IEEE 1588 Version 2IEEE 1588 Version 2

1 IEEE 1588 Version 2 IEEE 1588 Version 2 Gff MGGeoffrey M. GarnerConsultantSeptember 24, 2008 Outline - 1 Akldt Acknowledgment Purpose of IEEE 1588 Status and history of IEEE 1588 New features for Version 2 Overview of IEEE 1588 V2 Application service interfacepp Some basic PTP concepts and entities Synchronization basicsSynchronization basics Delay request-response mechanism Peer delay mechanismy End-to-end transparent clocks9/24/20082 Outline - 2 Peer-to-peer transparent clocks Time format Architectural choices Best master selection PTP profiles and conformancePTP profiles and conformance General optional features State configuration options State configuration options Compatibility requirements Transport specific field Transport specific field SecurityTtfltiffft Transport of cumulative frequency offset information9/24/20083 Outline - 3 Thi t t i

2 L id t diff This tutorial is an updated Version of reference 59/24/20084 AcknowledgmentThthld lik tkl ddg The author would like to acknowledge and thank John Eidson for having provided references 24 from which many of thereferences 2 4, from which many of the slides used here were taken or of IEEE 1588p IEEE 1588 is a protocol designed to synchronize real-timeIEEE 1588 is a protocol designed to synchronize realtime clocks in the nodes of a distributed system that communicate using a network It does not say how to use these clocks (this is specified by the It does not say how to use these clocks (this is specified by the respective application areas) NETWORK 9/24/20086 Status and History of IEEE 15881Vi1bli h dIEEE Std 1588TM2002 IEEE 1588 -1 Version 1 published as IEEE Std. 1588TM 2002 on November 8, 2002Vi1dIEC td d IEC 61588 Version 1 approved as IEC standard IEC 61588 on May 21, 2004V1 products and installations began appearing V1 products and installations began appearing in late 2003 Conferences on IEEE 1588 held 20032007 Conferences on IEEE 1588 held 2003 2007 Version 2 PAR approved March 20, 2005Vi2thil kltdFb9 Version 2 technical work completed February 9, 2007 Version 2 sponsor ballot opened July 2007 and Version 2 sponsor ballot opened July, 2007 and closed August 8, 20079/24/20087 Status and History of IEEE 15882 Version 2 sponsor ballot comment resolutionIEEE 1588 -2 Version 2 sponsor ballot comment resolution and coordination with IEEE Registration Authority Committee (RAC) occurred during y())

3 GAugust December, 2007 Version 2 recirculation ballot occurred January 14 24, 2008 P1588 committee voted on January 31, 2008 to send Version to IEEE RevCom Version 2 approved by RevCom on March 26, 2008d b IEEE Std d BdMh2008 and by IEEE Standards Board on March 27, 2008Vi2bli h dIEEE Std 1588TM Version 2 published as IEEE Std 1588TM 2008 on July 24, 2008 (reference 1)9/24/20088 Status and History of IEEE 15883 ApplicationsIEEE 1588 -3 Applications Current: industrial automation, T&M, military, power generation and distributiong New: consumer electronics, telecommunications Products (V1, V2 mainly under development): (,yp )microprocessors, GPS-linked clocks, boundary clocks, NIC cards, protocol stacks, RF ffinstrumentation, aircraft flight monitoring instrumentsR fd iIEEE P802 1AS D3 0 PC37 1 Referenced in: IEEE , , IEEE 1646-2004, LXI Consortium, ODVA IEEE 802 1AS will include a PTP profile (see IEEE will include a PTP profile (see reference 8 for details)9/24/20089 New Features for Version 2 1 Mit UDP/IP 4&6 Etht (dit-1 Mappings to UDP/IPv4&6, Ethernet (direct mapping), DeviceNetTM, PROFINET, ControlNetTMFlhifti Formal mechanisms for message extensions (using TLV)Transparent clocks Transparent clocks Synchronization accuracies better than 1 nsOtifd ddf lttl Options for redundancy and fault tolerance New management capabilities and options Higher sampling rates compared to V1.))

4 Asymmetry corrections9/24/200810 New Features for Version 2 2O tiliti(idditit-2 Optional unicast messaging (in addition to multicast)PTPfil PTP profiles Conformance specifications Configuration options Security (experimental specification only) Covered very briefly in this tutorial; see reference 6 for more informationMtltlti f Means to accumulate cumulative frequency scale factor offset relative to grandmaster (experimental specification only)(experimental specification only)9/24/200811 Overview of IEEE 1588 Version 21 Version 2 -1 ClausePurposeClausePurposeClausePurposeC lausePurpose1 Scope and purpose8 Data sets2 Standards references9 PTP protocol for ordinary2 Standards references9 PTP protocol for ordinary and boundary clocks3 Definitions10 PTP protocol for transparent clockstransparent clocks4 Notation Convention11 Clock offset, path delay, residence time, and asymmetry corrections5 Data types12 Synchronization and syntonizationy6 Description of PTP protocol (Informative))

5 13 Message formats7 PTP entities14 TLV entities9/24/2008127 PTP entities14 TLV entitiesOverview of IEEE 1588 Version 22 Version 2 -2 ClausePurposeAnnexPurposeClausePurposeAn nexPurpose15 ManagementAUsing the PTP protocol16 General optionalBTimescales and epochs16 General optional featuresBTimescales and epochs17 State configuration optionsCExamples of residence and asymmetryoptionsand asymmetry corrections18 Compatibility (V1/V2 DTransport over UDP/IPv4and V2/future versions)19 Conformance and PTP ETransport over UDP/IPv6profilespFTransport over IEEE 802 3/Ethernet9/24 of IEEE 1588 Version 23 Version 2 -3 AnnexPurposeAnnexPurposeAnnexPurposeAnne xPurposeGTransport over DeviceNetLTransport of cumulative frequency scale factor offset (experimental)HTransport over ControlNetMBibliographyControlNetITransp ort over IEC 61158 Type 10 JDefault PTP profilesJDefault PTP profilesKSecurity protocol (experimental)(p)9/24/200814 Application Service InterfaceThi it id thf IEEE 1588 (V1 Interface This is outside the scope of IEEE 1588 (V1 and V2), and also outside the scope of this tutorialtutorial However, it cannot be ignored The timing requirements (jitter wander time The timing requirements (jitter, wander, time synchronization)))

6 Of the respective applications that use the PTP clock must be metthat use the PTP clock must be met The quality of the clock delivered to the application depends on both the quality of the pppqyPTP clock and the application service interface See reference 7 for more information on this topic9/24/200815 Some Basic PTP Concepts and Entities1 PTP DiA l i lif PTP l kand Entities -1 PTP Domain: A logical grouping of PTP clocks that synchronize to each other using the PTP protocol but that are not necessarilyprotocol, but that are not necessarily synchronized to PTP clocks in another domain Domain concept is carried over from V1 Domain concept is carried over from V1 PTP clock types (will cover in more detail later) See Clause 3 of IEEE Std 1588TM 2008 See Clause 3 of IEEE Std 15882008 (reference 1) for exact wording of definitions9/24/200816 Some Basic PTP Concepts and Entities2 PTP l k t(t )Concepts and Entities -2 PTP clock types (cont.)

7 Ordinary clock (OC): has a single PTP port in a domain and maintains the timescale used in the domain It mayand maintains the timescale used in the domain. It may serve as a source of time, , be a master, or may synchronize to another clock, , be a slave. It may provide time to an application or end deviceprovide time to an application or end device. Boundary clock (BC): has multiple PTP ports in a domain and maintains the timescale used in the domain. It may serve as a source of time i e be a master orIt may serve as a source of time, , be a master, or may synchronize to another clock, , be a slave. It may provide time to an kth tilhi l l A boundary clock that is a slave has a single slave port, and transfers timing from that port to the master ports9/24/200817 Some Basic PTP Concepts and Entities3 PTP l k t(t )Concepts and Entities -3 PTP clock types (cont.)

8 Transparent clock (TC): A device that measures the time taken for a PTP event message to transitthe time taken for a PTP event message to transit the device and provides this information to clocks receiving this PTP event messagegg Peer-to-peer transparent clock (P2P TC): A transparent clock that, in addition to providing PTP event transit time information also provides corrections for the propagationinformation, also provides corrections for the propagation delay of the link connected to the port receiving the PTP event message. In the presence of peer-to-peer transparent clocks delay measurements between slavetransparent clocks, delay measurements between slave clocks and the master clock are performed using the peer delay measurement Basic PTP Concepts and Entities4 PTP l k t(t )Concepts and Entities -4 PTP clock types (cont.)

9 End-to-end transparent clock (E2E TC): A device that only measures the time taken for a PTP eventthat only measures the time taken for a PTP event message to transit the device and provides this information to clocks receiving this PTP event message; i e it does not provide corrections for themessage; , it does not provide corrections for the propagation delay of the link connected to the port receiving the PTP event message. It does not use the peer delay measurement mechanism but, instead,peer delay measurement mechanism but, instead, supports use of the delay request-response mechanism9/24/200819 Some Basic PTP Concepts and Entities5 PTP event messages (time stamped onConcepts and Entities -5 PTP event messages (time stamped on egress from a node (clock) and ingress to a node)) Sync Delay_Req Pdelay_Req Pdelay_Resp PTP general messages (not time stamped) PTP general messages (not time stamped) Follow_Up Delay_Respy_p Pdelay_Resp_Follow_Up Announce Management Signaling9/24/200820 Some Basic PTP Concepts and Entities6 PTPi tith ThilithConcepts and Entities -6 PTP communication path.

10 The signaling path portion of a particular network enabling direct communication among ordinary and boundarycommunication among ordinary and boundary clocks A communication path may contain transparentA communication path may contain transparent clocks Cannot mix end-to-end and peer-to-peer pptransparent clocks on the same communication path (except in a restricted class of topologies, e g linear chain) , linear chain)9/24/200821 Synchronization BasicsSt1 P ithi iithl ky Step 1: Prior to synchronizing, organize the clocks into a master-slave hierarchy (based on observing the clock property information contained inthe clock property information contained in Announce messages) Announce messages carry information used to establish the master-slave hierarchy; they are not used for synchronization Step 2: Each slave synchronizes to its master Step 2.