1. Making the phone not ring
Henning Schulzrinne
Department of Computer Science
Columbia University
Internet2 spring meeting
May 3, 2005 (Arlington, VA)
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2. Internet2 spring meeting
Overview
Ring-and-hope  presence-mediated communications
Uses for presence:
Old: “I’m on-line”
Location-based services
Presence-derived call handling
Presence-derived trust
Presence and privacy
Internet2 spring meeting

3. Context-aware communication
context = “the interrelated conditions in which something exists or occurs”
anything known about the participants in the (potential) communication relationship
both at caller and callee
time
CPL
capabilities
caller preferences
location
location-based call routing
location events
activity/availability
presence
sensor data (mood, bio)
privacy issues similar to location data
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4. Evolution of VoIP 1996-2000 2000-2003 2004- “does it do
“how can I make it
stop ringing?”
long-distance calling,
ca. 1930
“does it do
call transfer?”
going beyond
the black phone
“amazing – the
phone rings”
catching up
with the digital PBX
2004-
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5. Internet2 spring meeting
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
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6. Internet2 spring meeting
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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7. Internet2 spring meeting
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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8. Internet2 spring meeting
Presence data model
“calendar”
“cell”
“manual”
person
(presentity)
(views)
audio, video, text
video
services
devices
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9. Internet2 spring meeting
RPID = 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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10. The role of presence for call routing
PUBLISH
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) PA
NOTIFY
translate
RPID
CPL
LESS
INVITE
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11. Internet2 spring meeting
Presence and privacy
All presence data, particularly location, is highly sensitive
Basic location object (PIDF-LO) describes
distribution (binary)
retention duration
Policy rules for more detailed access control
who can subscribe to my presence
who can see what when
<tuple id="sg89ae">
<status>
<gp:geopriv>
<gp:location-info>
<gml:location>
<gml:Point gml:id="point1“
srsName="epsg:4326">
<gml:coordinates>37:46:30N 122:25:10W
</gml:coordinates>
</gml:Point>
</gml:location>
</gp:location-info>
<gp:usage-rules>
<gp:retransmission-allowed>no
</gp:retransmission-allowed>
<gp:retention-expiry> T04:57:29Z
</gp:retention-expiry>
</gp:usage-rules>
</gp:geopriv>
</status>
<timestamp> T20:57:29Z</timestamp>
</tuple>
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12. Location-based services
Finding services based on location
physical services (stores, restaurants, ATMs, …)
electronic services (media I/O, printer, display, …)
not covered here
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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13. Program location-based services
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14. 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
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15. Internet2 spring meeting
Conclusion
Media delivery  controlled interaction
Binary presence  rich presence
Presence as enabler of loosely-coupled advanced services
location-based services
serve as service script inputs
trust indicator for spit/spim prevention
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16. Internet2 spring meeting
Backup slides
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17. Presence data architecture
presence sources
PUBLISH
raw
presence
document
privacy
filtering
create
view
(compose)
depends on watcher
XCAP
select best source
resolve contradictions
XCAP
composition
policy
privacy
policy
(not defined yet)
draft-ietf-simple-presence-data-model
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18. Presence data architecture
candidate
presence
document
raw
presence
document
post-processing
composition
(merging)
watcher
filter
remove data not of
interest
SUBSCRIBE
difference
to previous notification
final
presence
document
watcher
NOTIFY
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19. Internet2 spring meeting
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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