I successfully tested SIP/RTP using a SIP Soft Phone , a VPN and VZW 4G-LTE network, my laptop with the Pantech UML295 4G-LTE modem.
Now, I want to do the same SIP/RTP tests without the VPN and just using the destination phone number (toll-free) and the MDN.
Is this possible with VZW 4G/LTE and the UML295 modem?..
I tried it, but without the VPN, the SIP Invite and its retries times-out and never gets any responses (Ringing, Trying or other).
The backend servers I am trying to connect to are not public IPs.so I cant specify them. A media gateway maps the call to
proper the backend servers. The toll-free number and backend services I am trying has been in-place and working for years.
The MDN is in the SIP Invite header.
How might this be done?
Solved! Go to Correct Answer
The article that was provided is dated July 2, 2013 -- almost two years ago. Is there an update on this subject. Has Verizon fixed the issue or has plans to fix?