1. 1 Introduction to IEEE Standardization & IEEE 802.11s Hang Liu Thomson Inc, Corporate Research Lab Princetion, NJ

2. 2 IEEE Standard Association [1] Standards Activities Board 802.3 CSMA/CD Ethernet 802.5 Token Passing Ring 802.11 Wireless LAN 802.15 Wireless Personal Area Networks 802.20 Mobile Broadband Wireless Access 802.19 Co-existence TAG Sponsor IEEE 802 Local and Metropolitan Area Networks (LMSC) Sponsor 802.17 Resilient Packet Ring 802.18 Radio Regulatory TAG 802.16 Broadband Wireless Access 802.21 Media Independent Handoff 802.1 Higher Layer LAN Protocols 802.22 Wireless Regional Area Networks Wired Wireless

3. 3 Standardization Process Disclaimer: The flowcharts for IEEE standardization process are based on the author’s understanding, not official IEEE Policies and Procedures Incubation: Present initial Idea for a standard or improvement to a standard (e.g. IEEE 802.11 WNG SC) Request to form a Study Group Form an ad-hoc group to continue to present ideas and gain interests Approved by Working Group (>=75%) & ExeCom? SG: gain support, prepare and submit a PAR to become a Task Group PAR Approved by WG (>=75%), ExeCom, NESCom? TG: Debate technology, write a draft standard Address comments & revision No Yes

4. 4 Draft Standard Development in TG Define usage model, requirements, proposal down- selection procedure, call for proposals Proposal presentations, merge, and down-selection Call for Proposals Baseline document Each Document Passage requires 75% or greater approval Approval (>= 75%) Draft Refinement and Letter Ballot Recirculation Sponsor Ballot Yes No Refine/enhance the draft baseline and resolve the comments (features could be added/deleted/changed) Yes WG Letter Ballot Approval? ReVCom Standard Resolve comments No

5. 5 Proposal Down-Selection Process: Example 1 1 st round proposal presentations and voting Bottom 25%? Yes No Out 2 st round proposal presentations and voting Support Votes >= 50%? No Out Confirmation vote on the final proposal as baseline draft (>=75%)? Final two or three most popular proposals come back, compete and merge Yes No 3 st round proposal presentations (normally 2 or 3 merged proposals left) Yes Most supported proposal? One winning proposal Yes No Out Baseline document

6. 6 Proposal Down-Selection Process: Example 2 Define a baseline ToC according to requirements Present the proposal + proposed text Support Votes >= 75%? No Out Incorporate into the baseline Yes

7. 7 Modify the Baseline Submit a comment on the baseline Present the modification + proposed text Support Votes >= 75%? No Out Incorporate the proposed change into the baseline Yes

8. 8 Voting Rights [1], [2] 2 types of meeting sessions Plenary: 3 sessions per calendar year (March, July, November) Organized by IEEE 802 Interim: 3 sessions per calendar year (January, May, September) Organized by working group and sponsored by a host IEEE 802.11/.15/.18/.22 IEEE 802.16 Voting rights can be earned by participation in 2 of the last 4 consecutive plenary sessions or 1 plenary and 1 interim. Voting rights are only granted in “Plenary Sessions”. Definition of participation Must be present in at least 75% of ALL meetings in a session

9. 9 Maintain Voting Right [1] Loose the Voting Right by one of the following Fail to participate at least 2 out of 4 consecutive Plenary sessions Participation is to attend 75% of ALL meetings within a session May substitute one Interim session for Plenary Fail to respond and vote on 2 out of 3 mandatory WG letter ballots Fail to pay either Interim or Plenary conference fees

10. 10 Highlights of the IEEE Patent Policy [2] [5] Participants have a duty to tell the IEEE if they know (based on personal awareness) of potentially Essential Patent Claims they or their employer own Participants are encouraged to tell the IEEE if they know of potentially Essential Patent Claims owned by others This encouragement is particularly strong as the third party may not be a participant in the standards process Working Group is required to request assurance Early assurance is encouraged Terms of assurance shall be either: Reasonable and nondiscriminatory, with or without monetary compensation; or, A statement of non-assertion of patent rights Assurances Shall be provided on the IEEE-SA Standards Board approved LOA form May optionally include not-to-exceed rates, terms, and conditions Shall not be circumvented through sale or transfer of patents Shall be brought to the attention of any future assignees or transferees Shall apply to Affiliates unless explicitly excluded Are irrevocable once submitted and accepted Shall be supplemented if Submitter becomes aware of other potential Essential Patent Claims A “Blanket Letter of Assurance” may be provided at the option of the patent holder A patent holder has no duty to perform a patent search Full policy available at http://standards.ieee.org/guides/bylaws/sect6-7.html#6

11. 11 IEEE-SA Standards Board Bylaws on Patents in Standards [2] [5] 6.2 Policy IEEE standards may be drafted in terms that include the use of Essential Patent Claims. If the IEEE receives notice that a [Proposed] IEEE Standard may require the use of a potential Essential Patent Claim, the IEEE shall request licensing assurance, on the IEEE Standards Board approved Letter of Assurance form, from the patent holder or patent applicant. The IEEE shall request this assurance without coercion. The Submitter of the Letter of Assurance may, after Reasonable and Good Faith Inquiry, indicate it is not aware of any Patent Claims that the Submitter may own, control, or have the ability to license that might be or become Essential Patent Claims. If the patent holder or patent applicant provides an assurance, it should do so as soon as reasonably feasible in the standards development process once the PAR is approved by the IEEE-SA Standards Board. This assurance shall be provided prior to the Standards Board’s approval of the standard. This assurance shall be provided prior to a reaffirmation/stabilization if the IEEE receives notice of a potential Essential Patent Claim after the standard’s approval or a prior reaffirmation/stabilization. An asserted potential Essential Patent Claim for which an assurance cannot be obtained (e.g., a Letter of Assurance is not provided or the Letter of Assurance indicates that assurance is not being provided) shall be referred to the Patent Committee. A Letter of Assurance shall be either: a) A general disclaimer to the effect that the Submitter without conditions will not enforce any present or future Essential Patent Claims against any person or entity making, using, selling, offering to sell, importing, distributing, or implementing a compliant implementation of the standard; or b) A statement that a license for a compliant implementation of the standard will be made available to an unrestricted number of applicants on a worldwide basis without compensation or under reasonable rates, with reasonable terms and conditions that are demonstrably free of any unfair discrimination. At its sole option, the Submitter may provide with its assurance any of the following: (i) a not-to-exceed license fee or rate commitment, (ii) a sample license agreement, or (iii) one or more material licensing terms.

12. 12 Introduction to IEEE 802.11s Mesh Networking Standard

13. 13 IEEE 802.11s Deployment Scenarios Safety/Military Networks Campus/Public Networks Office Networks Residential Networks

14. 14 A Network Example Internet Ethernet Mesh 2 Mesh 1 Router Mesh portal Mesh AP Mesh Point (MP) Legacy AP Layer 2 LAN segment Layer 2 LAN segment Ethernet Mesh Point (MP)

15. 15 Mesh MAC Architecture EDCA Enhancement DCF 11a/11b/11g/11n PHY Routing Security Mesh Interworking Discovery Other MAC Mesh Topology and Discovery Security 802.11i link security enhancement Routing Hybrid Wireless Mesh Protocol Mac Enhancement EDCA-based, MDA (optional) Interworking Powersaving

16. 16 Device Classes in a Mesh Network Mesh Point (MP) Mesh AP (MAP) Mesh Portal (MPP) Station (STA) Portal MP STA External Network MP AP MP AP STA MP STA Mesh Point Mesh Portal Mesh AP Station

17. 17 Topology Formation MPs discover candidate neighbors using beacons and probe response frames Mesh ID, Mesh Capability Element Mesh Services are supported by new IEs (in action frames), exchanged between associated MP neighbors E.g. path selection information etc. Membership in a mesh network is determined by secure association with neighbors Simple channel unification mode follow rules to coalesce into a common, fully connected graph on one channel Advanced mode (multi-radio, multi-channel) framework for flexible channel selection algorithms beyond the standard scope

18. 18 MP Boot Sequence Active/passive scanning to discover other MP Channel selection Begin mesh beaconing. Neighbor MP link establishment Local link state measurement Routing initialization AP initialization if mesh AP Association Request (incl. mesh IEs, e.g., RSNie) Association Response (incl. mesh IEs) Beacon (incl. mesh IEs, e.g., Hello, RSNie, …) 802. 1x EAP Auth 802.1X EAP Request 802.1X EAP Response Access Request EAP Authentication Protocol Exchange Accept (Keys) 802.1x Success Pairwise Keys / Group Keys Establishment Secure Communications (encrypted) Data, Mesh management frames MP1 MP2 AS

19. 19 Security Framework Provide link security based on 802.11i: Authenticity requires that a MP is authenticated to be true before it is allowed getting in the mesh. Confidentiality requires that no non-trusted third parties can access the messages Integrity requires that the messages can not be altered during the transit without detection. Support centralized and distributed IEEE 802.1x-based authentication and key management A mesh point performs Supplicant and Authenticator roles, and may optionally perform the role of an Authentication Server (AS).

20. 20 802.11i Basics IEEE 802.1X EAP Authentication Establishing Pairwise and Group Keys via four way handshake

21. 21 Extensible Routing Framework Layer 2 routing based on MAC addresses Extensible Routing Protocol Architecture Allow a vendor to implement any path selection protocol and/or path selection metric to meet special application requirements and optimize the performance. One routing protocol is operated in a specific mesh network In beacon and probe response messages, advertise routing capability 5 7 1 2 6 4 3 X Capabilities: Path Selection: HWMP, Metrics: airtime, latency 8 Mesh Identifier: Mesh 1 Mesh Profile: (HWMP, airtime metric) Specify a default mandatory routing protocol: Hybrid Wireless Mesh Protocol (HWMP) Combine the flexibility of on-demand path selection with proactive topology tree building

22. 22 On-demand Routing vs. Proactive Routing On-demand Routing: discovers and maintains routes only when they are needed. Pros: Low routing overhead Cons: Extra route discovery delay and data buffering Proactive Routing: each node maintains routes to all reachable destinations at all times, whether or not there is current need to deliver data to those destinations. Pros: Little delay Cons: High routing overhead to keep the routing information current especially when network topology changes frequently HWMP combines the advantages of on-demand and proactive routing schemes On-demand for peer-to-peer communications Proactive route establish for communications with gateway and other important nodes

23. 23 Hybrid Wireless Mesh Protocol (HWMP) On-demand: Use route request/route reply to discover the route on-demand (reduce routing overhead) Proactive: Gateway proactively announce itself to establish route to reach it (reduce route discovery delay) Source Destination Source floods PREQ Source Destination Reply PREP Mesh gateway floods proactive PREQ or root announcement to proactively establish the routes to it MP may send a PREP or PREQ to the gateway to establish a path from the mesh gateway to the mesh point

24. 24 Routing Metric Airtime: the amount of channel resources consumed by transmitting the frame over a particular link. O ca, O p and B t are constants r: link bit rate e pt : frame error rate ParameterValue (802.11a) Value (802.11b) Description O ca 75  s335  s Channel access overhead OpOp 110  s364  s Protocol overhead BtBt 8224 Number of bits in test frame

25. 25 References [1] IEEE 802.11-04/422r7, “New Participant Orientation” [2] IEEE 802.11-08/0333r0 “General 802.11-Opening-Presentation” [3] “IEEE Project 802 LMSC Policies and Procedures,” http://standards.ieee.org/board/ LMSC.pdf http://standards.ieee.org/board/ LMSC.pdf [4] IEEE 802.11-11-07-0360-04, “IEEE 802.11 Working Group Policies and Procedures” [5] IEEE Patent Policy, http://standards.ieee.org/board/pat/pat-slideset.ppt http://standards.ieee.org/board/pat/pat-slideset.ppt [6] IEEE 802.11s Mesh Networking, D1.06 [7] IEEE 802.11-06/0329r3, “Joint SEE-Mesh/Wi-Mesh Proposal to 802.11 TGs Overview,” March 2006 [8] IEEE 802.11s Tutorial, Nov. 2006

26. 26 Backup Slides

27. 27 Simple Channel Unification Protocol At boot time, an MP logical radio interface shall perform passive scanning to discover neighboring MPs If an MP is unable to detect any neighbor MPs, Adopt the Mesh ID for its highest priority profile, Select a channel for operation Select an initial channel precedence value. the number of microseconds since the boot time of the mesh point plus a random value. In the event that a mesh point logical radio interface discovers a disjoint mesh, that is, the list of candidate peer Mesh Points spans more than one channel, Select the channel that is indicated by the candidate peer Mesh Point that has the numerically highest channel precedence indicator to be the unification channel If the identified unification channel is different than the current operating channel the mesh point shall execute the channel cluster switch protocol

28. 28 Channel Switch Protocol The mesh point determines the need to switch the channel chooses a channel cluster switch wait timer sends a channel cluster switch announcement frame to each peer mesh point which contains the new candidate channel, new candidate channel precedence indicator, channel switch wait time Receive a channel cluster switch frame If new candidate channel precedence indicator > the current channel precedence value set the channel cluster switch timer and send the channel cluster switch announcement frame to each peer mesh point it is possible that more than one mesh point initiate channel switch simultaneously If a mesh point receives more than one channel cluster switch announcement frame, it only acts upon the frame if the channel precedence value is larger than the channel precedence value of a previously received channel cluster switch announcement frame. In case a newly received channel cluster announcement frame has the same channel precedence value as a previously received frame, the new frame is acted upon only if the source address is smaller than the source address from the previously received frame.

29. 29 Mesh Formation Peer Link Setup and Maintenance A MP must select which MPs to establish peer links based on some measure of signal quality or other statistics received from candidate neighbor MPs. A MP may be configured with the maximum number of peers Local Link State Discovery and Maintenance Measure local link quality Mesh Portal Discovery Portal information and metric to portal contained in beacons

30. 30 Basic Security Model New Mesh Point WLAN Mesh Security bubble Supplicant Authenticator