Submission

doc.: IEEE 11-13/0221r2Mar 2013

BroadcomSlide 1

802.11 QoS Queue Architecture and Possible 802.1bz Bridge Model “for P2P

Model”

Date: 2013-03-18

Name Affiliations Address Phone email Philippe Klein Broadcom Golan Building

Airport City, Israel +972 54 3134500 philippe@broadcom.com

David Goodall Broadcom 24 Campbell Street Haymarket, Sydney, NSW, 2000

+61-2-8030-7452 daveg@broadcom.com

Authors:

Submission

doc.: IEEE 11-13/0221r2

Broadcom

Abstract

This presentation describes

- the structure of the QoS Queuing in the 802.11 AP and non-AP STA devices,

- a possible architecture model for 802.1bz bridge.

- technical issues

Slide 2

Mar 2013

Submission

doc.: IEEE 11-13/0221r2

Broadcom

802.11 - QoS Specifications

EDCA (Enhanced Distributed Channel Access)- High-priority traffic has a higher chance of being sent than low-

priority traffic- Contention window (CW) and arbitration inter-frame space

(AIFS) determines the probability to gain the access to the medium

- CW and AIFS values are a function of the priority level.

- Transmit Opportunity (TXOP) is the bounded time interval during which the transmitter can send as many frames as possible 

Wi-Fi Alliance’s WMM (Wi-Fi Multimedia) is a subset of 802.11 (EDCA, TxOP)

Slide 3

Mar 2013

Submission

doc.: IEEE 11-13/0221r2

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802.11 Access Categories

EDCA/WMM Medium Access does not guarantee QoS QoS can be improved by Admission Control that limits admission

and bandwidth utilization per Access Category

Slide 4

Mar 2013

Submission

doc.: IEEE 11-13/0221r2

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Access Categories (AC)

EDCA levels of priority are called access categories (ACs). ACs map directly from 802.1D-2004 user priority levels:

Slide 5

Mar 2013

802.1D-2004 802.11 (UP)Wi-Fi WMM

802.11aa-2012w/ Alternate-EDCA activated

PriorityPriority

LevelDesignation AC Designation

WMMPriority

AC Designation

lowest 1 BK AC_BK BackgroundBackground BK Background

2 - AC_BK Background

0 BE AC_BE Best EffortBest Effort BE Best Effort

3 EE AC_BE Best Effort

4 CL AC_VI VideoVideo

A_VI Video (Alternative)

5 VI AC_VI Video VI Video (Primary)

6 VO AC_VO VoiceVoice

VO Voice (Primary)

highest 7 NC AC_VO Voice A_VO Voice (Alternative)

Submission

doc.: IEEE 11-13/0221r2

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802.11 QoS Queue Architecture

Slide 6

Mar 2013

Classification to Access Categories and Transmit queues

VO VI BE BK

VO BackoffVO AIFS, VO CW

VO TxOP

VI BackoffVI AIFS, VI CW

VI TxOP

BE BackoffBE AIFS, BE CW

BE TxOP

BK BackoffBK AIFS, BK CW

BK TxOP

Channel Access functions

(EDCA functionswith internal

collision resolution)

TransmitQueues

Submission

doc.: IEEE 11-13/0221r2

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802.11aa QoS Queues

Slide 7

Mar 2013

Classification to Access Categories and Transmit queues

VO

VO VI BE BKChannel Access

functions

TransmitQueues

A_VO VI A_VI BE BK

802.11aa introduces 2 additional queues for “alternate voice” and “alternate video”.

Submission

doc.: IEEE 11-13/0221r2

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Current Bridge & AP Queue Architecture

Slide 8

Mar 2013

BSSID A

“Access Point”

MAC 1Port

MAC 2Port

MAC 3Port

VO VI BKBE

PortalPort

AP

BSSID B

MAC 4Port

MAC 5Port

MAC 6Port

VO VI BKBE

802.11 Portal

MAC Port

MAC Port

MAC Port

MAC Port

802.1 Bridge

MAC 7Port

Non-AP STA

MAC 8Port

MAC 9Port

MAC 10Port

MAC 11Port

MAC 12Port

Wired link

Wired link

Wired link

Wireless links

802.11 DS (Distribution System)

Non-AP STA

Non-AP STA

Non-AP STA

Non-AP STA

Non-AP STA

MAC Relay AP MAC Relay

MAC port instantiation per

wireless link

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doc.: IEEE 11-13/0221r2

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BSS Bridging “Common” Queue Architecture

Slide 9

Mar 2013

MAC 1Port

MAC 2Port

MAC 3Port

MAC 4Port

MAC 5Port

MAC 6Port

MAC Port

MAC Port

MAC Port802.1

Bridge

MAC 7Port

Non-AP STA

“Access Point”

MAC Port

MAC Port

802.1 Bridge

Wireless link

Wired link

Wired link

Wired link

Wired link

Wired link

Bridge’s Queues

Bridge’s Queues

Note: For the clarity of the figure, optional Tx intermediate buffers within the wireless MAC, handling the deferred access to the medium and the Tx retransmission on failure to receive an ACK are not represented.

Submission

doc.: IEEE 11-13/0221r2

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802.11 – 802.1Q Default Priority Levels ACs default priority level mapping differ from 802.1Q-2012 default priority level

mapping

These mappings are informative only and could be freely modified

Slide 10

Mar 2013

802.1D 802.11 WMM 802.11aa 802.1Q-2012

PriorityPriority

LevelDesig.

Access Category

WMMPriority

AccessCategory

Priority Level

Traffic type

6 traffic types

4 traffic types

with SR Class A & B

with SR Class B only

lowest 1 BK AC_BKBackground BK

1 BK BKBE

BE

BE

2 - AC_BK 0 BE BE

0 BE AC_BEBest Effort BE

2 EECA CA

CA

3 EE AC_BE 3 CA

4 CL AC_VIVideo

A_VI 4 VIVO VO

SR-B NC

5 VI AC_VI VI 5 VO NC

6 VO AC_VOVoice

VO 6 IC ICNC

SR-A SR-B

highest 7 NC AC_VO A_VO 7 NC NC NC NC

Submission

doc.: IEEE 11-13/0221r2

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802.11 Portal

Slide 11

Mar 2013

802.11-2012, Section 4.3.6: “Logical point at which MSDUs from an integrated non-IEEE

802.11 LAN enter the IEEE 802.11 DS.” 802.1Q-2012, Section 6.7.2: “A Bridge to an IEEE 802.11 LAN shall connect to an IEEE 802.11

Portal, which in turn connects to an IEEE 802.11 Distribution System. For the purposes of bridging, the service interface presented at the Portal is identical to the service interface presented at the IEEE 802.11 MAC SAP.

802.11 Portal

802.1 Bridge

802.11 Distribution System

ISS_SAP (M_UNITDATA)

DS_SAP (DS_UNITDATA)

Submission

doc.: IEEE 11-13/0221r2

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802.3 – 802.11 MAC Relay

Slide 12

Mar 2013

802.11 to 802.11 MAC relay

802.11 to 802.3 MAC relay

802.3 to 802.3 MAC relay

802.3 to 802.11 MAC relay

802.11 MSDURx Queue

802.11 Tx Queue Selection

802.11 MSDUTx Queue

802.1x CtrlPort Filtering

802.11 MSDURx Queue

802.11 802.3MSDU Translation(“M_MA Portal”)

802.3 Tx Queue Selection

802.1x CtrlPort Filtering

802.3 MSDUTx Queue

802.3 MSDURx Queue

802.3 Tx Queue Selection

802.3 MSDUTx Queue

802.3 MSDURx Queue

802.11 Tx Queue Selection

802.11 MSDUTx Queue

Forwarding [Priority Handling]

802.3 802.11MSDU Translation(“M_MA Portal”)

Forwarding [Priority Handling]

Forwarding [Priority Handling]

Forwarding [Priority Handling]

Submission

doc.: IEEE 11-13/0221r2

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802.1bz Bridge Data Plane Model

Slide 13

Mar 2013

802.03 MAC Port

802.11 MAC Port

_ISS_

802.1x Ctrl Port Filtering

_IS_ MAC Relay

Entity

_ISS_

Sec Y

_IS_

M_MA Portal

LLCLLC LLCLLC_IS_ _IS_

IS = Insecure ServiceSS = Secure Service

Submission

doc.: IEEE 11-13/0221r2

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802.1bz Bridge Forwarding Process

Mar 2013

Slide 14

Active topology enforcement (8.6.1)

Ingress (8.6.2)

Frame filtering (8.6.3)

Egress (8.6.4)

Flow metering (8.6.5)

Queuing frames (8.6.6)

Transmission selection (8.6.8)

Reception Port

Transmission Port

Queue management (8.6.7) Queue management (8.6.7)

TransmissionPort State

Reception PortState

Filtering Database

• MAC DA• MAC SA• VID• Priority

802.1Q clauses to be modified

• MA / M Portal : - 802 11 - 802.3 MSDU translation • Multicast Handling - “Multicast Reflection” prevention

• 802.1x Ctrl Port Filtering

• 802.11 AC Queue selection

• No 802.11 PCF or flow control

• No shaping on EDCA medium access

• Common format “translation “

Submission

doc.: IEEE 11-13/0221r2

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A (non exclusive) list of issues to address

• Common filtering of 802.11 and 802.3 MSDUs:• is a conversion to a “common format” within the bridge the right solution ?

• Double ingress/egress conversion for every MSDU (including MSDUs forwarded between the same medium) could be taxing on performances…

• Duality P2P and Distributed bridge model :• a BSS can not be modeled as P2P only….(see following slide)

• 802.11 link metrics / variation thresholds compatible with 802.1 wired link bridging protocols.

• standardize the metrics computation; characterize the wireless link

• AP / Non-AP STA “bridge port” command protocol• reliability and synchronization between ports

• MACSec / 802.1x / security interworking• key management, (end-to-end similar) crypto level

Slide 15

Mar 2013

Submission

doc.: IEEE 11-13/0221r2

Broadcom

A BSS can not be modeled as P2P only….

• Each Wireless link is a point to point link between the ports of 2 “independent“ hybrid (wired/wireless) bridges...

Slide 16

Mar 2013

Hybrid Bridge B

wl Port 1

Wr Port 2 Wr Port 3

Hybrid Bridge C

Wr Port 2 Wr Port 3

Hybrid Bridge A

wl Port 1

Wr Port 2 Wr Port 3

wl Port 2

wl Port 1

Wireless BSS

wl Port 2 wl Port 2

DLS

Submission

doc.: IEEE 11-13/0221r2

Broadcom

A BSS can not be modeled as P2P only….

• Each Wireless link is a point to point link between the ports of 2 “independent“ hybrid (wired/wireless) bridges...

• However, the wireless ports are controlled by the AP (association , encryption setup, bit rate selection, bandwidth management, metrics,…)

Slide 17

Mar 2013

Hybrid Bridge B

wl Port 1

Wr Port 2 Wr Port 3

Hybrid Bridge C

Wr Port 2 Wr Port 3

Hybrid Bridge A

wl Port 1

Wr Port 2 Wr Port 3

wl Port 2

wl Port 1

Wireless BSS

AP

Ctrl

wl Port 2 wl Port 2

DLS

Submission

doc.: IEEE 11-13/0221r2

Broadcom

A BSS can not be modeled as P2P only….

• Each Wireless link is a point to point link between the ports of 2 “independent“ hybrid (wired/wireless) bridges...

• However, the wireless ports are controlled by the AP (association , encryption setup, bit rate selection, bandwidth management, metrics,…)

• Need for a new Mgnt Protocol between the hybrid bridges and the BSS AP

Slide 18

Mar 2013

Hybrid Bridge B

wl Port 1

Wr Port 2 Wr Port 3

Hybrid Bridge C

Wr Port 2 Wr Port 3

Hybrid Bridge A

wl Port 1

Wr Port 2 Wr Port 3

wl Port 2

wl Port 1

Wireless BSS

AP

Ctrl

wl Port 2 wl Port 2

DLS

Submission

doc.: IEEE 11-13/0221r2

Broadcom

Revisiting the BSS Distributed Bridge Model option

• IEEE 802.1BR specifies a Extended Bridge beyond its physical enclosure using 802 LAN technologies.• In the BSS case, the AP will be the Controlling Bridge and the

non-AP STA will be Bridge Port Extenders

• The 802.1BR Port Extender Control and Status Protocol (PE CSP) provides a basic acknowledgement and retransmit mechanism

Slide 19

Mar 2013

Submission

doc.: IEEE 11-13/0221r2

Broadcom

References

[1] IEEE 802.11-2012

http://standards.ieee.org/getieee802/download/802.11-2012.pdf

[2] IEEE 802.1D-2004

http://standards.ieee.org/getieee802/download/802.1D-2004.pdf

[3] IEEE 802.11aa-2012

http://standards.ieee.org/getieee802/download/802.11aa-2012.pdf

[4] Wi-Fi WMM Specification v1.2

www.wi-fi.org/knowledge-center/published-specifications

[5] IEEE P802.1BR/D3.3

www.ieee802.org/1/files/private/br-drafts/d3/802-1BR-d3-3cb.pdf

Slide 20

Mar 2013