SC-02-12-M Richard Cabot posted an update in the group SC-02-12-M 3 weeks ago No folders found. Please create and select folder. Documents Folder Title Following special characters are not supported: \ / ? % * : | " < > Privacy Public All Members My Connections Only Me Cancel Create CFC_AES67-xxxx_Danielson_Veselis_Levno.txt 6 KB Text File - Click to view Options Copy Download Link Subject: Regarding Call for comment on DRAFT REVISED AES67-xxxx From: Magnus Danielson Date: 3/14/2018 5:43 AM After reviewing the AES67-xxxx draft I have the following comments. 1) PTP Synchronization context has changed. While AES67-2013 anticipated SMPTE ST 2059, it has now arrived and it futher used in SMPTE ST 2110 which also includes an AES67 profile. The AES67 readers should be made aware of this additional context. Proposed text: Clause 4.2: add to end of clause: NOTE: AES67 as included into the SMPTE ST2110-30 and thus using SMPTE ST2110-10 PTP timing profile needs to follow SMPTE ST 2059-1 and ST 2059-2. A summary of PTP profiles exists in AES-R16-2016. Annex A.2.2: add after first paragraph: NOTE: AES67 as included into the SMPTE ST2110-30 and thus using SMPTE ST2110-10 PTP timing profile needs to follow SMPTE ST 2059-1 and ST 2059-2. A summary of PTP profiles exists in AES-R16-2016. 2) Media profile identification needs to be updated on publishing. Annex A.2.1: AES67-2013 needs to be replaced with AES67-2018. 3) Significant issues of using AES67 implementation in WAN context. Fortunately relative small adjustments will provide basic support hints, as solutions already exists. This was the basis of my VidTrans 2018 presentation. This is experienced built on many years of testing many implementations over various distances, and the increasing use thereof in TV productions amongst others. Clause 7.2.2: add to end of clause: NOTE: Longer packet delivery times may be supported to accommodate wide area (WAN) scenarios where minimum delay can be significant. Clause 7.4: add to end of clause: NOTE: For wide area network (WAN) use, the minimum delivery time of the network can be significant due to the distance and the speed of light in cables. For such scenario an estimation of minimum time can be used. Alternatively a synthonization mode can be used to time out samples based in receive time-stamps or buffer fill-level only. For both these methods the receive buffer only compensates experienced jitter. Clause 7.5: Add after first paragraph: NOTE: For LAN implementations minimum delivery times is assumed to be 0 s. For WAN scenarios this should either be set or estimated usign a minimum delay estimator. Such alternatives should be selectable receiver mode for that set of channels. Some implementation can support significant delays assuming minimum delay of 0, but then utilizing a huge memory buffer effectively not being used. Best Regards, Magnus Danielson Senior system architect Net Insight AB SWEDEN ------------------------------------------------------------------------------ Date: 3/20/2018 7:44 AM From: Normunds Veselis The proposed draft comes into conflict with an existing standard IEEE 1588-2008 (PTP). In draft AES67, Table A.1 first item and PICS clause A.2.2-4 both specify that the allowed range of the attribute "defaultDS.domainNumber" is to be 0-255. IEEE 1588-2008 only allows range 0-127 for this attribute, whereas numbers 128-255 are reserved. Proposing to change the text of AES67 as follows: Change 1: "Table A.1 – attribute values for use with Media profile" "Attribute": defaultDS.domainNumber "Values": Current edition: The default initialization value shall be 0. Other values (0 to 255) are allowed. Proposed change: The default initialization value shall be 0. The configurable range shall be 0 to 127. Change 2: Section "G.3.11.1.2 Table A.1 - PTP attribute values" "Statement number": A.2.2-4 "Feature": Current edition: defaultDS.domainNumber range 0-255 Proposed change: defaultDS.domainNumber range 0-127 "Notes": Current edition: Mark as supported if all other values (0 to 255) are allowed Proposed change: Mark as supported if all values 0 to 127 are allowed ------------------------------------------------------------------------------ From: Tom Levno Date: 3/21/2018 3:53 PM CC: William Hooper , Rich Hill We offer the following comment with reference to aes67-r-141107-draft-rev-cfc-rc4.doc With regard to the following “6 Transport 6.0 … 6.1 Network layer Media packets shall be transported using IP version 4 as defined in RFC 791. NOTE 1 Although care has been taken in the design of this standard to facilitate future support for IPv6, support for IPv6 is outside the scope of this revision of the standard.” We suggest the following substitution. “6 Transport 6.0 … 6.1 Network layer Media packets shall be transported using IP version 4 as defined in RFC 791 or using IP version 6 as defined in RFC 8200.” In view of the Internet Architecture Board's "Statement on IPv6," November 7, 2016 [1], and Internet Engineering Task Force (IETF) Best Current Practice (BCP) 177, "IPv6 Support Required for All IP-Capable Nodes," [2] we believe it is inappropriate for the AES to standardize a protocol that is not compatible with dual-stack (IPv4 and IPv6) or IPv6-only hosts. We recognize that some implementers may choose to disregard BCP 177 and continue to produce IPv4-only products, but considering the stated positions of the IAB and IETF, the exhaustion of the IPv4 address pools at all Regional Internet Registries, and the difficulties encountered by NTC's clients in assigning unique IPv4 addresses within large enterprises, we believe implementers of AES 67 should be free to meet marketplace demands for IPv6 compatibility, if they choose. [1] https://www.iab.org/2016/11/07/iab-statement-on-ipv6/ [2] https://tools.ietf.org/html/bcp177 Regards, Tom Thomas R. Levno, Senior Consultant, LEED® AP National TeleConsultants 550 N. Brand Blvd, 17th Floor Glendale CA 91203-1944 direct voice: 818-265-4435 NTC main voice: 818-265-4400 fax: 818-265-4455 Expand Annex-F.docx 20 KB Word Document - Click to view Options Copy Download Link AESSC_Master_Slave_Usage_20200904.pdf 56 KB PDF - Click to view Options Copy Download Link aes-r19-2019-191120.pdf 715 KB PDF - Click to view Options Copy Download Link Agenda-23May2018.pdf 73 KB PDF - Click to view Options Copy Download Link AG15-2015-Participation.pdf 90 KB PDF - Click to view Options Copy Download Link agenda-141007-sc-02-12-m-LA.pdf 68 KB PDF - Click to view Options Copy Download Link agenda-151020-sc-02-12-m-NY.pdf 87 KB PDF - Click to view Options Copy Download Link Agenda-171019-r1.pdf 70 KB PDF - Click to view Options Copy Download Link 0 Comments Public All Members My Connections Only Me PublicAll MembersMy ConnectionsOnly Me Public All Members My Connections Only Me
