11/6/20061 Presence By, Ram Vaithilingam

11/6/20062 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

11/6/20063 Evolution of Communication “amazing – the phone rings” “does it do call transfer?” “how can I make it stop ringing?” catching up with the digital PBX long-distance calling, going beyond the black phone

11/6/20064 Collaboration in transition intra-organization; small number of systems (meeting rooms) inter-organization multiple technology generations diverse end points proprietary (single- vendor) systems standards-based solutions

11/6/20065 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.”

11/6/20066 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 , with a corporate address list.

11/6/20067 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.

11/6/20068 Rich presence unifies interaction across media and devices

11/6/20069 Presence (availability) of multiple media facilitates the initiation or escalation to multimedia

11/6/ 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  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

11/6/ 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

11/6/ The presence pyramid represents group, user, and device presence.

11/6/ 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 .  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).

11/6/ 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 or voice mail. Alternatively, a mood indicator could automatically reroute messages — for example, from an IM to — 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.

11/6/ Presence Service

11/6/ 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.

11/6/ 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.

11/6/ 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.

11/6/ Presence data architecture raw presence document create view (compose) privacy filtering draft-ietf-simple-presence-data-model composition policy privacy policy presence sources XCAP (not defined yet) depends on watcher select best source resolve contradictions PUBLISH

11/6/ Presence data architecture candidate presence document watcher filter raw presence document post-processing composition (merging) final presence document difference to previous notification SUBSCRIBE NOTIFY remove data not of interest watcher

11/6/ 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, …)

11/6/ 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

11/6/ 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 translate RPID CPL PA PUBLISH NOTIFY INVITE

11/6/ 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

11/6/ 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 to nearest  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

11/6/ Location detection

11/6/ 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

11/6/ 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

11/6/ 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

11/6/ Presence for spam prevention  VoIP spam (“spit”) and IM spam (“spim”) likely to be more annoying than 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

11/6/ 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 et al) 3GPP (for 3G wireless) PacketCable  About 100 companies produce SIP products  Microsoft’s Windows Messenger (≥4.7) includes SIP

11/6/ 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)

11/6/ Advantages of Using SIP for Presence and IM  Unifies Major Communications Services Voice/video IM Presence  Shared Databases  Shared Proxies  Shared Servers

11/6/ RPID: rich presence

11/6/ 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/ References  Bhagavath, Vijay K., "How to Make VoIP Successful," Dec Forrester Research report.  Bhagavath, Vijay K., "Second Generation VoIP," Sep 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.