class-B Ganesh Venkatesan, Intel Corporation

  10. How are QoS Errors fed back? Traffic Stream/Category measurement report (7.3.2.22.10) Transmitted MSDU MSDU Discarded MSDU Failed MSDU Multiple Retry QoS CF-Polls Lost Average Queue Delay Average Transmit Delay Transmit Delay histogram in 6 bins Optional elements Triggers can be set to generate appropriate reports (7.3.2.21.10) STA Statistics Report – QoS statistics specific to a User Priority (7.3.22.8) TransmittedFragmentCount, FailedCount, RetryCount, MultipleRetryCount, FrameDuplicateCount, RTSSuccessCount, RTSFailureCount, ACKFailureCount, ReceivedFragmentCount, TransmittedFrameCount,DiscardedFrameCount , MPDUsReceivedCount, RetriesReceivedCount Triggers can be set to generate appropriate reports (TGv) Slide 10 Ganesh Venkatesan, Intel Corporation

  11. SRP over 802.11 How to carry SRP frames over 802.11 while keeping the SRP and 802.11 state machines stay consistent? How would AVB framework access the 802.11 management interface for feedback on the state of the 802.11 link? Document 09/403r0 provides background information Slide 11 Ganesh Venkatesan, Intel Corporation

  12. MSRPDU Handling* MSRPDU are transmitted “as is” in 802.11 data frames and delivered to the DMN DMN interacts with the AP through the AP’s MLME SAP DMN MSRPDU 802.11e MLME TS Service Primitive SAP STA AP MLME * Reproduced from http://www.ieee802.org/1/files/public/docs2009/avb-phkl-dmn-80211-0903.pdf Ganesh Venkatesan, Intel Corporation

  13. MSRP / 802.11e Flow* STA AP Eth DMN MSRPDU 802.11e MLME Request 802.11 BW Reservation 802.11e MLME Response MSRPDU reproduced from http://www.ieee802.org/1/files/public/docs2009/avb-phkl-dmn-80211-0903.pdf Ganesh Venkatesan, Intel Corporation

  14. SRP over 802.11 What MLME primitive gets used? MLME-ADDTS semantics not defined for APs Need support for unsolicited ADDTS response Slide 14 Ganesh Venkatesan, Intel Corporation

  15. SRP over 802.11 Higher layers have the burden of using appropriate 802.11 MLME primitives in order to keep the state of 802.11 link consistent – slide-8 Choices: Define additional primitives (frames) to support SRP Require SRP to invoke appropriate primitives to keep the 802.11 protocol consistent May need both Slide 15 Ganesh Venkatesan, Intel Corporation

  16. Status Update -- TGaa Draft 0.01 is available – specifies mechanisms for reliable/robust groupcast (MRG) over 802.11 Reviewed a proposal on mitigating issues due to Overlapping BSS Reviewed a proposal for graceful degradation (Drop Precedence) and Intra-AC prioritization This proposal also enables some 802.1AVB features over a 802.11 link Slip in TGaa timeline – goal was to have draft1.0 by November 2009 Slide 16 Ganesh Venkatesan, Intel Corporation

  17. Status Update -- TGv Letter Ballot 150 completed 140 Comments received Currently resolving comments Expect initial Sponsor Ballot in Oct/Nov 2009 Timing Measurement Feature has not changed as a result of LB150 An extension has been proposed to the Timing Measurement feature – render the timestamp information exchanged to be symmetric In order to allow for sufficient review of the extension, the extension will be considered in Sponsor Ballot Slide 17 Ganesh Venkatesan, Intel Corporation

  18. Goals for the November joint meeting To be updated at the joint meeting Slide 18 Ganesh Venkatesan, Intel Corporation

  19. Questions from 802.11 Where is the Drop Eligibility bit? TCLAS processing in .11aa – how completely does it map into AVB? Does AVB differentiate between B, P and I frames with unique tags? Slide 19 Ganesh Venkatesan, Intel Corporation

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