IEEE802.1 AVB: 차량용 AV Bridging 기술 윤종호한국항공대한국이더넷포럼 yoonch@kau.ac.kr 2013.1.17
Ethernet
Ethernet 계층구조 MAC PHY
Networking Requirements in Vehicle
AVB 출발점 1 ( 2003)
AVB 출발점 2 : IEEE1394/Firewire
IEEE802.3 Residential Ethernet NEXT Generation AV Connector
Networked Audio -Audio=Low Jitter/Delay -Audio Distribution over Ethernet - 방식 -L1 : EtherSound -L2 : CobraNet 8
이더넷기반 Audio 분배기술의종류 EtherSound CobraNet IEEE802.1 AVB
Limited Delays in Home Recording Applications
Need for Time Synchronization Left + Right Channels Synchronization
AVB 관련프로토콜스택 802.1av Forwarding and Queuing Enhancements for Time-Sensitive Stream AV 프레임전송기능지원및남는대역에서의일반프레임전송기능을지원하는 traffic shaper 기능 802.1as Timing and Synchronization for Time- Sensitive Applications in Bridged LAN AV장치간시간동기화기술 802.1at Stream Reservation Protocol 대역예약프로토콜 802.1ba AVB 브리지및단말이갖추어야할기능열거 IEEE 1722 AVB Transport Protocol AV 스트림전달을위한 encapsulation 기능
802.1av : Periodic + Aperiodic Transport MOST 기술 Ethernet PowerLink for Industrial Ethernet MOST, Ethernet PowerLink, WiFi, Bluetooth, Fieldbus,...
802.1av : Forwarding and Queuing for Time-Sensitive Streams AV용 MAC TX Fifo Scheduler with Traffic Shaper Shaper using Credit : Limits X bytes in cycle n
Ieee802.1av Credit based Traffic shaper
16 Aircraft Full-duplex Ethernet ( 참고 ) AFDX 항공용이더넷기반제어통신망기술 A380 에채용됨. 실시간지원기능 전송주기를결정하는 Bandwidth Allocation Gap(BAG) 에의한대역할당 Token bucket 을사용하는트래픽폴리싱지원
IEEE802.1at Multiple Stream Reservation Protocol(mSRP) Admission control 을통한 L2 기반대역예약프로토콜 참고 : Multiple Registration Protocol (MRP:802.1ak) SRP 의구성요소 Multiple Registration Protocol (MRP:802.1ak) 의응용인 MMRP, MVRP 와 이것의 3 번째응용으로추가된 MSRP (35.1) 로구성됨. MRP 의종류 Multiple MAC Registration Protocol (MMRP): used to control the propagation of Talker registrations Multiple VLAN Registration Protocol (MVRP) : declare membership in a VLAN where a Stream is being sourced. This allows the Data Frame Priority (35.2.2.8.5(a)) to be propagated along the path from Talker to Listener(s) in tagged frames. MSRP will not allow Streams to be established across Bridge Ports that are members of the untagged set (8.8.2) for the related VLAN ID. Multiple Stream Registration Protocol (MSRP) : signaling protocol that provides end stations with the ability to reserve network resources. [ 참고 ] 802.1ak : Multiple Registration Protocol (MRP) 기존 2가지 MRP Applications MVRP : VLAN 등록 MMRP : Group MAC주소등록 [SRP를위해, MSRP가세번째 MRP 응용으로추가됨 ) [ 참고 ] 이것은기존 GVRP 및 GMRP를대체함. ( 즉 GARP를대체한것이 MRP임 )
MSRP TSpec Using a simple TSpec (Traffic Specification) Bandwidth in Kbytes/s Frame Rate in frames/s
MSRP 절차 1 : Registration Initiated by a Listener
MSRP 절차 2 : Reservation
MSRP : ACK
[ 참고 ] 실패시
IEEE802.1as : Time synchronization
Jitter/ 영향 지터 이더넷허브출력예 24
Need for Time Syncrhonization SUBMARINE SALVAGE OPERATION
동기용프로토콜 상호연결된시스템에서클럭들간에마스터 - 슬레이브관계를정하고, 모든클럭을그랜드마스터클럭에동기시키는기술 IEC61158 Synchronous Ethernet Carrier 급 IEEE1588 V1/V2/(V3) Hardware-assisted time sampling 기능사용 Frequency 및 Time 동기 IEEE802.1AS IEEE1588 Capability over multiple MAC(Ethernet,WLAN, EPON,) RFC1305 Network Timing Protocol (NTP) 26
PHY level Timestamping 27
Cascaded 될경우 Jitter 가증가됨. 28
IEEE1588 Ver.1 Synchronization 기능 Symmetric link 가정 29
IEEE1588 Ver.1 절차 Sync/FollowUp/DelayReq/DelayResp 메시지사용 30
IEEE1588 v2 추가된기능 Transparent Clock(TC) 추가 Path Delay(PDelay) 측정기능추가 이웃간전파지연시간측정 802.1as 에서사용됨. 31
구현예 (1588 PTP v1) Ethernet Switch 경유시 직접연결시
[ 참고 ]1588 v1 패킷의예
IEEE 1722: AVB L2 Transport Protocol(AVB TP) 기능 Encapsulation Raw, compressed audio format 표시등 Latency Normalization using timestamp Timing and Synchronization Session Management AVB stream ID 할당 IEC 61883-1 ~-7[ 참고 ] 61883-2 (SD-DVCR) 61883-4 (MPEG2 Compressed Audio/Video) 61883-6 (Uncompressed Audio/Music) 61883-7 (Satellite TV MPEG) 61883-8 (Uncompressed Video) IIDC (Uncompressed Industrial Cameras) [ 참고 ] IEC 61883 Consumer audio/video equipment - Digital interface is a technical standard for a digital interface that is used by IEEE 1394 (FireWire) de vices for audio and video equipment. IEEE1722.1 : Device Discover, Enumeration, Connection Management and Control Protocol for AVTP devices
예 : I 2 S Digital Audio 의수납절차
P1722 : Latency Normalization 기능
P1722 : Latency Normalization 기능
IEEE802.1ba AVB 요구사항규격서 MSRP절차를이용한 AVB stream설정 AVB domain탐색 (SRP 및 gptp를지원하는영역 ) Payload size = 1500 byte Energy Efficient Ethernet 기능지원
IEEE802.1ba: Architecture of AVB networks Non-AVB components : 배제함 Domain boundary의감지방법 MSRP(Multiple Stream Registration Protocol) gptp(generalized precision time protocol)
IEEE802.1ba: Latency Requirements 2 가지요구사항 2 ms for SR Class A : 7 hops of 100 Mb/s Ethernet with maximum frame size of 1522 octets. 50ms : 802.11 에염두를둠. 무선구간지연 =20msec 이므로, 2 hops of 802.11n WiFi 는가변대역폭을가지므로, 6.6 절참조 (6.6 Variable data rate LANs)
IEEE802.1ba : Sync packet 송신규격 송신주기 : 1/8 ~1s 시간정밀도 : 7 hops 인경우, 1usec 이내
관련 evaluation board XMOS - AVB Audio Endpoint Kit Stereo analog audio in/out via 3.5mm jack/rca sockets Up to 8 channels via I2S headers
XMOS AVB System Description
XMOS AVB Software Reference
AVB Testbed
Ether Tap 의구성 KSZ8051MLL PHY KSZ8051MLL 1:2 LV244A Fanout LV244A 1:2 LV244A Fanout LV244A KSZ8051MLL PHY HY KSZ8051MLL PHY KSZ8051MLL PHY KSZ8051MLL KSZ8051MLL Tapper
Protocol Analyzer(IEEE P1722) IEEE 1722 AVBTP
Protocol Analyzer(IEEE(IEEE802.1at) IEEE 802.1 Qat
Protocol Analyzer(IEEE(IEEE802.1as) IEEE 802.1 AS
AVB for Automotives
Automotive Data Bus CAN 1987 1Mbps with CSMA/NDBA(Non-destructive bit-wise arbitration ) over 40m~1Km Short Message with 8bytes LIN 19.2Kbps, Single wire FlexRay < 10Mbps with TDMA Bus MOST < 150Mbps with TDMA Ring Ethernet : Low-cost, Field-Proven On-Board-Diag (OBD) AVB : AVNu Alliance 참조 * AFDX ( 항공기용데이터버스 )
CAN motor sensor actuator application CPU messages Stand-alone CAN controller transceiver Bit stream 3.3~5V 0V Embedded MCU application CPU On-chip CAN Controller transceiver Terminator Resistor 120R 3.5V 2.5V 2.5V 1.5V CAN_H CAN_L 120R
LIN Local Interconnect Network 19.2Kbps Single Wire UART format
Issues Real Time Performance (QoS) Guaranteed Bandwidth per Virtual Link Low Latency 802.1av can support. Light-weight cabling BroadR-Reach : One pair cable with 100Mbps, OPEN(One Pair EtherNet) Alliance One pair cable with 1Gbps : Reduced Pair Gigabit Ethernet(RTPGE) Reliability in Extreme Conditions -40 C to +125 C RSTP with quick recovery => it might need RSTP quick version (e.g. better timers). 802.1AS with quick [re-]synchronization 802.1Qat with quick stream [re-]reservation Topology Ring or Star? Star Extended Life Times and Support silicon level life times of 30 years or more
Ethernet for Automotives 1 st phase : On-board diagnostics (OBD) 용 2 nd phase : Entertainment/Suround View 3 rd phase : Backbone network
구성
Gateway 의구성 Bosch/ETAS s GW
CAN-GW-Ethernet 계층구조
Automotive Profile with AVB by AVnU Alliance 32 endpoints 7 switch hop 24m per link, e2e link = 30 m Cycle : 125 usec, 250 usec(classb) E2e delay : 100usec over 3 hops (general AVB=2 msec) Network Recovery < 100ms with Rapid STP Using small frame of 258 bytes
ACK Frame 추가사용 CAN 은 Link 계층 ACK 기능이있으므로, 이를 emulation 하기위하여 IEEE1722 헤더에 subtype 을지정하여사용.
One Pair EtherNet (OPEN) 100Mbps 125Mbaud 66.6Mbaud : UTP 사용가능 10-10 BER over single pair cable with FDX
AVB Gen 2 for Automotive Control To be.. Ultra Low latency < 3usec/hop (GbE)... How to? Refine SRP(802.1at) and 802.1av Time-aware shaper Preemption Multipath/Redundant SRP Cut-through Time-Triggered...
AUTOSAR with AVB (AUTomotive Open Software ARchitecture) APP Runtime Environment (RTE) Comm Services AUTOSAR COM Diagnostic Communication Manager Communication Manager Socket Adapter CAN Transport Communication PDU Router HAL FlexRay Transport I/O HAL System/Memory Services application UDP, TCP, IP, ICMP CPU Comm Controller IEEE 1722 802.1av, as, at AVB Gen2 Eth if Communication HAL Can if Onboard Device/Memory HAL Microcontroller Abstraction Layer(MCAL) Eth driver Communication Drivers Can driver Lin driver Fr driver IO Drivers(ADC,PWM) I2s driver I2c driver Memory/Microcontoller Drivers (Memory, WDT,..) transceiver r 802.3 MAC 802.3 PHY One Pair Cable CAN LIN FlexRay/MOST codec sensor actuator
AVB 문제점 Recall AV frame Async frame Async frame MAC hdr S 수퍼프레임 idle slot S S idle slot Cycle(125usec) S S A (a) Ethernet over TDM slot 기반 idle slot A 동기구간 비동기구간 MAC hdr idle slot idle slot (b) 고정된길이의 AV 트래픽전달방법 cycle Async frame Async frame 동기구간 비동기구간 AV frame AV frame AV frame Async frame Async frame Async frame (c) 가변길이의 AV 트래픽전달방법
A close look S S A S S A Credit-based scheduler with separate buffers Receiver Sender MAC HOL blocking MAC AV frm AV frm Async frm AV frm AV frm Async frm AV frm Cycle (125usec) Delayed AV frame A S A S S sw sw sw S S A S A
802.1p Jitter:(Simulation Result) 30 28 26 24 30 28 26 24 30 25 T A (usec) 22 20 18 16 14 12 10 12 10 10 0 10000 20000 30000 40000 50000 Time (usec) 0 10000 20000 30000 40000 50000 0 10000 20000 30000 40000 50000 Time (usec) Time (usec) (a)802.1p(ρ S =0.1, ρ A =0.1) T A (usec) 22 20 18 16 14 (b)802.1p(ρ S =0.5, ρ A =0.4) T A (usec) 20 15 (a)ideal (Zero Jitter) AV 패킷의시스템지연시간
Hold, Fragmentation 방법 Hold 수퍼프레임 수퍼프레임 수퍼프레임시작지연 동기구간 비동기프레임 #1 비동기프레임 #2 동기구간 기존방식 동기구간 비동기프레임 #1 동기구간 비동기프레임 #2 Hold 방식 Fragmentation/Reassembly 동기구간 동기구간 비동기프레임 #1 비동기프레임 #1 수퍼프레임 수퍼프레임시작지연 비동기프레임 #2 #2-1 동기구간 동기구간 동기구간축소 #2-2 수퍼프레임 기존방식 분할방식
To be.. Flow-based IP layer IP Expedited Flow IP Classifier Flow-based IP layer IP Expedited Flow IP Flow Classifier MPLS layer CoS Scheduler Shaper/Dropper Marker/ Meter MPLS over Ethernet encap Over-Provisioning, RSVP-TE, Routing Protocols(OSPF, BGP) Label Switching Link Layer AV Queue Scheduler Shaper/Dropper Marker/ Meter Async Queue Link-layer Reservation protocols Spanning Tree Protocols Link Layer 802.1p Ethernet Sync Ethernet MAC/VLANid Switching Guaranteed Digital Pipe 802.1p CoS pipe 802.1p pipe (a) Semi-QoS Scheme (b) Full-QoS Scheme with AVB Ethernet (TBD)
요약 AVB 기술소개 Automotive bus 소개 Stay tune... AVNu : AVB Alliance AVB Gen.2 IEEE1588 v3(?) AutoSAR over Ethernet Remind... 실제기술채용회사는자동차조립및부품제조회사임을명심 자동차제조사는 IT분야의전문가집단이아님. IT관련개발도구 (IDE)/ 부품은이들을배려하여개발 / 제공해야함.
또다른응용분야 : Industrial Ethernet
FIN Thanks Danke schön Merci Grazie