said by ZeuS32: i see your suggestion very good as you said using 443 but in the case of using TCP for SIP may cause some lose of QOS, but i will tray your solution soon
Remember that SIP is only the signaling, not the media. A little bit of latency on the SIP packets won't hurt call quality at all. In fact de-prioritizing the SIP packets can actually help call quality by keeping said packets from getting in the way of the RTP.
That said, encrypting the RTP will also introduce some latency into the audio. But, we are talking about grey routes, and better to have a little bit of latency than have the call blocked, no?
VPNs typically introduce latency as well - hence my suggestion to try both approaches separately, and test to see which performs better on your network.
said by ZeuS32:regarding Sim cards and GSM GW many friends get sim blocked in few hours and we are looking for some solutions to reduce this sim blocking , many peoples said the best way is rotate between BTS using BTS autochange
Probably a good idea.
said by ZeuS32:others said operator block sim after lot of short calls
A large number of short calls is typically a sign of dialer traffic. One idea might be to actively monitor your own customers' ASR and ACD to block dialer traffic, unless of course that is your target market.