Presence and IM as SIP Services Jonathan Rosenberg Chief Scientist.

Presence and IM as SIP Services

Jonathan RosenbergChief Scientist

www.dynamicsoft.comSIP 2001 2.21Presence and IM as SIP Services

Presence as a Key Application Today, Presence is Just Online/Offline, Used for Instant

Messaging (IM)

Tomorrow, Will Describe Much More Than Online/Offline Status Presence is the dynamically changing set of means, willingness,

capabilities, characteristics and ability for users to communicate and interact with each other

The Means VoIP IM Mobile phone PSTN phone Email Games


Presence Tomorrow continued

Willingness “Only if urgent” “Try mobile phone first, then business line” “Always send email”

Capabilities and Characteristics Voicemail available Voice or video Mobile or fixed Support for multiple languages Secretary available Geographic locale


Presence: The Best Thing that Could Happen to Voice

Two Reasons Call completion Innovative services

Call Completion Problem A small fraction of calls result in useful conversations

Busy No Answer Voicemail Assistants “Call me back later”

Result is user frustration and no provider revenue


Presence: The Best Thing that Could Happen to Voice

Solution Only call if I know where the called party is available, when they are

available, and how they are available Presence conveys exactly this information Result: successful call completion rates can skyrocket!

Services Presence is one of the key enablers Examples...


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


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 email addresses into a

web form (1) Application subscribes to users (2) When all online, application calls

each participant (3), calls a conference bridge (4), connects them together Presence

HTTPSIP Calls

Application Server

Conference Server

Presence Server

1

2

4

3


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)


Session Initiation and Presence/IM Share Other Requirements

Security Privacy Access controls Authentication

Carriage of MIME Data

Extensibility


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

Registrar


Advantages of Using SIP for Presence and IM

Unifies Major Communications Services Voice/video IM Presence

Shared Databases

Shared Proxies

Shared Servers


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 email 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


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


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? QAUTH DIAMETER Local policy database

configured via web CPL


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


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 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


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


SIMPLE Group SIMPLE = SIP for Instant Messaging Leveraging Extensions

BoF Session Held at IETF 49 December 00 Chaired by Jon Peterson, Level(3) Clear consensus to move forward

IESG Officially Considering Charter at This Time

Charter Encompasses SIP for presence specification

Built off of CPIM and SIP event framework April 01

SIP for IM specification March 01

Information Resource Jonathan RosenbergChief Scientist+1 973.952.5060 [email protected]

Presence and IM as SIP Services Jonathan Rosenberg Chief Scientist.

Documents

sip services presence

sip services sip extension

available presence

presence agent

presence data

alignment of presence

use presence

sip network