1. Developing A Sip User Agent Using The Jain Sip Stack. Robert.V Masango Supervisors: Alfredo Terzoli, Ming Hsieh

2. Introduction (1) What Are User Agents In A Telecommunications Context ? These are Internet endpoints,that exchange information,in the form of video,text messages and voice.

3. Introduction (2) What Is Sip ? - Sip stands for session initiation protocol - Based on a response-request paradigm,sip initiates sessions between users on the internet.

4. What Are (Multimedia) Sessions? - From the Session Description Protocol specification: "A multimedia session is a set of multimedia senders and receivers and the data streams flowing from senders to receivers.”

5. How Sip Works (1) - A caller sends an INVITE request to a callee either : 1) Via a proxy server. 2) Point -to -Point.

6. How Sip Works (2) - After the session has been established audio,video and text messages are exchanged,depending on the agreement between the user agents.

7. How Sip Works (3) Model of the SIP environment

8. Most Important Sip Methods - Invite - Ack - Bye - Cancel - Registers - Options

9. Establishing Communication (1) - Registering,initiating and locating the user. - Determining the media to use. - Determining the willingness of the called party to communicate. - Setup the media streams.

10. Establishing Communication(2) - Call modification or handling. - Call termination.

11. What I’m going to do? - Develop a user agent using the jain sip stack. - And if there is time develop a simple proxy server.

12. Example Of An Invite Request (1) - INVITE sip:Robert@cs.ru.ac.za - To: sip:Robert@cs.ru.ac.za - From: sip:Ming@cs.ru.ac.za - Call-ID: Rhodes_CompSci@10.0.0.1 - CSeq: 8 INVITE

13. Example Of An Invite Request (2) - Content-Type: application/new format

14. Example Of A Register Request - REGISTER: cs.ru.ac.za SIP/2.0 - To: Robert@cs.ru.ac.za - From: Robert@cs.ru.ac.za - Call-ID: Fort_Hare@10.0.2.2 - Contact: Robert @cs.ru.ac.za - CSeq: 8 REGISTER - Content-Length: 0

15. Resources Available (1) - http://www.ietf.org/rfc/rfc2543.txt - Papers from various Universities/Companies working with sip,including Rhodes.

16. Resources Available (2) - The jain sip stack is open source and freely available.It’s targeted towards telephony over networks.

17. Expected Output - A platform independent sip user agent.

18. Questions Are There Any Questions?

19. Thank You Very Much