1. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Date: 2010-04-30 Fast Session Transfer May 2010 L. Cariou, Orange LabsSlide 1 Authors:

2. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Collaboration between 2.4/5 and 60 GHz bands allows the 802.11 user experience to be met by seamlessly providing both the wide coverage of WLAN and the very high throughput of 60 GHz when available A key merit of 802.11.ad is that it can build on past successful standards –e.g. 802.11a/n/ad system –This will provide many new market opportunities for the 802.11.ad standard In [1] and [2] we introduced several use cases dedicated to fast session transfer. A method of fast session transfer is proposed which enables very fast transparent switching to deal with user mobility, dynamic channel conditions and to allow joint management of multiple bands Abstract May 2010 L. Cariou, Orange LabsSlide 2

3. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs AP Set-top box Use case 1: FST with a switchable interface in STA Media server FTTH Switchable interface Slide 3 Concurrent dual interfaces Single link either at 5 or 60 WiFi 60GHz ( 1 Gbps) WiFi 5GHz ( 500 Mbps)

4. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs AP Set-top box Media server FTTH Use case 2: FST with concurrent dual interfaces in STA Slide 4 Concurrent dual interfaces Flow transfer between interfaces or bonding of the two interfaces Two links, at 5 and 60 WiFi 60GHz ( 1 Gbps) WiFi 5GHz ( 500 Mbps)

5. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Use cases 1&2: Switch from 2.4/5 to 60GHz or from 60 to 2.4/5GHz Band selection for all flows of a station (stations with only one band active at a given time (Switchable interface) or stations with multiple bands active simultaneously at a given time) –AP-STB either in 2.4/5 GHz band or in 60 GHz band (one at a time) Band selection for each flow of a station separately (only stations with multiple bands active simultaneously at a given time) –Multiple HD flows between AP and STB either in 2.4/5 GHz band or in 60 GHz band –Session transfer of some HD flows in case of saturation of 2.4/5GHz or 60GHz  Band selection may be based on (a) maintaining coverage with user mobility, (b) dynamically changing channel quality, (c) throughput enhancement, (d) load balancing between bands, etc  We believe that this interface convergence will improve the overall home network In this presentation, we only consider the case 1 with -an AP concurrent dual band -a STA with switchable interface Slide 5

6. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Requirements on seamless fast session transfer Requirements for speed of a seamless fast session transfer –For video applications: 1080p 60Hz => frame every 16.6 ms Assuming packet loss: latency between 5 and 10 ms –For VoIP applications: Maximum acceptable BSS transfer for VoIP roaming is 50 ms –For gaming applications, distributed storage or contents sharing: Same constraints as for video  Session transfer should not exceed 5 to 10 ms Quite severe constraint: needs to be better than 11r Other requirements –Switch should be able to be initiated by either device in a link (AP or STA) Slide 6

7. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs How to perform the seamless fast session transfer BSSID SSID Encryption key AID database BSSID SSID Encryption key AID database AID1 BSSID SSID Encryption key AID1 BSSID SSID Encryption key f 5GHz f 60GHz Example scenario: –One AP working at both 60 GHz and at 5 GHz link to TV at 5GHz (red) link to laptop at 60GHz (blue) to be switched to 5GHz Slide 7 5 GHz 60 GHz

8. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs How to perform the seamless fast session transfer Required functions for FST:  Preparation phase: –Exchange of FST capabilities and FST negotiation for each link prior to transmission. We believe the negotiation should lead to the direct acceptance of future switches, to suppress the need to provide a response when a switch is requested –Sharing of the association parameters between the two bands To speed up the process by removing the need for disassociation/re-association during the switch –Definition in STA of a unique logical MAC address, switchable from one interface to another  FST phase (phase during which FST can be done): –Report request/response on one band/channel of particular metrics (such as the load and SNR) of the other band/channel –Triggering of the session transfer by the transmission of a signal frame No need for a response to the trigger frame because of the prior negotiation No need for disassociation/re-association because of the sharing of association parameters Slide 8

9. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs How to perform the seamless fast session transfer Sharing of association parameters (1/2) Split between association function and forwarding function –Association to an AP, independently of the current interface/band: Negotiation of MAC parameters (security, power save, ….) Reception of a unique AID, whatever the band/channel Slide 9

10. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs f f BSSID SSID Encryption key BSSID SSID Encryption key AID1 BSSID SSID Encryption key AID2 BSSID SSID Encryption key Association parameters match BSSID SSID Encryption key AID database How to perform the seamless fast session transfer Sharing of association parameters (2/2) Trigger signal frame Slide 10

11. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs How to perform the seamless fast session transfer Forwarding (1/2) common MAC MAC 60 MAC 5 PHY 5 PHY 60 PHY 5 MAC 5 Physical MAC addr: MAC1 MAC 60 Physical MAC addr: MAC2 Logical MAC addr: MAClog0 IP IP addr linked to the unique logical MAC addr: MAClog0 MAC 60 MAC addr: MAC_ad0 PHY60 AP FST STA 11ad STA Definition in FST STA of a unique logical MAC address, switchable from one interface to another Definition in AP of a common MAC with a forwarding table indicating the active interface of a FST STA MAC addr MAClog0 5GHz MAC_ad0 60GHz

12. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Definition in FST STA of a unique logical MAC address, switchable from one interface to another Definition in AP of a common MAC with a forwarding table indicating the active interface of a FST STA How to perform the seamless fast session transfer Forwarding (2/2) common MAC MAC 60 MAC 5 PHY 5 PHY 60 PHY 5 MAC 5 Physical MAC addr: MAC1 MAC 60 Physical MAC addr: MAC2 Logical MAC addr: MAClog0 IP IP addr linked to the unique logical MAC addr: MAClog0 MAC 60 MAC addr: MAC_ad0 PHY60 AP FST STA 11ad STA MAC addr MAClog0 60GHz MAC_ad0 60GHz

13. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs How to perform the seamless fast session transfer Trigger the switch by a signal frame (1/3) The trigger signal frame should provide the information to localize the destination band and to indicate which station the switch concerns FST signal frame needs to include –The channel number from the destination channel –The BSSID of the destination band –The AID of the station that will switch band Slide 13

14. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs How to perform the seamless fast session transfer Trigger the switch by a signal frame (2/3) Additional information in FST signal frame to speed up the FST –Option 1: include the capabilities of the destination channel in the FST signal frame  By doing this, the station does not need to wait for the next beacon once arrived in the destination band in order to get the capabilities  This will be very efficient for destination bands/channels working with CSMA-CA (ex: from 802.11ad to 802.11n or 802.11ac): very low FST duration  However, for TDMA-based destination bands/channels like 802.11ad 60 GHz, the station will anyway need to wait for the next beacon to be informed a) of the next contention-period to request a reserved slot b) of its reserved slot, if a slot has been pre-reserved Slide 14

15. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs How to perform the seamless fast session transfer Trigger the switch by a signal frame (3/3) Additional information in FST signal frame to speed up the FST –Option 2: use the principle of the "channel switch announcement frame" to plan the arrival in the destination band just before the beacon transmission signaling of the destination band/channel TBTT in the FST signal frame in addition, the switch can be planned using the "channel switch announcement element" field in the FST signal frame  By doing this, the station will directly receive the capabilities and the contention-period time in case of TDMA.  This will be very efficient for all destination band/channels working with either CSMA-CA or TDMA Slide 15

16. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Seamless fast session transfer performance Speed of the FST –When using option 2, the FST switch time easily satisfies the 5 to 10 ms switching requirements FST duration only includes the time needed to perform the switch and the reception of the beacon on the destination band/channel Trigger of the FST by the AP Trigger by a FST signal frame Such a decision requires a report on one band/channel of particular metrics (such as the load and SNR) of the other band/channel Trigger of the FST by the station The FST can be instantaneous thanks to UL data transmission in the new band Slide 16

17. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Fast session transfer is a very important feature to improve home network by allowing the joint management of multiple bands, and to open new market opportunities. To be efficient, FST needs to be seamless and triggered by either one or the other device of a link and to be as fast as 5 to 10ms. We proposed to share the association parameters and a new trigger frame that enable such an efficient FST. Conclusions May 2010 Slide 17

18. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Reference May 2010 Slide 18 [1] “5-60 GHz use cases”, 802/11-09-0835r0 [2] “Fast Session Transfer use cases”, 802/11-10-0134r0 [3] “Collaboration between 2.4/5 and 60GHz”, 802/11-10- 0492r0

19. doc.: IEEE 802.11-10/491r2 SubmissionL. Cariou, Orange Labs Time TBTT signaled in FST signal frame FST signal frame FST Switching instant How to perform the fast session transfer Trigger the switch by a signal frame Slide 19 FST switch duration << 5ms