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Introduction to IEEE Standardization & IEEE 802.11s

Hang Liu

Thomson Inc, Corporate Research LabPrincetion, NJ

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IEEE Standard Association [1]

Standards Activities Board

802.3CSMA/CDEthernet

802.5Token

Passing Ring

802.11Wireless

LAN

802.15WirelessPersonal

Area Networks

802.20Mobile

BroadbandWirelessAccess

802.19Co-existence

TAG

SponsorIEEE 802

Local and Metropolitan Area Networks(LMSC)

Sponsor Sponsor Sponsor

802.17ResilientPacketRing

802.18Radio

RegulatoryTAG

802.16Broadband

WirelessAccess

802.21Media

IndependentHandoff

802.1HigherLayerLAN

Protocols

802.22WirelessRegional

AreaNetworks

Wired Wireless

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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

Address comments & revision

No

No

Yes

Yes

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Draft Standard Development in TGDefine 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

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Proposal Down-Selection Process: Example 1

1st round proposal presentations and voting

Bottom 25%?

Yes

No

Out

2st 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

3st round proposal presentations (normally 2 or 3 merged proposals left)

Yes

Most supported proposal?

One winning proposal

Yes

No

Out

Baseline document

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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

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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

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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

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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

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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

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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.

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Introduction to IEEE 802.11s Mesh Networking Standard

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IEEE 802.11s Deployment Scenarios

Safety/Military NetworksCampus/Public Networks

Office Networks Residential Networks

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A Network Example

Internet

Ethernet

Mesh 2Mesh 1

Router

Mesh portal

Mesh AP

Mesh Point (MP)

Legacy AP

Layer 2 LAN segment

Layer 2 LAN segment

Ethernet

Mesh Point (MP)

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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

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Device Classes in a Mesh Network

Mesh Point (MP) Mesh AP (MAP) Mesh Portal (MPP) Station (STA)

PortalMP

STA

External Network

MPAP

MPAP

STA

MP

STA STA

Mesh PointMesh Portal

Mesh AP

Station

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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

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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 Request (incl. mesh IEs, e.g., RSNie)

Association Response (incl. mesh IEs)Association Response (incl. mesh IEs)

Beacon (incl. mesh IEs, e.g., Hello, RSNie, …)Beacon (incl. mesh IEs, e.g., Hello, RSNie, …)

802. 1x EAP Auth

802.1X EAP Request802.1X EAP Request

802.1X EAP Response802.1X EAP Response Access RequestAccess Request

EAP Authentication Protocol ExchangeEAP Authentication Protocol Exchange

Accept (Keys)Accept (Keys)

802.1x Success802.1x Success

Pairwise Keys / Group Keys Establishment

Secure Communications (encrypted)Secure Communications (encrypted)

Data, Mesh management framesData, Mesh management frames

MP1MP2 AS

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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).

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802.11i Basics

Supplicant Authenticator AS

EAP Request

EAP Response Access Request (EAP Request)

EAP Authentication Protocol Exchange

Accept/EAP Success/Key Material

EAP Success

Supplicant Authenticator

Message 1: EAPOL-Key(ANounce, unicasts)

Message 3: EAPOL-Key(Install PTK, unicast, MIC, Encrypted GTK)

PMK knownGenerate SNouce

PMK knownGenerate ANouce

Drive PTK

Message 2: EAPOL-Key(SNounce, unicasts, MIC)

Drive PTKGenerate GTK

Message 4: EAPOL-Key(unicast, MIC)

Install PTKInstall PTK and

GTK

IEEE 802.1X EAP Authentication Establishing Pairwise and Group Keys via four way handshake

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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

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12

6

4

3

X

Capabilities: Path Selection: HWMP, Metrics: airtime, latency

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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

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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

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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

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Routing Metric

Airtime: the amount of channel resources consumed by transmitting the frame over a particular link.

pt

tpcaa er

BOOc

1

1 Oca, Op and Bt are

constants r: link bit rate ept: frame error rate

Parameter Value (802.11a)

Value (802.11b)

Description

Oca 75s 335s Channel access overhead

Op 110s 364s Protocol overhead

Bt 8224 8224 Number of bits in test frame

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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

[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

[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

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Backup Slides

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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

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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.

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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

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Basic Security Model

New Mesh Point

WLAN Mesh Security bubble

Supplicant

Authenticator