1. Event notification and filtering
Henning Schulzrinne
Columbia University

2. Event notification
Core coordination tool for real-time decision making
coordinating human availability
distributing events of interest
coordinating devices
Lots of event notification systems for small or closed systems (e.g., SIENA, Gryphon)
emphasis on large-scale message replication and routing
Less emphasis on higher-level functions:
composition of messages
filtering
access control

3. Internet event notification
Assume relatively small fanout for each message (dozens)
Domain-based publish/subscribe/notify
Developed and standardized based on SIP/SIMPLE suite of protocols

4. 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

5. 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

6. Objectives
How to discover relevant and accessible (need-to-know) event sources?
Composing events from tributary streams of events
Aggregating event information over time
avoid flooding incremental event updates, e.g., no need for 10m updates on location