1. SEMS Speaker: Changyu Wu Adviser: Quincy Wu Date:2006/11/13

2. 2 Overview Introduction  SEMS  SER How it works  SEMS application modules  SEMS audio modules SER-SEMS relation and intercommunication Reference

3. 3 Introduction SEMS(SIP express media server) is a extensible media server which helps you adding voice services to your VoIP system 。 IP Telephone SEMSSMTP server SER INVITE 200 OK RTP SMTP mail

4. 4 Introduction-SER SER(SIP Express Router) is an open-source SIP proxy, redirect and registrar server. SER’ s configuration file is divided into four main sections.  Global parameter  External module loading  Module parameters  Routing blocks

5. 5 How it works Redirecting SIP messages to SEMS  A caller gets connected to SEMS. SER has to pass every SIP message concerning that call to SEMS through unix socket (or FIFO). IP Telephone SEMS SMTP server SER INVITE 200 OK RTP SMTP mail

6. 6 SEMS-Modules Loading default modules  Application modules provide service logic  Audio modules provide codecs and file formats

7. 7 SEMS application modules Voicemail  Records voice messages and mail them to the callee ISDN Gateway  Support calls from and to the PSTN Conference  Enables many people to talk together

8. 8 SEMS application modules (cont) Announcement  Play audio file (wav file) Echo  Test module echoing your voice

9. 9 Announcement modules IP telephone SEMS RTP

10. 10 Conference modules RTP IP telephone SEMS

11. 11 Voicemail modules SEMS IP telephone SMTP server SMTP email RTP

12. 12 Echo modules IP telephone SEMS Re: Hello Hello

13. 13 SEMS audio modules Audio modules provide codecs and file formats  wav: G711u, G711a,.wav file  gsm: GSM 06.10 codec  iLBC: iLBC internet low bitrate codec  mp3:.mp3 file writer for mp3 voicemail

14. 14 The relation between SER+SEMS SEMS acts as UA and uses SER as SIP stack SER SEMS FIFO / sockets IP telephone

15. 15 SER-SEMS intercommunication SER provides two functions to pass a request to SEMS 1. t_write_req (FIFO) 2. t_write_unix (sockets) SER SEMS FIFO / sockets

16. 16 SER-SEMS intercommunication (cont) ser.cfg request routing example: If (method == “INVITE”) { If (uri=~”sip:2.*@”) { if(!t_write_req(“/tmp/am_fifo”,”announcement”)) { t_reply(“500”,”error contacting sems”); }; break; }; }

17. 17 Reference SEMS  http://www.iptel.org/sems SER  http://www.iptel.org/ser SIP.edu  http://www.internet2.edu/sip.edu/ Regular Expressions  http://www.regular-expressions.info/tutorial.html