It’s All About Sync Achieving sub-ns synchronization in computer based measurements via Time Sensitive Networks in COTS Ethernet ni.com Time Sensitive Networks (TSN) are revolutionizing monitoring, control & test applications • Signal Based: Timing signals are shared directly via cables • Time Based: Timing signals are based off of a common time reference i.e., IEEE-1588, 802.1 AVB etc. ni.com 2 Large distances between nodes give long transmission delays 10-12 sec 10-9 sec 10-6 sec ? Signal-Based 10-3 sec sec 100m 101m 103m 102m Proximity ni.com 3 104m 105m Global Using message based protocols allows synchronization of clocks by compensating for path delays … Generate Signals ni.com Share Time Ethernet (IEEE 1588) 802.1 4 Generate Signals Using Time-Based Synchronization Time Reference Interact w/ Time GPS I/O 1588 FPGA-based IRIG Timekeeper PPS ni.com 5 Timestamping Clock Gen Trigger Gen Ethernet – IEEE 1588 Synchronization Network synchronization protocol intended for use over local networks. •Pros •High Performance (<50ns synchronization) •Automatic Peer-To-Peer Configuration •Remote Management •Cons •Not designed for wide area networks ni.com Accurate synchronization requires determination of network transit time of Sync Messages Master T1: 53ns 50 11ns Cable Propagation Delay 60 60 90 80 (96 –– T1) 53) –– (T3 (62 ––T2) 41)==OWD 11ns (T4 2 2 130 -23ns = - 53 - 11 Offset = 41 T2-T1-OWD 113 90 7 Adjust by 23ns 123 100 133 110 140 ni.com T3: 62ns 70 100 120 T2: 41ns 50 80 110 -23ns Offset 30 40 70 T4: 96ns Slave No Error! Time Based Synchronization Accuracy Test Results Test Results IEEE-1588 3m Ethernet Direct Cable ±25 ns, <4 ns standard deviation IEEE-1588 through a 1588 switch ±40 ns, <8 ns standard deviation GPS /PPS ±40 ns, <8 ns standard deviation IRIG-B DC ±55 ns, <13 ns standard deviation IEEE-1588 through a hub ±60 ns, <35 ns standard deviation IRIG-B AM matching ±1.15 μs, <260 ns standard deviation IEEE-1588 through a switch ±25 μs,<150 ns standard deviation IEEE-1588v2.1 / White Rabbit < 1ns ni.com ± 0.5◦ ± 1◦ ± 2◦ 10 kHz ±138 ns ± 276 ns ± 552 ns 20 kHz ± 69 ns ± 138 ns ± 276 ns 92 kHz ±15 ns ± 30 ns ± 60 ns 8 Time Sensitive Networking will bring deterministic Ethernet • • • Universal time synchronization - devices on the network, including switches and routers, can be synchronized very precisely via the IEEE 1588 and IEEE 802.1AS "precision time protocol" standards. Time sensitive queuing and forwarding in all devices to provide lower, and guaranteed, delays for time-sensitive data. Bandwidth and latency reservations - Enables both Time Sensitive and Best Effort data to coexist ni.com 9 CERN’s Timing Triggering and Control System uses optical networks to achieve sub-ns synchronization ni.com 10 CERN uses 108 collimators based on PXI for shaping the plasma beam in the new LHC with high reliability and accuracy CERN Large Hadron Collider “the most powerful instrument on earth” ni.com 11 ni.com 12 PXI Systems that make up the control and feedback systems used in each collimator ni.com 13 ni.com 14 White Rabbit Project provides Sub-ns synchronization using Complementary Technologies Technology ~ Performance IEEE 1588 +/- 25ns + Communicate to Share Time Locked Clock +/- 5ns skew < 500ps jitter Synchronous Ethernet + White Rabbit < 1ns skew < 20ps jitter > 10 km Precise Timestamping Phase Adjust Fiber optic ni.com 16 White Rabbit enhances Ethernet with Synchronization and Determinism Two separate services (enhancements to Ethernet) provided by WR: High accuracy/precision synchronization Deterministic, reliable and low-latency Control Data delivery ni.com 17 White Rabbit Network Components A White Rabbit network is composed of WR Switches WR Nodes WR Timing Master WR switch WR node IP core Timing Master WR Switch Copper/ Fiber links ni.com 18 Advanced PXIe T&S Modules This PXIe module will bring White Rabbit Synchronization to the PXIe platform. •Synchronization: < 1ns •Distance: > 10km •Electrical Isolation (Fiber) ni.com Synchronization over Distance Precision 10-12 sec 10-9 sec 10-6 sec White Rabbit ? Signal-Based 10-3 sec Time-Based sec 100m 101m 103m 102m Proximity ni.com 20 104m 105m Global Updating standards provide improved data acquisition and control with Ethernet • IEEE 1588 • • Work on revision 2.1 has started What’s in Scope o o • Improved Accuracy (White Rabbit) – “High accuracy extension/option/profile of PTP Synchronization over Wireless Ethernet (802.11V) IEEE 802.1AS-2011 Time Sensitive Networking • • • • • ni.com Brings determinism into mainstream – deterministic and traditional traffic on same network. Standards are currently in progress Renamed from AVB Gen 2 HW support for IEEE 1588 Defines how IEEE 802.3 (Ethernet) IEEE 802.11 (Wi-Fi) can be parts of same timing domain 21
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