Event%20notification%20and%20filtering

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Event notification and filtering

• Henning Schulzrinne
• Columbia University

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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

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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

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Presence data architecture
presence sources
PUBLISH
raw presence document
privacy filtering
create view (compose)
depends on watcher
XCAP
XCAP
select best source resolve contradictions
composition policy
privacy policy
(not defined yet)
draft-ietf-simple-presence-data-model
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Presence data architecture
candidate presence document
raw presence document
post-processing composition (merging)
watcher filter
SUBSCRIBE
remove data not of interest
difference to previous notification
final presence document
watcher
NOTIFY
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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