doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 1 QBSS Downlink Broadcast and Multicast Data Frame Handling Sid Schrum Texas Instruments, Inc.

doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 2 Issue Summary Which frame format (Basic Data vs. QoS Data) should be used for Data broadcast and multicast MSDUs sent by a QAP is not clearly specified. –Several possible QAP behaviors –Affects interoperability Prioritization of non-best effort Data broadcast and multicast frames is not clearly specified in the current draft.

doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 3 Current Draft 5.2.5, last paragraph “Non-QoS STAs may associate in a QBSS. All frames that are sent to non QoS STAs by an AP are conformant to IEEE Std , 1999 or its extensions, if applicable. An AP also sends frames that are defined in IEEE Std , 1999 or its extensions, if applicable.” “The HC shall perform delivery of queued broadcast and multicast frames following DTIM beacons in a CFP.” Other Related MSDU Ordering Reordering of frames between TCs permitted bc/mc not excluded

doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 4 BC/MC Considerations MAC SAP: does not preclude non-best effort priority parameters for bc/mc Wired Ethernet: bc/mc frames may be “tagged” with a priority Broadcast –Targeted for all stations –Might be used for priority protocol signalling Multicast –Targeted for a limited set of stations –might be used for priority protocol signaling or distribution of multimedia streams

doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 5 Frame Format Considerations Basic Data Frame –Does not contain priority information –lack of information which otherwise could be used by receiver to provide preferential treatment –Best effort traffic – priority indication not particularly useful QoS Data Frame –cannot be understood by legacy stations

doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 6 BC/MC Transmit Options Option 1 - Always use Basic Data Frame –Simple –All stations are capable of receiving –Loss of priority information Option 2 - Always use QoS Data Frame –Simple –Only QSTA are capable of receiving –Not an option – precludes backwards compatibility

doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 7 Hybrid Options Option 3 - Use QoS format if no legacy stations associated, Basic otherwise –Best of both options –BUT – behavior may change over time and without warning to STAs Variant Option - Different treatment for bc and mc –Mc are targeted for a group of stations, not all stations –Delivery not intended to all stations

doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 8 Proposal Best effort bc/mc  Basic Data Frame Non-best effort bc  may use QoS Data Frame if no non-QoS STA are associated Non-best effort mc  may use QoS Data Frame

doc.: IEEE /102r0 Submission January 2003 Sid Schrum, Texas Instruments, Inc.Slide 9 BC/MC Prioritization Proposal Add text to require QAP to prioritize transmission of bc/mc traffic consistent with the TID, irrespective of the transmitted Data Frame format.