Vector 车载以太网基础软件

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Time-Sensitive Networking (TSN)
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Automotive Ethernet in POSIX-Based Systems
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Service-Oriented Communication
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Time-Sensitive Networking
Motivation
Traffic convergence must be handled Control data Streaming data Diverging transmission behavior & requirements
Ethernet Basic Software – What’s next?
8. Vector Congress – Nov. 30th 2016
V0.1 | 2016-09-05
Introduction – Automotive Ethernet
The dissemination of Automotive Ethernet increases
The AVTP protocol is lower layer to media applications
It supports media synchronization mechanisms, e.g. presentation time
AVB/TSN Protocols
There is a set of other protocols in the AVB/TSN world
Specific, but not automotive-specific Can be added as user-mode modules
Complex topology Independent, full-duplex links Several hops within one cluster Frame duplication (multi- and broadcast) Congestion at egress ports Complex timing & load analysis compared to CAN
ECU µC
Switch
ECU ECU ECU
Prio 0
Shaper
Scheduler
Prio 1
Shaper
…
Link
Prio 6
Prio 7
Time-Sensitive Networking
The Predecessor - Audio Video Bridging (AVB)
What is AVB? A set of IEEE standards Provided by the AVB task group Predecessor of TSN (until Nov. 2012) A toolbox
They are mostly for dynamically setting up the network
gPTP
gPTP provides time synchronization
It benefits from hardware timestamping
Hardware Related Modules
Src Src
Src
Ctrl
t
t
concert outputs
Ctrl
Dst Dst
Dst
t
源自文库
Time-Sensitive Networking
Time Sensitive Networking (TSN)
What is TSN? Extension of the AVB toolbox AVB focus: Streaming with real time guarantees TSN focus: Reliable control data with hard real time guarantees Is partly still under discussion
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Switch Driver SPI
µController
UDP
TCP
IP
AvTp
AVB/TSN Protocols
Ethernet Driver
Ethernet Controller (MAC)
gPTP
Switch
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Time-Sensitive Networking (TSN)
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Automotive Ethernet in POSIX-Based Systems
This is also true for Automotive Ethernet!
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Automotive Ethernet in POSIX-based Systems
What automotive-specific Ethernet functions are there?
Ethernet Driver
Complex topology Independent, full-duplex links Several hops within one cluster Frame duplication (multi- and broadcast) Congestion at egress ports Complex timing & load analysis compared to CAN
Standard Modules (ARP, IP, TCP, UDP, etc.)
Standard components can typically be used Configuration parameters may differ (e.g. timeout times)
AVB/TSN Modules (AvTp, SRP, BMCA, etc.)
What can be done with TSN? Achieve stricter timing requirements Increase reliability through redundancy
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Prio 0 Prio 1 Prio 2
t
T
FQTSS
A S
*
Sched
Link
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scheduled time slots
But automotive ECUs require automotive-specific features Configuration Diagnostics Network Management Communication These are not included in the standard feature set of a POSIX-based system
It should support the required hardware-related features It runs in kernel-mode, extending it is difficult
Switch Driver
Is specific to typical automotive switches Can be added as separate user mode component
What can be done with AVB? Provide latency guarantees Provide bandwidth guarantees Synchronize nodes and data
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without shaping with shaping
correlate inputs
> Stream data (AVB, RTP, etc.) > Control data (SOME/IP, Multi-PDU)
What’s next? Reliable control data with Time-Sensitive Networking Automotive Ethernet in POSIX-based systems Dynamic use of service-oriented communication
The hardware-related parts are most affected Switch + Switch Driver MAC + Ethernet Driver
AVB/TSN-related features QoS FQTSS shaper Time-aware shaper Hardware timestamping Ingress policing
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Service-Oriented Communication
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Automotive Ethernet in POSIX-based Systems
Motivation
POSIX-based operating systems, especially Linux, provide: Support for high performance CPUs Support for dynamic programming and configuration Rich set of existing features (connectivity, infotainment, image recognition, …) POSIX-based systems are on the advance
TSN provides mechanisms to target this: Some of which focus on the egress port and are based on existing standards (e.g. VLAN, QoS).
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µC Switch
ECU ECU ECU
Prio 0 Prio 1
Sched.
reduce bursts
FQTSS
Link
What are AVB’s main components? Credit based traffic shaper (FQTSS) Time synchronization (gPTP) Stream reservation (SRP) Transport Protocol (AVTP)
400% 350% 300%
Ethernet: Growth rate (Basis: orders 2013 = 100%)
250%
200%
150%
100%
50%
0% 2008
2009
2010
2011
2012
2013
2014
2015
2016
The use cases evolve High-speed diagnostic access (DoIP) Smart Charging (V2G) In-Vehicle Ethernet
ECU ECU ECU
µC Switch
ECU µC
Switch
ECU ECU ECU
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Time-Sensitive Networking
Motivation
Traffic convergence must be handled Control data Streaming data Diverging transmission behavior & requirements
t
guard band
t
t
*TAS – Time-aware shaper
Time-Sensitive Networking
Impact on Basic-Software
Which Basic-Software modules are impacted by AVB and TSN
Standard Stack
What are TSN’s main components?
Time-aware shaper (TDMA) latency
Frame preemption
Ingress policing
Fault tolerant clocks
reliability
Redundant communication
The standard Ethernet stack is mostly unaffected
AVB/TSN is designed for interoperability
AVB/TSN protocols have dedicated EtherTypes
AV Transport Protocol