IEEE 802.3 Residential Synchronous Ethernet

기술

윤종호/한국항공대2005.1

Home Connectivity Today

Ad-hoc manner Non realtime

Home audio/videoBackside View…

And..

1394

• Computer 연결• CE

– all digiCam– Only way to connect DTV/STB/Cam

• New Market– A/V Receiver

• Networking 1394 bus– 아직은 수요가 없다. – 집에 2대 이상의 DTV가 설치될 경우에는 수요가 창출될 것이다.

Current Solutions

• 1394b/c–100/800 Mbps on UTP–No Product yet.–Not Ethernet

• 802.15.3, 802.11e WLAN–Limited range–QoS Issues–How to connect devices..

Ethernet for Home Appliances

Gibson Guitar’s MAGIC• “Guitar maker preps digital network platform”,EE Times,

January 28, 2003• “Guitars tune into digital sounds”, BBC News, Feb. 11, 2003.

Next Generation AV Connectorvia Synchronous Ethernet

Clean and Simple

RSE=Next Gen AV Connector

A solution for 1394 backbone

네트워크 DivX DVD플레이어, KiSS DP-500

• DVD플레이어에Ethernet 포트가...

PDP with Ethernet Port

Problems on Prioritized Ethernet

Why not legacy Ethernet

• Non-deterministic delays at–Ethernet MAC–Switches–Protocol stacks

• jitter• No native time synchronisation

Non-preemption property in a 802.1p switch

• 802.1p Non-preemption delay : 122 µs

802.1p 스위치의 Jitter 문제점

1 2 3 4 1 2 3 4

1 2 3 4 1 2 3 4

Real-timeCODECsource

125usec

1 2Async frame 3 4

1 2 3 4

1 2 3 4 1 2 3 4sync frame

Tx

1 2 3 4 1 2 3 4Real-time CODEC sink

delayed sync frames

Starvation/Overbooking

1 2 3 4 1 2 3

4

1 2Async frame 3 4

1 2 3 4 1 2 3 4sync frame source #1

Tx

1 2 3 4 1 2 3 4sync frame source #2

1 2 3 4 1 2 3 4

buffer overflow

starvation

다단 연결시 문제점

Sync Frame의 Jitter

VBR source

CBR source #1

1

1

1

1

1

1

2

1

3

2

1

CBR source #2 CBR source #3

Typical worst-case switch latency

(example)• 100 Mbps • switch latency = 10us. • real time packet length = 200 bytes• 5 other real time stations------• Worst case switch latency of a realtime packet :

– 16 us : transmission time of a real time packet. – 10 us : minimum switch latency. – 122 us : worst case latency for transmitting an async

frame– 80 us : 5 real time packets already in the same priority

queue. – Total : 228 us.

Real-time Ethernet :Industrial Ethernet

Ethernet based Industrial Network

Two types of real-time

• Hard real-time system :– fails if the timing requirements are not met– (예) Industrial control, networking in a car

• Soft real-time system :– can tolerate some deadline overruns, as long

as– the mean latency time is smaller than the

deadline– (예) DVD-player, streaming media

Real-time in terms of deadline

time

processing time

deadline

deadline

..V

actionevent

•a missed hard deadline can have serious consequences.

Real-time in terms of Jitter

•All RT systems have a certain level of jitter (a variance on actual timing). •In a RT system, jitter should be measurable so system performance can be guaranteed.

time

processing time

..V

event

processing time

processing time

Jitter boundary

TDMA Railroad

•Every train (frame) runs on a schedule•Space is reserved•No spacing between cars (no variable back-off / wait)•Arrival times are guaranteed (latency, jitter)•Space assigned long term or for a single trip (Isochronous, asynchronous) •No collisions, hidden nodes, Traffic Jams – fully managed system

Industrial Ethernet의 종류

All provide sub-microsecond synchronisationaccuracy of distributed clocks over Ethernet.

PROFInet

• a fieldbus standard for automation systems• built on IEEE 802.3• 종류

– PROFInet V1: response time of 10-100 ms– PROFInet-SRT (soft realtime): cycle time of 5-10 ms – PROFInet-IRT : hard-RT with sub-microsecond

synchronisation / cylce=250usec

• 특징– 1 ms cycle time– 1 µs jitter accuracy, and guaranteed determinism – Using full-duplex switched fast Ethernet– Special ASIC사용– allows both RT and non-RT traffic to co-exist on one

network

PROFINETv3

Time Syncrhonization for Realtime Ethernet

Need for Time Synchronization

INDUSTRIAL ETHERNET CONTROLS SUBMARINE SALVAGE OPERATION

노래자랑…

전화기

arami

전화망

반주기

라디오

mixer FM

arami

IP전화기

All IP 망 (e.g. BcN)

반주기

IP radio

mixer AudioCast

in addition …HDTV Video…

Need for Time Synchronization

ethernet

Solutions

• Simple Network Time Protocol (SNTP) – 123 UDP port 사용.

• IEEE1588 Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems– Precision Time Protocol (PTP)사용

SNTP time updates

0 T1 = 1

T2 =1 2

T3 = 2 3

3 T

T2,T3

4 =4

Propagation Delay = {(T4 -T1)-(T3-T2)}/2 = {(4-1)-(2-1)}/2 = 1Offset = {(T2 -T1)+(T3-T4)}/2 = {(1-1)-(2-4)}/2 = +1

Who stamps the time?

• Timing accuracy depends on where the time stamping is performed and network latency variations.

• Time stamping can be performed in – SNTP/NTP application layer

• millisec

– Ethernet driver level (software)• 10~100microsec

– Ethernet data link/physical layer (hardware)• <1 microsec

3 Time Stamping

IEEE1588 Precision Time Protocol(PTP) 구조

IEEE 1588:Timestamping at MII

Eval Kit

MII

RSE

IEEE 802.3 Residential (Synchronous) Ethernet SG

• 2004.7월 조직됨• PAR 준비 중

RSE MAC개념

1

2

3

4

1

1

2

3

4

2 3 4 1 2 3 4

cycle=125usec

Sync-E MUX

a max 15K bytes FIFOfor Sync-E frame

4 4

4 4

max 1522bytes

구조

Cycle and Frame Format

Ethernet Header22bytes

Sync Header32bytes

Sync Data Slot192*32bit = 768 bytes

HCS4bytes

FCS4bytes

Iso Version4 bits

Sync1 bit

Frame Couterin the cycle 1 byte

Reserved19 bits

Cycle Couter4 bytes

Data Slot Validity24 bytes

Sync/Async in a cycle

유사한 cycle-based MAC•1394•WPAN•802.11 •Industrial Ethernet

WLAN/PCF, WPAN MAC의문제점

1 2 3 4 1 2 3 4

1 2 3 4 1 2 3 4

Real-timeCODEC

Sync-e #2 timimg(best-case)

125usec

1

1

2

2

Async frame 3

3

4

4

delayed cycle start

shortened asynch duration

target cycle start time

1 2 3 4 1 2 3 4sync frame

Slot Routing

Slot Reservation/Routing

계층구조

브리지에의 응용

• Admission Control service를 브리지에추가.

Issues on RE

RE Applications

• Networked Audio– Both compressed and uncompressed streams– Issue : Room to room phasing

• Video Distribution– Primarily compressed streams– High Definition (HDTV) Satellite/Cable

Receivers– HD Digital Video Recorders– Issue : Lip-sync with networked audio

Issues• Backward compatibility

– 100Mbps를 수용할 것인가?– HDX를 수용할 것인가?– 토폴로지는?

• Time-sensitive requirements – Jitter bound– Latency bound– Timing master

• User Requirements– Plug & Play without

interruption– Easy– Low cost

• BW management– Admission Control– Slot reservation procedure– Slot reuse– Slot interchange– Sync/Async Ratio

• Market– 802.1p와의 경쟁– 1394와의 경쟁– Home backbone ? device

interconnection?– BcN? Sonet? – Industrial Ethernet?– Ubiquitous Ethernet?

How to coexist with legacy Ethernet backbone?

class 2switch

class 1 NIClegacy NIC

legacyswitch

legacy switchclass 1 NIC

legacy switch

prioritized?

100Mbps RSE

Cycle = 125usec– For 1Gbps : 10% of Asynch traffic : OK– For 100Mbps : 123.36/125 = 98.688%

해결책 : – 동기 프레임 길이 축소– 비동기 프레임 분할 전송– 사이클 구간 확장 : n * 125usec

Topology Issues

Class2장치

Switch

Class1장치

Class12장치

Class12장치

Class12장치

Interconnected Network

hub

class 1

class 1+

class 2

class 1

hub

class 1

class 1

class 0 : Legacy Hub/Repeater/Switch/NICclass 1 : a device without switching capabilityclass 1+ : a class 1 device with timing master capabilityclass 2 : a device with switching capability

Time-sensitive requirements

• Bounded jitter and latency• End point synchronization

–Network Timing should be deterministic

Lip-Sync

Same Audio Track in multiple Rooms

이때, 각 방에서 들리는 소리가 동기되어야 reverberation을 방지할 수 있다.

Phase-Sync

Need for House Clock

• Global precise synchronization

Cascaded TOD sync.

Timing Master

master 결정브리지처럼 연결된 망에서, 누가 master가 될 것인가?

- BridgeID- StationID- ?

ToD Precision

Admission Control

• Bandwidth allocation–Non-interfering streams–Guaranteed BW

• Allocate slots with GMRP?• Request/Relase BW procedure

User Requirements

• Minimal setup/admin = Easy of use• Low cost

PoE

• Power over Ethernet(PoE)–15.4W, 48V Rev2의 경우 40W제공 가능

• Digital Camcoder:3W~20W• Ethernet Speaker: 5~40W• LCD Monitor : 30W• Elec Guitar• Elec Keyboard : 10~20W

기존 기술과의 경쟁Sync-e VS 802.1P/1394

802.1p/RE Comparison:(Simulation Result)

(a)802.1P((a)802.1P(ρρSS=0.1,=0.1, ρρAA=0.1=0.1))

0 10000 20000 30000 40000 50000

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T A (u

sec)

Time (usec)

0 10000 20000 30000 40000 50000

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T A (u

sec)

Time (usec) 0 10000 20000 30000 40000 50000

10

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T A (u

sec)

Time (usec)(a)802.1P((a)802.1P(ρρSS=0.5,=0.5, ρρAA=0.4=0.4)) ((a)Synca)Sync--EE (Zero Jitter)(Zero Jitter)

((ρρSS=0.1,0.5 =0.1,0.5 ρρAA=0.1,0.4=0.1,0.4))

동기동기 패킷의패킷의 시스템시스템 지연지연 시간시간

Result

0 10000 20000 30000 40000 50000-20

0

20

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200

T A (u

sec)

Time (usec)0 10000 20000 30000 40000 50000

-20

0

20

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120

140

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200

T A (u

sec)

Time (usec)

0 10000 20000 30000 40000 50000

-20

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T A (u

sec)

Time (usec)

(a) IEEE 802.1p(a) IEEE 802.1p (b) Sync(b) Sync--E (NoneE (None--ZeroZero--Jitter)Jitter) (C) Sync(C) Sync--E (ZeroE (Zero--Jitter)Jitter)

비동기비동기 패킷의패킷의 시스템시스템 지연지연 시간시간 비교비교( ( ρρSS=0.5 , =0.5 , ρρAA=0.4=0.4))

1394b

• 3200Mbps (800Mbps available today)

• 100m per hop• Unshielded Twisted Pair Category 5

1394

ethernet(Internet access)

1394(home backbone)

1394

TV

DigitalLibrary

지하실

?

Remind: 인천공항

GigaEther

ATM

Ethernet

Ethernet Home Backbone

ethernet(access)

Ethernet(home backbone)

1394

TV

DigitalLibrary

지하실

A unified transmission

ethernet(access)

Ethernet(home backbone)

Ethernet

TV

DigitalLibrary

지하실

Sync-E for BcN

QSS의 기능• ATM/Frame Relay

convergence on IP/MPLS• Per-Flow Traffic Shaping :

for low-jitter guaranteed rate service

• Macro" and "micro" QoS:supporting both aggregate and per flow QoS

• CAC for Premium IP service

QSS

QSS스위치의 문제점

• 802.1p Non-preemption delay : 122 µs• 다단 연결시 더 큰 jitter발생• 단말에 큰 jitter버퍼 필요

구조 비교

MPLS Switch

Flow Classfication,CAC,

Shaping,Scheduling

Transport&

Applications

MPLS Switch

Flow Classfication,CAC,

Shaping,Scheduling

Transport&

Applications

IPIP

MPLS over(ATM)/(SONET)

MPLS over Ethernet MPLS over Ethernet

Legacy 802.1p Ethernet(non-zero jitter, unbounded delay)

Slotted Ethernet(Zero-jitter, Zero-loss)

Legacy 802.1p Ethernet(jitter, loss)

기존 QSS Sync-E based QSS

QoS-enabled Networks

ACCESSNETWORK

(EPON)

ACCESSNETWORK

(EPON)

Backbone

METROMETRO

SWITCHROUTER

HOMELIVING ROOM

BED ROOM

SWITCH

R

R

R

SWITCHSWITCH

PVR

video, audio,data streams over a single Ethernet

Summary and Suggestions• Ethernet :

– Cheap, mature tech, everyone knows..• Ethernet can provide Strict QoS Services

– TDM Superframe or Token-based• Many Issues to be solved

– Synchronization, Segmentation,…– Admission control, OAM– New Chips, Switches, – Interface to PSTN?

• Broad applications– Home Networking, and link to even SONET– Industrial Networking

Note

Backup

Real-time Ethernets• Iso_Ethernet• Rtnet

– Token passing over Ethernet– Software based

• Rether– Token passing over Ethernet– Real-Time Ethernet for PLC Networks– Software based

• Vtnet : virtual token net– Software

• Synchronous Ethernet– Gibson Guitar Co. and Pioneer– MAGIC

Iso_ethernet

125usec Cycle•P-Channel : 10Mbps Asynch Ethernet•B/D channels : As you known…•M-channel: A full-duplex 96 kbit/s. physical layer control and status informations

RTnet for Home Networking

• Home Real-time Multimedia Commun.• U.of Twente

Rtnet based on Token

Ethernet Switches for Military Applications

• Reliable operation from –40 to +85 °C

• Tested for vibration and harsh conditions

• Special technology for military apps.

• Easily adapted to special requirements

Reservation Procedure• Listener must confirm resources available along entire path to destination– sends “join request” control packet to talker with amount of bandwidth

needed (in bytes/cycle)– intermediate bridges make reservation, update delay count and pass on

control packet– if resources not available, packet is stamped as “unavailable”, but still sent to

talker– talker returns “join response” packet to listener with status status includes

resource available (or not), and delay• Obviously, various timeouts and disconnects affect this• Additional listeners also send “join” request – but this time an intermediate bridge can respond if it is already routing the

stream• Listener sends “leave” when done– only gets to talker if this is the last listener, bridges intercept all others• Talker is required to send one packet every cycle– may be zero length– if missing for more than “x” cycles, can be used to take down the connection