PTPv1 and PTPv2 translation IN FTI Systems

Overview PTP in FTI Overview of PTP PTPv1 and PTPv2 Architecture Exchange Switch support PTP version translation June 12, 2018

Precision Time Protocol (PTP) in FTI 2006 PTPv1 selected for FTI First PTPv1 devices launched 2002 PTPv1 Standard 2012 PTPv2 Adoption for FTI First PTPv2 devices launched 2008 PTPv2 Standard Today…. Hybrid PTP Networks Mixture of Version 1 and Version 2 June 12, 2018

PTP in FTI Why PTP in FTI? IEEE1588 PTP: two versions PTP replaces proprietary time sync protocols Appropriate for closed networks with small/slow variation in round-trip delay such as FTI networks Typical sync accuracy < 100 ns IEEE1588 PTP: two versions iNET initially selected PTPv1, IEEE 1588 Std 2002 iNET updated the requirement for PTP to PTPv2, IEEE 1588 Std 2008 in 2011. June 12, 2018

PTPv1 Propagation delay =(Δ1+Δ2)/2 Offset = Δ1 June 12, 2018

PTPv2 – new features Transparent Clock defined Higher sync message rate for improved accuracy Smaller sync message size to save network bandwidth Peer-to-peer (P2P) delay mechanism Message extensions using Type-Length-Value (TLV) fields. Extended Management support Signaling messages introduced June 12, 2018

PTPv2 - P2P June 12, 2018

Management packets in PTPv2 (1) For PTP monitoring and trouble shooting Particular useful in systems with equipment from different vendors Easy to compare PTP datasets and fix compatibility issues. June 12, 2018

Management packets in PTPv2 (2) Monitoring of PTP synchronization Monitor Slave Clocks accuracy vs. Grand Master Clock December 13, 2012

PTP v1 and v2 Problem: Poor backward compatibility between PTPv2 and PTPv1 Consequences: PTPv2 Grand Masters Clocks cannot synchronize PTPv1 DAUs Switches with PTPv1 Transparency support cannot handle PTPv2 packets Solution #1 - Upgrade firmware of all equipment to PTPv2 Solution #2 - Use a PTP version translation in the switches June 12, 2018

PTP version translation PTPv2 and PTPv1 Grandmaster Legacy v1 ONLY PTPv2 slave PTP version translation Legacy v1 ONLY June 12, 2018

PTP version translation FOLLOW-UPv2 ∆Tsync1 = T1tx - Trx SYNCv2 ∆Tsync2 = T2tx - Trx FOLLOW-UPv1 SYNCv1 IEEE1588 SC IEEE1588 TC CPU 2-step TC Implementation with PTP version translation TCP UDP Switch core IP SYNCv2 T1tx SYNCv1 T2tx SYNCv1 FOLLOW-UPv1 Trx Ethernet PHY PTPv2 capable port SYNCv2 FOLLOW-UPv2 SYNCv1 FOLLOW-UPv1 PTPv1 capable port SYNCv1 FOLLOW-UPv1 PTPv1 capable port June 12, 2018

PTP version translation ∆TdelReqN = TNtx – TMrx DEL_REQ table DEL_REQv1 DEL_RESPv2 table IEEE1588 SC IEEE1588 TC CPU 2-step TC Implementation with PTP version translation TCP UDP Switch core IP DEL_REQv2 TMrx DEL_REQv1 TNtx Ethernet PHY PTPv2 capable port DEL_RESPv2 DEL_REQv2 DEL_RESPv1 PTPv1 capable port PTPv1 capable port June 12, 2018

PTP automatic version detection Whether a port is PTPv1 or PTPv2 capable can either be static configured or automatically detected on run-time Automatic detection : A switch port is be default configured as a PTPv1 capable port A switch port will change to PTPv2 if a PTPv2 P2P message is received on the port This approach requires that manual PTP version configuration is used on the switch for clocks configured for PTPv2 and E2E as the delay mechanism 12 juin 2018

Conclusions PTPv1 is becoming obsolete All new FTI equipment are based on PTPv2 FTI networks must be able to support both PTPv1 and PTPv2 in the mid-term perspective PTPv2 are not backward compatible to PTPv1 Solutions: Replace all PTPv1 equipment Firmware upgrade to PTPv2 if possible Use PTP version translation in the switch in order to allow both PTP versions to coexist in the same network June 12, 2018

Thank you for your attention. Any questions ?