1. SIP 逄愛君 ijpong@pcs.csie.nctu.edu.tw

2. SIP&SDP2 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Outline  SIP Overview  SIP Components  SIP Messages  SIP Services  SDP  Conclusion

3. SIP&SDP3 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Overview  Session Initiation Protocol  The signaling protocol for creating, modifying and terminating sessions  Session=audio, video…  IETF Proposed Standard (RFC 2543)  February 2, 1999  Currently under development within the Multiparty Multimedia Session Control (MMUSIC) working group

4. SIP&SDP4 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Overview  15 Companies test interoperability between their equipment  April 1999  3Com, Alcatel, Cisco, British, British Telecom, Columbia University, Dialogic, Ericsson, HP, Lucent, MCI, Nortel,…

5. SIP Architecture

6. SIP&SDP6 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP’s Role to SS7 Signaling Gateway Signaling Gateway Media Gateway Controller Media Gateway Controller MGC SG SIP Proxy SIP Proxy RTP Megaco IP Network to PSTN SIP sigtran Media Gateway Media Gateway Media Gateway Media Gateway SIP Client SIP Client sigtran Megaco to PSTN to SS7

7. SIP&SDP7 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Overview  Client-Server Model  Flexibility & Extensibility  Text-based Encoding  Transport Independence  UDP or TCP  Security  Secure Sockets Layer (SSL) for TCP-based SIP

8. SIP&SDP8 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Components  User Agents  Client (UAC) To initiate a SIP request  Server (UAS) To receive the request and return responses  Servers  Proxy  Redirect  Registrar

9. SIP&SDP9 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Addressing & Naming  The entities addressed by SIP are users at hosts  email-like identifier of the form user@host  Examples  sip:patrik@example.com  sip:beagleboy@176.7.6.1

10. SIP&SDP10 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Messages  Two kinds of SIP messages  Request and Response  Request message format  Request Line Method, Request URI, Version  General, Request, Entity Headers  An Empty Line (CRLF) Indicating the end of the header fields  Message Body Session Description Protocol (SDP) : Optional

11. SIP&SDP11 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Messages (cont’d)  Response message format  Start-line Status-Line  General, Response, Entity Headers  An Empty Line (CRLF) Indicating the end of the header fields  Message Body Session Description Protocol (SDP) : Optional

12. SIP&SDP12 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Methods  INVITE  The user is being invited to participate in a session.  ACK  The request confirms that the client has received a final response to an INVITE request.  BYE  The client wishes to release the call.

13. SIP&SDP13 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Methods (cont’d)  OPTIONS  It queries the features the other side supports.  CANCEL  It cancels a pending request (not completed request).  REGISTER  It conveys the user’s location information to a SIP server.

14. SIP&SDP14 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Header Fields  General  Apply to both request and response messages  Entity  Define information about the message body  Request  Allow the user agent client to pass additional information about the request  Response  Allow the user agent server to pass additional information about the response

15. SIP&SDP15 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Headers

16. SIP&SDP16 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Request Example INVITE sip:pgn@example.se SIP/2.0 Via: SIP/2.0/UDP science.fiction.com From: Fingal To: Patric Call-ID: 1234567890@science.fiction.com Cseq: 1 INVITE Subject: lunch at La Empenada? Content-Type: applcation/sdp Content-Length: …

17. SIP&SDP17 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Response

18. SIP&SDP18 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Response (cont’d)

19. SIP&SDP19 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Response Example SIP/2.0 200 OK Via: SIP/2.0/UDP sippo.example.se Via: SIP/2.0/UDP science.fiction.com From: Fingal To: Patric Call-ID: 1234567890@science.fiction.com Cseq: 1 INVITE Content-Type: applcation/sdp Content-Length: …

20. SIP&SDP20 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Invitation for SIP Proxy

21. SIP&SDP21 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Invitation for Redirect Server

22. SIP&SDP22 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP+ISDN (Q.931)

23. SIP+MGCP

24. SIP / MGCP / ISUP

25. SIP&SDP25 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang SIP Services  Similar to the Intelligent Network (IN) services  Call Transfer, Call Forwarding, Conference Calling, User Mobility…

26. SIP Mobility

27. SIP&SDP27 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Conclusion  SIP is a light-weight signaling protocol.  The amount of companies backing SIP is crucial for survival.  MCI (the biggest backer), 3Com, Lucent and DynamicSoft…  The low complexity level of the SIP, compared to H.323 (H.245 & H.225), should make companies interested.  3G Wireless Technology  3GPP-> H.323  3GIP->SIP

28. SIP&SDP28 Industrial Technology Research Institute Computer & Communication Research Laboratories Elgin Pang Discussion