Android Voice Call (VoIP) application using SIP

Question

One of my client want to develop Free voice call application. They need an application like Viber or Line. I googled about this what i understood is i have to use SIP. But i am not clear how to do this. Mainly i have many doubts.

1- What i have to do in android? 2- What i have to do in server side? 3- How to setup sip server? 4- Is it possible to setup SIP on normal dedicated remote server? 5- Do i have anything to do programatically on remote server?

I Don't know that the above questions are meaningful or not. Actually i have zero info on this. I am totally confused. Can anyone explain how to develop Voice call application using SIP in Android. I am waiting for a clear and A to Z answer.

Answer 1

SIP is the protocol that does all the necessary stuff to get the call connected. Once the call is connected you need to transmitt the voice. Its done by protocol know as RTP. So you have to learn how both SIP and RTP works if you are going to program the dialler for android. In android you may use SIP stack that is built right into the API, in the android.net.sip package. Or you can learn JAIN SIP.

On server side you basically install a soft switch. you don't have to do any program there. Just install the software and do all the necessary like,create the account, define the user/pass,do the routing where to send call etc. Some of the open source options available are asterisk, freeswitch, opensips etc.

Also you dont need to do any programming in client side either to achieve this. You may use some free diallers available in android market(like zoiper). All you need is to create the account in your soft switch and register the dialler to the soft switch server(also may call it the proxy server) by using the user/pass.And you make make necessary routing in the server so that if the other callee is also registered with this server you can make the call.