1. PTPv1 and PTPv2 translation IN FTI Systems

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

3. 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

4. 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

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

6. 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

7. PTPv2 - P2P
June 12, 2018

8. 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

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

10. 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

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

12. 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

13. 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

14. 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

15. 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

16. Thank you for your attention.
Any questions ?