RSC Pools for Mgmt Frames Month Year doc.: IEEE 802.11-yy/xxxxr0 March 2006 RSC Pools for Mgmt Frames Date: June 17, 2006 Author: 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>. K.Hayes John Doe, Some Company

Replay Checking background March 2006 Replay Checking background With a single session flow, frames must be sent in an ordered sequence across the link – frames cannot be reordered within the session For multiple sessions, the rule above still holds, but frames may be reordered across sessions (i.e. output scheduling may occur) K.Hayes

March 2006 Crypto sequences TKIP and CCMP require replay checking as receiver function Verification is asserted with Packet Numbers derived from the IV, extended IV Transmitter must allocate all Packet Numbers in the sequence received from the network stack, even for multiple sessions; gaps in the increasing Packet Number sequence are allowed Packet Numbers must never be reused with the same RSN key K.Hayes

Output Scheduling March 2006 Low Prio PN = 11 PN = 9 Priority Scheduler PN = 13 PN = 12 Hi Prio PN = 13 K.Hayes

March 2006 Crypto sequences (2) Multi-session receiver cannot use a single Receive Sequence Counter (RSC) to do replay checks; it must have N, where N is the number of streams/sessions Data frames are “steered” into a discrete RSC bin by virtue of their QoS Control Field’s 4-bit TID, or 0 (zero) if QoS Control Field is absent from frame header K.Hayes

Management Frame Steering March 2006 Management Frame Steering Management frames have no QoS Control Field in their 802.11 header They have no “priority”. Some implementations may give them preferential output scheduling and others may not. Their different frame type field (0x0) means they can be easily steered into a distinct RSC pool K.Hayes

March 2006 TGw cipher suites TKIP and CCMP use a QoS TID field in calculation of their respective MICs; they use 0 (zero) if the QoS TID field is absent CCMP also uses the QoS TID field in the definition of the Nonce; again it uses 0 (zero) if the QoS TID field is absent The field used here for mgmt frames for MIC and Nonce inputs must be 0 (zero) The unique PNs guarantee keys will not be reused on a given payload K.Hayes

March 2006 Management RSCs If management frames are subject to preferential scheduling, then the implementation must use a separate management RSC for replay checking This is a receive-side only operation K.Hayes

March 2006 Questions? K.Hayes