1. Fast Handover Date: 2009-05-10 Authors: May 2009 Feb, 2008
doc.: IEEE /xxxx
May 2009
Fast Handover
Date:
Authors:
L. Chu et al
Liwen Chu, STMicroelectronics

2. The Interworking Service
May 2009
The Interworking Service
AP1 stores STA1’s SSPN information.
AP1 police the frames from STA1 based on STA1’s SSPN information.
SSPN
SSPN Context Response
SSPN Context Req
Gateway
Create SSPN Interface
Portal DS
WLAN
AP2
AP1
GAS Query Response
GAS Query Req
BSS2
STA1
BSS1
L. Chu et al

3. The Interworking Service
May 2009
The Interworking Service
AP1 stores STA1’s SSPN information.
AP1 police the frames from STA1 based on STA1’s SSPN information.
SSPN
Gateway
SSPN Interface
WLAN
Portal DS
AP2
AP1
GAS Comeback Response
GAS Comeback Req
BSS2
STA1
BSS1
L. Chu et al

4. STA Handover AP2 does not have STA1’s SSPN information.
May 2009
STA Handover
AP2 does not have STA1’s SSPN information.
AP2 can not police STA1’s frames.
SSPN will wrongly send service provision instructions to AP1.
SSPN
Gateway
SSPN Interface
WLAN
Portal DS
AP2
STA1’s SSPN Interface??
AP1
GAS Comeback Response
GAS Comeback Req
BSS2
STA1
BSS1
L. Chu et al

5. Solution – Rate Limiting Transfer
May 2009
Solution – Rate Limiting Transfer
The target AP gets rate limiting information from the current AP:
In over-the-air FT method, a STA notifies the target AP of the current AP’s ID. Then the target AP gets interworking context through InterworkingContext IE from the current BSS by two new public action frames: InterworkContexgtReq and InterworkContextResponse.
The payload of InterworkingContext is a generic container that includes the interworking context.
In over-the-DS FT method, when the current AP receives FT Request or FT Confirm, it insert InterworkingContext IE to the frame and forwards it to the target AP.
L. Chu et al

6. Over-the-air FT Context Transfer
May 2009
Over-the-air FT Context Transfer
When a STA with enabled interworking sends Reassociation Request, it notifies the target AP of its current BSS.
The target AP gets interworking context from the current BSS through two new public action frames: InterworkContexgtReq and InterworkContextResponse.
STA
Current AP
Target AP
Data Transmission
Authentication Request (FTAA, RSNIE, MDIE, FTIE)
Authentication Response (FTAA, RSNIE, MDIE, FTIE)
Reassociation Request (RSNIE, MDIE, FTIE, RIC-Request, Current AP ID)
InterworkContextReq ()
InterworkContextResponse (InterworkingContext IE)
Reassociation Response (FTAA, RSNIE, MDIE, FTIE, RIC-Response)
Data Transmission
L. Chu et al

7. Over-the-DS FT Context Transfer
May 2009
Over-the-DS FT Context Transfer
When the current AP receives FT Request, it inserts InterworkingContext IE in FT Request and forwards it to the target AP.
STA
Current AP
Target AP
Data Transmission
FT Request (FTAA, RSNIE, MDIE, FTIE, InterworkingContext IE)
FT Response (FTAA, RSNIE, MDIE, FTIE)
Reassociation Request (RSNIE, MDIE, FTIE, RIC-Request)
Reassociation Response (FTAA, RSNIE, MDIE, FTIE, RIC-Response)
Data Transmission
L. Chu et al

8. Over-the-air FT Context Transfer with Resource Request
May 2009
Over-the-air FT Context Transfer with Resource Request
When a STA with enabled interworking sends Authentication Confirm, it notifies the target AP of its current BSS.
The target AP gets interworking context from the current BSS through two new public action frames: InterworkContexgtReq and InterworkContextResponse.
STA
Current AP
Target AP
Data Transmission
Authentication Request (FTAA, RSNIE, MDIE, FTIE)
Authentication Response (FTAA, RSNIE, MDIE, FTIE)
Authentication Confirm (FTAA, RSNIE, MDIE, FTIE,
RIC-Request, Current AP ID)
InterworkContextReq ()
InterworkContextResponse (InterworkingContext IE)
Authentication ACK (FTAA, RSNIE, MDIE, FTIE,
RIC-Response)
Reassociation Request (RSNIE, MDIE, FTIE)
Reassociation Response (FTAA, RSNIE, MDIE, FTIE)
Data Transmission
L. Chu et al

9. Over-the-DS FT Context Transfer with Resource Request
May 2009
Over-the-DS FT Context Transfer with Resource Request
When the current AP receives FT Confirm, it inserts InterworkingContext IE in FT Confirm and forwards it to the target AP.
STA
Current AP
Target AP
Data Transmission
FT Request (FTAA, RSNIE, MDIE, FTIE)
FT Response (FTAA, RSNIE, MDIE, FTIE)
FT Confirm (FTAA, RSNIE, MDIE, FTIE,
RIC-Request, InterworkingContext IE)
FT ACK (FTAA, RSNIE, MDIE, FTIE,
RIC-Response)
Reassociation Request (RSNIE, MDIE, FTIE)
Reassociation Response (FTAA, RSNIE, MDIE, FTIE)
Data Transmission
L. Chu et al

10. Solution – Routing SSPN’s Notification to the Destination BSS
May 2009
Solution – Routing SSPN’s Notification to the Destination BSS
The notification information from the SSPN is sent to the target AP:
Method1:
The target AP notifies the portal in access network of the association change of the STAs,
The portal in access network records the STA and AP’s mapping information,
The portal forwards SSPN notification to the destination AP.
Method2: The target AP (SME of the AP) notifies the central network (for example, SSPN) to change the association information of the STA.
L. Chu et al