Easy Accessible Voice Gateway between Mbone and ISDN/PSTN Networks Linqing Liu and Torsten Braun Institute of Computer Science and Applied Mathematics University of Berne

2-3 April, 2001The 2nd IP-Telephony Workshop2 Outline Introduction Scenario Main functionalities Structure Audio forwarding and support unit Gateway control unit Usage and some sample snapshots Gateway administration Limitation and future work

2-3 April, 2001The 2nd IP-Telephony Workshop3 Introduction IP based telephony is booming with low cost long-distance calls. IP telephony is convenient to set up conference without the need of expensive Multipoint Control Unit (MCU). Related work: -ISDN4Linux -Mbone2Tel -AudioGate in MECCANO project Architecture and implementation of an easy accessible voice gateway between MBONE and ISDN with integration of existing component from public domain software.

2-3 April, 2001The 2nd IP-Telephony Workshop4 Scenario

2-3 April, 2001The 2nd IP-Telephony Workshop5 Conference scenario

2-3 April, 2001The 2nd IP-Telephony Workshop6 Main functionalities Display available multicast session list via HTML/WML pages, keyword searchable. User registration/creating new session via HTML/WML. Get session contact information via HTML/WML/SMS/ . “Click-to-dial” for existing gateway users. Gateway administration/configuration via HTML.

2-3 April, 2001The 2nd IP-Telephony Workshop7 Processing client request

2-3 April, 2001The 2nd IP-Telephony Workshop8 Main structure

2-3 April, 2001The 2nd IP-Telephony Workshop9 Audio forwarding and support unit Responsible for converting audio data between Mbone and ISDN/PSTN networks, listening to existing Mbone sessions and announcing new sessions over the Mbone Try to use existing software in public domain as components for audio forwarding and support unit: -Using AudioGate in MECCANO project as audio forwarding component. -Using mSD as daemon to listen Mbone session information. -Using mAnnouncer to send out SDP file over Mbone for new session announcement.

AudioGate functionalities Calling users can be authenticated based upon their Calling Line Identification (CLI) Allow to assign a full name to each of these numbers for presentation in the Mbone Sesion. Provide a simple (easily configurable) voice menu for prompting callers for a conference selection. Conferences can either be explicitly selected through the voice menu or callers can automatically be put into a particular conference. Imposes no artificial limits on the number of simultaneous calls it can handle. The only practical limit is the number of B channels that are available. Support one or more ISDN BRI boards. Supports up to nine simultaneous conferences. Can be configured to use any number of ISDN Multiple Subscriber Numbering (MSN). Some of them can be directly mapped into a conference while others may first lead into a voice menu. Supports muting/ unmuting callers using Dual- Tone Multi-Frequency (DTMF) for control. The initial status for the callers can be configured in the AudioGate initialization file. All codecs and transmission modes (particularly including redundancy coding) supported by Robust Audio Tool (RAT) are supported by AudioGate.

2-3 April, 2001The 2nd IP-Telephony Workshop11 Gateway control unit Main component to achieve easy accessibility. Provide user registration via HTML/WML web pages with selectable Mbone session list. Create new Mbone session via HTML/WML. Enable user calling participant via HTML/WML(“click-to-dial”). Gateway administration/configuration via HTML.

2-3 April, 2001The 2nd IP-Telephony Workshop12 Gateway control unit(cont.)

2-3 April, 2001The 2nd IP-Telephony Workshop13 Display Session Information and User Registration Transform mSD cache files to HTML/WML pages. Generate HTML/WML page according to keywords inputted by users, together with registration form. Provide gateway contact information after user registration.

2-3 April, 2001The 2nd IP-Telephony Workshop14 Screen snapshot after inputting “TV” as searching keyword

Display gateway contact information

2-3 April, 2001The 2nd IP-Telephony Workshop16 Create New Sessions via HTML/WML Generate SDP files via HTML/WML interfaces in compliance with SDP, MALLOC, SAP requirements. Announce the new sessions via mAnnouncer. Display new session information in HTML/WML pages and send the new session information to /SMS. Support “click-to-dial” by utilizing the relevant functionality from AudioGate.

Snapshot for creating a new session with WAP mobile phone

2-3 April, 2001The 2nd IP-Telephony Workshop18 Gateway Administration Gateway configuration via HTML interface with system administrator authentication. Gateway accounting mechanism via parsing AudioGate log files.

2-3 April, 2001The 2nd IP-Telephony Workshop19 Snapshot for gateway administration

2-3 April, 2001The 2nd IP-Telephony Workshop20 Limitations and future works Implemented in Linux PC with ISDN BRI board. One ISDN board support two lines. Limited slots for ISDN boards. AudioGate supports nine sessions simultaneously. Future works: -To develop a mechanism for seamless service without interrupting existing users. -To support AudioGate Mbus interface in future versions.