Specific or universal Beacons? March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Specific or universal Beacons? Date: 2007-03-13 Notice: This document has been prepared to assist IEEE 802.11. 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. Release: 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 IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s 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 802.11. Patent Policy and Procedures: The contributor is familiar with the IEEE 802 Patent Policy and Procedures <http:// ieee802.org/guides/bylaws/sb-bylaws.pdf>, including the statement "IEEE standards may include the known use of patent(s), including patent applications, provided the IEEE receives assurance from the patent holder or applicant with respect to patents essential for compliance with both mandatory and optional portions of the standard." Early disclosure to the Working Group of patent information that might be relevant to the standard is essential to reduce the possibility for delays in the development process and increase the likelihood that the draft publication will be approved for publication. Please notify the Chair stuart@ok-brit.com as early as possible, in written or electronic form, if patented technology (or technology under patent application) might be incorporated into a draft standard being developed within the IEEE 802.11 Working Group. If you have questions, contact the IEEE Patent Committee Administrator at <patcom@ieee.org>. Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Authors: March 2007 March 2007 doc.: IEEE 802.11-07/0403r0 Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Outline 802.11 Beacons reviewed Concept: „Mesh-only“ beacon Conlusions March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Outline 802.11 Beacons reviewed Structure Frame body contents Examples Calculations Future Information Elements Measurements Concept: „Mesh-only“ beacon Pros & Cons Conlusions Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Management frame format March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Management frame format Frame Type (Beacon frame) = Management Management frame format Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Beacon: Frame body contents (1-13) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Beacon: Frame body contents (1-13) Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Beacon: Frame body contents (14-21) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Beacon: Frame body contents (14-21) Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Beacon: Frame body contents (22-24 & 256) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Beacon: Frame body contents (22-24 & 256) Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Example calculation (1) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Example calculation (1) Assume minimal functionality beacon 802.11a/g OFDM PHY Minimum 26 B Maximum 569 B Typical Depends on Power saving stations Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Example calculation (2) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Example calculation (2) Assume non-US AP location 802.11a/g OFDM PHY, DFS & TPC required Minimum 54 B Maximum 845 B Typical Depends on Power saving stations Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Example calculation (3) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Example calculation (3) Assume non-US QAP location 802.11a/g OFDM PHY, DFS & TPC required, BSS Load, EDCA parameter set announced Minimum 81B Maximum 872B Typical Depends on Power saving stations Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

802.11k AP Channel Report BSS Average Access Delay Antenna Information March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 802.11k AP Channel Report 3-257B BSS Average Access Delay 3B Antenna Information BSS Available Admission Capacity 4-28B BSS AC Access Delay 6B Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

802.11r Mobility Domain Information NAS-ID 9 B 3-257 (?) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 802.11r Mobility Domain Information 9 B NAS-ID 3-257 (?) Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

802.11u Interworking Capability March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 802.11u Interworking Capability 4B Generic Advertisement Service Capability 2-257B (?) Generic Advertising Service Traffic Indication Map 6-257B ESSID 8B Default Emergency Services Realm Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Beacon from 802.11b AP March 2007 March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Beacon from 802.11b AP Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Beacon from 802.11b/g AP March 2007 March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Beacon from 802.11b/g AP Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Beacon from 802.11b/g STA (IBSS) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Beacon from 802.11b/g STA (IBSS) Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

IEEE beacon (SSID: \000) March 2007 March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 IEEE beacon (SSID: \000) Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

IEEE beacon (SSID: IEEE) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 IEEE beacon (SSID: IEEE) Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

IEEE beacon (SSID: IEEE.1x) March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 IEEE beacon (SSID: IEEE.1x) Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

MP-only network Only MPs connect with each other March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 MP-only network Only MPs connect with each other No need for „legacy“ beacon IEs No stations in the network No AP functionality provided Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Combined Mesh and infrastructure BSS March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Combined Mesh and infrastructure BSS MP A is collocated with an AP Only this combined device needs to send information for STAs Uncombined MPs do not serve STAs Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

All MPs collocated with APs March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 All MPs collocated with APs Shall all beacons carry the same information? Shall the Mesh provide to STAs a seamless view of the network? How to ensure? Is that 802.11s business? Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Competing IEs What is the most important information in a beacon frame? If beacon frame size increases, the frame body may not provide sufficient room for all desired IEs How to decide on the IEs to include? Schedule (round robin etc.) IEs for inclusion? Time-critical IEs? Can IEs be dropped? What does 802.11 say in the absence about expected IEs? Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Concept: „Mesh-only“ beacon March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Concept: „Mesh-only“ beacon Create a beacon that is designed specifically for the needs of a Wireless Mesh Network No need to tweak beacon frame to avoid compatibility issues with existing 802.11 compliant devices Do not integrate “legacy” elements Possibility to split information among multiple “Mesh-only” beacons Avoid association attempts from STAs Optimize structure for Wireless Mesh Network Provide for possibility of beacon frame fragmentation/aggregation Avoid “legacy” elements Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Separate beacons Separate logical „entities“ send separate “group messages” (beacons) Allow for different beaconing intervals Supports different update intervals Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Con “Mesh-only” beacon March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Con “Mesh-only” beacon Remain single beacon frame format for all 802.11 amendments Keep Mesh and non-Mesh consistent Mesh beacon has additional IEs, but no other changes No introduction of a new management type frame Avoid some overhead Each separate frame needs separate PHY (PLCP header, preamble etc.) & MAC (backoff) Easily support the most likely use case MP collocated with an AP Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Pro “Mesh-only” beacon March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Pro “Mesh-only” beacon Avoid overhead of compatibility Why put the burden of beaconing on MPs? STA communicates with STA STA communicates with AP STA cannot communicate with MP If MP and STA/AP are disjoint entities, there is no need to share functionality/signaling overhead Allow for logical separation of AP/MP functionality Orthogonal design Flexible solution to adopt to the specific Mesh needs Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Conclusion Separation of beaconing proposed March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Conclusion Separation of beaconing proposed Orthogonal concepts should use orthogonal mechanisms Mesh vs. non-Mesh Supports TGs motto (“Perfection is achieved not when there is nothing left to add but when there is nothing left to take away.”) Helps to overcome overhead Allows for different beaconing intervals Optimized contents Increase flexibility Avoid compatibility issues with existing devices Mesh beacon keeps focused to its target objective Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

Straw Poll Is beacon separation a concept that should go into 802.11s? March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 Straw Poll Is beacon separation a concept that should go into 802.11s? Yes/No/Abstain: Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips

References P802.11-REVma-D9.0-red-line-all-pages.pdf March 2007 doc.: IEEE 802.11-07/0403r0 March 2007 References P802.11-REVma-D9.0-red-line-all-pages.pdf Draft P802.11u_D0.03.pdf Draft P802.11r_D4.1.pdf Draft P802.11k_D7.0.pdf Draft_P802.11s_D1.01.pdf http://www.wireshark.org/ Guido R. Hiertz et al., Philips Guido R. Hiertz et al., Philips