VoN Developers Conference -- July 2000 Introduction to IMPP Jonathan Rosenberg Chief Scientist

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP Role of a Presence Service Users Ask Service to Subscribe to Some Other User - Presentity Presence Service Service Asks Presentity to Authorize Subscription Acceptance Passed to Subscriber Service Remembers Other Subscriptions Presentity Tells Service of Change in Communications State Service Delivers Notifications to Subscribers

VoN Developers Conference -- July 2000 Introduction to IMPP Architectural Components User Agent Represents people Sends subscriptions Receives Notifications SUBSCRIBE Presence Server Repository of subscriptions Repository of presence state Proxy Servers Forwards subscription and notification messages Authorization Namespace division Load balancing

VoN Developers Conference -- July 2000 Introduction to IMPP Protocol Components Subscription Notification Publication Presence Data Format Watcher Data Format Subscription Data Format

VoN Developers Conference -- July 2000 Introduction to IMPP SUBSCRIBE Mechanism Naming and Routing Authentication of Subscriber Authorization from Presentity Acceptance/Rejection/Redirection to Subscription Opaque Subscription Document Details on filtering of notifications Description of precise event Soft State - Periodic Refresh Notification Address

VoN Developers Conference -- July 2000 Introduction to IMPP NOTIFY Mechanism Routing Transport of Opaque Presence Document Describes the presence state of presentity Correlation to Subscription Authentication of Presentity or its Server Encryption

VoN Developers Conference -- July 2000 Introduction to IMPP Publication Mechanism Want Many Possible Ways Distributed Publishers For One Presentity Wireless Phone PDA Laptop Desktop Authentication Naming Soft State Presentity Publisher

VoN Developers Conference -- July 2000 Introduction to IMPP Presence Data Format Describes State of Presentity Extensible Nested Data Baseline Information Set of communications means Voice, video, IM, Address for each mean URL Status for each mean Available, busy Capabilities busy

VoN Developers Conference -- July 2000 Introduction to IMPP Watcher Data Format Who is Subscribed to Someone Functions Status of my own subscription Who is subscribed to me? Administrator maintenance Extensible Baseline Information Subscriber Presentity Status of subscription Notification address Wed, 17 May :01:52 GMT

VoN Developers Conference -- July 2000 Introduction to IMPP Subscription Data Format Purpose Define types of events Define type of presence information to get Carried in SUBSCRIBE Extensible Baseline Information Type of status changes Type of communications means <event-filter type=allow priority=1> <presence-filter type=allow priority=1>

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP Session Initiation and Presence/IM Share Requirements cont. Security Privacy Access controls Authentication Carriage of MIME Data Extensibility

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP Transitioning PA from Server to Client User Agent Can Perform Notifications UA + PA = PUA Scalability Benefits Subscriptions Gradually Migrate to PUA As They Are Refreshed PA role is on a subscription by subscription basis Both presence server and PUA can be generating notifications for same PUA, but for different subscribers Rapid Migration Back to Presence Server If PUA Crashes SUBSCRIBE 200 OK REGISTER 200 OK NOTIFY 200 OK login SUBSCRIBE 200 OK PA migrated for this subscriber

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP How to Achieve Scale System Load Equation LOAD = PRESENTITIES X SUBSCRIBERS X NOTIFICATION RATE Three Primary Mechanisms Reduce Presentity Load Distribute namespace Reduce Subscriber Load Distribute state Reduce Notification Rate Push notifications to edges

VoN Developers Conference -- July 2000 Introduction to IMPP Distribute Namespace Break Large Domain Into Hierarchy of Subdomains Through Proxies Leaf Subdomains Handle Actual Presence Service for a Small Set of Users Minimal Involvement and Operation by Proxies Results in scale Mimics ibm.com a.ibm.com b.ibm.com Proxy Server Presence Server

VoN Developers Conference -- July 2000 Introduction to IMPP Distribute State Subscription State Can Be Distributed Presence server does not hold all subscriptions Each Domain Holds Subscriptions for All Users in Its Domain Single Subscription from Each Domain to Presentitys Domain Authorization an Issue Presence Server Presence Server Presence Server

VoN Developers Conference -- July 2000 Introduction to IMPP Push Notification to the Edges Internet Scalability Principle Smart end systems Stupid network Trying to Scale Any Other Way Does Not Work RSVP Diffserv Push Notifications to Clients Clients directly notify other clients Requires subscriptions to be known to clients Requires failover to network if client not available Presence Server Proxy Server

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP Advantages of Using SIP for Presence and IM Unifies Major Communications Services Voice/video IM Presence Shared Databases Shared Proxies Shared Servers

VoN Developers Conference -- July 2000 Introduction to IMPP 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

VoN Developers Conference -- July 2000 Introduction to IMPP IMPP Proposals Nine Separate Proposals Submitted for June 15th Deadline SIP (J. Rosenberg et. Al.), dynamicsoft, Cisco, Microsoft, Columbia U. IMXP (M. Rose, G. Klyne, D. Crocker) based on BXXP Privacy Enhanced Presence Protocol (PePP) - Fujitsu MIT Proposal (G. Hudson), MIT RSVP-PP - Real-Time Messaging Transport Protocol (A. Fanti) IMX - Architecture (not a protocol), AOL Jabber - (J. Miller), Jabber.org OneIM - (F. Mazzoldi, A. Diacakis), Network Projects, Inc. RVP - (R. Osborne et. Al.), Microsoft

VoN Developers Conference -- July 2000 Introduction to IMPP IMPP Proposals cont. IESG Completed Review of Proposals July 15 Summary of Recommendations Protocol should be compatible with SIP, allow SIP servers to be presence servers Protocol should be able to run ontop of a BXXP Mesh Protocol should not itself be based on SIP or RVP Protocol should be based on one of the other 7 proposals Proposal Being Debated (Heatedly) on List Hope is to Reach Consensus by Pittsburgh IETF

VoN Developers Conference -- July 2000 Introduction to IMPP Information Resource Jonathan Rosenberg