We have a single site deployment with calls to/from telephone numbers on the PSTN coming over a SIP trunk via a CUBE and SIP calls being routed via our expressway pair to/from the internet. We are experiencing a long delay for incoming SIP calls over the internet.
I have a phone on a completely seperate network belonging to another business and when I make a SIP URI call there is a delay of about 10 seconds before that call hits our expressway-e, the time from when the call hits our expressway-e to when the phone rings is minimal. I have had someone from a third business try and they had the same delay. We can make/receive calls to/from the PSTN with minimal delay and make outbound SIP calls over the internet with minimal delay.
I'm not too sure what the cause is. Do I need to configure reverse DNS for the expressway-e? Would a non-publicly trusted expressway-e certificate cause a delay? Any other possibilities? Due to such a long delay it seems like something must be timing out. Thanks in advance.
