Real-time multimedia and communication in packet networks

1. Real-time multimedia and communication in packet networks iLanga

2. The Big Idea • The flexibility of Asterisk • what we have learnt • Working in the software domain • bridge between software and hardware closing • open environment; more flexible to change • Allows us to create something very functional yet simple - iLanga

4. SIP Express Router • Focuses only on SIP messaging • Performs forking properly • Is able to handle high volumes of SIP traffic • Has forked into two separate open source projects: • OpenSER • Kamailio

5. Registration with SER REGISTER 401 UNAUTHORISED (nonce,realm)‏ REGISTER (with MD5Hash(user+nonce+pwd))‏ 200 OK

6. User Devices

7. Example Call Set-up INVITE:3000@sip.ict.ru.ac.za INVITE:7521@sip.ict.ru.ac.za Asterisk INVITE:1013000@sip.ict.ru.ac.za INVITE:1013021@sip.ict.ru.ac.za INVITE:0786346926@sip.ict.ru.ac.za 3001 Hangup OK Hangup 3000 3021 0786346926

8. Asterisk • The core of iLanga • Speaks • RTP • IAX2 • Zap (1 QUADBRI)‏ • 4 channels to markreader premium line • 2 to Telkom and 2 to Rhodes PBX

9. Asterisk • Uses AGI • Prepaid application • Mark reader application • Extensive use of the Dialplan • Routing to Telkom and Rhodes • Routing to applications • Conferencing • Directory • Voicemail etc;

10. MySQL Database • We have been configuring asterisk via files in /etc/asterisk • You can also provide configuration via a Database using /etc/asterisk/extconfig.conf • IAX registrations • SIP registrations (SER talks to the database)‏ • Voicemail • Extensions still configured in extensions.conf! • We added “usercontext.conf”

11. Web Frontend • Provides a second way of accessing iLanga • Accessing your PBX from anything other than a telephone is a new concept – Made easy by soft switches. • Update your details • Edit ring-able devices • Listen to and control voice mail • Add prepaid credit • View call log • View the directory – click to dial • Everything you can do on the site – you should be able to do on a phone

12. Web Frontend • Hosted by an Apache web server • Written in Flash • Also allows us to make the web site dynamic! • Talks to • Perl (CGI)‏ • PHP • Java Proxy (used to be Python)

13. iLanga Proxy • Many entities talking to the manager interface caused problems • A Proxy was built • First in Python, now in Java • Passes messages from the web interface to Asterisk • Passes messages from Asterisk to the MySQL DB • Some actions • Icon information • Extension state information • Dynamic content on the front end

15. Short tutorial on Services Develop (in your head / on paper) a brief action plan for how you would develop one of the following services: • SPIT (Spam over Internet Telephony) generator • Application to curb SPIT in telephony applications • Asterisk-based markreader that integrates with ROSS to deliver marks to calling students over a phone • Audio database for storing and replaying all the telephone conversations that you make • Meeting scheduler for setting up meetings with other iLanga users • A ‘Hangman’ game that is played over the phone between two players Present your ideas to the rest of the class