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802.11 -- Interworking with 802.1Qat Stream Reservation Protocol. Date: 2010-01-19. Authors:. Abstract. This submission is an overview of proposed input from 802.11 to 802.1Qat Annex-Q Clause Q.2. A companion word document will be generated when the details in this submission are finalized.
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802.11 -- Interworking with 802.1Qat Stream Reservation Protocol Date: 2010-01-19 Authors: Ganesh Venkatesan, Intel Corporation
Abstract This submission is an overview of proposed input from 802.11 to 802.1Qat Annex-Q Clause Q.2. A companion word document will be generated when the details in this submission are finalized. Includes inputs from the 802.11aa teleconference on Aug 10th, 2009 and has been iteratively refined in later teleconferences/meetings. Slide 2 Ganesh Venkatesan, Intel Corporation
Overview • Annex-Q in IEEE 802.1Qat-Draft 3.2 is informative and describes implementation details for a Designated MSRP Node (DMN). 802.1Qat has decided to mark Annex-Q as normative. • From 802.11’s perspective, the DMN is co-located with the device that supports the QAP function in a BSS • When stream reservations are made the following needs to be completed: • Appropriate TSPECs are passed to the QAP in order to accomplish the desired level of QoS for the stream (Cl. Q.2.2 Table Q-4) • All protocol and MLME interface semantics are maintained within 802.11 (Cl. Q.2.2 Table Q-3) • Goals are to • make no or minimal changes to Q-STAs and • render the DMN implementation as agnostic to the underlying link technology (802.11, MoCA, etc.) used. Ganesh Venkatesan, Intel Corporation
Handling SRP Reservation Requests Ganesh Venkatesan, Intel Corporation
Topologies • Figure Q-5 Talker is wired to the Q-AP. Listeners can be STA(s) in the BSS or device(s) wired to the Q-STA(s) in the BSS, • Figure Q-6 Talker is wired to a Q-STA in the BSS. Listeners can be other Q-STA(s) in the BSS and/or device(s) wired to the Q-AP/Q-STA(s) • Figure Q-7 Talker is wired to a Q-STA (STA-A) in the BSS. Listener is another Q-STA in the BSS which has a direct link established with STA-A. Ganesh Venkatesan, Intel Corporation
Case-1: STA is the Talker/Listener Listener(s) Listener(s) DMN DMN Q-AP Q-AP Q-AP Q-STA Q-STA Q-STA Q-STA Q-STA Talker Talker Listener(s) Talker Listener(s) Ganesh Venkatesan, Intel Corporation
Case-2: STA is an Intermediate node or a Talker/Listener • Q-STA are intermediate nodes, Talker or Listener • Q-STAs need to understand the new Reserve action frame • Q-STAs need not parse SRP reservation message • The additional complexity is limited to the Q-AP • Note: This scenario is included for completeness. Support for this requires resolution of the “Station Bridge issue*”. Talker/Listener(s) DMN Q-AP Q-STA Q-STA Listener(s) Talker Listener(s) * See http://www.ieee802.org/1/files/public/docs2008/avb-nfinn-802-11-bridging-0308-v3.pdf Ganesh Venkatesan, Intel Corporation
Case-3: STA is the Talker/Listener DMN Q-AP SRP Control Flow Q-STA Q-STA Listener(s) Talker Listener(s) Dqta Flow Ganesh Venkatesan, Intel Corporation
MSPRDU Processing at the Q-AP/DMN • A Q-STA can either be Talker/Listener or an intermediate node in the path from the Talker to the Listener. • An intermediate node Q-STA or a Q-STA that is also the Talker/Listener just pass the MSRPDU to the Q-AP • Q-AP forwards the MSRPDU to the Q-AP’s DMN • Q-AP’s DMN invokes MLME-Reserve.request or MLME-Query.request with parameters corresponding to the received SRP Reservation/Query request • If the MSRPDU is a Reservation Request and the Q-AP has sufficient resources: • Q-AP’s SME issues a MLME.ADDTS.response to the talker • Q-AP’s SME issues a MLME.ADDTS.response to the listener • Q-AP responds to the DMN with a MLME-Reserve.confirm or MLME-Query.confirm Ganesh Venkatesan, Intel Corporation
Case 2: MSRP Handling at Q-AP/DMN (to Talker/Listener) Ganesh Venkatesan, Intel Corporation
Case 2: MSRP Handling at Q-AP/DMN (to Talker/Listener) (Modified) Ganesh Venkatesan, Intel Corporation
Table Q.3 SRP to MLME QoS Services Mapping MAD – MRP (Multiple Registration Protocol) Attribute Declaration Ganesh Venkatesan, Intel Corporation
Table Q.3 SRP to 802.11 SME QoS Services Mapping (Modified) MAD – MRP (Multiple Registration Protocol) Attribute Declaration Ganesh Venkatesan, Intel Corporation
Changes to 802.11 -- Summary Ability for QAPs to send Autonomous ADDTS Response Add MLME-QUERY.{request|confirm} Modify MLME-ADDTS.{request|confirm} Allow MLME-ADDTS.{request|confirm} to be invoked at the AP STA 802.1Qat Mandate that 802.11 STAs and APs supporting SRP shall also support EDCA Admission Control The 802.11 AP and SRP DMN shall co-exist in the same device The SRP DMN shall generate 802.11 TSPECs as described in slide and slide Mandate that 802.11STAs and APs supporting SRP shall encapsulate and de-encapsulate the 802.1q Tag Ganesh Venkatesan, Intel Corporation
Changes to 802.11 – Summary (Modified) • Ability for QAPs to send Autonomous ADDTS Response • To the DMN 802.11 interface (out of scope for 802.11) • Add SME-QUERY.{request|confirm} • Add SME-ADDTS.{request|confirm} 802.1Qat Mandate that 802.11 STAs and APs supporting SRP shall also support EDCA Admission Control The 802.11 AP and SRP DMN shall co-exist in the same device The SRP DMN shall generate 802.11 TSPECs as described in slide and slide Mandate that 802.11STAs and APs supporting SRP shall encapsulate and de-encapsulate the 802.1q Tag Ganesh Venkatesan, Intel Corporation
Mapping SRP Traffic classes to 802.11 TSPECs Ganesh Venkatesan, Intel Corporation
TSPEC mapping (from July joint meeting) 802.11 TSPEC mapping to 802.1Qav TSPEC 802.11 QoS mechanisms: EDCA-AC HCCA What is the delay over a 802.11 link? Power save introduces at least 20msec delay What is possible for delay/frame size/rate in .11? 08/10/2009 teleconference – 4000 intervals per second. How many frames get sent in an interval depends on max frame size – What can 802.11 do in 250 usecs? Slide 17 Ganesh Venkatesan, Intel Corporation
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 WMM IEEE 801.D User Priority Up Down Bi 0-7 WMM 8-15 HCCA 1=APSD 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 Ganesh Venkatesan, Intel Corporation
Minimum PHY Rate Derivation • Overhead = 10 byte VLAN tag + 8 byte Protocol definition • Mean Data Rate = (SRP TSpec MaxFrameSize+overhead) * SRP TSpec MaxIntervalFrames bytes/sec • The Mean Data Rate is also the Max Data Rate (since we assume MSDU size is fixed). • Assuming 70%* efficiency between the MAC and the PHY this translates into (10/7)* (SRP TSpec MaxFrameSize+overhead) * SRP TSpec MaxIntervalFrames bytes/sec (10/7) * 8 * (SRP TSpec MaxFrameSize+overhead) * SRP TSpec MaxIntervalFrames bits/sec • Minimum PHY Rate is = 11.42857 *(SRP TSpec MaxFrameSize + overhead) * SRP TSpec MaxIntervalFrames bits/sec • E.g., • With 1500 and 4000 for MaxFrameSize and MaxIntervalFrames the above turns into 69.394285 (~78Mbps) • For 64 byte SRP payload the equivalent minimum PHY rate is 3.748571 Mbps Ganesh Venkatesan, Intel Corporation
EDCA-AC (Input to 802.1Qat) *Time in usecs between when the frame arrived at the transmitting MAC to when it is transmitted to the destination – includes reception of any required Acknowledgements. + 20% surplus allocation 2 Bit-15 set to 1, indicates that the MSDU size is fixed Ganesh Venkatesan, Intel Corporation
TSPECs for HCCA 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.) Ganesh Venkatesan, Intel Corporation
TSPECs for HCCA Ganesh Venkatesan, Intel Corporation
How User Priority is preserved end-to-end The priority from 802.1 is in the 802.1q Tag To preserve the priority end-to-end the 802.11aa STA shall encapsulate the VLAN Tag using a 10 byte SNAP encoding as shown in the example above Ganesh Venkatesan, Intel Corporation
Table Q-4 • Recommend replacing this table with two tables • EDCA-AC for Class-B (Table from slide) • HCCA for Class-B (Table from slide) Ganesh Venkatesan, Intel Corporation
QoS Maintenance Report • 802.11k provides a transmit stream/category measurement report. This report can be generated based on a trigger. • SRP DMN may use the MLME-MREQUEST.request to setup triggers for the specific stream in order to generate triggered transmit stream/category measurement reports as needed to generate reports when channel conditions deteriorate • Based on the data in the triggered transmit stream/category measurement report, the SRP DMN can generate appropriate QoS Maintenance Report. Ganesh Venkatesan, Intel Corporation
References 802.11 QoS Tutorial (08/1214r02) http://www.ieee802.org/1/files/public/docs2008/avb-nfinn-802-11-bridging-0308-v3.pdf Annex-K Example Use of TSPEC for Admission Control in Draft 803.11Revmb_D1.0.pdf 802.11n Slide 26 Ganesh Venkatesan, Intel Corporation