IEEE P1722 technical issues and talking points Version 0.01, 2007-08-21 Alan K. Bartky alan@snap-networks.com SNAP Networks Send comments to AVBTP@listserv.ieee.org April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

Notice of copyright release This document has been prepared to assist the work of the IEEE P1722 and IEEE 802 Working Groups. It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Copyright Release to IEEE: The contributor grants a free, irrevocable license to the IEEE to incorporate material contained in this contribution, and any modifications thereof, in the creation of an IEEE Standards publication; to copyright in the IEEE’s name any IEEE Standards publication even though it may include portions of this contribution; and at the IEEE’s sole discretion to permit others to reproduce in whole or in part the resulting IEEE Standards publication. The contributor also acknowledges and accepts that this contribution may be made public by the IEEE P1722 Working Group or the IEEE 802 Working Group. April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

gm_discontinuity / holdover Bump count on every discontinuity? Picked for simplicity and to not have listeners need to have a timeout. A step in time (no GM changes) does not need to have the talker set the hold Bump only once until holdover cleared? NO Either? holdover Maximum holdover time? There is no maximum time for 802.1AS to stabilize. This is dependency for us There is a discussion going on in AS Minimum holdover time? We don’t believe there is a need to define in 1722 If you step the time, the minimum could be zero. Holdover time/timeout reset? Timestamp field use during holdover 802.1BA does not exist and won’t in our timeframe needs. We need to define the minimum accuracy for 802.1AS 100 ppm Talkers must be GM capable April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

Permanent holder over (h bit always 1) A maximum time for AVBTP in addition to AS maximum time is required Notes from meeting AS time Detection of loss of GM 200-300 ms Election of new grandmaster Wish from 1722 team: Keep max to 600-700 ms Must be less than 1 second April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

Media clock Reset/discontinuity Bit to indicate? Proposal Toggle on change Consensus this is a useful thing to add Consensus if there is a toggle, there also must be a minimum time before you can toggle it again. Tie into holdover bit? No April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

IEEE P1722 AVBTP Working Group Contribution Presentation time Late presentation time As normal case, with LP bit Consensus to drop this bit from the spec Occasional & permanently late time Application specific April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

IEEE P1722 AVBTP Working Group Contribution Data smoothing Multiple packets per 8 kHz tick single stream Multiple streams (smoothing across streams) What does and what should 802.1Qav handle? Qav will handle this and we don’t have to talk about this in 1722 April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

Mandatory padding of 1722 frame Should it be required? No, Alan to change spec to remove this requirement April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

IEEE P1722 AVBTP Working Group Contribution Deprecated 61883 types: Summary of 61883-6 support in AVB Below is a preliminary list of supported and unsupported parts of the TA Document 2001024 Audio and Music Data Transmission Protocol 2.1 for P1722 audio end-stations. P1722 Gateways may need to support any format available for maximum compatibility. April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

IEEE P1722 AVBTP Working Group Contribution Deprecated 61883 types These are recommendations for the minimal required support and are based on real world uses of the protocol on IEEE1394 devices. Removal of support for formats like DVD Audio may seem short sighted but DRM restrictions have made use of the format impractical and DVD players use the non-DRM version audio formats instead. The 32bit floating point format is included even though there are no existing implementations using the format because new audio CODECS will support 32bit floating point formatted audio directly and P1722 should be prepared to stream the new format. April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

Supported 61883-6 Event Types 8.1 AM824 Data 8.1.2 IEC 60958 Conformant Data 8.1.3 Multi-bit Linear Audio (MBLA) 8.1.5 MIDI Conformant Data Allow mix of the above per 61883-6 rules 8.2 32-bit Floating Point Data All the above agree to keep April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

Deprecated 61883-6 Event Types AM824 options to be deprecated 8.1.1 Generic Format 8.1.4 One Bit Audio 8.1.6 SMPTE Time Code Data 8.1.7 Sample Count Data 8.1.8 High Precision Multi-bit Linear Audio 8.1.9 Ancillary Data 8.1.10 Application Specific Ancillary Data 8.3 24-bit * 4 Audio Pack All the above agree to deprecate Matt to inform 1394TA of our plans to support and deprecate April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

IEEE P1722 AVBTP Working Group Contribution 61883 timing Is current method of “editing instructions” adequate? Agreed this is an issue, especially for 61883-6 over AVBTP. Matt to start working on a contribution April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

IEEE P1722 AVBTP Working Group Contribution “Gateway” / “IWU” Which term to use Details Work on Annex B Agreed single term is needed Alan to ping Norm on thoughts on a name Will copy AVBTP team If no suggestion in 2 weeks, Editor’s discretion on picking new name, then we can re-visit April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

IEEE P1722 AVBTP Working Group Contribution IIDC Channel mapping 31 on AVBTP Current IIDC spec specifies only 0 to 15 for valid IDs Same kind of “edit instructions” as done for 61883 series is needed Additional work for Gateway/IWU for channel mapping Alan to make fixes based on John’s comments April 24, 2017 IEEE P1722 AVBTP Working Group Contribution

Q tagging and TPID field MAAP protocol Question: Should this be best effort instead of priority 6? This standard will not specify nor recommend. Will only specify Protocol MAC address Protocol Ethertype Don and Michael to discuss this with Norm at the next 802 AVB meeting Stream data Can the bridge strip the TPID and VLAN field on sending to end stations for AVB streams? April 24, 2017 IEEE P1722 AVBTP Working Group Contribution