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WhiteRabbit Timing System. Goals. WhiteRabbit is designed to do... Time Synchronisation Timestamping Deterministic Switching Machine Control. Features. WhiteRabbit offers... Timing Accuracy: < 1ns, low ps jitter Robustness: event loss < 10 -12 Scalability: 2000 timing receivers
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Goals • WhiteRabbit is designed to do... • Time Synchronisation • Timestamping • Deterministic Switching • Machine Control
Features • WhiteRabbit offers... • Timing Accuracy: < 1ns, low ps jitter • Robustness: event loss < 10-12 • Scalability: 2000 timing receivers • Link length: up to 10 km
Technology • WhiteRabbit employs ... • SyncE – Synchronous Ethernet • PTP – Precision Timing Protocol • QoS – Quality of Service • FEC – Forward Error Correction
SyncE – Synchronous Ethernet • SyncE: One clock is enough • Nodes adjust to same physical clock • Clock encoded in Ethernet carrier • Clock recovered by PLL
multi-layered WR Switches System Timing Master WR Nodes GPS SyncE – Synchronous Ethernet The way of the Rabbit: WR Clock propagation
PTP – Precision Time Protocol Precise phase measurement – Aiming for accuracy • Undersample Clocks • Feed resulting alias frequencies to PLL • Determine phase difference
PTP – Precision Time Protocol PTP – Time Sync at a handshake • Exchange messages between nodes • Timestamp Msg arrivals and departures • Calculate link delay and time difference • Share results, adjust client clock
QoS - Preemption & Determinism • QoS – Not all packets were created equal • Ethernet traffic split into: • High Priority (HP) packets • Standard Priority (SP) packets • HP packets can preempt other packets „on-the-fly”
WR Switch SP Packet Port 1 HP Packet Port 2 Port 3 SP… HP Packet Packet QoS - Preemption & Determinism QoS – Allowing to cut the line
FAIR Timing Master • Timing Data Master – Telling everyone what to do • Generate Event Sequences • Control Accelerator Production Chains • Real Time Parallel Scheduling in FPGA • Granularity Window for Load Balancing
WhiteRabbit Hardware TODO: WR Switch Slide
WhiteRabbit Hardware SPEC - Simple PCIe FPGA-Mezzanine-Card Carrier Board
Status • Where WhiteRabbit is now: • High precision Time Sync functionality since 2009 • Switch, master and receiver specs in progress • WR switch prototype since 2010 • WR protocol implementation under development
Perspective • Where WhiteRabbit will be: • Timing receiver board prototype late 2011 • WR capable ‚Simple PCIe FMC carrier‘ board early 2011 • WR Switch board manufacture in 2011 • FAIR Timing Data Master prototype in 2011
Thank you for your attention
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