High Jitter with TC5.1.4 and CTS

[t.svatek]

Hi

We´ve added several new SX20 with TC5.1.4 to our existing installation. On these endpoints we found high Jitter rates (up to 1600ms) when calling a Cisco CTS-Device like CTS-3000. It only happens in the direction SX20->CTS. Received Traffic is ok.

I´ve done the same Test with several endpoints running 5.1.2 or 5.1.0 and there, everything works fine.

There is no packet-loss on any endpoint and there are no buffer overflows in the network.

Has anyone had the same issue or can anyone do a test in his environment ot doublecheck this, before I open a TAC-Case?

Thank you!

Tino

[Danny De Ridder]

From earliers TC release notes I read following on jitter buffer :

The C-series endpoint utilizes a dynamic jitter buffer that can increase  in value depending on the performance of the network. To minimize  introduced latency, this buffer will begin at 20ms and continue to 100ms  if sufficient packet loss or jitter is occurring.  Additionally, the C-series endpoints supports RTP time stamping into  the audio packets in order to help reduce lip sync issues that may occur  over an H.323 call.

I assume same applies for SIP.

MCU and other platforms I do not know. I somebody knows, please add it for the sake of completeness.