Time Sensitive Networks for Flexible
Manufacturing Testbed Description of Converged Traffic Types
An Industrial Internet Consortium Results White Paper
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Description of Converged Traffic Types

Table of Contents
The IIC’s Time-Sensitive Networks for Flexible Manufacturing Testbed ........................................... 3
TSN Overview ............................................................................................................................... 3
TSN Benefits ................................................................................................................................. 4
Overview of Traffic Types .............................................................................................................. 4
Vertical and Horizontal .................................................................................................................. 5

Traffic Type Characteristics .................................................................................................... 7
Traffic Type Descriptions ..................................................................................................... 11
Isochronous ................................................................................................................................ 11
Cyclic ......................................................................................................................................... 12
Alarms and Events....................................................................................................................... 13
Configuration & Diagnostics ........................................................................................................ 14
Network Control ......................................................................................................................... 15
Best Effort................................................................................................................................... 16
Video ......................................................................................................................................... 17
Audio/Voice ................................................................................................................................ 18

Conclusion........................................................................................................................... 18
Authors and Legal Notice ..................................................................................................... 19

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Description of Converged Traffic Types
This white paper describes application traffic types that are supported in the Industrial Internet
Consortium’s Time Sensitive Networks for Flexible Manufacturing Testbed, including different
types of critical control traffic and other traffic that may be in a manufacturing network. The IEEE
802.1Q specification, Annex I lists traffic types as a means to structure network transmission
priority and packet drop preference. We enhance those traffic types by adding those found in
typical manufacturing Industrial Automation and Control Systems (IACS), with a list of
characteristics to describe them precisely. We intend later to recommend IEEE 802.1 TSN
mechanisms to support those traffic types.
We write for those working on establishing TSN as a core communication technology forindustrial automation and control and therefore expect the reader to be familiar with terms ofart in these domains. Readers should have a basic understanding of manufacturing applications
and IACS. We intend to share the white paper with the various standards organizations andconsortia working on TSN adoption, including but not limited to the Institute of Electrical andElectronics Engineers (IEEE), International Electrotechnical Commision (IEC), Avnu Alliance, CCLink Partner Organization (CLPA), Labs Network Industrie 4.0 (LNI4.0), ODVA, OPC Foundation,
Profinet International and Sercos International.

THE IIC’S TIME-SENSITIVE NETWORKS FOR FLEXIBLE MANUFACTURING TESTBEDThe Industrial Internet Consortium (IIC), with over 250 members, aims to deliver a trustworthy
Industrial Internet of Things (IIoT) in which the world’s systems and devices are securely
connected and controlled to deliver transformational outcomes. The IIC has three main areas ofactivity: engage IIoT communities (ecosystem), develop guidance with technology and security
architectures and drive innovation through testbeds. In 2015, the IIC Steering Committee
authorized the Time-Sensitive Networks for Flexible Manufacturing Testbed to display the value
and readiness of time-sensitive networks to support real-time control and synchronization ofhigh performance machines. Currently, the testbed has over 25 participants with a range ofcompanies including chip vendors, IACS vendors, network infrastructure/testing vendors andtesting/certification organizations. The testbed liaises with many standard development
organizations including the IEEE, Avnu Alliance, OPC Foundation, IEC, ODVA, LNI4.0 and others.
By aligning adopters, technology providers and standards developers, the testbed accelerates
the adoption of this beneficial technology.

TSN OVERVIEW
Time-Sensitive Networking (TSN) enhances Ethernet (specifically IEEE 802.1 and 802.3), a
foundational piece of the “internet of things”. TSN adds a variety of functions and capabilities toEthernet to make it more suitable to industrial applications that require more deterministic
characteristics than were possible in previous Ethernet implementations. The following tablesummarizes these enhancements.

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Description of Converged Traffic Types
Standard
IEEE 802.1Qav
IEEE 802.1AS-Rev
IEEE 802.1Qbu & IEEE
802.3br
IEEE 802.1Qbv
IEEE 802.1Qca
IEEE 802.1Qcc
IEEE 802.1Qci
IEEE 802.1CB

Title
Forwarding and Queuing Enhancements for Time-Sensitive Streams
Timing and Synchronization for Time-Sensitive Applications
Frame preemption
Enhancements for Scheduled Traffic
Path Control and Reservation
Stream Reservation Protocol (SRP) Enhancements and Performance
Improvements
Per-Stream Filtering and Policing
Frame Replication & Elimination for Reliability

Table: Set of IEEE TSN Enhancements

Automation and control systems comprise a large part of the estimated 50 billion things in IIoT,
and these systems require the various devices, including the network, to perform in a
deterministic way. The IIC’s TSN Testbed for Flexible Manufacturing Testbed applies TSN
technology to a manufacturing system to support the type of manufacturing application found in
production environments and to display its capabilities and value.

TSN BENEFITSTSN provides benefits to automation and control vendors as well as end customers, including:

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


robust, reliable delivery of data,
guaranteed latency,
increased availability of devices and data driving IIoT big-data analytics and machinelearning applications,
automated system configuration and management,
system composability to add sub-systems and functions to existing systems withsignificantly reduced testingeasy integration of innovations from open networks (more bandwidth, reliability andoptions) andability to converge applications and traffic on a single, open network.

This white paper focuses on that last and describes the traffic patterns in a manufacturing
environment that converge onto a single, open TSN network. A future revision of the whitepaper
will map the defined traffic types to the existing and recently updated Ethernet Quality of Service(QoS) mechanisms, such as TSN traffic-shaping mechanisms.

OVERVIEW OF TRAFFIC TYPES
Annex I.1 of the IEEE Standard for Local and metropolitan area networks: Bridges and Bridged
Networks (802.1Q) lists eight traffic types. Of those listed, in particular, network control, voice,video, critical applications, excellent effort and best effort have direct relevance to IACS, whileinternetwork control and background traffic generally do not.

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Description of Converged Traffic Types
We focus on the types of traffic flows that IACS use that may rely on the QoS they receive fromthe network and how that may affect the QoS of other traffic types. The specific traffic types are:


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

Network Control, which includes Precision Time Protocol (PTP) traffic critical to the IACS
and the network’s ability to provide TSN services,
Excellent Effort, which includes IACS configuration and diagnostics traffic,
Voice (audio), which may be part of an IACS or used for audio services provided in the
manufacturing zone,
Video, which may be part of an IACS or used for video services provided in the
manufacturing zone andBest Effort.

And the following three new types that may be considered sub-types of Critical Application, buthave specific characteristics:Isochronous, where IACS devices need to exchange data synchronously at a defined
periodic rate,
Cyclic, where IACS devices exchange data at a defined rate, andAlarms and Events, where IACS devices create messages that need to be received andacted upon in a defined time period without loss.

VERTICAL AND HORIZONTALIn a discrete or process automation plant, there are various traffic types, with different delivery
requirements. Generally speaking, there is vertical communication between the automation
control devices and the plant-level systems and applications, and horizontal communication
between the automation and control devices. Horizontal communication can be broken down tocontroller-to-controller and controller-to-field-equipment (a.k.a. input and outputs or I/O).
Historically, various types of fieldbuses, besides the Ethernet-based communication, support
these diverse communication requirements and thereby segmenting the IACS traffic flows inseparate networks.
Current, pre-TSN Ethernet (IEEE 802.1 and 802.3) QoS capabilities include traffic-shaping
mechanisms, bandwidth allocation, prioritization and queue management techniques, but lackthe ability to guarantee latency (the amount of time to transmit a packet in the network), jitter(the latency variation of the packet’s transmission) or packet delivery. Without these guarantees,
Ethernet is predominantly used for vertical communication, such as management, configuration,
backup, historical data, diagnostics, alarms and process graphics updates, usually taking place
between the controllers and the plant management and historian servers.
Horizontal communication is where real-time traffic types exist, either as controller-to-controller
communication or controller-to-field-equipment, and are often supported by specific industrial
Ethernet solutions (e.g. EtherNet/IP, Sercos, Powerlink, Profinet IO, Ethercat, CC-Link) that
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Description of Converged Traffic Types
worked around the precise QoS guarantees of pre-TSN Ethernet by including existing standard
QoS mechanisms of prioritization and queue management, or by proprietary enhancements toEthernet for synchronization and time-based bandwidth utilization. Alternatively, real-timetraffic types may use legacy fieldbuses (e.g. Profibus, Foundation Fieldbus, DeviceNet, CAN,Interbus, etc.) in special local networks. The use of proprietary enhanced, segmented Ethernet
protocols or fieldbus technologies hinder access to and sharing of data in those networks as
opposed to where standard Ethernet is used.
Vertical communication traffic comprises communication between the controllers, the local plant
management servers and cloud services. It may include:
Alarms and events: the controllers, after processing data received from I/O field devices, reportbreaches of the process variable range (an event) or larger breach of such ranges (an alarm) to
the servers and thus to the operators of the plant,
Process graphics update information: the operators monitor the status of the process equipment
and current process values in the industrial process,Historian information: to observe the behavior of the process using various complex analysis
where process variables evolution over time must be taken into account,
Operator commands: the operators must be capable of intervening on the various processdevices,
Configuration: the files and commands used to configure the various automation and control
devices,Server backup: the application servers and critical devices in the plant usually backed up forrecovery purposes regularly, which can create bandwidth utilization peaks andDiagnostics: to perform maintenance and analysis of reported alarms and diagnostics on fieldequipment.

Horizontal communication comprises communication between controllers, I/O equipment,
drives, encoders and other field-level communication. We may distinguish here these traffic
types:
Isochronous: with small frame sizes (often no more than 84 bytes), very short cycle times (usuallyless than 1 millisecond or ms) and a low jitter requirement. An example is turbine control in a
power generation hydro plant, or a controller to drive an encoder.
Cyclic controller-controller: where controllers exchange variables as a part of shared applications,
usually with maximum frame sizes 1500 bytes and cycle times between 100microseconds (µs) up
to 1 second. There is more tolerance to jitter and frame loss than isochronous communication.
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Description of Converged Traffic Types

Traffic Type Characteristics

Cyclic controller-IO or controller-drive for automation applications: where sensors and actuators
exchange data with controllers with smaller frame sizes up to 600 bytes and cycle times up to
60ms. There is a tolerance to jitter and to frame loss.
Alarms and events: where sensors, actuators and controllers communicate change-of-state,warnings when thresholds are exceeded or operator commands. These are acyclic with variable
frame sizes and are tolerant to jitter and frame loss.

TRAFFIC TYPE CHARACTERISTICS
TSN lets information technology (IT) and operational technology (OT) applications share the same
physical network infrastructure without influencing the other by introducing a toolbox ofmechanisms, such as scheduled traffic (IEEE 802.1Qbv), to provide new levels of data delivery
guarantees to Ethernet-based communication. The following application-centric communication
characteristics enable the identification of a small number of distinct traffic types that are shared
among sets of industrial applications:

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Description of Converged Traffic Types

Traffic Type Characteristics
Traffic Types

Characteristic

Description

Data transmission
periodicity

Traffic types consist of data streams that can either be transmitted in acyclic/periodic (e.g. signal transmission) or acyclic/sporadic (e.g. event-driven)manner.

PeriodFor traffic types that transmit cyclic/periodic data streams, period denotes theplanned data transmission interval (often also called “cycle”) at the application
layer. The interval is provided as a typical range in orders of magnitude of time, i.e.
80% of the industrial applications in scope of the given traffic type are within theprovided range.
For the acylcic/sporadic traffic types, this characteristic does not apply.

Applicationsynchronized to
network

Denotes whether an application producing a traffic type is synchronized to the
network time at the application layer. Applications that are synchronized to the
network time can align their sending behavior to mechanisms provided by the
network (e.g. scheduling) for reduced latency and jitter in the network
communication.
Available options are: yes or no.

Data delivery guarantee

Denotes the application’s delivery constraints of the network for unimpaired
operation. To guide the selection of appropriate Ethernet QoS mechanisms
including the enhancements from IEEE 802.1 TSN, the scope of this characteristic islimited to the application’s data transmission requirements. Any non-applicationrelated requirements and any impact from the application itself and the sending
and receiving device’s communication stack are out of scope. Three data delivery
guarantees are defined:

deadline: data delivery of each packet in a stream is guaranteed to occur
at all registered receivers at or before a predictable time (i.e. in acommunication cycle),latency: data delivery of each packet in a stream is guaranteed to occur at
all registered receivers within a predictable timespan starting when thepacket is transmitted by the sender and ending when the packet isreceived andbandwidth: data delivery of each packet in a stream is guaranteed tooccur at all registered receivers if the bandwidth utilization is within the
resources reserved by the sender.

For each option, a typical quantification shall be provided with the data delivery
guarantee, i.e. 80% of the industrial applications in scope of the given traffic typeare within the provided quantification.
In the case that a packet cannot be delivered within the given latency or deadline
requirement, that packet may be considered as lost or discarded by theapplication.
In the case of traffic types with no special data delivery guarantee requirements,
the available option is “n.a.” or not applicable.

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Description of Converged Traffic Types

Traffic Type Characteristics
Traffic Types

Characteristic
Tolerance tointerference

Description
Denotes the application’s tolerance of a certain amount of communication jitter(the latency variation of the packet’s transmission) for the traffic types withcyclic/periodic data transmission periodicity.
In the case of a highly jitter-sensitive application, no jitter is expected and is to be
indicated with the jitter value of zero, meaning that this jitter must be negligible.
If the application can cope with jitter, the response is yes and the amount of jitteris to be specified.
Other sources of jitter in application processing besides network communication
jitter exist, e.g. stemming from local OS scheduling or time synchronization. These
additional sources of jitter commonly have effects beyond individual traffic types
and need to be considered separately.
For acylcic/sporadic data transmission periodicity types, this characteristic does
not apply (n.a.) and jitter need not be specified.

Tolerance to loss

Denotes the application’s tolerance to a certain amount of consecutive packet loss
in network transmission. In this case, a quantifiable number of tolerable lost
packets shall be provided. Alternatively, the option “yes” can be provided for
applications that tolerate packet loss to the extent that basic redundancy protocols
such as Spanning Tree suffice to recover from potential network interruptions.
In the case of a highly loss-sensitive application, where no single packet may belost, “no (0 frames)” is the only available option.
Packet loss can occur from network congestion and network error. In the mappingof required features, both cases should be considered.

Application data size

Denotes the size of application data (payload) to be transmitted in the Ethernet
frames. The size can be fixed (the data is always with the exact same size) or
variable (the data is sent with variable size, but not exceeding the given maximumsize).
The application data size provides a typical range in orders of magnitude of bytes,
i.e. 80% of the industrial applications in scope of the given traffic type in theprovided range.
Where individual packet sizes vary exceedingly or cannot be determined at design
or configuration time, data volume estimates (e.g. required bandwidth) is
provided.

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Description of Converged Traffic Types

Traffic Type Characteristics
Traffic Types

Characteristic
Criticality

Description
Describes the criticality of the data for the operation of the critical parts of thesystem. Application criticality is used to guide the selection of the appropriate
QoS/TSN mechanisms in case of conflicting requirements.
The following categories of criticality are defined:

high: for traffic types used either by application or the network services
that are highly critical for the operation of the system. Unmet QoS
guarantees (e.g. latency, jitter or data loss) of this traffic type may cause
critical system malfunction and data cannot be repeated or retransmitted
by the application,

medium: for traffic types used either by application or the network
services that are relevant but not continuously needed for the operationof the critical part of the system. Unmet QoS guarantees of this traffic
type may cause degraded operation but not a system malfunction. Dataloss can be compensated by repeating/retransmitting the same data and

low: for traffic types used either by application or the network services
that are not relevant for the operation of the critical part of the system.
Data loss can be compensated by repeating/retransmitting the same data.
These traffic types typically don’t have specific latency or jitter
guarantees.

Note that the criticality of the data is not to be confused with the traffic classpriority. Traffic class priority is one mechanism to address the criticality, but not
the only one. TSN provides additional mechanisms, such as frame preemption,scheduled traffic, to address the criticality of the traffic.

NOTE: Solution-specific characteristics including any type of traffic-class prioritization,
coordination or dependencies (e.g. offsets between flows) among the traffic streams and types
are out-of-scope for the above.
NOTE: Application data streams may be based on 1:1 transmissions between the sender andreceiver or 1:many (a.k.a. multicast) between a sender and multiple receivers. It is not expectedthat the cardinality of application traffic (i.e. 1:1 or 1:many) has an immediate influence on the
QoS mechanisms (beyond stream configuration) and is therefore out-of-scope of thiswhitepaper.

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Description of Converged Traffic Types

Traffic Type Descriptions

TRAFFIC TYPE DESCRIPTIONSISOCHRONOUS
The applications in each device are synchronized to a common time, which is strictly monotonic
and steadily increasing, without jumps or leaps. Devices synchronously sample inputs and apply
outputs by exchanging data at a defined periodic rate or cycle. When applied to motion
applications, this rate can be fast, in some cases, under 100µs. For tight control loops,
communication jitter must be minimal, with no interference from other traffic. Messages need aguaranteed delivery time. If they arrive later than this deadline, they are ignored for that cycle ordiscarded, thus potentially affecting the control loop. Message sizes are fixed at design time andremain constant for each cycle. Payload sizes are typically under 100 bytes per device. This typecan be used for controller-to-controller and controller-to-I/O-communication in synchronousexchanges.
Examples includetime-synchronized applications where data must be produced and delivered consistently
and where packets are delivered with a bounded latency, in other words before or by thedeadline andapplications with implicit synchronization where devices act on reception of a frame andtherefore lack tolerance to interference and require very low jitter to produce an on-time
delivery (at a specific point in time).
Traffic Type I: Isochronous
Characteristics

Notes

Periodicity

Cyclic/periodic

Period100µs ~ 2ms

Application synchronized to
network

Yes

Data delivery guarantee

Deadline

Tolerance to interference0

Tolerance to loss

No (0 frames)

Application Data size

Fixed (30 ~ 100 bytes)

Criticality

High

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Usually within one data transmission period

Seamless redundancy is required- 11 -

Description of Converged Traffic Types

Traffic Type DescriptionsCYCLICThis type involves cyclic/periodic communication between devices. The applications in eachdevice are not synchronized to a common time. Devices sample inputs and apply outputs
cyclically, which may or may not be the same as the data transmission period. When applied toa client-server protocol (e.g. Profinet IO), messages will be clustered while in a publish/subscribe
environment (e.g. EtherNet/IP) messages will be distributed over the cycle time. For best control,
the time between a device sending a message and its reception should be minimized, withpredictable interruptions from other traffic. Messages need a defined maximum latency time.
Data message sizes are fixed at design time and remain constant for each cycle. This type can beused for controller to controller and controller to I/O communication.
Examples include:







input/output updates sent to/from actuators and sensors and a programmable logic
controller in a discrete manufacturing facility with request packet interval (RPI) times
usually measured in milliseconds and cycle times usually 3 to 4 times the RPI,
process graphic updates that need to be updated on a cyclic polling basis, with up to 1
second cycle times; the process controllers send this information to the servers of theplant; maximum frame size varies following each vendor but may reach 1500 bytes andfast diagnostic data for drives that produce 1500 bytes samples at a rate up to every 4 ms
that is used to verify drive functionality,
historian information where process controllers create data traffic which is cyclic, but withan update rate or cycle time of around one second. Maximum frame size varies following
each vendor but may reach 1500 bytes;
Traffic Type II: Cyclic
Characteristics

Notes

Periodicity

Cyclic/periodic

Period2 ~ 20ms

Application synchronized to
networkNo

Data delivery guarantee

Latency

Typically 50% of the period is worst case andlower network latency improves control.

Tolerance to interference

Yes, <= latency guarantee

The jitter is constrained by the latency
requirement.

Tolerance to loss

1 ~ 4 frames

Applications are designed to tolerate the lossof one to 4 successive frames (1 ~ 4 periods).

Application Data size

Fixed (50 ~ 1000 bytes)

Criticality

High

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Description of Converged Traffic Types

Traffic Type Descriptions

ALARMS AND EVENTSIn a system when an input or output variable change occurs that requires attention, Alarm andEvent messages are generated. Depending upon the change, this might be a single message, or aflurry of messages (domino effect). While the messages may be directed to different end devices,typically, they are directed at a single device, like an HMI or SCADA system. The network must beable to handle a burst of messages without loss, up to a certain number of messages or data size
over a defined period.
After this period, messages can be lost until the allowed bandwidth quantity has been restored.
Examples include

process alarms and events that create traffic that may require 1 to 2 seconds latencies
and is acyclic but prone to flooding when issues arise in the process being controlled.
Maximum frame size varies by vendor and application but may reach 1500 bytes andoperator commands create another type of alarm and event traffic that is acyclic and hasa latency up to 1 second. Maximum frame sizes vary following each vendor but are usuallysmaller than the previous ones, reaching 500 ~ 600 bytes.
Traffic Type III: Alarms and Events
Characteristics

Periodicity

Acyclic/sporadic

Periodn.a.

Application synchronized to
networkNo

Data delivery guarantee
Tolerance to interference

Notes

Latency (100ms ~ 1s)

A bandwidth guarantee is also implied as statedabove.

n.a.

To be defined by the application.

Yes

For example, alarm showers of up to 2000 alarms
per second must be guaranteed, after which somepacket loss is acceptable. The number isapplication dependent.

Tolerance to loss

Application data size

Variable (50 ~1500 bytes)

Criticality

High

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Description of Converged Traffic Types

Traffic Type Descriptions

CONFIGURATION & DIAGNOSTICS
This type is used for the transport of configuration data, such as device configuration andfirmware downloads. This data is traditionally sent using TCP/IP-based protocols that contain lost
message recovery capabilities. This data is not time critical, but it must eventually be delivered.
IACS configuration, maintenance and operator triggered diagnostics use this traffic type. Networkand system management and configuration (e.g. SNMP, RESTCONF/NETCONF, firmware updates)
protocol traffic also belongs to this traffic type.
Examples include:

configuration activities create traffic with maximum frame sizes (1500 bytes) in an acyclicmanner. This traffic type may occasionally create peaks of bandwidth utilization with alatency of up to 1 second,diagnostic activities to monitor equipment health that creates acyclic traffic type, andprocess information from the application, such as order scheduling and production.
Traffic Type IV: Configuration & Diagnostics
Characteristics

Periodicity

Acyclic/sporadic

Notes
Some process supervision/diagnostic data may be sent
periodically with higher periods (500ms ~2s).

Periodn.a.

Application synchronized to
networkNo

Data delivery guarantee

Bandwidth

Tolerance to interferencen.a.

Tolerance to loss

Yes

No seamless redundancy is required.

Application Data size

VariableCan be large packets of 500 ~ 1500 bytes

Criticality

Medium

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Description of Converged Traffic Types

Traffic Type Descriptions

NETWORK CONTROLThis type contains network control messages, like those for synchronizing time (IEEE 802.1AS
a.k.a. Precision Time Protocol or PTP), for network redundancy (e.g. MSTP, RSTP), topology
detection (e.g. LLDP). These messages are low in volume but have critical delivery requirements.
Many of the messages are cyclic, but not relative to any TSN network cycle times. PTP traffic due
to its small size and the nature of the time-stamping shall not be preempted.
Traffic Type V: Network Control
Characteristics

Notes

Periodicity

Cyclic/periodic

Period50ms ~ 1s

Application synchronized to
networkNo

Data delivery guarantee

Bandwidth

Typically 1 ~ 2 Mbps.

Tolerance to interference

Yes

Transmission of PTP frames should not beinterrupted. Communication jitter should not exceed
the period.

Tolerance to loss

Yes

Excessive loss of network control frames can lead toloss of network functions (e.g. link-down state or
grand master fail-over).

Application data size

Variable (50 ~ 500 bytes)

Criticality

High

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Description of Converged Traffic Types

Traffic Type Descriptions

BEST EFFORTBest effort traffic follows one of two rules: either it suffers from data loss when higher priority
traffic uses all the allocated bandwidth (default), or it can use a guaranteed bandwidth allocation.
Best effort provides no delivery guarantees in the former case, and bandwidth guarantees in thelatter.
Traffic Type VI: Best Effort
Characteristics

Notes

Periodicity

Acyclic/sporadic

Periodn.a.

Application synchronized to
networkNo

Data delivery guarantee

None

Tolerance to interferencen.a.

Tolerance to loss

Yes

Application data size

Variable (30 ~1500 bytes)

Criticality

Low

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Typically networks are configured to provide somebandwidth to best effort.

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Description of Converged Traffic Types

Traffic Type Descriptions

VIDEO
Video traffic is the streaming of video data between end-points. IACS often include video
systems, but this traffic will be mapped to previous types such as Cyclic or potentially Isochronous
data depending on the criticality of the application. The characteristics below describe video forhuman consumption. Video streaming for human consumption tends to have lower performancerequirements and is reflected in the IEEE 802.1Q, where video “traffic is characterized by lessthan 10ms delay and, hence, maximum jitter (one way transmission through the LAN
infrastructure of a single campus).”Traffic Type VII: Video
Characteristics

Notes

Periodicity

Acyclic/sporadic

Periodn.a.

Application synchronized to
networkNo

Data delivery guarantee

LatencyTolerance to interferencen.a.

Tolerance to loss

Yes

Loss of packets may lead to decreased quality, but notnecessarily application failure

Application Data size

Variable

Large packets (1000 - 1500 bytes)

Criticality

Low

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Less than 10ms depending on the application- 17 -

Description of Converged Traffic Types

Conclusion

AUDIO/VOICE
Audio traffic is the streaming of audio or voice traffic between end-points. As with video traffic,
IACS systems often include sound sensors and actuators, but such end devices treat thestreaming data as Cyclic or potentially Isochronous data depending on the criticality of theapplication. Audio streaming for human consumption tends to have lower performancerequirements and is reflected in the IEEE 802.1Q where audio traffic is “characterized by less than
100ms delay, or other applications with low latency as the primary QoS requirement”.
Traffic Type VIII: Audio/Voice
Characteristics

Notes

Periodicity

Acyclic/sporadic

Periodn.a.

Application synchronized to
networkNo

Data delivery guarantee

LatencyTolerance to interferencen.a.

Tolerance to loss

Yes

Loss of packets may lead to decreased quality, but notnecessarily application failure.

Application Data size

Variable

Large packets (1000 - 1500 bytes)

Criticality

Low

Less than 100ms depending on the application

CONCLUSION
This white paper outlined the types of traffic found in typical manufacturing IACS and the network
performance characteristics they need. In a future release, the paper will be expanded to include
mappings of the traffic types and performance characteristics to QoS capabilities, including theenhanced TSN capabilities. This mapping should help the underlying standards organizations todeliver interoperable and certifiable devices and network infrastructure to the industry overall.
With the enhanced QoS capabilities from IEEE 802.1 TSN, the manufacturing ecosystem canconverge devices and applications onto a single, open, standard network in ways not possible
before. This convergence will lead to greater openness to IIoT innovations demanded bycustomers. That is the overall goal of the IIC and the companies working in this testbed.

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Description of Converged Traffic Types

Authors and Legal Notice

AUTHORS AND LEGAL NOTICEThis document is a work product of the Industrial Internet Consortium Time-Sensitive Networks
for Flexible Manufacturing Testbed chaired by Paul Didier (Cisco).
Authors: The following persons contributed substantial written content to this document:











Astrit Ademaj (TTTech)David Puffer (B&R Automation)
Dietmar Bruckner (B&R Automation)
George Ditzel (Schneider Electric)
Ludwig Leurs (Bosch Rexroth)Marius-Petru Stanica (ABB)
Paul Didier (Cisco)René Hummen (Belden/Hirschmann)
Richard Blair (Schneider Electric)
Thomas Enzinger (B&R Automation)

Contributors: The following persons contributed valuable ideas and feedback that significantly
improved the content and quality of this document:Florian Frick (ISW)
Jeff Lund (Belden/Hirschmann)

Technical Editor: Stephen Mellor (IIC staff) oversaw the process of organizing the contributionsof the above Authors, Editors and Contributors into an integrated document.
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