Acceptable value of RTD for IP Phone to work over WAN

Unanswered Question
May 29th, 2008


I am using callmanager 6.1. Can i place ip phones over internet link where the rtd is too high. Whats the acceptable value of RTD for the IP Phone to work over WAN.


I have this problem too.
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Paolo Bevilacqua Thu, 05/29/2008 - 04:39

Hi, RTTs of 800+ ms are common for sites via VSAT, phones be used normally and really not an issue. I recommend g711 on these links unless you can do iLBC.

Hope this helps, please rate post if it does!

kolkatagtc Thu, 05/29/2008 - 04:43


Thanks for your response. But over WAN or MPLS whatever the scenario may be if the RTD is 800+ then if you press the "New Call" softkey in your phone you will get the dialtone after 2secs which will indicate the delay. Moreover over WAN codec will be g729 rather g711.

How does g729 codec affect the phones....


iptuser55 Thu, 05/29/2008 - 04:55

Is there any guide lines for Call Control. I`m looking to configure a remote site so that voice traffic is via the local Telco but call control is via a WAN- what delay for Call Control can I get away with



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