I'm not clear if after the Call Setup (SIP) on an inbound or outbound call to\from the ITP that (RTP) passes from the ITP to the 7030 over the VPN and then to ITSP or if the ITP passes (RTP) traffic directly out the local router to the Internet(not over VPN).
I admit I'm still a little green on the Samsung way, but my past experience is call setup will be done via the PBX, but on connection RTP will route directly between the endpoints. I suspect that there might be an issue with the call setup routing out the internet connection from one site, and then suddenly appearing to come from the other once connected. I might be way off the mark, but it might be a simple test to add a route to the ITP end router that points traffic destined for the SIP provider across the VPN instead of directly out the local internet connection.
Both locations access the Internet directly, only site-to-site traffic is routed over the VPN. I'm not seeing any VoIP\NAT traffic on the remote router so I assume all ITP traffic goes directly to the 7030 over the VPN and then to ITSP. If I had router\firewall issues wouldn't the problem consistently not work? the 50\50 random occurrences is what is throwing me for a loop.
If you make a call and it fails, does it work on the second try? It might point at the firewall closing the ports after a period of time. The first attempt opens them, then they are available for the second attempt. I figure this could tie in with my musing above about the two internet connections being used at different parts of the call.
I would like to test or rule out anything simple before I start trying to analyze traffic.
Good luck. This stuff has us tied in knots at times, too.
