Signal Delay Compensation Example 1

Time-Stamping and Time Synchronization

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Intel® PAC
Napatech SmartNIC
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User Guide

In this section

This section contains the delay compensation calculations for the system configuration in SmartNIC Daisy Chain.

Assumptions

These assumptions are made for the system configuration:

  • SmartNIC #1: NT20E3-2-PTP
  • SmartNIC #2: NT20E3-2-PTP
  • SmartNIC #3: NT20E3-2-PTP
  • Cable lengths for all cables: 0.2 m

Signal delay for SmartNIC #2

The signal delay for SmartNIC #2 consists of these contributions:

  • TS_Out_Delay (SmartNIC #1, NT20E3-2-PTP)
  • Cable_Delay (0.2 m)
  • TS_In_Delay (SmartNIC #2, NT20E3-2-PTP)

Total signal delay in ns: 8 + 0.2 × 5 + 6 = 15

ntservice.ini code line: TimeSyncTimeOffset = 15

Signal delay for SmartNIC #3

The signal delay for SmartNIC #3 consists of these contributions:

  • TS_Out_Delay (SmartNIC #1, NT20E3-2-PTP)
  • Cable_Delay (0.2 m)
  • Daisy_Chain_Delay (SmartNIC #2, NT20E3-2-PTP)
  • Cable_Delay (0.2 m)
  • TS_In_Delay (SmartNIC #3, NT20E3-2-PTP)

Total signal delay in ns: 8 + 0.2 × 5 + 14 + 0.2 × 5 + 6 = 30

ntservice.ini code line: TimeSyncTimeOffset = 30