Frequency Allocation by l15I5FV

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									May 2008                                                              doc.: IEEE 802.11-08/0049r1


              Directed Multicast Service (DMS)
Authors:                                Date: 2008-5-10

Name            Company                 Address                  Phone             email
                                        One London Road,
Alex Ashley     NDS Ltd                                          +44 1784 848770 aashley@nds.com
                                        Staines, Middlesex, UK
Raja Banerjea   Marvell Semiconductor   5488 Marvell Lane,       408.222.3713      rajab@marvell.com
                                        Santa Clara, CA
                                        95054
Subbu           Aruba Networks          1322 Crossman Ave,       408-754-1213      subbu@arubanetworks.com
Ponnuswamy                              Sunnyvale CA
Emily Qi        Intel Corporation       2111 NE 25th Ave,        503-264-7799      Emily.h.qi@intel.com
                                        Hillsboro OR
Ganesh          Intel Corporation       JF3-381, 2111NE 25th     +1 503 334 6720   ganesh.venkatesan@intel.com
Venkatesan                              Ave, Hillsboro, OR
                                        97124




Submission                                        Slide 1                                Emily Qi (Intel Corp) et al
May 2008                                  doc.: IEEE 802.11-08/0049r1

                       Background
• The Directed Multicast was presented in TGv
  Orlando meeting.
      – The proposal intends to address CID#89 in TGv LB108
        and CID#503 in TGv LB123
• The issue was raised that Directed Multicast
  proposal may overlap with TGaa Scope:
      – “Improved link reliability and low jitter characteristics
        for multicast/broadcast audio/video streams.”
•      Objectives of the presentation:
      – Review Directed Multicast Proposal
      – Seek for feedback from TGv/TGaa joint meeting.

Submission                     Slide 2                Emily Qi (Intel Corp) et al
May 2008                                          doc.: IEEE 802.11-08/0049r1

                                  Agenda

     •       Directed Multicast (DMS): Motivation
     •       Directed Multicast Proposal Overview
     •       Directed Multicast should be considered in TGv
             or TGaa
             •   Existing Multicast Enhancements in TGv
             •   TGaa Requirements




Submission                             Slide 3                Emily Qi (Intel Corp) et al
May 2008                                             doc.: IEEE 802.11-08/0049r1

             Directed Multicast: Motivation
• Enable aggressive or flexible client power saving scheme
     – Sleeping STA doesn’t need to wake up at every DTIM or FBMS
       interval to receive multicast frames
     – Address Req2120:TGv shall provide mechanisms to enhance the
       power efficiency of broadcast and multicast data delivery
• Other benefits:
  – Protect directed multicast by using the client’s
    negotiated Pairwise cipher with the AP
             • Today, multicast is protected by the lowest common (or open)
               authentication
     – Enable reliable service
             • Unicast is more reliable than multicast

Submission                               Slide 4                 Emily Qi (Intel Corp) et al
May 2008                                               doc.: IEEE 802.11-08/0049r1

       Directed Multicast Service (DMS) Overview
   • STA advertises Directed Multicast Service (DMS) Capability
   • Non-AP STA sends a request to specify traffic classes for the
     directed multicast traffic delivery
   • AP may accept or reject the traffic class specified by the non-AP
     STA
   • If the service is accepted by the AP,
         – AP shall transmit the requested group addressed (multicast) traffic as the
           individual addressed (unicast) traffic to the requesting STA in an A-
           MSDU frame format, and AP may still transmit the group addressed
           traffic for other STAs within the multicast group in the BSS as normal.
         – The requesting STA shall discard group addressed frame that matches a
           multicast address entry of the list.
         – Other STAs will process group addressed traffic as normal.
   • See doc 08/0050r1

Submission                               Slide 5                     Emily Qi (Intel Corp) et al
May 2008                                                           doc.: IEEE 802.11-08/0049r1

             DMS Request and Response frames
•DMS Request frame:
                 Category             Action   Dialog Token      Request Type        DMS Descriptor
                                                                   (“Add” or             List
                                                                  “Remove”)
       Octets:      1                   1             1               1                 variable



                                      DMSID          Length        TCLAS Elements        TCLAS Processing
DMS                                                                   (optional)         Element (optional)

Descriptor              Octets:         1                 1              variable                   3


•DMS Response frame:
                         Category              Action           Dialog Token        DMS Status List

         Octets:                  1              1                   1                       1


                                                                    DMSID             DMS Status
                          DMS Status
                                                      Octets:         1                     1

Submission                                                                           Emily Qi (Intel Corp) et al
                                                  Slide 6
 May 2008                                                 doc.: IEEE 802.11-08/0049r1

       A-MSDU is used for Directed Multicast




• Original destination address (DA) is transmitted in A-MSDU subframe
  header (the DA field)
     • The DA and SA fields of the A-MSDU subframe header contain the values passed in the
     MA-UNITDATA.request and MA-UNITDATA.indication primitives. (e.g. DA=multicast
     address)
• RA (Address 1) in the MAC header is set to the requesting non-AP STA
  address
• Support of A-MSDU processing is mandatory according to the IEEE
  802.11n specification.
 Submission                                                              Emily Qi (Intel Corp) et al
May 2008                        doc.: IEEE 802.11-08/0049r1




   Should Directed Multicast be considered in
                TGv or TGaa ?




Submission            Slide 8               Emily Qi (Intel Corp) et al
 May 2008                                          doc.: IEEE 802.11-08/0049r1

     Existing Multicast Enhancements in TGv
 • FBMS – Flexible Broadcast/Multicast Service
       – Enables flexible delivery interval for broadcast/multicast as STA’s
         request (at multiples of the DTIM intervals)
       – Enables group addressed frames to be transmitted at higher data
         rates, reducing the amount of basic rate traffic sent over the radio
         link.
 • Multicast Diagnostics Reporting
       – STA provides the AP an indication of the number of dropped group
         addressed frames in order to enable reliable service



DMS adds to existing multicast enhancements in TGv, naturally fits in TGv


 Submission                            Slide 9                  Emily Qi (Intel Corp) et al
May 2008                                              doc.: IEEE 802.11-08/0049r1


                     802.11aa Requirements
 • Reliable Multicast is a complex problem, and different
   applications may require different solutions.
 • DMS provides same level of reliability as unicast for all traffic
   classes, at the cost of bandwidth
       – Directed multicast can be used while streaming a multicast Standard
         Definition (SD) stream to 2 or 3 STAs, it does not scale well for High
         Definition (HD) video streaming.
 • 802.11aa targets B/M robustness (reliability is a part of
   robustness) for HD video streaming (high bandwidth) applications
       – .11n is sufficient for Standard Definition video streaming
 • DMS targets low bandwidth applications, which is not the target of
   802.11aa


        DMS and 802.11aa targets different applications space
Submission                                                            Emily Qi (Intel Corp) et al
  May 2008                                              doc.: IEEE 802.11-08/0049r1


               DMS should be considered in TGv
• DMS addresses TGv objective [Req 2120], complements TGv FBMS
    – FBMS provides power saving for TGv devices. However, the legacy device (non-
      TGv device) within the BSS will experience unexpected B/M delivery delay.
    – DMS provides power saving for TGv devices without introducing latency on the
      legacy (non-TGv) device. However, its usage is limited to a small number of
      associated STAs due to bandwidth requirements.
• Including DMS in TGv can benefit low bandwidth applications sooner
    – TGv is in the process of initial ballots, expected sponsor ballot in Jan-09
    – TGaa is at the stage of calling for proposals, expected sponsor ballot Nov-10
• Including DMS in TGv should also benefit TGaa
    – All features (e.g. DMS) specified in the existing draft standard and draft
      amendments (e.g. TGv) can be utilized by later amendments (e.g. TGaa)




  Submission                                                          Emily Qi (Intel Corp) et al
May 2008                    doc.: IEEE 802.11-08/0049r1




             Questions?




Submission       Slide 12               Emily Qi (Intel Corp) et al
May 2008                                 doc.: IEEE 802.11-08/0049r1

                         Straw Poll

•     Directed multicast should be considered in:
      TGv:
      TGaa:
      Don’t care:




Submission                    Slide 13               Emily Qi (Intel Corp) et al

								
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