Time Sensitive Networking (TSN) Explained

Calnex PFV

• Why Ethernet?

• What is Time Sensitive Networking?

• Who Needs it and Why?

• TSN Standards including gPTP

• What Happens if it Breaks?

• Summary and Conclusions

Time Sensitive Networking

Agenda

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Why Ethernet?

So, how can ethernet support the real-time requirements we have mentioned?

• Ready for higher bandwidth

• Huge weight reduction (automotive, avionics…)

• Cost reductions

• Network/topology simplification

• Ethernet is a toolbox!

TSN and gPTP

Many new developments leverage Ethernet to move from multiple discrete (sometimes proprietary) networks and topologies:

なぜ、イーサネットなのか？イーサネットはどのようにリアルタイムの要求をサポートすることができるのでしょうか？

Calnex PFVTime Senstive Networking

Ethernet and Time Sensitive Networking

Ethernet – Cheap and easy to deploy

BUT

It is unpredictable – and as traffic builds up it becomes slower and even less predictable.

The Ethernet standards are being extended to provide predictable behaviour under the

headline of Time Sensitive Networking

標準的なイーサネットは、TSN(Time Sensitive Network)により拡張される。

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One or more of…

- Guarantees bandwidth

- Minimises and guarantees latency

- Guarantees deterministic timing

Different standards address different aspects of TSN – but they are all aimed at the above challenges.

Time Sensitive Networking

What Does Time Sensitive Networking Do?

TSNは何をする？帯域、低レイテンシ、タイミングを保証。

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Many diverse Systems Need Real-Time Data Transfer

• Industrial applications – e.g. Motion control

• Pro Audio-Video – e.g. Stadium sound sync

• Automotive systems – e.g. Parking assist

• Power distribution – Real-time fault monitoring

What communications system needs to support this?

Time Sensitive Networking

Who Needs Time Sensitive Networking?

多種多様なシステムでリアルタイムのデータ転送が必要。

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IEEE 802.1 (Time Sensitive Networking)

Accurate Synchronization with IEEE 802.1AS (gPTP) is integral to many of the 802.1 standards

The IEEE Time Sensitive Networking (TSN) Task Group is building and developing the 802.1 standards as a ‘toolbox’ for networks requiring:

Time Sensitive Networking

•Accurate Synchronization

•Deterministic Latency

•Controlled Bandwidth

IEEE 802.1AS（gPTP）による正確な同期は、数多くの802.1規格に必要。

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The TSN Standards ‘Family’

Many standards still in development, many not implemented at all – many require accurate timing

Time Sensitive Networking

802.1AS-rev – Timing and Synchronisation for TSN

802.1Qbv – Enhancements for Scheduled Traffic

802.1Qbu – Frame Preemption

802.1CB – Seamless Redundancy

802.1Qcc – SRP Enhancements and Performance Improvements

802.1Qci – Per-Stream Filtering and Policing

802.1Qch – Cyclic Queuing and Forwarding

802.1Qat Bandwidth Reservation

802.1Qav Queuing and Forwarding

802.1Qbz – Enhancements to Bridging of 802.11

802.1Qca – Path Control and Reservation

802.1QAC– MAC Service Definition

802.1QCM – Time-Sensitive Networking for Fronthaul

802.1Qcn – VDP Extension for NVO3

802.1Qcp – Bridged Network Amendment: YANG Data Model

現在、開発中の規格が多く存在し、正確なタイミングが必要。

• General Precision Timing Protocol

• Specifies protocol and procedures to ensure synchronization requirements are met for time-sensitive applications

• Specifies the use of IEEE 1588, with own profile (gPTP)

• Defines Time-Aware systems – End Stations and Relays(Bridges)

802.1AS - gPTP - Timing Accuracy for TSN

9Note: 802.1AS-REV also in development

Time Sensitive Networking

802.1AS - gPTPは高精度なタイミングを提供し、TSN規格に必要不可欠。

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802.1Qbv – Scheduled Traffic

Qbv may be as important a use for synchronization (via gPTP) as any end application…

TSN and gPTP

Deterministic latency achieved by transmitting critical traffic (and only critical traffic) in scheduled windows

•All devices must share time

•Time must be accurate!

•Better time = smaller guardbands, higher capacity?

低レイテンシーを実現させる802.1Qbvにおいて、gPTPの高精度な同期は重要な技術。

Calnex PFVTime Sensitive Networking

- Factories may shut down production because of control loop failures.

- Accidents and damage may happen – robots could crash into each other or people.

What Can Happen When Industrial TSN Breaks?

産業用TSNが機能しないとき、工場内の制御障害による生産停止や事故の発生が懸念される。

Calnex PFVTime Sensitive Networking

- Fault reporting fails – leading to unplanned network shutdown or explosions.

- Power added out of phase with the electricity network, leads to loss of energy and shutdown

What Can Happen When Power Network TSN Breaks?

電力向けTSNが機能しないとき、電力網において位相ズレが発生し供給が停止する可能性が懸念される。

Calnex PFVTime Sensitive Networking

- Video and audio streams out of sync leading to poor user experience

- Stadium audio out of sync – poor user experience

- Insufficient bandwidth allocated to video streams – interrupted transmissions.

What Can Happen When Audio-Visual TSN Breaks?

放送向けTSNが機能しないとき、映像と音声が未同期になるとユーザーの体感性低下が懸念される。

Calnex PFVTime Sensitive Networking

- Entertainment system failures

- Autonomous Vehicles crashing.

What Can Happen When Vehicle TSN Breaks?

車載向けTSNが機能しないとき、オーディオシステムの不具合、事故などが懸念される。

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How Can We Minimise the Likelihood of TSN Breaking?

15

Test It

TSNの機能しない状況を最小限に抑える方法として、対象機器の試験が不可欠。

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Summary and Conclusions

Time Sensitive Networking

• Ethernet is everywhere.

• There are many time sensitive applications that want to switch from traditional networks and protocols to Ethernet.

• Ethernet has to be extended to satisfy the needs of these applications. This is done using standards developed under the umbrella of “Time Sensitive Networking”.

• Underlying many of these extensions is the need to accurately transfer time – which is done using gPTP – standardised in IEEE 802.1AS.

• TSN Needs Testing to ensure that the likelihood of things going wrong is minimised.

多くの拡張機能の根底にIEEE 802.1ASがあり、gPTPによる高精度同期が必要。TSNによる問題の発生を最小限に抑えるためにはテストが必要。