IEEE Standards Update
On-going work in Audio-Video-Bridging,
Precise Time Synchronization & TimeSensitive Networking
Technical Trackwww.odva.org

IEEE Standards Update
Brief History of AVB/TSN
Motivation for TSN in Industrial
New Work in IEEE – 802 & 1588
Implications of TSN to EtherNet/IP

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 2www.odva.org

IEEE Standards Update

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 3www.odva.org

Evolution of Ethernet
10base2/5

Full Duplex, Switched

Convergence via TSN

Best Effort

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 4www.odva.org

Foresight of Layering

Application
Presentation
SessionTransport
Network
Data Link
Physical

Device Profiles &Application Objects
Explicit
Messaging

Implicit
Messaging

CommonIndustrial
Protocol (CIP)

TCP/UDPInternet Protocol (IP)TCP/IP Suite

Ethernet CSMA/CD
Ethernet

IEEE Standards

TSN is Here
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 5www.odva.org

IEEE Standards UpdateIEEE Audio Video Bridging(AVB) Standards

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 6www.odva.org

IEEE AVB/TSN History & Purpose
An IEEE 802.3 Residential Ethernet Study Group was formed in
2005, with major contributions by Broadcom, Nortel, Pioneer,
Samsung, NEC, and Gibson (yes, the guitar people).
This morphed into the IEEE 802.1 Audio Video Bridging Task Group(AVB) in 2006. Key players: Intel, Broadcom, Marvell, Samsung,
Originally aimed at home electronics market, for when Ethernet and
Wi-Fi replace all other signal wires in the home (HDMI, speaker
wire, etc.)
Original goals:







Make IEEE 1588 Precision Time Protocol Plug-and-Play.
Offer the ability to reserve bandwidth for particular streams,
and to give those streams a low, specified latency and nearzero congestion loss.
Create an L2 transport protocol for time-stamped (display thispacket on the speaker/screen at this moment) AV data. (Thiswork taken to IEEE 1722.)
Support these features no matter what best-effort traffic is alsopresent.
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 7www.odva.org

Who Wants TSN?
Large interest in AVB from:
Fox Network, ESPN, Formula I, etc., for the next generation
television studio.
Disney, Harman, for the next generation theme park and/or
football stadium.
Gibson, Meyer Laboratories, Riedel, for the next generation audio
studio.
Large interest in TSN from:Audi, GM, Hyundai, BMW for automobiles

General Electric, Rockwell, Siemens for industrial control processes.
Large interest in TSN from:
Broadcom, Marvell, Intel, (chip vendors like standards).

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 8www.odva.org

Institute of Electrical andElectronics Engineers
IEEE



(Communications Magazine …)
IEEE Standards Association• (IEEE 1588 …)• IEEE 802 LAN/MAN Standards Committee– (IEEE 802.11 Wireless LANs Working Group …)– IEEE 802.1 Higher Layer LAN Protocols
Working Group» (IEEE 802.1 Security TG, Data Center Bridging TG)» IEEE 802.1 Interworking (IWK) Task Group» IEEE 802.1 Time-Sensitive Networking(TSN) Task Group (was AVB)
» (802.1 Task Groups are by area of expertise, not perproject.)Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 9www.odva.org

IEEE 802.1 AVB/TSN FinishedStandards
IEEE Std 802.1AS-2011 Timing and Synchronization
Plug-and-play profile of IEEE 1588 Precision Time Protocol• Provides automatic master clock selection and clock distribution tree
construction.
• No non-participating network nodes allowed in the distribution tree.

Every participant is, effectively, a 1588 “boundary clock.”
Practically speaking, 802.1AS supports only two-step, notone-step, clocking.

• Inserting time stamps into data frames is hard to do and doesn’t
play well with encryption.
• Remembering when a “sync” frame entered or left the PHY using aninternal mechanism, and then following the sync with a Follow-Up
packet with that information translated by software, takes twice as
many packets, but uses vastly less hardware to achieve the sameaccuracy as in-packet timestamps. (And, all of the variability forsupporting new protocols is in the software, instead of the ASIC!)

IEEE Std 802.11v Wireless Network Management includes
features to support 802.1AS.
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 10www.odva.org

IEEE 802.1 AVB/TSN FinishedStandards
IEEE Std 802.1Qat-2010 Stream Reservation ProtocolAdds TLVs to IEEE Std 802.1AB-2009 Link Layer Discovery Protocol(LLDP)• Allows one to discover which neighbors participate in AVB.
• Bridges tell end stations what classes of latency are available on what priority
levels, and what VLAN to use.
• Used to ensure that 802.1AS doesn’t use non-time-aware devices.
• Bridges protect AVB priority levels by remapping any input from a non-AVB
neighbor away from the AVB priorities.

Runs a protocol, “Multiple Stream Reservation Protocol (MSRP)” toactually make reservations.

• Talkers advertise streams, each with a network-unique multicast destination MAC
address (likely obtained via IEEE 1722.1), via MSRP, a hop-by-hop flooding
protocol.
• MSRP advertisements can be flooded to all AVB-capable bridges and end stations,or can follow multicast listener reservations (made by either 802.1Q MVRP or by
IGMP).
• Hop-by-hop replies from Listener(s) actually enable hardware queues, from
Listener to Talker..
• When Talker gets reply, transmission can start with guarantees enforced.

No longer an independent standard – rolled into IEEE 802.1Q-2012
edition.
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 11www.odva.org

IEEE 802.1 AVB/TSN FinishedStandards
IEEE Std 802.1Qav-2009 Forwarding and Queuing for Time-Sensitive
Streams

Defines a credit-based shaper on which MSRP depends for
actual data.
The sum of the bandwidths of all streams exiting a given port at
a given priority is set as the bandwidth of the shaper for thatpriority queue.
The 802.1Qav shaper’s properties make it easy to do the mathwhen aggregating streams into classes of service.
No longer an independent standard – rolled into IEEE 802.1Q2012 edition.

IEEE Std 802.1BA-2011 Audio Video Bridging Systems

Defines profiles of a number of standards for both end stations
and bridges, including all of the above and 802.1Q, to obtain
plug-and-play AVB.
Defines specific values for “Class A” and “Class B” latency
guarantees.
Root standard for answering the question, “Are you AVBcapable?”
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 12www.odva.org

What do the AVB Standards GiveYou?
Plug-and-play time synchronization with (typically)< 1µs error.
A high probability that a reserved stream will not
encounter congestion loss, which is, of course, thebiggest cause of packet loss.
A high probability that every frame in a reserved
stream will be delivered within the promised
latency.
A converged networking infrastructure – no need tohave two networks, one for production, and one
for best-effort use.

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 13www.odva.org

IEEE Standards Update

New IEEE Work

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 14www.odva.org

IEEE 802.1 AVB/TSN Purpose
By the time the AVB standards were complete, the homeelectronics market had not climbed aboard the
bandwagon.
But, the professional audio and video community had
become so interested that products are being offered,
today, that comply with AVB standards.
At the same time, the industrial control and vehicle
control communities have started to realize that digital
networks based on proprietary schemes (ProfiBus, CAN
Bus, Flexray, and so on down to RS-232) were a losing
proposition in the long term, and that they should shift
to Ethernet, instead.
After creating a number of proprietary sort-of-Ethernet
schemes, they have realized that truly standardized
Ethernet would be even better. And AVB is very close
to what they need!
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 15www.odva.org

IEEE 802.1 AVB/TSN Purpose
This new industrial constituency has caused the AVB TG to change its name to theIEEE 802.1 Time-Sensitive Networking Task Group (TSN). (Key players now
Broadcom, Marvell, Intel, Cisco, Extreme, Ericsson, Gibson, Harman, Siemens,
BMW, GM, Hirschman, Rockwell, GE.)
The goals are now to achieve the union of the audio/video and industrial markets’
needs:


Make IEEE 1588 Precision Time Protocol simpler to use, more robust, andmore accurate, while keeping its plug-and-play capabilities.



Offer the ability to reserve bandwidth for particular streams, and toabsolutely guarantee those streams a low, specified latency and zerocongestion loss.

Allow a single data stream to take multiple pinned-down paths throughthe network to ensure that equipment failure will not cause packet loss.

Allow any data stream to reserve this QoS, whether unicast or multicast,regardless of high-layer protocol, whether L2 or L3 end-to-end.

Converge all the usual existing Qualities of Service into the TSN network(at reduced bandwidth) while maintaining the TSN guarantees.

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 16www.odva.org

What is Missing (to be Supplied)?
Robustness of the clock accuracy in the face of amaster clock failure.
Fast bring-up after power-on.
The ability to handle a large number (1000s or
10,000s) of very slow streams.
100% guarantees of latency and congestion loss.
Frame loss rates in the 10–9 to 10–12 range overlong periods of time (hours – years).
Wi-Fi for TSN.
These features in routers.
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 17www.odva.org

IEEE 802 Current TSN-Related
Projects
P802.1ASbt (TSN) Enhancements for Timing andSynchronizationMultiple clock sources
Fast failover from source to source
Robustness against master clock failure including
complex failure cases.

P802.1Qbu (TSN) Frame Preemption (see P802.3br)Interrupt an 802.3 frame with lower latency
requirements one or more times during its
transmission, in order to send frames with more
stringent latency requirements.
This 802.1 effort is the (rather minor) bridge sideof the (much larger) 802.3br effort.

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 18
www.odva.org

IEEE 802 Current TSN-Related
Projects
P802.1Qbv (TSN) Enhancements for Scheduled TrafficProvide a rotating schedule of time slots that enable and disable
Class of Service Queues.
All 1 ≤ N ≤ 8 queues are gated independently, and the gating
function is placed between “this queue is not empty” and“select a queue for transmission”.
This makes possible just about any kind of scenario for overlap,
send-this-unless-this-other-is-ready, use-unused-bandwidthonly-for-these-queues, etc.

P802.1Qca (IWK) Path Control and Reservation (IWK)






Limited to modifications to IS-IS (as used by bridges – IEEE Std
802.1aq-2012)
Can replace MSRP as a medium for distributing the stream
requests.
May be used to distribute the results from a Path Computation
Element (implication: the IETF PCE) to establish pinned-down
paths (we’ll see).
May be used to distribute 802.1Qbv time schedules (we’ll see).
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 19
www.odva.org

IEEE 802 Current TSN-Related
Projects
P802.1CB (TSN) Frame Replication and Elimination for
Reliability (Seamless Redundancy)






Just getting started.
Will probably define a new tag, following VLAN tag, that will
carry a sequence number.
Unicast or multicast stream data is sequence and replicatedby host or by bridge, sent along all of more than one path,and the duplicates eliminated based on sequence number,either in the receiving host(s) or edge bridge(s).
802.1 may choose to provide, at intermediate points in the
network, this replication / elimination service, in order toregenerate dual streams after a single failure, thus ensuring
against multiple failures.

P802.1Qcc (TSN) Stream Reservation Protocol Enhancements


Fix the user interface to MSRP and/or P802.1Qca so that we
won’t have to visit the problem again, even if we define new
ways to make the data plane work better.

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 20www.odva.org

IEEE 802 Current TSN-Related
Projects
IEEE P802.3br Interspersed Express Traffic (see P802.1Qbu)









Finally on track, after much political (not in the bad sense)
haggling.
Interrupt an 802.3 frame with lower latency requirements
one or more times during its transmission, in order to send
frames with more stringent latency requirements.
Supports lock-down, to prevent resumption of interrupted
frame in a small pause between interrupting frames.
The 802.1 effort is the (rather minor) bridge side of the(much larger) 802.3br effort.
Only one level of interruption, meaning two buffers in thereceiver.
Software negotiation will be used to enable the feature.
Changes go between the MAC and the PHY, to minimize
ASIC impact.
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 21www.odva.org

IEEE 802 Current TSN-Related
Projects
P802.1Qbz (TSN) Enhancements to Bridging of 802.11


Small effort required to support P802.11ak.

IEEE P802.11ak Enhancements For Transit Links Within Bridged
Networks (See also P802.1Qbz)







Non-trivial effort to provide a bridge (or router or whatever)that is co-resident with an Access Point (a collection of logical
AP functions) to be able to treat each association with a non-AP
station like an independent point-to-point link for the purposesof multicast transmission.
This means using a new frame format, similar to 802.11n AMSDUs (aggregated frames), that carry a list of non-AP
stations’ association IDs to be includes or excluded fromreceiving the A-MSDU.
This format also replaces the 802.2 LLC format with 802.3
Type/Length encoding.
With this change, an AP station or a non-AP station can be partof an ordinary 802.1Q bridge, which means that 802.11 canbe used inside, as well as at the edge of, a Bridged LAN.
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 22www.odva.org

Some non-obvious “Why”s
Transmission preemption is not simply to improve the latency of thepreempting frames. At best, that only reduces the high-priority queue bya single frame transmission time.






Preemption does, of course, allow the use of giant frames without
killing the TSN frames’ latency.
But equally important, it allows the precise scheduling of TSN frames
for 0 jitter, without worrying about the size of the gaps between
scheduled frames.
So, it both improves critical jitter, and reduces the impact of TSN on
existing QoS algorithms.
When combined with scheduling, supports end-to-end cut-throughforwarding.

Industrial networks are built to extremely high standards for reliable datadelivery.


In a factory with 1000s of Ethernet networks, where one machine’s
failure stops the line, requirements for 10–6 packet loss ratios are notuncommon, and 10–9 desired.
And, the critical network must be converged with the Enterprisenetwork, in order to support virtual machine controllers in the
Data Center.

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 23www.odva.org

Relevance to the ODVA “style”
Scheduling and credit-based shapers are
not the ODVA style.
But, they offer a low-latency capability that, when

you need it, is handy to have.
These are tools in the IEEE 802.1 TSN toolbox, notmandatory usage models.
TSN always leaves a guaranteed bandwidth andlatency for the highest-priority best-effort traffic.

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 24www.odva.org

IEEE Standards Update

What More is Needed?

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 25www.odva.org

Layer 3, Layer 3, Layer 3This AVB/TSN stuff only works if you have an end-to-end
path through bridges.
Most users (though not the automobile people – YET)
realize that this sort of capability has to be routable.
A number of people (mostly from Cisco, Ericsson andBroadcom) are working on casting these features in aform useable by routers.
 Preferably based on existing technologies such as MPLS and
IP multicast.
 Preferably replacing the L2-only protocols with merged
L2/L3 protocols that start from the base of L3 IETF work.

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 26
www.odva.org

New Data Plane Mechanisms
The 802.1Qav shaper is not adequate as used on a Class ofService Queue. There are several proposals for new data
plane mechanisms.
1. Peristaltic Scheduler: All ports on all bridges are in lockstep, and alternate between buffers at cycle boundaries.
Any given stream is defined as using ≤ X bytes per cycle(including interframe gap), where cycle size ≥ X ≥ 64+20.
Per-hop transmission and forwarding delay is negligible.
2. Various improvements on (1), being developed by Cisco(and presumably, others).
3. One 802.1Qav shaper per prioritized flow, instead of per
CoS. Requires an NP-complete calculation to configure,but delivers the best possible latency numbers.
4. Every single input and every single output to/from a
buffer is scheduled explicitly by a pre-run-time algorithm.
(This is the method pioneered and deployed in AirBus
planes and Audi automobiles by TTTech of Vienna,
Austria.)
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 27www.odva.org

IEEE Standards Update

Other Standards ofInterest

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 28
www.odva.org

Other Standards of Interest
IEEE Std 1588-2002 Precision Time Protocol. (Version 2 inprogress).
Some people, especially Broadcom and Marvel, are trying torationalize this standard so that “profiles” don’t have to reinvent the wheel.

IEEE Std 1722-2011 Layer 2 Transport for Time Sensitive
Streams
This is not unlike RTP, but it uses the 802.1AS or 1588 timesynch, instead of trying to do time sync and transport in thesame protocol.

IEEE P1722a Amendments to 1722-2011.
This may go as far as defining CAN Bus over Ethernet.

IEEE P1722.1 Discovery, Enumeration, Connection andControlProvides a means of obtaining multicast MAC addresses touse for AVB flows that are unique in a Bridged LAN. (Atleast, for a while.)

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 29
www.odva.org

Other Standards of Interest
SAE AS6802: Time Triggered EthernetSociety of Automotive Engineers standard that enshrines,
without actually specifying the details of, TTTech’s clock
algorithms.

IEC 62439-3: Parallel Redundancy Protocol (PRP) and Highavailability Seamless Redundancy (HSR)








PRP: Allows a dual-homed host to connect to two completely
independent bridged networks, and to talk redundantly withanother, similar, dual-homed host.
PRP: Defines a Redundancy Box (RedBox) that dual homes
for some number of single-homed hosts.
HSR: Defines an encapsulation for a dual-homed host tooperate in a ring of similar hosts, sending data in both
directions.
HSR: Defines a “QuadBox” that interconnects two HSR rings.
These protocols can be used together to build networks thatare sort of Ethernet, but provide no redundancy at therouted (L3) layer.

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 30
www.odva.org

AVnu Alliance
AVnu Alliance is an industry consortium.
Cisco is a founding member, along with Intel,
Broadcom, and several other of the usual suspects(above).
This provides marketing and technical support forIEEE 802.1 AVB/TSN, rather like Wi-Fi Alliancedoes for IEEE 802.11.
They are in the process of expanding theirmembership to include major industrial
networking suppliers and users, and automobile
makers and equipment vendors.
They are expanding their focus to include L3 issues,
as well as L2 issues.
Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 31www.odva.org

One Last Note…

Participation in the development of these
TSN standards is encouraged!

Technical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 32
www.odva.org

IEEE Standards Update

Thank YouTechnical Track© 2014 ODVA, Inc.

2014 Industry Conference & 16th Annual Meeting
All rights reserved.

page 33
www.odva.org