Proposal for Resolving Comments on Intra-Mesh Congestion Control February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Proposal for Resolving Comments on Intra-Mesh Congestion Control Date: 2007-02-28 Authors: Notice: This document has been prepared to assist IEEE 802.11. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by IEEE 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair <stuart.kerry@philips.com> as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>. Bahareh Sadeghi Steven Conner

February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Abstract Review of congestion control scheme and proposal for its simplification to address lb93 comments. Bahareh Sadeghi Steven Conner

Congestion Control as in the draft February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Congestion Control as in the draft Local congestion monitoring Out of scope Congestion control signaling The trigger for signaling is an internal matter and out of scope The signaling is defined by the standard The behavior of the nodes as a reaction to the congestion control signal is defined by the standard; how they achieve that behavior is out of scope. Bahareh Sadeghi Steven Conner

Congestion signaling Congestion Control Request February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Congestion signaling Congestion Control Request Congestion Control Response Neighborhood Congestion Announcement Most of the comments question Target transmission rate element and Neighborhood congestion control announcement Complexity of the solution Bahareh Sadeghi Steven Conner

Congestion Control Request February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Congestion Control Request Category action Target transmission rate element 1 byte 1 byte 20 bytes Congestion control request frame format ID length Target Data Rate (AC-BK) Target Data Rate (AC-BE) Target Data Rate (AC-VI) Target Data Rate (AC-VO) Expiration Timer 1 byte 1 byte 4 bytes 4 bytes 4 bytes 4 bytes 2 bytes Target transmission rate element Many comments have questioned target data rate How it is defined How compliance to it is measured Makes implementations too complicated Bahareh Sadeghi Steven Conner

Congestion Control Request February 2007 doc.: IEEE 802.11-07/0250r0 Congestion Control Request February 2007 Red indicates the modifications Category action Expiration Timer element 1 byte 1 byte 11 bytes Congestion control request frame format ID length Expiration Timer (AC-BK) Expiration Timer (AC-BE) Expiration Timer (AC-VI) Expiration Timer (AC-VO) Congestion Control Mode 1 byte 1 byte 2 bytes 2 bytes 2 bytes 2 bytes 1 byte Expiration timer element One expiration timer per AC Nodes defer from transmitting in that AC for duration of expiration timer Expiration timer = 0 means no congestion in that AC Congestion Control Mode allows extension to more advanced and efficient solutions Simple and yet extensible Bahareh Sadeghi Steven Conner

Congestion Control Response February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Congestion Control Response Category action Offered traffic load element 1 byte 1 byte 18 bytes Congestion control Response frame format ID length Offered Traffic Load (AC-BK) Offered Traffic Load (AC-BE) Offered Traffic Load (AC-VI) Offered Traffic Load (AC-VO) 1 byte 1 byte 4 bytes 4 bytes 4 bytes 4 bytes Target transmission rate element Offered traffic load needed for computation of target transmission rate Bahareh Sadeghi Steven Conner

Congestion Control Response February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Congestion Control Response Red indicates the modifications Category action Congestion control response element 1 byte 1 byte 1 byte Congestion control Response frame format ID length Congestion Control Mode 1 byte 1 byte 1 byte Congestion control response element Congestion Control mode used to extend the response matching the congestion control request message Bahareh Sadeghi Steven Conner

Neighborhood Congestion Announcement February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Neighborhood Congestion Announcement Category action Neighborhood congestion element 1 byte 1 byte 5 bytes Neighborhood congestion announcement frame format ID length Congestion Level Expiration Timer 1 byte 1 byte 1 byte 2 bytes Neighborhood congestion element Many many comments as congestion level and reaction of the receivers to this message are undefined. Bahareh Sadeghi Steven Conner

Neighborhood congestion announcement February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Neighborhood congestion announcement Red indicates the modifications Transmission of Congestion Control Request message in broadcast achieves the same goal. Bahareh Sadeghi Steven Conner

February 2007 doc.: IEEE 802.11-07/0250r0 February 2007 Summary Modify congestion control signaling to simplify the mechanism and allow for extensibility for more advanced approaches Replace target transmission rate by expiration timer Use congestion control request message in broadcast for neighborhood congestion control messages Use Congestion Control Mode to allow for other congestion control schemes. Bahareh Sadeghi Steven Conner