IEEE 802.11s Standardization and Implications February 2006

1. IEEE 802.11s Standardization and ImplicationsFebruary 2006 Stephen G. Rayment, CTO

2. Structure of IEEE 802 • 802.1 Higher Layer LAN Protocols WG • 802.3 Ethernet WG • 802.11 Wireless Local Area Network (WLAN) WG • 802.15 Wireless Personal Area Network (WPAN) WG • 802.16 Broadband Wireless Access WG • 802.17 Resilient Packet Ring WG • 802.18 Radio Regulatory TAG • 802.19 Coexistence TAG • 802.20 Mobile Broadband Wireless Access (MBWA) WG • 802.21 Media Independent Handover Systems WG • 802.22 Wireless Regional Area Network (WRAN) WG WG = Working Group TAG = Technical Advisory Group } 2/3 of 802 members

3. Related Industry Consortia Provide certification testinginteroperability trials, branding, marketing, etc.

4. Structure of the 802.11 WG • 802.11k, TGk, Radio Resources Measurement • 802.11REV-ma, TGm, Maintenance • 802.11n, TGn, High Throughput • 802.11p, TGp, Wireless Access in the Vehicle Environment • 802.11r, TGr, Fast Roaming • 802.11s, TGs, ESS Mesh Networking • 802.11.2, TGT, Wireless Performance Prediction • 802.11u, TGu, Interworking with External Networks • 802.11v, TGv, Wireless Network Management • 802.11w, TGw, Protected Management Frames These are the currently active TG’s Technical Groups

5. 802.11s Envisaged Uses • Residential • Primarily indoor, small-medium scale, low mobility • Enterprise • Indoor and mixed indoor/outdoor examples • Primarily medium-large scale, low mobility • Campus/Community/Public Access • Primarily outdoor or mixed indoor/outdoormedium-large scale • Various mobility and antenna configurations • Public Safety • Primarily outdoor or mixed indoor/outdoormedium-large scale • Variations in mobility and traffic patterns • Military Voted to remove a Car-to-Car case and add the Military case The Military and Public Safety cases were almost merged

6. Residential Usage Case In the digital home usage model, the primary purposes for the mesh network are to create low-cost, easily deployable, high performance wireless coverage throughout the home. The mesh network should help to eliminate RF dead-spots and areas of low-quality wireless coverage throughout the home. High-bandwidth applications such as video distribution are likely to be used within a home network, thus high bandwidth performance will be very important for residential mesh networks.

7. Office Usage Case In the office usage model, the primary motivation for using mesh network technology is to create low-cost, easily deployable wireless networks that provide reliable coverage and performance. WLAN Mesh networks are particularly useful in areas where Ethernet cabling does not exist or is cost prohibitive to install. Offices can reduce capital costs associated with cable installation and reduce time required for deployment. They may also benefit from an increase in employee productivity through expanded connectivity to key data network resources Indoor or outside

8. Campus / Community /Public Access Usage Case • Seamless connectivity over large geographic areas. • Rapidly provide connectivity to locations where wired infrastructure is not available or is cost prohibitive. • Lower cost / higher bandwidth alternative to traditional internet access methods (dial up, cable, DSL, fiber). • Enable advanced applications/services through ubiquitous access & reliable connectivity. • Enable location based services.

9. Public Safety Usage Case Public safety mesh networks provide wireless network access to emergency and municipal safety personnel such as fire, police, and emergency workers responding to an incident scene. The network may be used for video surveillance, tracking emergency workers with bio-sensors, voice and data communication between emergency workers, uploading images, downloading hazmat information, tracking air status, etc.

10. Military Usage Case Military usage of mesh networks can be classified into two categories. The first category, non-combat usage, is adequately represented by the usage cases previously described in this document. The second category, combat operational usage, is distinguished by node mobility, a heavy reliance on fully automated network management and, for disadvantaged nodes, e.g., dismounted troops, sensitivity to energy conservation.

11. 802.11s Scope • Interconnects 802.11 APs using a “Wireless Distribution System” (WDS) four address format already specified in 802.11 • Uses existing 802.11 PHY layers, assumes modifications to 802.11 MAC only • Works with existing 802.11 devices and existing 802 networks • Targeting about 32 forwarding nodes • Supports broadcast/multicast and unicast • Uses 802.11i security with a “single administrative entity” • Will specify a scheme for self configuration / topology learning • Will specify a scheme for auto discovery / mesh association • Will specify a MAC layer dynamic routing scheme for a multi hop environment using metrics that are “radio aware” • Extensible routing to allow for alternative forwarding path selection metrics and/or protocols

12. “Classic” ESS Wired Infrastructure AP AP STA AP STA STA STA AP STA STA STA STA STA STA ESS ≈ SSID radio link

13. Mesh ESS Wired Infrastructure Mesh Portal Mesh Portal AP AP STA AP STA STA STA AP STA STA STA STA STA STA ESS ≈ SSID mesh radio link radio link

14. Mesh Points / Mesh APs Venn Diagram of Terms 802.11 Stations STAs Mesh Access PointsMAPs Mesh PointsMPs Access PointsAPs

15. Distribution System (DS) 802.11 BSS 802.11s Meshes Mesh Portal 802.11s Mesh Mesh Links 802.11 MAC/PHY (4-addr data frames) 802.11 ESS Client-to-AP Links 802.11 MAC/PHY (3-addr data frames) Mesh APs

16. Mesh QoS Considerations • 802.11e primarily deals with QoS on the Station to AP link. • In a mesh environment, QoS through the mesh is desirable • Delay per hop can add up for mesh paths. • To avoid degrading 802.11e QoS and damaging QoS sensitive services such as VoIP Footnote Very hard to do with shared mesh architectures!

17. Mesh Security Considerations • WEP and new 802.11i (WPA / WPA2) provide link security (authentication and encryption) only between a station and an AP • With 802.11s, the AP to AP radio links will also require protection to avoid degrading overall 802.11 security • This includes link encryption and node authentication • Some debate about the need for end to end security • Management frames, such as routing information will also require protection - 802.11w?

18. Benefits of 802.11s • Interoperability !! • More relevant to some uses than others • Unlike hardware standards will not help reduce component costs

19. Technical Benefits of 802.11s • Forwarding protocols with improved performance • Tree-Based forwarding provides better throughput under load • Alternative AODV and Optional OLSR forwarding allows ad-hoc applications, eg. for Public Safety • Robust forwarding - handles several simultaneous link failures • Efficient forwarding - can use all links, no need to break loops, offers load balancing • Multi-channel MAC improves capacity and throughput • Higher capacity for single radio meshes by allowing multi channel operation with CCF (Common Channel Framework) • Network throughput improvement through congestion control messaging • Security for management frames based on 802.11w • Protects forwarding information • Standardized methods for • Mesh beaconing to allow automatic topology discovery • Node authentication - distributed or centralized keys

20. But TGs is Still ALL About Shared Meshes • Single radio shared - 2-8Mbps (.11b-.11g) • Dual radio shared - 20Mbps • Multi radio switched - 75Mbps

21. Two Remaining Camps • SEE-Mesh • ATR, BelAir, Cisco, DoCoMo, Firetide, Fujitsu, Hewlett Packard, Huawei, Intel, ITRI, Mitsubishi Electric, Motorola, NICT, Nokia, NTUST, Oki Electric, PacketHop, Qualcomm, Samsung, Siemens, Sony, ST-Microelectronics, Texas Instruments, Tropos, Wipro • Wi-Mesh Alliance • Accton, Comnets, Extreme Networks, InterDigital, MITRE, NextHop, Nortel, Philips, Thomson, NRL, Swisscom Joint Proposal team formed Planning to submit Draft by end February for Confirmation at March meeting

22. Future 802.11s Schedule • Official projection for 802.11s: • March 2006 first draft • July 2006 initial 802 Working Group Letter Ballot • November 2006 first 802 WG LB recirculation • July 2007 initial Sponsor Letter Ballot • September 2007 first Sponsor LB recirculation • March 2008 final 802 WG sign off • June 2008 final IEEE-SA sign off • As you go through the process, changes usually get smaller and smaller • Major changes after the start of Sponsor Ballot are very rare • Official schedules for all 802.11 projects are available at http://grouper.ieee.org/groups/802/11/802.11_Timelines.htm