Related work in other SDOs Silvana Rodrigues System Architect Phone: +1 613 2707258 silvana.rodrigues@zarlink.com http://timing.zarlink.com/

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 – IEEE1588TM 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”

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

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

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

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 http://ieee1588.nist.gov/

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

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

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.” The purpose of an IEEE 1588 profile is to allow organizations to specify specific selections of attribute values and optional features of IEEE 1588 that when using the same transport protocol will inter-work and achieve a performance that meets the requirements of a particular application.

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 http://www.ieee802.org/1/pages/802.1as.html Editor: Geoff Garner from Samsung AVB stands for Audio Video Bridging 1st bullet -> Residential Ethernet can be considered the backbone for home. There are also non-residential applications like Professional Audio/Video studios. All these applications need precise synchronization 2nd bullet: Sometimes, the user wants one digital audio receiver to be the “master” and control what songs are played in other rooms through “slave” receivers – A single song in the whole house – A single song in selected rooms; e.g. living room, dining room, and study, but not bedroom • Simultaneous audio playing in multiple rooms requires synchronization and phase control of audio within the limits of human hearing to prevent “reverberation” throughout the house

ATIS – OPTXS OPTXS-SYNC (formerly T1X1.3) United States input to ITU-T 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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