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Joint meeting with 802.1AVB. Date: 2009-07-12. Authors:. This is a work-in-progress version. Proposed Agenda. What is the worst case delay when streaming under different conditions over a 802.11 link?
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Joint meeting with 802.1AVB Date: 2009-07-12 Authors: Ganesh Venkatesan, Intel Corporation
This is a work-in-progress version Ganesh Venkatesan, Intel Corporation
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 3 Ganesh Venkatesan, Intel Corporation
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; Slide 4 Ganesh Venkatesan, Intel Corporation
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 [TBD] What other data makes the most sense? [TBD] Is there a 802.11k/v measurement we could use to deduce this data? [TBD] Do we need additional mechanisms defined? Slide 5 Ganesh Venkatesan, Intel Corporation
TSPEC mapping <wip> 802.11 TSPEC mapping to 802.1Qav TSPEC Adapt from 08/1214r2. Slide 6 Ganesh Venkatesan, Intel Corporation
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 7 Ganesh Venkatesan, Intel Corporation
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 8 Ganesh Venkatesan, Intel Corporation
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
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
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 11 Ganesh Venkatesan, Intel Corporation
Status Update -- TGaa Draft 0.01 is available – specifies mechanisms for reliable/robust groupcast 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 12 Ganesh Venkatesan, Intel Corporation
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 13 Ganesh Venkatesan, Intel Corporation
Goals for the November joint meeting To be updated at the joint meeting Slide 14 Ganesh Venkatesan, Intel Corporation
Questions from 802.11 Where is the Drop Eligibility bit? SCS processing in .11aa – how completely does it map into AVB? Does AVB differentiate between B, P and I frames with unique tags? Slide 15 Ganesh Venkatesan, Intel Corporation