1. 21-06-0471-01-0000 1 IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-06-0471-01-0000 Title: Report on Potential Link Sync Events for IEEE 802.11r Date Submitted: Jan xx, 2006 Presented at IEEE 802.21 session #12, Big Island, Hawaii Sources : Ajoy Singh, Qiaobing Xie, Yogesh Bhatt Abstract: This is our report on an action item taken from the last session with the aim to investigating and identifying any 802.11r link events that can potential be considered as new 802.21 link sync events.

2. 21-06-0471-01-0000 2 IEEE 802.21 Presentation Release Statements This document has been prepared to assist the IEEE 802.21 Working Group. 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. 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 IEEEs name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEEs 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 802.21. The contributor is familiar with IEEE patent policy, as outlined in Section 6.3 of the IEEE-SA Standards Board Operations Manual and in Understanding Patent Issues During IEEE Standards Development Section 6.3 of the IEEE-SA Standards Board Operations Manualhttp://standards.ieee.org/guides/opman/sect6.html#6.3http://standards.ieee.org/board/pat/guide.html

3. 21-06-0471-01-0000 3 Background An action item was given at the last session to investigate whether there are any existing 802.11r native link events that are potentially of value to the upper layer MM decision making if passed as additional MIH link sync events. This is our report on our preliminary findings.

4. 21-06-0471-01-0000 4 IEEE 802.11 Mobility Scenarios No-transition: Station either has no motion or stays in the same BSS. BSS-transition: Station moves from one BSS in one ESS to another BSS within the same ESS. This is the focus of 11r. ESS-transition: Station moves from one ESS to another. Not covered by.11r spec, but a potential area of.11 improvement.

5. 21-06-0471-01-0000 5 IEEE 802.11r Mobility Enhancement Overview Five steps of 802.11 BSS – BSS transition: –Scanning – active or passive for other APs in the area –Authentication with a (one or more) target TAP –Re-association to establish connection at target TAP Have a connection, but still can't *DO* anything… –PTK derivation – 4-way handshake of session keys –QoS admission control to re-establish QoS streams 802.11r Fast BSS transition reduces five steps to 3 steps by eliminating last two stages (PTK derivation and QoS and admission control). –Functionality provided by PTK derivation and QoS admission control is merged along with earlier steps.

6. 21-06-0471-01-0000 6 IEEE 802.11r Mobility Enhancement Overview –cont 802.11r describes following two types of inter-BSS transition. –Base Mechanism: Enables mobile (TSTA) to make a transition to a target TAP in the event that it wants to make a transition under following conditions: Without invoking a reservation Or when deployment policy enforces base mechanism –Pre-reservation mechanism: Mobile uses this mechanism when it needs assurance from that required security and QoS resources be available prior to a transition. –Pre-reservation decouples the allocation of the security and QoS resources from the mobiles critical path, e.g., (re)association. –Provides better assurance of meeting transition time required by applications.

7. 21-06-0471-01-0000 7 IEEE 802.11 Mobility Management Overview–cont Base and Pre-reservation mechanisms can be further classified into following two categories: –Using over-the-Air Message: TSTA communicates directly with the target TAP using 802.11 Authentication frames with the Authentication Algorithm set to Fast BSS Transition. –Using over-the-DS Message : TSTA communicates with the target TAP via the current TAP. »Fast BSS Transition Action Frame is used to communicate between TSTA and current TAP »An encapsulation mechanism is used to communicate between current TAP and new TAP

8. 21-06-0471-01-0000 8 Potential MIH link synchronous events for.11r Fast BSS Transition: MIH Link synchronous events could be defined and used for upper layer smoothing (e.g., enabling and disabling transport layer congestion control). Fast ESS Transition: Not supported by.11r spec. –First inter-ESS mobility mechanism will be required to enable fast-ESS transition –Subsequently link layer events can be defined to perform make-before- break L3 handoff.

9. 21-06-0471-01-0000 9 802.11r Base Over-the-DS Mechanism : Potential Trigger Points Mobile C-TAP Secure Session and Data TX STA FT-ACTION REQUEST / RESP RE-ASSOC REQ / RESP Potential Link Sync Trigger Potential Link Sync Trigger Potential MIH Link Sync Events Trigger Points T-TAP SCANNING Potential Link Sync Trigger

10. 21-06-0471-01-0000 10 801.11r Base Over-the-Air Mechanism : Potential Trigger Points Mobile C-TAP Secure Session and Data TX STA AUHH REQ / RESP RE-ASSOC REQ / RESP Potential Link Sync Trigger Potential Link Sync Trigger Potential MIH Link Sync Events Trigger Points T-TAP SCANNING Potential Link Sync Trigger

11. 21-06-0471-01-0000 11 802.11r Pre-reservation Over-the-DS Mechanism : Potential Trigger Points Mobile C-TAP Secure Session and Data TX STA FT-ACTION REQ / RESP / CONF / ACK RE-ASSOC REQ / RESP Potential Link Sync Trigger Potential Link Sync Trigger Potential MIH Link Sync Events Trigger Points T-TAP SCANNING Potential Link Sync Trigger

12. 21-06-0471-01-0000 12 802.11r Pre-reservation Over-the-Air Mechanism : Potential Trigger Points Mobile C-TAP Secure Session and Data TX STA AUTH REQ / RESP / CONF / ACK RE-ASSOC REQ / RESP Potential Link Sync Trigger Potential Link Sync Trigger Potential MIH Link Sync Events Trigger Points T-TAP SCANNING Potential Link Sync Trigger