SIP and Instant Messaging

SIP Summit SIP and Instant Messaging What Does Presence Have to Do With SIP? How to Deliver Presence Need a network that can identify users independent of location Need a way to forward subscription requests to server handling that user Need a way for user to tell server its location and other presence data Need a network which can forward notifications to subscribers Needs to scale Needs to deliver messages in real time What Does a SIP Network Do? Identifies users independent of location Forwards requests (INVITE or otherwise) to server handling user REGISTER allows network to tell server its location and other information Can forward messages back to originators in reverse direction Scales Delivers messages in real time (call setup delays)

SIP Summit SIP and Instant Messaging Session Initiation and Presence/IM Share Other Requirements Security Privacy Access controls Authentication Carriage of MIME Data Extensibility

SIP Summit SIP and Instant Messaging 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

SIP Summit SIP and Instant Messaging Advantages of Using SIP for Presence and IM Unifies Major Communications Services Voice/video IM Presence Shared Databases Shared Proxies Shared Servers

SIP Summit SIP and Instant Messaging 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 and 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 Applications will be the clients of presence, not people

SIP Summit SIP and Instant Messaging 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

SIP Summit SIP and Instant Messaging Important Details Subscriptions Refreshed Expires mechanism, same as with REGISTER, determines lifetime Subscription Has INVITE Semantics for Record-route/ Contact Processing SUBSCRIBE creates a session Refreshes have same Call-ID, as do Notifications Intermediate entities can record-route Body of NOTIFY Contains Presence Data Authorization and Access Controls Are Orthogonal Presence agent sends 200 OK if subscription is accepted How it determines whether to accept? DIAMETER Local policy database configured via web CPL

SIP Summit SIP and Instant Messaging 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 Authorization from User Can Be Obtained by Presence Server

SIP Summit SIP and Instant Messaging Features of SIP For Presence Extension continued 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

SIP Summit SIP and Instant Messaging 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 Can also use SIP to establish messaging session On same level as RTP Can apply SIP tools – multiparty, transfers, etc. Features Associates an IM with an existing call Any MIME data can be sent Routed by existing proxies and registrars Possible to have a different client for IM and communications

SIP Summit SIP and Instant Messaging What Is Happening in the IETF? Instant Messaging and Presence Working Group (IMPP) Could not come to consensus on a single proposal Chartered to develop CPIM – Common Presence and Instant Messaging – common pieces across all protocols Presence data format Other groups will be chartered to do protocols Application Exchange (APEX) Formerly IMXP Does IM and presence on top of a BEEP Mesh BEEP = Blocks Extensible Exchange Protocol XML protocol for application frameworks Presence and IM (PRIM) Not clear it will be chartered From scratch TCP protocol, much like SIP SIMPLE

SIP Summit SIP and Instant Messaging SIMPLE Group SIMPLE = SIP for Instant Messaging Leveraging Extensions Working group approved February 2001 Co-chaired by Jon Peterson, Level(3) Co-chaired by Robert Sparks, dynamicsoft Charter Encompasses SIP for presence specification Built off of CPIM and SIP event framework May 01 SIP for IM specification May 01

SIP Summit SIP and Instant Messaging Auto-Conference Web form with users POSTED to controller Presence HTTP IM SIP Call Application Server Conference Server Presence Server Media Server Controller initiates SUBSCRIBE session with presence server On NOTIFYs update presence When all online Send IM to some with HTTP URL for accept Use 3pcc to connect others to MS HTTP POST of each accept/reject Use 3pcc to connect each to same conference URL MS fetches VoiceXML from AS

Information Resource Jonathan Rosenberg