Related work in other SDOs Silvana Rodrigues System Architect Phone:

[Page 1] Standards Organizations  Multiple standards bodies are involved with Synchronisation of the Packet Network –International Telecommunication Union (ITU-T) Defining synchronization requirements for Packet Networks –Institute of Electrical and Electronic Engineer – IEEE1588 TM Defining the Protocol to be used to carry Synchronisation over the Packet Network –IEEE802.1AS – Audio/Video Bridging Task Group Timing and Synchronization for Time-Sensitive Applications in Bridged Local Area Networks –ATIS - Optical Transport and Synchronization Committee – OPTXS-SYNC Defining a technical report “Synchronization of Packet Networks”

[Page 2] ITU-T – Study Group 15, Working Part 3, Question 13 – Synchronization experts group  October 2003 –Proposal for investigating precision timing synchronization requirements & characteristics over asynchronous packet Networks were presented  April 2004 – Start the work on G.pactiming  February 2006 –G.8261 (former G.pactiming) was consented  February 2006 – Question 13 decided to: –Continue to work on G.8261 –Start the work on G.paclock –Start the work on G.pacmod  Rapporteur – Jean-Loup Ferrant from Alcatel

[Page 3] ITU, Study Group 15, Question 13 cont’d  ITU-T G.8261 –Recommendation published in May 2006 available –Defines timing and synchronization elements of packet networks –Specifies the minimum equipment tolerance to jitter and wander at the boundary of the packet networks at TDM interfaces –Outlines the minimum requirements for the synchronization function of network elements –Editor: Stefano Ruffini from Ericsson  ITU-T G.pacmod –Under development –Defines various aspects related to timing distribution in packet networks and to its modeling. –Includes clock distribution (network and equipment), network equipment modeling and SSM usage –Editor: Michael Mayer from Nortel

[Page 4] ITU, Study Group 15, Question 13 cont’d  ITU-T G.paclock –Under development –Outlines minimum requirements for timing devices used in synchronizing network equipment that operates in the IWF and to other Network Elements as defined in G.8261 –Supports clock distribution based on plesiochronous and network synchronous method (e.g. Synchronous Ethernet) and packet-based methods (e.g. Adaptive and Differential Clock Recovery) –Defines clock (PLL) performance characteristics such as wander, jitter, phase transients, clock bandwidth, frequency accuracy, holdover, etc… –Synchronous Ethernet clocks will be similar to G.813 (Timing characteristics of SDH equipment slave clocks – SEC) performance characteristics –Editor: Silvana Rodrigues from Zarlink

[Page 5] IEEE-1588  IEEE-1588 – Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems –Defines a Precision Time Protocol (PTP) designed to synchronize real-time clocks in a distributed system –Intended for Local Area Networks using multicast communications (including Ethernet) –IEEE-1588 designed to work within a building or factory Intended typically for industrial automation and test and measurement systems (e.g. synchronized printing presses) –Targeted accuracy of microsecond to sub-microsecond –Approved in September 2002 and published November 2002 –Available from the IEEE-1588 web site

[Page 6] IEEE-1588 – Version 2  The PAR (Project Authorization Request) was approved in March 2005 –P1588 – Precise Networked Clock Synchronization Working Group was formed Resolution of known errors Conformance enhancements Enhancements to address new applications (including telecom)  P1588 meets twice a week via conference calls –Chairman – John Eidson from Agilent –Secretary – Silvana Rodrigues from Zarlink –Editor – John MacKay from Progeny

[Page 7] IEEE-1588 – Version 2 cont’d  Version 2 of the standard includes key features for Telecom –Short Frame –Unicast –Fault Tolerant Clocks –Allows different methods for Master clock selection  The technical work is complete –No technical features will be introduced or deleted in the standard –Correct errors and ambiguities of technical facts –Correct editorial mistakes and English –Consider inputs from NIST for the security informative appendix  Letter ballot in April/May 2007

[Page 8] Profiles in Version 2  Profile is a set of required options, prohibited options, and the ranges and defaults of configurable attributes  “An IEEE-1588 profile may be developed by external organizations including: a) A recognized standards organization with jurisdiction over the industry, e.g. IEC, IEEE, IETF, ANSI, ITU, or; b) An industry trade association or other similar organization recognized within the industry as having standards authority for the industry; c) Other organizations as appropriate.”

[Page 9] IEEE 802.1AS  Home entertainment applications for voice, video, interactive applications and musical equipment  Trend is to use Ethernet to connect home entertainment equipment –For example, playing different audio tracks in each room, or playing same track in multiple room  Network model of 7 Switches  Synchronization accuracy –1us maximum wander from the grand-master station  Status –PAR approved May 25, 2006 –Draft 0.6 available at  Editor: Geoff Garner from Samsung

[Page 10] ATIS – OPTXS  OPTXS-SYNC (formerly T1X1.3) –Working on a technical report “Synchronization of Packet Networks” addresses synchronization issues in packet networks –The technical report is going through the letter ballot process  United States input to ITU-T –US position –Sector member contributions  Next meeting –May 2007

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