11/6/2006 1

Presence

By,Ram Vaithilingam

11/6/2006 2

Philosophy transition

One computer,many users

One computer,one user

Many computers,one user

anywhere,any time

any media

right place (device),right time,right media

~ ubiquitous computing

mainframe era

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Evolution of Communication

“amazing – thephone rings”

“does it docall transfer?”

“how can I make itstop ringing?”

1996-2000 2000-2005 2005-

catching upwith the digital PBX

long-distance calling,going beyond

the black phone

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Collaboration in transition

intra-organization;

small number of systems

(meeting rooms)

inter-organization

multiple technology generationsdiverse end

points

proprietary (single-vendor)

systems

standards-based solutions

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Presence

“In the field of communication, presence is the ability of a person or device to communicate with others and to display levels of availability. Presence awareness, a closely related concept, is the knowledge of the person or device’s presence.”

11/6/2006 6

Presence in IM

Most people know about presence in a limited sense, through consumer IM services. In consumer IM, presence technology shows whether the PC of someone on a user's "buddy list" is online, and the buddy may set automatic notifications, such as when the PC is idle for a certain amount of time.

Disadvantages:This information is partial and can be deceptive — the buddy's PC may be online even when the person has left the building. In addition, this use of presence technology has been limited to a single application (IM), and it works person-to-person, rather than as a companywide medium, such as e-mail, with a corporate address list.

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Why Presence?

Presence technology is capable of indicating a much wider range of information, which will depict the situation that people are really in, not simply what's going on with their systems. Therefore, a user can judge more accurately what kind of interaction someone else is capable of having at the moment.

Example: Someone in a meeting with a cell phone may answer a quick question on IM, but contacting him or her for help in revising a document could be disruptive, thereby delaying the revisions.

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Rich presence unifies interaction across media and devices

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Presence (availability) of multiple media facilitates the initiation or escalation to multimedia

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The role of presence

Guess-and-ring high probability of failure:

“telephone tag” inappropriate time (call

during meeting) inappropriate media (audio

in public place) current solutions:

voice mail tedious, doesn’t scale, hard to search and catalogue, no indication of when call might be returned

automated call back rarely used, too inflexible

most successful calls are now scheduled by email

Presence-based facilitates unscheduled

communications provide recipient-specific

information only contact in real-time if

destination is willing and able

appropriately use synchronous vs. asynchronous communication

guide media use (text vs. audio)

predict availability in the near future (timed presence)

Prediction: almost all (professional) communication will be presence-initiated or

pre-scheduled

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Basic presence

Role of presence initially: “can I send an instant message and

expect a response?” now: “should I use voice or IM? is my call going to

interrupt a meeting? is the callee awake?” Yahoo, MSN, Skype presence services:

on-line & off-line useful in modem days – but many people are

(technically) on-line 24x7 thus, need to provide more context

+ simple status (“not at my desk”) entered manually rarely correct does not provide enough context for directing

interactive communications

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The presence pyramid represents group, user, and device presence.

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Presence technology can indicate:

Status — Based on each user's behavior, updates in real time can indicate, for example, whether a user is online or offline, busy or free, in a meeting, on call or at lunch. Links to the user's calendar might trigger status updates.

Connection — Presence technology can indicate which connections are available to the user (for example, mobile communications, Internet or voice).

Device — Information about which devices are available to the user can help decisions regarding the medium to use. For example, if a user only has a mobile phone, a Short Message Service (SMS) communication would work better than an e-mail.

Application — Presence technology can report which applications and documents users have open at a given time, which ones they're using and what they're doing (typing, for example).

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Presence technology can indicate:

Location — A user can manually provide information about his physical location, or global positioning satellites and other location technologies can detect it automatically (see"When to Seek High Accuracy in Mobile Location Services").

Mood — A recipient's mood indicator (such as, rushed) would enable senders to choose the most appropriate means of communication, such as e-mail or voice mail. Alternatively, a mood indicator could automatically reroute messages — for example, from an IM to e-mail — if the recipient has requested it.

Preferences — Profile information dictates users' preferences about how they wish to be contacted, depending on the scenario. For example, users could direct people to call the office phone when they're at work and send an SMS when they're traveling.

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Presence Service

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Presence Service – 1/3

The Presence Service has two distinct sets of "clients".

One set of clients, called Presentities, provides Presence Information to be stored and distributed.

The other set of clients, called Watchers, receives Presence Information from the service.

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Presence Service – 2/3

There are two kinds of Watchers, called Fetchers and Subscribers.

A Fetcher simply requests the current value of some Presentity's Presence Information from the Presence Service.

A Subscriber requests notification from the Presence Service of (future) changes in some Presentity's Presence Information.

A special kind of Fetcher is one that fetches information on a regular basis: a Poller.

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Presence Service – 3/3

The Presence Service also has Watcher Information about Watchers and their activities in terms of fetching or subscribing to Presence Information.

The Presence Service may also distribute Watcher Information to some Watchers, using the same mechanisms that are available for distributing Presence Information.

Changes to Presence Information are distributed to Subscribers via Notifications.

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Presence data architecture

rawpresencedocument

createview

(compose)

privacyfiltering

draft-ietf-simple-presence-data-model

compositionpolicy

privacypolicy

presence sources

XCAP XCAP

(not defined yet)

depends on watcherselect best sourceresolve contradictions

PUBLISH

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Presence data architecture

candidatepresencedocument

watcherfilter

rawpresencedocument

post-processingcomposition(merging)

finalpresencedocument

differenceto previous notification

SUBSCRIBE

NOTIFY

remove data not of interest

watcher

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Rich presence More information automatically derived from

sensors: physical presence, movement electronic activity: calendars

Rich information: multiple contacts per presentity

device (cell, PDA, phone, …) service (“audio”)

activities, current and planned surroundings (noise, privacy, vehicle, …) contact information composing (typing, recording audio/video IM, …)

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Rich presence

Provide watchers with better information about the what, where, how of presentities

facilitate appropriate communications: “wait until end of meeting” “use text messaging instead of phone call” “make quick call before flight takes off”

designed to be derivable from calendar information or provided by sensors in the environment

allow filtering by “sphere” – the parts of our life don’t show recreation details to colleagues

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The role of presence for call routing Two modes:

watcher uses presence information to select suitable contacts advisory – caller may

not adhere to suggestions and still call when you’re in a meeting

user call routing policy informed by presence likely less flexible –

machine intelligence “if activities indicate

meeting, route to tuple indicating assistant”

“try most-recently-active contact first” (seq. forking)

LESS

translateRPID

CPL

PA

PUBLISH

NOTIFY

INVITE

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Location-based services Finding services based on location

physical services (stores, restaurants, ATMs, …) electronic services (media I/O, printer, display,

…)

Using location to improve (network) services communication

incoming communications changes based on where I am configuration

devices in room adapt to their current users awareness

others are (selectively) made aware of my location security

proximity grants temporary access to local resources

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Location-based SIP services Location-aware inbound routing

do not forward call if time at callee location is [11 pm, 8 am] only forward time-for-lunch if destination is on campus do not ring phone if I’m in a theater

outbound call routing contact nearest emergency call center send delivery@pizza.com to nearest branch

location-based events subscribe to locations, not people Alice has entered the meeting room subscriber may be device in room our lab stereo changes

CDs for each person that enters the room

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Location detection

SIP UAGPS

receiver

Bluetooth

DHCPserver

swipecard

activebadge

manually

SUBSCRIBE

NOTIFY

Locationserver

iButton

PUBLISH

WiFi

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Location-based service language

false

true

NOTIFY

action alert

conditions

proximity

occupancy

time

IM

actions

alert

message

log

call

transfer

join

events

incoming

outgoing

notify

message

subscription

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Session mobility Walk into office, switch

from cell phone to desk phone call transfer problem

SIP REFER related problem: split

session across end devices e.g., wall display +

desk phone + PC for collaborative application

assume devices (or stand-ins) are SIP-enabled

third-party call control

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How to find services? Two complementary developments:

smaller devices carried on user instead of stationary devices devices that can be time-shared

large plasma displays projector hi-res cameras echo-canceling speaker systems wide-area network access

Need to discover services in local environment SLP (Service Location Protocol) allows querying for services

“find all color displays with at least XGA resolution” slp://example.com/SrvRqst?public?type=printer

SLP in multicast mode SLP in DA mode

Need to discover services before getting to environment “is there a camera in the meeting room?” SLP extension: find remote DA via DNS SRV

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Presence for spam prevention VoIP spam (“spit”) and IM spam

(“spim”) likely to be more annoying than email spam

Subscription to another person is indication of mutual trust other person allows me to see their

status trusts me Thus, use watcher list (who is

watching me) as trust vector

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What is SIP? Session Initiation Protocol protocol that

establishes, manages (multimedia) sessions also used for IM, presence & event

notification uses SDP to describe multimedia sessions

Developed at Columbia U. (with others) Standardized by

IETF (RFC 3261-3265 et al) 3GPP (for 3G wireless) PacketCable

About 100 companies produce SIP products Microsoft’s Windows Messenger (≥4.7)

includes SIP

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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)

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Advantages of Using SIP for Presence and IM

Unifies Major Communications Services Voice/video IM Presence

Shared Databases

Shared Proxies

Shared Servers

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RPID: rich presence

<person> <tuple> <device><activities>

<class>

<mood>

<place-is>

<place-type>

<privacy>

<relationship>

<service-class>

<sphere>

<status-icon>

<time-offset>

<user-input>

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Questions

What is presence? What are the different applications of

presence in the field of communication?

List some possible information that could be obtained by using presence?

11/6/2006 36

References Bhagavath, Vijay K., "How to Make VoIP Successful," Dec. 2002

Forrester Research report. Bhagavath, Vijay K., "Second Generation VoIP," Sep. 2003 Forrester

Research report. Golvin, C., "This is Not Your Teenager’s IM,“ Forrester report. Advanced Multimedia and Presence Services using Classical and P2P

SIP, Henning Schulzrinne. Develop a Strategy for Presence Technologies David Mario Smith,

Matthew W. Cain, Lou Latham, Betsy Burton. SIP and Instant Messaging, Dynamic Soft. Presence-Aware Communications, Siemens.