Pedro Moreira CERN BE-CO-HT 1/31/2018 Pedro Moreira CERN BE-CO-HT White Rabbit

White Rabbit Agenda Requirements White Rabbit Protocol IEEE 1588 (PTP) 1/31/2018 White Rabbit Agenda Requirements White Rabbit Protocol IEEE 1588 (PTP) White Rabbit Control Message Protocol (WRCMP) Q&A

White Rabbit Requirements 1/31/2018 White Rabbit Requirements Synchronize up to 2000 stations with sub-nanosecond accuracy (jitter < 100ps) Bidirectional links Timing and Data Traffic 3 layers based protocol (Physical, Data Link, Network)

White Rabbit - Overview 1/31/2018 White Rabbit - Overview White Rabbit OSI MODEL Application Not Specified PowerLink ? LXI ? Presentation EtherCat ? Session Transport Network PTP | WRCMP DataLink White Rabbit MAC WR Specification Physical Synchronous Ethernet

White Rabbit – Network Topology 1/31/2018 White Rabbit – Network Topology Timing Traffic Data Traffic White Rabbit Network Timing Receiver WR Switch . . . White Rabbit Master GPS

White Rabbit – The Protocol Its is the set of (layer 2) standard rules for data representation, signaling and error detection required to send information over the Ethernet channel. Objectives To tailor Ethernet to be used as real-time communications network Keep it Simple, Stupit!

White Rabbit – The Protocol The Ethernet Frame The Medium Access Control (MAC) CSMA/CD (not used in switched Ethernet) Problem High Latency

White RABBIT – The protocol High Priority Packet (HP) Ethertype: 0xA0A0 Higher priority Critical control messages Fixed low latency Standard Priority Packet (SP) Ethertype: 0xA0A1 Lower priority than HP same as standard Ethernet traffic Non-critical control messages (management, diagnostic)

White RABBIT – The protocol High Priority Packet (HP) Preemption If there is a frame being transmitted the node stops its transmission, store the frame, and start the transmission of the incoming HP packet. Fix Latency

White RABBIT – The protocol High Priority Packet (HP) For further discussions ( Layer 2+ issues)

White RABBIT – The protocol Standard Priority Packet (SP) For further discussions ( Layer 2+ issues)

White RABBIT – IEEE 1588 IEEE 1588 - Precise Time Protocol (PTP) Standard for time distribution over package based networks Present benchmarks 1μs for topologies with no more than 30 consecutive slaves IEEE 802.1 AS Timing and Synchronization for Time-Sensitive Applications in Bridged Local Area Networks Standard for IEEE 1558 over Ethernet for Audio, Video Broadcast One of the AVB (Audio Video Bridging) standards, IEEE 802.1AS, specifies the distribution of precise timing and synchronization over the AVB network. The requirements of IEEE 802.1AS will allow the media timing for each respective A/V application to meet its jitter, wander, and time synchronization requirements with appropriate filtering at the endpoints.

White RABBIT – IEEE 1588 IEEE 1588 - Precise Time Protocol (PTP) White Rabbit Master/Slave – Ordinary Clocks White Rabbit Switch – Boundary Clock No Transparent Clocks The use of synchrounous ethernet reduces the phase noise accumulated in the cascades clocks

White RABBIT – IEEE 1588 Synchronization

White RABBIT – IEEE 1588 PTP Header Correction Field : Resolution: 152 fs. Max Value 2 s Used for transparent clocks to calculate the travelling time in the transparent clocks. In White Rabbit it‘s used for phase and link delay compensation It doen‘t break the standard does it?

White Rabbit – IEEE 1588 Delay Model Device (White Rabbit master) slave) PHY SFP TX RX SFP PHY RX TX

WHITE RABBIT – WRCMP WRCMP – White Rabbit Control Message Protocol WR network configuration/diagnostic Connection of WR node Sends WRCMP INVITE Receives WRCMP INVITE RESPONSE Setup the PTP Daemon Connection of non-WR PTP node Sends WRCMP INVITE msg Timeout for WRCMP INVITE RESPONSE Setup PTP Daemon for non-white rabbit node PTP configuration Sends WRCMP_PTPCONF Interval sync Phase Interval WR management and network control

WHITE RABBIT Thank You ! Q&A Thank you Q&A