STCLive T&D Coordinated testing to another probe: Why does a 2 way (or Roundtrip) netquality test Q2Q run with 0% lost packets, but a 1 way netquality test to the same probe / same service suffers 100% packet loss?

Doc ID: FAQ13811

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STCLive T&D Coordinated testing to another probe: Why does a 2 way (or Roundtrip) netquality test Q2Q run with 0% lost packets, but a 1 way netquality test to the same probe / same service suffers 100% packet loss?

Environment/Versions

STCLive T&D , coordinated testing to another probe.

Answer

Answer: Check the time protocols on both units via the “rtrv-dat” command. Both units should use the same Time protocol – either PTP or NTP. If one unit is running with PTP and the other is running NTP, there will be a 100% loss of packets during the test. Or if one probe has NTP and the other has "none", the test will likewise fail.

A note from the STCLive T&D user and admin guide:

Because All latency measurements are based on the time required for the server to receive the traffic and it is therefore important that the units are time-precisely synchronized with a network time protocol such as NTP or PTP

Version 1.0

Publish Date 2013-06-12

Categories
Product : VW Controller PM Classic,VW Controller T&D Classic,STCLive

Customer Service Center

Spirent KB Article

STCLive T&D Coordinated testing to another probe: Why does a 2 way (or Roundtrip) netquality test Q2Q run with 0% lost packets, but a 1 way netquality test to the same probe / same service suffers 100% packet loss?