Configuration for Scheduling of Time-sensitiveand Bursty Traffic (STSBT) in TSN
October14, 2019Name
Hasegawa, Akio
Nishikawa, Takurou
Sato, Shinichi
Itaya, Satoko
Kojima, Fumihide
Koto, Hajime
Murata, Syuuichi
Ohsawa, Tomoki
Osuga, Toru
Nakajima, Taketoshi
Maruhashi, Kenichi
Onishi, Takeo
Zein, Nader
Nakano, Hiroki
Nosaka, Tetusya
Ohue, Hiroshi

Company
Advanced Telecommunications Research Institute International (ATR)
Fujitsu Limited
Fujitsu Limited
National Institute of Information and Communications Technology (NICT)
National Institute of Information and Communications Technology (NICT)
National Institute of Information and Communications Technology (NICT)
National Institute of Information and Communications Technology (NICT)
National Institute of Information and Communications Technology (NICT)
National Institute of Information and Communications Technology (NICT)NEC Corporation
NEC Corporation
NEC Corporation
NEC Europe Ltd.(NLE GmbH)
NETREQS Co., Ltd
Omron Corporation
Panasonic Corporation

email
ahase@atr.jp
nisikawa.taku@jp.fujitsu.com
sato_shinichi@jp.fujitsu.com
itaya@nict.go.jp
f-kojima@nict.go.jp
h-koto@nict.go.jp
murata.syuuichi@nict.go.jp
tohsawa@nict.go.jp
osuga@nict.go.jp
nakajima@cp.jp.nec.com
k-maruhashi@bl.jp.nec.com
t-onishi@cj.jp.nec.com
Nader.Zein@emea.nec.com
nakano@netreqs.co.jp
tetsuya.nosaka@omron.com
ohue.hiroshi@jp.panasonic.com

Introduction• This document addresses the need for configuration mechanism forthe scheduling of sporadic and bursty* traffic in time-sensitive
network.
• The first target is Flexible Factory[1], however, applicable use cases
are extended in warehouses, hospitals, airports/stations, etc.
• Technical basis has been explained at interim session in Edinburgh [2].
Modifications have been made considering received feedback.
* All mentions of bursty traffic in this presentation imply bursty and sporadic traffic.

[1] https://mentor.ieee.org/802.1/dcn/19/1-19-0026-03-ICne-flexible-factory-iot-use-casesand-communication-requirements-for-wired-and-wireless-bridged-networks.pdf[2] http://www.ieee802.org/1/files/public/docs2019/new-NakanoZein-Scheduling-of-Timesensitive-and-Bursty-Traffic-in-Reduced-Available-Bandwidth-0919-v02.pdf

2Flexible Factory [1]• The Flexible Factory represents an evolved site for flexible
on-demand manufacturing of variable product types withvariable production volumes.
• Flexibility in the factory environment emphasizes mobility
and configurability of manufacturing facilities.
• In support of the flexibility, human operators are engaged
with the production process in order to oversee the ondemand production.
[1] https://mentor.ieee.org/802.1/dcn/19/1-19-0026-03-ICne-flexible-factory-iot-use-casesand-communication-requirements-for-wired-and-wireless-bridged-networks.pdf
3Network Environment - Brownfield [3] • Network usage is changing from the time when it was designed and commissioned
because new devices are added on demand to the network based on step-by-step
approach.
• Replacing all devices is difficult and new functions can not be implemented in all
existing devices.

Brownfield is the name given to extending or
expanding automation environments that
already exist[3]. Flexible Factory[1] is the same.

[3] http://www.ieee802.org/3/ad_hoc/ngrates/public/18_03/woods_nea_01_0318.pdf
4

Risk of Availability due to IoT Devices• The number of IoT devices which generate busty traffic is increasing in Flexible Factory.
• Large bursts of data have negative impact on the overall performance and will result inrisk of service availability at peak traffic condition.
Traffic: Sporadic & bursty
Byte/sec
Intelligent tool

Inspection camera

1nAverage: lowtimeSensors

AR

Examples of sources of busty traffic

Unpredictable interval(=sporadic)

Packet latency tolerance(=time-sensitive)

Traffic pattern of intelligent tool (torque wrench)5Bandwidth Allocation/Stream Reservation• Over-provisioning is required to allocate bandwidth at peak-rate fora bursty stream.
• SRP supports periodic and bursty traffic but it can’t support sporadic
and bursty traffic.

• No information how much bandwidth needs to be allocated forsporadic and bursty traffic.

6

Peak-shaving（burst streams conflict）• The process of peak-shaving is used to mitigate the effect of burst streams
conflict by minimizing bandwidth occupation while keeping E2E QoS.
tolerable latency
data size
minimum bandwidth = tolerable latency × 𝛼, 𝑤ℎ𝑒𝑟𝑒 𝛼 = tolerable latency − Accumlated Latency∗*Accumulated Latency is defined in its path from the Talker to a given Listener (Std. 802.1Q, Clause 35.2.2.8.6)

Available bandwidth

MarginContinuous

DelayBurstContinuousTimeTime(a) Normal operation(b) Burst streams conflict

Bandwidth

Burst

Bandwidth

Bandwidth

Burst
Burst

Peak-shaving to fit
minimum bandwidth

Burst
Burst
ContinuousTime(c) Peak-shaving for bursty traffic

7

STSBT Operation•

Mitigating traffic load at bottleneck segment of a link for whatever reason thatis causing it.
•Shaping for peak shaving.
Higher priority assignment (i.e. either with priority forwarding or by bandwidthreservation) for the shaped stream to avoid additional delay.

Simulation results have been shown in [2].
higher priority for peak-shaved streamsTalker(Burst)

BridgeBursty Traffic

peak-shaving

BridgeBridgeBottleneckat peak traffic

SourceListener
Go throughany numberof bridges

Other Traffic(continuous)
8

Ideas of Amendments for STSBT
Control Plane• Distribute information of targeted bursty traffics with ”minimum bandwidth.” Amend .1Q with new information.
Configuration of• Configure bridges next to source nodes to peak-shave the traffics.
 Use CBS, ATS or any other shapers
Data Plane• Configure bridges across the path towards the listeners to protect the STSBT streams to guarantee E2E bounded
latency.
 Use a queue with higher priority• Identify streams to be controlled with this mechanism
 Use .1CB/CBdb.
• In addition to the above modifications, description of the STSBT operation mechanism is needed in an Annex in 1Q.

higher priority for peak-shaved streams
Talker(Burst)

BridgeBursty Traffic

peak-shaving

BridgeBridgeBottleneckat peak traffic

SourceListener
Go throughany numberof bridges

Other Traffic(continuous)
9Concept of General STSBT• Proposal: Configuration mechanism to be added in 1Q for schedulingof sporadic and bursty traffic in time-sensitive network. Details areopen to discuss.
1. Shaping bursty streams for peak2. High priority assignment for the shaped
shaving to mitigate peak traffic load.
streams to avoid further delay.
Talker(Burst)higher priority for peak-shaved streams

Bridgepeak-shaving

Talker(Burst)Bridgepeak-shaving

Listener

BridgeBridgehigher priority for peak-shaved streams

Listener

BridgeListener

Talker(Continuous)

802 Network10

Draft for Main parts of PAR and CSD

11

Main Part of PAR• 2.1 – Project Title
Standard for Local and metropolitan area networks--Bridges and BridgedNetworks
Amendment: Scheduler for Time-Sensitive and Bursty Traffic• 4.2 and 4.3 Project dates
4.2 Expected Date of submission of draft to the IEEE-SA for Initial Sponsor Ballot:
03/2021• 4.3 Projected Completion Date for Submittal to RevCom
01/202212

Main Part of PAR –cont’d• 5.2A – Standard scopeThis standard specifies Bridges that interconnect individual LANs,
each supporting the IEEE 802 MAC Service using a different or
identical media access control method, to provide Bridged Networksand VLANs.
• 5.2B – Project scopeThis project specifies procedures and managed objects for bridges
and end stations to configure and perform shapers over reduced
available bandwidth links for sporadic bursty traffic type.
13

Main Part of PAR –cont’d• 5.3 – Project contingency
5.3 Is the completion of this standard dependent upon thecompletion of another standard:No• 5.4 – Project purpose
Bridges, as specified by this standard, allow the compatible
interconnection of information technology equipment attached toseparate individual LANs.
14

Main Part of PAR –cont’d• 5.5 – Project needIndustrial networks serve a variety of traffic types including irregular bursty
traffics which requires to be conveyed across reduced available bandwidth
links with deterministic latency. Shaping is needed in order to mitigate theimpact of reduced bandwidth while maintaining QoS for multiple traffic.
Current bridging standards do not address configuration mechanism forshaper for reduced available bandwidth for variety of traffic types including
Sporadic bursty traffic.
• 5.6 Stakeholders for the Standard:
Developers, providers, and users of networking services and equipment for
streaming of time-sensitive data. This includes software developers,
networking integrated circuit developers, bridge and network interface
controller vendors, and users.
15Main Part of CSD - 1.1.1 Managed objects
Describe the plan for developing a definition of managed objects. The plan shall specify one of
the following:a) The definitions will be part of this project.
b) The definitions will be part of a different project and provide the plan for that project or anticipated futureproject.
c) The definitions will not be developed and explain why such definitions are not needed.

This project will use method a). The managed objects definitions will be part of this project.Main Part of CSD - Coexistence
A WG proposing a wireless project shall demonstrate coexistence through the preparation of aCoexistence Assurance (CA) document unless it is not applicable.
a) Will the WG create a CA document as part of the WG balloting process as described in Clause 13?
(yes/no)b) If not, explain why the CA document is not applicable.

This project will use method b). This project is not a wireless project.

Main Part of CSD - Broad market potential
Each proposed IEEE 802 LMSC standard shall have broad market potential. At a minimum, address thefollowing areas:a) Broad sets of applicability.
b) Multiple vendors and numerous users.

The proposed amendment enhances bridges functionality allowing systems to further provision forbroad variety services, applications and traffic types in reduced available bandwidth networks.
TSN has been applicable for many applications including industrial automation and otherapplications. This amendment further extends the application of TSN to include IoT devices
broadening TSN applications and use.
Furthermore, the proposed amendment enable efficient utilization of legacy network in support ofincreased traffic in industrial applications.
This proposal supports network with dense IoT devices that are deployed in factories, warehouses,
hospitals, market places, stadiums and etc.
Multiple vendors and users of industrial automation, professional audio-video, automotive, andother systems require complete and comprehensive management of TSN features in bridged LAN
networks through common interfaces.

Main Part of CSD - Compatibility
Each proposed IEEE 802 LMSC standard should be in conformance with IEEE Std 802, IEEE 802.1AC,and IEEE 802.1Q. If any variances in conformance emerge, they shall be thoroughly disclosed andreviewed with IEEE 802.1 WG prior to submitting a PAR to the Sponsor.
a) Will the proposed standard comply with IEEE Std 802, IEEE Std 802.1AC and IEEE Std 802.1Q?
b) If the answer to a) is no, supply the response from the IEEE 802.1 WG.

The review and response is not required if the proposed standard is an amendment or revision toan existing standard for which it has been previously determined that compliance with the above
IEEE 802 standards is not possible. In this case, the CSD statement shall state that this is the case.
As an amendment to 802.1Q, the proposed standard shall comply with IEEE Std 802, IEEE Std
802.1AC and IEEE 802.1Q.

Main Part of CSD - Distinct Identity
Each proposed IEEE 802 LMSC standard shall provide evidence of a distinct identity. Identify
standards and standards projects with similar scopes and for each one describe why the proposed
project is substantially different.
This amendment differs from existing IEEE 802.1 standard in that it address scheduling and shaperfor variety of traffic types including bursty data rates traffic over links with varying bandwidth
operating at reduced available bandwidth.

Main Part of CSD - Technical Feasibility
Each proposed IEEE 802 LMSC standard shall provide evidence that the project is technically feasible
within the time frame of the project. At a minimum, address the following items to demonstratetechnical feasibility:a) Demonstrated system feasibility.

The proposed shaper is similar in principle to the ones introduced in IEEE Std 802.1Q-2018 and willbuild on them to provide additional capabilities.
b) Proven similar technology via testing, modeling, simulation, etc.

The technical feasibility has been demonstrated by analysis. In particular, feasibility has been shownby modeling and simulation (see http://www.ieee802.org/1/files/public/docs2019/NewNakanoZein-Scheduling_of_Time_sensitive_and_Bursty_Traffic_in_Reduced_Available_Bandwidth0919.ppx).
This project is based on mature virtual LAN bridging and transmit selection and schedulingMain Part of CSD - Economic Feasibility
Each proposed IEEE 802 LMSC standard shall provide evidence of economic feasibility. Demonstrate,
as far as can reasonably be estimated, the economic feasibility of the proposed project for its
intended applications. Among the areas that may be addressed in the cost for performance analysis
are the following:a) Balanced costs (infrastructure versus attached stations).
b) Known cost factors.
c) Consideration of installation costs.
d) Consideration of operational costs (e.g., energy consumption).
e) Other areas, as appropriate.

The well-established balance between infrastructure and attached stations will not be changed bythis enhancement.
The cost factors, including installation and operational factors, are well known from similar
technologies and proportional to the benefits gained.

The proposed amendment does not require additional hardware cost as it proposes STSBT shaperthat can be accommodated into the current specifications.