PSTN calls drop with-in 15 - 30 mins with Audiocodes SBC


Hi Community,


Recently, I have come across a scenario worth sharing. PSTN calls drops after 15 mins or 30 mins with Audio Codes SBC or Gateway.


This can be related or occur due to numerous reason, however if everything is in place (Network to Configuration) and still the call fails, then you can try the below and if it makes the difference.


User makes PSTN call > the flow and connectivity is established > after 15 or 30 mins you see BYE message generated resulting in call drop.


changing/modifying  the "RTCPActiveCalls" and "EnableSessionTimer" may help or simple does't make any difference.


Upon isolation, found that issue is mostly triggered due to a setting in Audio Codes S.B.C "Reset SRTP Upon Re-Key" is enabled (usually disabled by default)


By going in to the IP profiles > disabling the setting in AudioCodes the issue was resolved and calls no longer were dropped.


P.S - This solution may or may not help you (no harm in trying), But its best recommended to contact support and take assistance if needed :) 


3 Replies

@Aamir Baig 

Great to see someone taking the effort to post to the community with a fix.

Thank you 

For anyone needing more step by step instructions,

Login to your AudioCodes

Navigate to Setup > Signalling and Media >Coders and Profiles > IP Profiles and click on your Skype4B IP profile, then click Edit

In the box that pops up, change the Reset SRTP upon re-key setting and click Apply, Then click Save and Yes.



Another thing to be aware of that can commonly cause this is NAT session timers / Firewalls running ALG if you're running through them

Thank you @James Arber and thanks for providing more insight on the fix :) 

@Aamir Baig 

I'm wondering that this setting is described in all configuration guides from audiocodes to be set to enabled. 

Did you get any feedback of others that have switched the "Reset SRTP Upon Re-Key" from enabled to disabled on productive Audiocodes devices?