November 2007 doc IEEE 802 11 072901 r

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Use of BSSID in WAVE Date: 2007 -12 -06 Authors: Submission 1 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Abstract A solution is proposed to permit simultaneous reception of BSS data frames and non-BSS data frames on the same channel by the same STA. Submission 2 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Desired Functionality • WAVE mode permits transmission of data frames without an established WAVE BSS using a wildcard BSSID • It may be desirable now or in the future to permit this in conjunction with data frames within an established WAVE BSS from the same STA – 802. 11 p does not explicitly exclude this operation currently – Note: BSSID for a WAVE BSS is the MAC address of the WAVE BSS Initiator Submission 3 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 The Problem • There is no way to set the BSSID in a data frame to the wildcard BSSID while joined to a BSS • The BSSID in transmitted data frames is the currently joined BSSID – BSSID is not currently specified on a frame-by-frame basis from higher layers – See IEEE Std 802. 11 -2007, clause 6. 2. 1. 1. 2 Submission 4 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Recommended Solution • Add an optional parameter to MA-UNITDATA. request to specify a specific BSSID for the frame • Add an optional parameter to MAUNITDATA. indication to report a received BSSID other than the currently joined BSSID • Use of the new parameters is not restricted to WAVE mode Submission 5 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Implications of the Solution • Received BSS data frames are still subject to traditional filtering • Received non-BSS data frames are filtered on the non. BSSID criteria – 802. 11 p already contains the exception to allow reception of data frames with a wildcard BSSID • Higher layers must know when to set a specific BSSID – In WAVE, non-BSS data frames are for WSMP only – WSMP can be enhanced to have knowledge of the new parameter Submission 6 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Rejected Solutions (1) • Using a non-wildcard WAVE BSSID for non-BSS data frames is problematic – Assume two nearby WAVE BSSs with BSSID=3 and BSSID=4 – STAs on BSSID 3 will filter all data frames from BSSID 4 – Non-BSS data frames sent from a STA on BSSID 4 will also be filtered by STAs on BSSID 3 – Running in promiscuous mode would circumvent the primary purpose of multiple BSSIDs, which is to permit filtering of broadcast/multicast data frames • See IEEE Std 802. 11 -2007, p. 78 first sentence Submission 7 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Rejected Solutions (2) • Resetting the MAC to change the BSSID is not feasible – Loss of MAC state and queued packets – Latency • Creating a MLME-SET-BSSID. request to change the BSSID without resetting the MAC would require tight coupling and synchronization of management and data planes Submission 8 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Rejected Solutions (3) • Set BSSID in the MAC Header to the wildcard BSSID when: – DA/RA is a locally administered multicast address with the non_bss_multicast_bit = 1 (non_bss_multicast_bit is an arbitrary value to be selected by the editor) – Broadcast MAC address (FF FF) qualifies as a locally administered multicast address with non_bss_multicast_bit = 1 • Implications to filtering of WAVE BSS Data Frames – Unicast Data Frames: None • Filtering is already based on the RA alone – Broadcast Data Frames: Filtering not supported • Use a specific multicast address instead – Multicast Data Frames: Filtered if non_bss_multicast_bit = 0 – Case of non_bss_multicast_bit = 0 when not joined to a WAVE BSS is undefined • • Note that to/from DS data frames are sent unicast While this solution could work, after a long discussion in the November 2007 TGp sessions, the opinion of the group was that it is too clumsy Submission 9 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Rejected Solutions (4) • Add new MA-UNITDATA-NON-BSS. request/confirm/indication primitives to support transmission of data frames outside of a BSS – Parameters same as for MA-UNITDATA. request/confirm/indication – BSSID in MAC Header always set to wildcard BSSID – Permits a non-wildcard BSSID to be used for data frames sent with current MA-UNITDATA. request • On receive, MAC would invoke MA-UNITDATA-NONBSS. indication if the BSSID is the wildcard BSSID • Splitting MA-UNITDATA creates confusion in the architecture and is not supportable in the long-term if other parameters need to be added Submission 10 Doug Kavner, Raytheon

November 2007 doc. : IEEE 802. 11 -07/2901 r 06 Motion • Move to accept the recommended solution and instruct the editor to make updates to the draft • Moved: • Second: • For: • Against: • Abstain: Submission 11 Doug Kavner, Raytheon