We are working with a Mitel dealer who is having some issues with calls after the second time the call is put on hold. We are the SIP trunk provider and we have multiple Mitel systems and other brands connected to our SIP trunks. We use the Netvanta 3430 as an SBC connected back to our soft switch. Regular calls are no problem and the are able to carry on conversations. If the call gets put on hold for a second time the audio from the phone to the SBC stops. From what I can see the RTP ports remain the same through out the call and I see RTP traffic going to the phone from the SBC but it never reconnects. The call remains live but no audio. Just looking for what else to look for or if anyone else has had this issue.
Thank you
