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Changing payload size does not appear in SDP offer

Occasional Advisor

Changing payload size does not appear in SDP offer

I am trying to make G.722 calls from a VVX 500 with a payload size different than the default (20ms). I use the web GUI to change payload size to 40ms and I can see the following line show up in my cfg file:




However, when I make a call to another device the default payload size is used. I verified this with Wireshark and have attached the invite SDP. My cfg file is also attached. UC software version is


Is there something else I need to change to make this work? I would appreciate your suggestions.

Polycom Employee & Community Manager

Re: Changing payload size does not appear in SDP offer

Hello @nmadani,

welcome back to the Polycom Community.


Did you ever solve your older issue => here <= ?

Usually I would remind you to post the currently used software version but your attached Backup shows me that you are using an unsupported software UC 5.4.3


The next question would be why are you posting within the openSIP community when your backup shows me you are using Skype for Business or LYNC:



Could you kindly clarify your old post and the new post and then use a currently supported software UC Software 5.6.0 or UC Software 5.5.3 instead?


Please also clarify if you are using Skype for Business / LYNC and if yes post your phones MAC address so I can check internally if you have the relevant required licences.


If this is openSIP please factory default your phone and ensure it is in Generic Mode prior to any new test providing a full wireshark trace and phone logs.


This is explained here:


Jan 19, 2012 Question: How to troubleshoot Polycom VoIP related Issues?

Resolution: Please check => here <=

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services

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Please be aware:For questions about the type of support to expect please check here

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The title Polycom Employee & Community Manager is an automatic setting within the community and any forum reply or post is based upon my personal experience and does not reflect the opinion or view of my employer.
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Message 2 of 5
Occasional Advisor

Re: Changing payload size does not appear in SDP offer

Hello Steffen,


Yes, I solved my older issue (with another VVX phone) and updated my previous topic.


My current issue: Following your instructions, I upgraded the software to 5.6.0, factory defaulted the phone and changed Base Profile to Generic. I am still experiencing the problem.


I have attached a Wireshark trace and log files for a G.722 call with payload size = 40ms.


Thank you for your assistance.


Message 3 of 5
Occasional Advisor

Re: Changing payload size does not appear in SDP offer

Hello Steffen,


I am still experiencing this issue and would appreciate your help. I have attached Wireshark trace and log files in my previous reply.


Thank you,


Message 4 of 5
Occasional Advisor

Re: Changing payload size does not appear in SDP offer

It has been over a year and I still have not been able to resolve this issue. Changing the payload size for individual codecs does not result in the "ptime" value changing in the SDP offer. I would appreciate any suggestions.


UC Software Version:

Message 5 of 5