How to build a softphone (using SIP protocol) using C#

Question

Hi all! I have this challenge to build an sip softphone using c# or .net technologies.

Please guide me the technology, requirements and specifications that is needed to build such.

Possible requirements:

Supported codecs:

G.722.1, G.723.1, G.726, G.728, G.711, G.729, G.723.1, iLBC,: G.711 (A and m-law),G.729A/B/D/E, AMR, GSM 6.10/EFR, iLBC, Speex

• Voice:

  Real time Quality Monitoring (MOS) 3 independent phone lines
  Auto-Answer/Do Not Disturb Call
  Forwarding Full Duplex Audio
  Recording compress the audio data.

• Fully SIP compatible softphone/dialer for PC2Phone and Mobile2Phone (iPhone, Nokia N95) application with symbian s60 , full source code should provide.

• Compatible with Windows 2000/XP/2003/Vista/Mac

• NAT/Firewall traversal feature

• Works with any 3rd party SIP Server

• Supports SIP outbound proxy

• Displays callers account balance

• Displays call credit time

• Automatic Echo Cancellation

• Automatic jitter buffer adjustment

• Last number Redial

• History of 10 last dialed numbers

• Quick dial user list

• Quick provision for customers, only user name and password required

Answer 1

Here are a few pointers

• See this article on Code Project for implementing an SIP stack in C#
• See this post for audio compression using LAME

Post Scriptum: Tag the question as "homework" if this is a homework.

Answer 2

Microsoft Real-Time Communications: Protocols and Technologies http://technet.microsoft.com/en-us/library/bb457036.aspx

Answer 3

how create program contain (code c#+sip+rtp)for vpio

Answer 4

Konnetic provide fully managed SIP components for .NET development.

Their standard SIP SDK is available here: http://www.konnetic.com/products/products_sip_sdk_std.aspx

Otherwise, Microsoft's Lync server comes with a very good managed SIP library, available here: www.microsoft.com/en-us/lync/default.aspx

Answer 5

And read these to get you started

http://www.codeproject.com/KB/IP/SIPIntroduction.aspx

www.codeproject.com/KB/IP/SDPIntroduction.aspx

Answer 6

http://www.konnetic.com is a relatively new addition. Fully managed. Everything you need to work with SIP and SDP. They haven’t picked the low-hanging fruit in the standard like a lot of the others. Just as good but tied to Microsoft is the Microsoft Lync server.