Network Time Sync Presented by Tahmina J Hoque, Systems Engineer JDSU Solutions Specialist Organization © 2014 Utilities Telecom Council of Canada 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta Agenda • • • • • • • Timing Sync in Ethernet Networks Why is Timing required SyncE vs PTP How does it work? PTP Workflow Field Deployment Challenges Testing PTP 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 2 Typical Timing Distribution Application IEEE 1588v2 PTP used to transport timing information across Ethernet Network and synthesize clock on the far end Source: http://www.chronos.co.uk/files/pdfs/sym/TimeProv_500.pdf What would we want to test? 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 3 ITU-T TDM vs Packet Recommendations Requirements TDM network Functional G.803(SDH), G.810, architecture and G.823(E1), G. network 824(T1), G.825(SDH) synchronization requirements Equipment clock G.812(SSU), G. specification 813(SEC) Synchronization layer G.783(SDH), G. functions, functional 781(SSM) blocks, timing flow, and SSM Jitter and wander O.171(PDH), O. measuring equipment 172(SDH), O. 173(OTN) Packet network G.8260, G. 8261(SyncE), G. 8265(PTP) G.8262(EEC), G. 8265.1(PTP) G.8264(ESMC) O.174(SyncE) SSU = Synchronization Supply Unit SEC = SDH Equipment Clock EEC = Ethernet Equipment Clock SSM = Synchronization Status Message ESMC = Ethernet Synchronization Messaging Channel 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 4 PTP Profiles Comparison Profile Telecom ITU-T G.8275.1 AVB IEEE 802.1AS Smart Grid IEEE PC37.238 ID 00-19-A7-00-01-00 00-80-C2-00-01-00 1C-12-9D-00-00-00 Communication unicast multicast multicast Protocol UDP/IPv4 Ethernet w/o VLAN Ethernet w/ VLAN Clock Type 1-step or 2-step 2-step 1-step or 2-step Path Delay e2e p2p p2p Announce 2s 1 ps 1 ps Announce TO 2 2 3 Sync 8 ps 8 ps 1 ps Delay/PDelay 2 ps 1 ps 1 ps 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 5 SyncE and PTP What are they? Traditional Ethernet GE PHY ±100ppm free run data Synchronous Ethernet GE PHY GE PHY ±4.6ppm PLL ±100ppm free run data EEC GE PHY ±4.6ppm PLL EEC PRC/ PRS • Each Ethernet switch or router is timed from its own internal oscillator • Timing passed from one switch to the next just like in SONET/SDH • All network elements operate asynchronously • ESMC (Ethernet Synchronization Messaging Channel) protocol used to advertise clock quality Percision Timing Protocol (PTP) IEEE 1588v2 • Timing passed from timing source (grandmaster) to end points (slaves) via time stamped Ethernet fames (layer 2) or UDP packets (layer 4) • Switches in the path do not need to support PTP but boundary and transparent clocks improve preformance Ethernet Network PTP Grandmaster PTP Slave 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 6 SyncE vs PTP Attribute SyncE PTP Capacity Frequency Layer Physical Distribution Schema Transport Media Physical layer Point to point Ethernet Interoperability SyncE switches only Sensitivity Ethernet switches Standards ITU-T G.8261, G. 8262, G.8264 Frequency, Phase, Time Ethernet/IPv4/IPv6/ UDP In-band packets Point to multipoint Ethernet, xDSL, Microwave Grandmaster(OC), slave(OC), BC, and TC Packet jitter, bandwidth utilization (no BC/TC) IEEE 1588, ITU-T G. 8265, G.8265.1 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 7 PTP Protocol At Work Master Clock Time Slave Clock Time Offset θ = ½[(T2 – T1) + (T3 – T4)] TM T1 T2m TS = TM + θ Delay δ = ½[(T4 – T1) – (T3 – T2)] Sync message Data at slave clock T2 Follow_Up message containing value of T1 T2 T1, T2 T3 T3m T2 = T1 + δ + θ T1, T2, T3 Delay_Req message T4 Delay_Resp message containing value of T4 Time 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta T1, T2, T3, T4 T4 = T3 + δ – θ 8 PTP Field Deployment challenges • • • • • Connectivity to GM QoS/Prioritization set correctly Network PDV OWD Redundancy test/APS? 9 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 9 Test Equipment Capability/Features • • • • • • • Slave, Master Supports L2, L4 Supports Dynamic Unicast, Multicast Recovered clock for PDV measurements Accurate PDV and OWD measurements with External Reference Streams support for background traffic loading for QoS check 1PPS Analysis for deployed Slave performance test – With external reference 10 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 10 PTP 1588 Test Applications Overview TDM TDM CE IWF The image cannot be displayed. Your computer may not have enough Ethernet Ethernet NTE NTE TDM IWF TDM CE MEN Master Slave PRS § Packet Connectivity and Throughput Tester § Can devices connect to the master? § Emulate a Slave with test set – UDP or L2 § Verify PTP configuration and ability to sync to Master § QoS § Is PTP properly prioritized in the network? § Observe relative PDV trends and offset delays from Master § Load network with background traffic to verify PTP stability § Troubleshooting § How do I isolate the problem? § Capture & Decode PTP frames 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 11 Testing Network Sync with JDSU Portable Instruments Basic Workflow T-BERD/MTS-5800 Alone Recommended for Every Cell Site Advanced Workflow T-BERD/MTS-5800 + High Quality Time Reference (TM4M) Recommended for a Statistical Sampling of Cell Sites or for Troubleshooting 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 12 IEEE 1588 Application 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 13 Takeaways • Traditional Ethernet Service Activation Tests Still Important • Emergence of Network Synchronization distribution via PTP & SyncE introduces new capabilities into networks • Also introduces new types of network problems • JDSU Network Sync Workflows address both Configuration and Quality 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 14 PTP Standards • IEEE 1588-2008 aka 1588v2 – PTP for Networked Measurement and Control Systems • ITU-T G.8265/Y.1365 (10/2010) – Packet-based Frequency Delivery • ITU-T G.8265.1/Y.1365.1 (10/2010) – PTP Profile for Frequency Synchronization • IEEE 802.1AS-2011 – PTP Profile for AVB • IEEE PC37.238/D6-2011 – PTP Profile for Smart Grid • IEEE 802.3bf-2011 – PTP Timestamping PTP = Precision Time Protocol = Audio/Video Bridging 2014 Canadian Utilities IT & TelecomAVB Conference | September 23-26 | Calgary, Alberta 15 For More Information • Network Synchronization Tests are available in the following JDSU Products § T-BERD/MTS-5000 & -6000A MSAM • Visit us on the web – Network Synchronization Application Note: www.jdsu.com/ProductLiterature/ethernetnetsync-an-tfs-ae.pdf • Small Cell Forum Release: – http://scf.io/en/documents/075__Synchronisation_for_LTE_small_cells.php • Speaker Contact Information: [email protected] 2014 Canadian Utilities IT & Telecom Conference | September 23-26 | Calgary, Alberta 16
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