Precision Time Protocol (PTP) is a critical part of keeping synchronization of IP media devices across a network. Therefore, it is important to have an understanding of system configurations and an understanding of the processes involved in PTP. In this presentation, we will look at some of the basics of PTP, the potential pitfalls that can happen within the network system that cause issues in the reliability of the system, and the steps that can be taken to ensure a redundant PTP system within various network configurations.
File Type:
pdf
Categories:
PTP and Sync
Presenters :
Mike Waidson - Tektronix
Year :
2019
dlp_document_download :
C U R A T E D B Y I P S H O W C A S E T H E AT E R AT N A B – A P R I L 8 -11 , 2 01 9 Keeping Time with Precision Time Protocol (PTP) Michael Waidson, Application Engineer Tektronix, Inc. What time is it? • What time is it now! • Precision Time Protocol – IEEE 1588 -2008 ‒ Sends a Sync message periodic ‒ How many seconds ‒ How many nanoseconds ‒ From the SMPTE Epoch ‒ January 1 st midnight, 1970 2 BMCA Best Master Clock Algorithm • How to elect a Grandmaster Clock? • Priority 1 (0 -255) lowest number wins set by user • Clock Class, Clock Accuracy, Clock Variance set by device • Priority 2 (0 -255) set by user • MAC address of device 3 Hybrid Master Clock & SPG 4 SPG Master Clock SPG Master Clock Priority 1 - 128 Clock Class 6 Priority 2 - 64 Priority 1 - 128 Clock Class 6 Priority 2 - 96 Network Cloud GM Hybrid Master Clock & SPG 5 SPG Master Clock SPG Master Clock Priority 1 - 128 Clock Class 7 Priority 2 - 64 Priority 1 - 128 Clock Class 6 Priority 2 - 96 Network Cloud GM Hybrid Master Clock & SPG 6 SPG Master Clock SPG Master Clock Priority 1 - 128 Clock Class 6 Priority 2 - 64 Priority 1 - 64 Clock Class 6 Priority 2 - 96 Network Cloud GM Message Types • Announce • Sync • Follow -Up • Delay Request • Delay Response • Management • Signaling 7 224.0.1.129 192.168.1.10 192.168.1.20 Announce Message (320) Delay_Request (319) Sync Message (319) Delay_Response Message (320) Management Message (320) Follow_Up Message (320) Troubleshooting PTP • Check Domain Value • Check Grandmaster ID • Check Message Rates • Check Communication Mode 8 Ensuring PTP Lock • Grandmaster ID • Domain • Master/Slave Phase Lag should have low value for lock • Messages Rates ‒ SMPTE 2059 ‒ 4 Announce messages per second ‒ 8 Sync, Delay Request, Delay Response • Steps removed from Master 9 10 IP Status – Checking Domain • Check Following ‒ Domain Values ‒ Data Rates of PTP messages ‒ Check source IP & MAC BMCA Keeps Toggling ID • Check Configuration of Boundary Clock • Check for loop of messages • Check Messages Rates • Check Announce Timeout 11 2017 – 12 -06 23:44:00 (UTC) 08:00:11:ff:fe:2 1:90:2 b 2017 – 12 -06 23:44:01 (UTC) 28:99:3a:ff:ff:d3:4f:72 2017 – 12 -06 23:44:02 (UTC) 08:00:11:ff:fe:2 1:90:2 b Monitoring PTP Graphs • Check ‒ Phase Lag ‒ M -S Delay ‒ S -M Delay 12 PTP Network Topology 13 End Device Backup 1G 1G Transparent Switch Boundary Switches Primary End Device 10G 10G 10G 10G 10G 1G Grand Master Passive End Device Checking PTP at the Switch • show ptp • show ptp brief • show ptp clock • show ptp parent 14 Checking PTP Messages at the Switch Port • watch 1 diff show ptp interface ethernet xx • sh ptp port interface ethernet 1/x counters 15 Checking PTP Messages at the Switch Port • sh ptp port interface ethernet 1/x counters 16 What time is it? • What time is it now! • Precision Time Protocol – IEEE 1588 -2008 • SMPTE 2059 -1 & 2059 -2 • Provides Timing Reference across a Media Network 17 C U R A T E D B Y I P S H O W C A S E T H E AT E R AT N A B – A P R I L 8 -11 , 2 01 9 Thank You Michael Waidson, Tektronix, Inc. michael.h.waidson@tek.com
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