Fall VoN 2000 SIP for IP Communications Jonathan Rosenberg Chief Scientist

Fall VoN 2000 SIP for IP Communications IP Communications Communications is more than just voice video IM presence wireless Presence and IM are of particular interest Question for discussion: What is SIPs role in presence and IM?

Fall VoN 2000 SIP for IP Communications Presence Today Also Known as Buddy Lists Indicates Online/Offline Status Largely to Enable IM Users Subscribe to Friends List When User is Online Click to send instant message Initiate voice chat (newer) When Friends Log On/Off, Notifications are Sent Sometimes User Status Can Be Indicated Busy, not at my desk Subscriber Publisher Notify Subscribe Publish Presence Server

Fall VoN 2000 SIP for IP Communications Presence Today cont. No Standard for IM or Presence Many Players (i.e., AOL, Yahoo and Tribal Voice) Each with Different, Non-interoperable Systems User Experience is Reduced Metcalfes Law Running many different applications IETF IMPP Group to Develop a Standard Solution Proposals Solicited for a Complete Solution at April 2000 Meeting A SIP Solution was Submitted Co-authors from dynamicsoft, Microsoft, Cisco and Columbia University

Fall VoN 2000 SIP for IP Communications Components of a Presence Solution Subscription Definition: to subscribe to some entity Requires huge scalability Distributed subscription state Lightweight transactions Authentication of subscribers Ability to convey complex subscription rules Routing and namespace partitioning

Fall VoN 2000 SIP for IP Communications Components of a Presence Solution cont. Publication Enables a user to send information to server for distribution Must be possible to have multiple entities publish for a single address My cell phone My IM client Describes communications means, state, capabilities and characteristics

Fall VoN 2000 SIP for IP Communications Components of a Presence Solution cont. Notification Rapid delivery of published data to subscribers Makes use of distributed subscription state Highly scalable Presence data changes often Many subscribers Must be able to convey a variety of presence data formats

Fall VoN 2000 SIP for IP Communications Session Initiation and Presence/IM Share Requirements Network Awareness of Presence State SIP for call routing Presence for distribution to subscribers Real Time Delivery Forwarding to Server Responsible for a User Scalability

Fall VoN 2000 SIP for IP Communications Session Initiation and Presence/IM Share Requirements cont. Security Privacy Access controls Authentication Carriage of MIME Data Extensibility

Fall VoN 2000 SIP for IP Communications SIP Already Provides Publication Capability REGISTER is a Publication Message for Locations Allows for SIP and Other URL Types Multiple Entities Can Publish for the Same Address SIP Caller Preferences Extension Allows for Attributes for Locations Mobile, landline Home, business Preferences Audio,video - MIME capability Registrar Client Registrar

Fall VoN 2000 SIP for IP Communications SIP Extension for Presence New Entity: Presence Agent Purely logical entity Knows presence state of user Receives SUBSCRIBE requests Generates NOTIFY requests Co-located with proxy/registrar or User Agent Basic Operation Subscriber send SUBSCRIBE Routed to PA using normal SIP PA authorizes subscriber Acceptance contains presence state NOTIFY sent when state changes Routed using SIP Record-Route REGISTER SUBSCRIBE NOTIFY Presence Agent + Proxy/Registrar = Presence Server Proxy Subscriber Presentity

Fall VoN 2000 SIP for IP Communications Features of SIP For Presence Extension End Users Can Perform Notifications Scalability Presence Agent Function Can Migrate Network provides service when user is offline When user is online, subscriptions migrate to user Offline Subscriptions Handled Presence server always asks user if a subscription should be accepted

Fall VoN 2000 SIP for IP Communications Features of SIP For Presence Extension cont. Multiple Entities Can Generate Presence Information for One Presentity Mobile phone, PDA, laptop and desktop PC Multiple Presence Clients Can Be Online at Once Traditional SIP Proxies Route SUBSCRIBE and NOTIFY Presence Data is Orthogonal

Fall VoN 2000 SIP for IP Communications SIP Extension for Instant Messaging Operation of Extension Messages carried in SIP messages New method - MESSAGE Routed to recipient using normal SIP techniques Simple extension Features Associates an IM with an existing call Any MIME data can be sent TCP for large messages Routed by existing proxies and registrars Possible to have a different client for IM and communications

Fall VoN 2000 SIP for IP Communications Advantages of Using SIP for Presence and IM Unifies Major Communications Services Voice/video IM Presence Shared Databases Shared Proxies Shared Servers

Fall VoN 2000 SIP for IP Communications Advantages of Using SIP For Presence and IM Reduces Management Costs One infrastructure instead of two One NOC instead of two One set of managers instead of two Enables New Combined Services Combined services integrate voice, video, IM, presence, web amd These new services will be a killer app for communications on the Internet Delivery of combined services is greatly facilitated by alignment of presence and communication signaling protocols

Fall VoN 2000 SIP for IP Communications Traffic Jam Alerts Uses Geographic Locale as Presence Component Mobile phone site location GPS Service Definition Turn on mobile phone in car As you drive, application server monitors location As you approach traffic, service will call you Voice response system reads out alternate route NOTIFY INVITE REGISTER Application Server Presence Server

Fall VoN 2000 SIP for IP Communications Auto Conference Problem: tough to get busy people into a conference call Solution: use presence to create the call when everyone is available! Procedure: Enter addresses into a web form (1) Application subscribes to users (2) When all online, application calls each participant, calls a conference bridge, connects them together Presence HTTP SIP Calls AS Conference Server Presence Server

Fall VoN 2000 SIP for IP Communications Information Resource Jonathan Rosenberg