Agenda Introduction Requirements Architecture Issues Implementation Q/A Kundan Singh and Henning Schulzrinne, Columbia University

Traditional voice mail system Alice Bob Dial Phone is ringing.. The person is not available now please leave a message Your voice message... Disconnect Bob can listen to his voice mails by dialing some number.

Problems Voice mail system tied to PBX or phone company (if CFB) Integration of video, fax, whiteboard? How to integrate with Internet telephony? How to integrate with , web and other user applications?

Existing solutions Voice Profile for Internet Messaging (VPIM) Web-based unified messaging systems with personalized PSTN voice mail number.

Design Goals Message recording and playback Universal access: web, , VoIP, PSTN notification Scalability for large domains Separable from ITSP or ISP Reuse existing infrastructure Media-agnostic Tool-agnostic Telephony interface - DTMF

Why SIP and RTSP ? Use SIP for accepting voice/video calls (other services, and infrastructure for Internet telephony) RTSP for storage and access of voice messages. RTSP already in common use, e.g., RealPlayer Large-scale RTSP MoD servers exist. Easy integration with web, , video and fax. Access from PSTN using a gateway.

Architecture INVITE Alice phone1.office.com Bob Alice calls through SIP proxy. SIP proxy forks the request to Bob’s phone as well as to a voic server. vm.office.com The voice mail server registers with the SIP proxy, sipd, on behalf of every user. INVITE INVITE REGISTER

Architecture v-mail rtspd Alice vm.office.com; 200 OK CANCEL SETUP RTP/RTCP phone1.office.com; Bob After 10 seconds vm contacts the RTSP server for recording. vm accepts the call. Sipd cancels the other branch and......accepts the call from Alice. Now user message gets recorded

Architecture v-mail BYE Alice vm.office.com 200 OK to RTP phone1.office.com Bob Once the call is closed by Alice, vm sends an to Bob informing him of the arrival of a voice mail.

Architecture v-mail rtspd Alice vm.office.com Quick-time RTSP INVITE SETUP/PLAY RTP phone1.office.com Bob Bob can listen to voice mail using either an RTSP client like QuickTime or......by calling the v-mail using SIP. …or by visiting his web-based voic account

Architecture Alternatives –The SIP phone redirects the call to voice mail after 10 seconds. –The SIP proxy is configured to forward the call to voice mail if your phone is busy or there is no response (static, or using sip-cgi, CPL) –Voice mail server acts as another phone for the user but delays accepting the call by 10 seconds, with CANCEL if user picks up.

Issues Call reclaiming Deleting voice/video mail Integration with PSTN phone Integration with VPIM, IMAP, POP3

Implementation Prototype system. Recording and playback using.au files.

Implementation Features Integration with web/ for more control over voic configuration (e.g., folder management, notification.) Web based voice mail accounts for users (Similar to Hotmail) Retrieval using RTSP clients ( Quicktime ), SIP user agent ( e*phone ) or Web browser.

Implementation Future DTMF based navigation Support for other media formats in rtspd Deployment Multimedia mail SIP retrieval

Conclusion SIP and RTSP - good framework for unified messaging Integration of voice/video mail/answering machine, , instant messaging, fax, etc.

Conclusion Wide range of applicability Campus/corporate network sipum rtspd Internet sipum Within a domain External application service provider