Qualifying Time Synchronization

Qualifying, Fine-Tuning and Troubleshooting Time Synchronization

Platform
Napatech SmartNIC
Content Type
Application Note
Capture Software Version
N-ANL11
N-ANL10
N-ANL9
Link™ Capture Software 12.11
Link™ Capture Software 12.10
Link™ Capture Software 12.9
Link™ Capture Software 12.8
Link™ Capture Software 12.7
Link™ Capture Software 12.6
Link™ Capture Software 12.5
Link™ Capture Software 12.4
Link™ Capture Software 12.3
Link™ Capture Software 12.2
Link™ Capture Software 12.1
Link™ Capture Software 12.0
Link™ Capture Software 11.9
Link™ Capture Software 11.8
Link™ Capture Software 11.7
Link™ Capture Software 11.6
Link™ Capture Software 11.5
Link™ Capture Software 11.4
Link™ Capture Software 11.3
Link™ Capture Software 11.2

PPS statistics without compensation

These figures display PPS statistics for SmartNICs #1 and #2 in the configuration described in SmartNIC Daisy Chain without compensation for propagation delay, that is, values of TimeSyncTimeOffset is set to 0.

In this figure, the external time synchronization connector of SmartNIC #1 is connected to SmartNIC #0.

Monitoring screen, showing time sync PPS statistics

In this figure, the external time synchronization connector of SmartNIC #2 is connected to SmartNIC #0.

Monitoring screen, showing time sync PPS statistics

The difference between the mean offsets is 10 ns, corresponding to the expected propagation delay between SmartNIC #1 and SmartNIC #2.

The offsets are somewhat larger than the calculated propagation delays, but within measurement accuracy.

PPS statistics with compensation

These figures display PPS statistics for SmartNICs #1 and #2 in the configuration described in SmartNIC Daisy Chain with compensation for propagation delay as described in ntservice.ini configuration.

In this figure, the external time synchronization connector of SmartNIC #1 is connected to SmartNIC #0.

Monitoring screen, showing time sync PPS statistics

In this figure, the external time synchronization connector of SmartNIC #2 is connected to SmartNIC #0.

Monitoring screen, showing time sync PPS statistics

The difference between the mean offsets is now 0 ns, verifying the effect of setting TimeSyncTimeOffset.

The offset is somewhat larger than the calculated propagation delay, but within measurement accuracy.

Style Conventions

Bold typeface is used for names of, for instance, user interface elements and software components.

Italic typeface is used for replaceable text.

Monospaced typeface is used for code, commands and file names.

Abbreviations

BP

ByPass

CLK

CLocK

Cnt

CouNT

Con

CONnector

dev

DEViation

DN

Document Number

Ext

EXTernal

FPGA

Field-Programmable Gate Array

Gen

GENeration

IEEE

The Institute of Electrical and Electronics Engineers

In

INput

Int

INTernal

Max

MAXimum

Min

MINimum

NT

NapaTech

NT-TS

NapaTech Time Synchronization

Ntts

NapaTech Time Synchronization

Os, OS

Operating System

Out

OUTput

PCIe

Peripheral Component Interconnect Express

Pps, PPS

Pulse-Per-Second

PTP

Precision Time Protocol

Rev.

REVision

stat

STATistics

STD

STanDard

Std.

STanDard

sync, Sync

SYNChronization

TS

Time Synchronization

UTC

Coordinated Universal Time

References