ITU-T Q13/15 Updates TICTOC / IETF-83 Jean-Loup Ferrant, Calnex, Q13/15 Rapporteur Stefano RUffini, Ericsson, Q13/15 Associate Rapporteur
Introduction Q13/15 met at the SG15 in December and held Interim meeting in March 2012 hosted by NIST Next meeting: June 2012, hosted by NSN (Helsinki) A number of recommendations have been approved at the last SG15 meeting, Frequency sync packet timing: G.8261.1 (PDV Limits), G.8263 (Packet Clock), G.8260/Appendix I (PDV metrics) First recommendation on time sync: G.8271 (high level requirements, time sync interfaces) Others: G.8262 Amd (SyncE), G.8251 Amd (OTN), G.8264 Amd (SyncE) Some progress on Time sync at last meeting (G.827x series) 2
Transport of frequency in packet networks PRC Grand master CES SyncE Profile End to end Other Profiles Tbd G.8261 G.8261 G.8261 G.8262 G.8264 G.8261.1 G.8265 G.8265.1 G.8261 G.8261.1 G.8265 G.8265.x Slave G.8263 G.8260metric G.8261.1 Mobile application G.810 metric,.. 3
G.8260 Appendix I: PDV Metrics Packet Delay Variation metrics Packet network Packet interface PEC slave Physical layer timing interface PDV stability quantities Clock stability quantities [ Clock stability quantities estimation] = function ( PDV stability quantities) G.8260(10)_FI.1 Figure I.1 Packet equipment clock interfaces Two categories of PDV metrics Metrics for specifying PDV network limits metrics studying floor delay packet population Possibly others in the future Metrics for studying the characteristics of the network mintdev, etc. 4
G.8260 Appendix I: PDV Metrics, Cont. PDV metrics studying floor delay packet population Study Timing packets within a fixed cluster range starting at observed floor delay Compare population with acceptance thresholds 5
G.8261.1: Network limits for frequency transport End Application Clock C2 PNT-F PRC Physical Layer based Synchronization N etw ork Packet Master Clock PNT -F timing packets Packet Network E: End Application requirements (e.g. F requency accuracy) A: PRC, EEC, SSU or SEC Network Limits PEC-M B: PEC-M output Packet Network Limits C1 C: PEC-S input Packet N etw ork Limits PEC-S PNT-F D: PEC-S output Network Limits (deployment C ase 2) End Application Clock MTIE For any window interval of 200 seconds at least 1% of transmitted 16ppb timing packets shall be received 18 µs within a fixed cluster, starting at 9 µs the observed floor delay, and having a range of 150 µs. 0.05 0.2 32 64 1125 6
G.8263: PAcket Clock for Frequency G.8263 outlines minimum requirements for the timing functions of the Packet Slave Clocks as defined in G.8265: Frequency accuracy Tolerance Noise generation Etc. It supports frequency synchronization distribution when using packet based methods. It focuses on mobile applications, and in particular on the delivery of frequency synchronization for end applications such as mobile base stations. Local reference PEC-S Packet Timing Signal Packet Selection Time Scale Comparator Low Pass filter Oscillator Output Clock Local Time scale 7
Transport of time in packet networks PRTC G.8272 Grand master G.8273.1 SyncE G.8261 G.8262 G.8264 Profile with BC G.8271 G.8273.1/2 G.8275 G.8275.1 Profiles Tbd G.8271 G.8273.1/x G.8275 G.8275.y Slave G.8273.z G.8260 metric? G.8271.1 limits Mobile application G.810 metric 8
Time Sync Updates: Network limits G.8271 approved High level Requirements (e.g. +/-1.5 us) Time sync interface (1PPS) Network Limits moved into new G.8271.1 Planned for consent in September 2012 Various HRMs have been defined with and without SyncE support Additional results from simulations for Time sync over 20 BC chain with SyncE support : Random noise in the 100 ns range Additional time error in case of SyncE rearrangements 9
Time sync Architecture, PRofile and CLocks Time Sync Architecture and PTP Profile (G.8275) Recommendation planned to be consented in 2013 Initial discussion on the Best Master Clock Algorithm (G.781-like vs. Defualt BMCA) Time sync Profile (G.8275.1) Recommendation planned to be consented in 2013 Default mapping: Ethernet with Link local addressing (possible optional IP mapping; under discussion) Ongoing discussion on packet rate (between 8 pps and 64 pps) Path delay mechanism: Delay Request/Response provisionally agreed PRTC (G.8272) Recommendations planned to be consented in September 2012 Initial agreement: +/-100 ns max Time Error Telecom GM (T-GM): G.8273.1 Recommendation planned to be consented in september 2012 Telecom BC (T-BC): G.8273.2 Recommendation planned to be consented in 2013 0.1 Hz filtering on time sync provisionally agreed 10
SyncE G.8264 Amendment consented at the SG15 meeting, December 2011 Clarification on SyncE over LAG G.8262 Amendment consented at next SG15 meeting, December 2011 Clarification on SyncE over copper 1G and 10 G (Autonegotiation issue) 11
Current DocUment Structure Completed Ongoing Future? Definitions / terminology Basics / Network requirements Frequency: G.826x SyncE NetwkJitter-Wander: Included in G.8261 G.8261.1 (NetwkPDV_frequency) G.8260 (Definition/metrics) G.8261 G.8271 Time/Phase:G.827x G.8271.1 (NetwkPDV_time/phase G.8271.2 may be needed in future Clock G.8262 (-SyncE) G.8263 G.8272 PRTC G.8273 73.1 T-GM 73.2 T-BC 73.x T-TC? Methods G.8264 (SyncE-architecture) G.8265 (-Packet-architecture-Frequency) G.8275 (Packet-architecture-time) Profiles G.8265.1 (PTPprofileFrequency) G.8265.m (PTP Profile frequency m) G.8275.1 (PTPprofileTime/phase) G.8275.n (PTPprofileTime/phase n) 12