WhiteRabbit Timing System
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Transcript of WhiteRabbit Timing System
M. Kreider,T. Fleck
WhiteRabbit
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WhiteRabbitTiming System
M. Kreider,T. Fleck
WhiteRabbit
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WhiteRabbit is designed to do...
• Time Synchronisation
• Timestamping
• Deterministic Switching
• Machine Control
Goals
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WhiteRabbit offers...
• Timing Accuracy: < 1ns, low ps jitter
• Robustness: event loss < 10-12
• Scalability: 2000 timing receivers
• Link length: up to 10 km
Features
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WhiteRabbit employs ...
• SyncE – Synchronous Ethernet
• PTP – Precision Timing Protocol
• QoS – Quality of Service
• FEC – Forward Error Correction
Technology
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SyncE: One clock is enough
• Nodes adjust to same physical clock
• Clock encoded in Ethernet carrier
• Clock recovered by PLL
SyncE – Synchronous Ethernet
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SyncE – Synchronous Ethernet
System TimingMaster
multi-layeredWR Switches
WRNodesGPS
The way of the Rabbit: WR Clock propagation
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PTP – Precision Time Protocol
Precise phase measurement – Aiming for accuracy
• Undersample Clocks
• Feed resulting alias frequencies to PLL
• Determine phase difference
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PTP – Precision Time Protocol
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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
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PTP – A Simplified Example
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PTP – A Simplified Example
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PTP – A Simplified Example
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PTP – A Simplified Example
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PTP – A Simplified Example
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PTP – A Simplified Example
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PTP – A Simplified Example
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PTP – A Simplified Example
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PTP – A Simplified Example
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PTP – A Simplified Example
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QoS – Not all packets were created equal
• Ethernet traffic split into:High Priority (HP) packetsStandard Priority (SP) packets
• HP packets can preempt other packets „on-the-fly”
QoS - Preemption & Determinism
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Port 1
Port 2
Port 3
WR Switch
SP Packet
HP Packet
SP… HP Packet Packet
QoS - Preemption & Determinism
QoS – Allowing to cut the line
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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
FAIR Timing Master
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TODO: WR Switch Slide
WhiteRabbit Hardware
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SPEC - Simple PCIe FPGA-Mezzanine-Card Carrier Board
WhiteRabbit Hardware
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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
Status
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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
Perspective
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Thank you for your attention
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Time for your Questions? ??
?