How to make a call directly between two SIP clients (peer to peer calls without a PBX)

This article is a detailed guide about making peer to peer SIP calls in relation with Ozeki VoIP SIP SDK. After reading through this page you will be fully familiar with all the essential terms concerning direct calls between two SIP clients and what you will need for creating your own solution using Ozeki VoIP SIP SDK.

Introduction

A VoIP phone call is usually made through a phone line that is established by a private branch exchange (PBX) using SIP messages. After establishing the phone call, the PBX quits the conversation and the communication is made by the two clients directly.

Figure 1 - VoIP peer to peer call

There are some cases when the PBX is not required in the connection phase and the VoIP clients can establish the connection directly. This connection is called peer to peer.

The following program code uses the background support of Ozeki VoIP SIP SDK, therefore you will need to download and install the SDK on your computer before starting to use the program code. You will also need to have Visual Studio 2010 or compatible IDE and .NET Framework installed on your system, as the program code below is written in C# language.

The direct SIP calls between two SIP client applications can be easily realized by using Ozeki VoIP SIP SDK. You need to register the two clients with a SIP account in a special way. You need to set that no registration is needed for the clients and give the IP address of the other softphone as the domain host (Code 1).

phoneLine = softPhone.CreatePhoneLine(new SIPAccount(false, "","","","","192.168.112.100"), new NatConfiguration(NatTraversalMethod.None));

phoneLine.PhoneLineStateChanged += new EventHandler<VoIPEventArgs<PhoneLineState>>(phoneLine_PhoneLineInformation);

softPhone.RegisterPhoneLine(phoneLine);

Code 1 - Setting the softphone for peer to peer communication

After setting the proper IP addresses in both softphones, you can use them to communicate peer to peer with any phone number they call.

This article introduced you the basic knowledge about peer to peer calls between SIP clients and showed how Ozeki VoIP SIP SDK can help you to fulfill your wishes about this topic. If you have read through this page carefully, you already have all the knowledge you need to start on your own solution.

As you are now familiar with all the terms concerning this topic, now it is time to take a step further and explore what other extraordinary solution Ozeki VoIP SIP SDK can provide to you.

If you have any questions or need assistance, please contact us at info@voip-sip-sdk.com

You can select a suitable Ozeki VoIP SIP SDK license for your project on Pricing and licensing information page

Related Pages

• Setup Ozeki VoIP SIP SDK efficiently: Quick start guide
• Download Ozeki VoIP SIP SDK form the Ozeki VoIP SIP SDK download page
• You can find licensing information of Ozeki VoIP SIP SDK on Pricing and licensing information page