Sharmistha Chatterjee

1
Instant Messaging and Presence with SIP

• Sharmistha Chatterjee
• 82349D
• Helsinki University of Technology

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Topics

• Origin
• Features
• Subscribe/Notify
• Presence Server
• Message format
• Modes
• Provisioning
• Problems
• Security
• Implementations
• Conclusions

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SIMPLE

• Origin
• Originated from SIP (Session Initiation
  Protocol).
• Internet Engineering Task Forces SIMPLE working
  group formalized a set of backwards compatible
  extensions to SIP.
• This standard came to be known as SIMPLE(SIP
  Instant Messaging and Presence Leveraging
  Extensions).

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Features of SIMPLE

• SIMPLE ,extension of SIP is backward compatible.
• Presence data is centrally managed by the server
  by implementing SUBSCRIBE/NOTIFY.
• SIMPLE is used extensively in CRM applications
  for corporate Communications.
• Supports Instant Messaging during online gaming
  sessions.
• Supports Instant Messaging and Presence in
  mobile systems.
• Presence information enables automatic alerts
  and notifications to database queries via an
  instant messaging interface.

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SIMPLE SUBSCRIBE/NOTIFY

• User agent subscribes to a presence server for a
  limited period of time.
• Receives notifications from the presence server.
• Watcher Information Event generated allows
  authorization decision on requests.

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SIMPLE PRESENCE SERVER
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SIMPLE Message Format

• SIMPLE implements Presence Information Data
  Format (PIDF).
• CIPID Contact Information in Presence
  Information Data Format contains
  display-name,icon,map,sound.
• User Agent Capability SIP user agent reports
  technical capabilities of the device.
• RPID The Rich Presence Information Data format
  represents user mood and activity, physical
  properties such as location and environment

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SIMPLE Message Format

• Place-is
• Place-type
• Privacy
• Mood
• Relationship
• Activities
• User-input
• Partial Presence (PIDF-diff) Maintains recent
  information updates through versioning.
• Timed Presence Availability of the user.
• Location data Facilitates location-based
  services.

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Different modes of SIMPLE

• Page mode - Contains the contents of the instant
  message.Efficient for short messages.
• Session mode - Supports conferencing,long
  conversations.

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SIMPLE Provisioning

• Dynamic means of data management by XML
  Configuration Access Protocol (XCAP).
• Uses HTTP.
• Manages Buddy lists, privacy policies and offline
  presence status.
• Preserves entire list of changes through history
  of Etags.

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Federation

• Exchange of IM within a single domain(intra
  domain) or across multiple domains(inter
  domains).
• Main drawback of scaling.
• Huge amount of notification traffic.
• View sharing reduces subscription overhead.

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SIMPLE Problems

• Messages load Low Bandwidth and high latency.
• State management Huge complex state processing
  of all watchers.
• Processing complexities Frequent operations on
  all messages.
• Groups Ease of subsription creates large
  groups.
• Stopping notifications No method that a watcher
  could stop receiving notifications

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Privacy and Security

• XCAP and the presence server takes the role of
  providing privacy filtering.
• User Agent signs SIP message bodies using own
  certificates.
• SIP Identity header ensures notifications are not
  forged.
• Foreign domain presence server communicates over
  a secure TLS channel.
• S/MIME (Secure/Multipurpose Internet Mail
  Extensions) provides a consistent way to send and
  receive secure MIME data using RSA.
• Presence server maintains ACL(Access Control
  Lists).

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Implementations

• Agile Mobile SIP/SIMPLE Client Supports
  XCAP,multimedia instant messaging,group
  chat,presence management and contact list
  management.
• The SIP Communicator Allows block or ignore,
  contacts.
• SIMPLE Remote Monitoring System A user can
  remotely monitor presence at his home

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Conclusions

• SIMPLE using the framework of SIP serves a
  perfect building block for advanced communication
  systems in mobile environment.
• AOL introduced capabilities of tracking users
  having Wifi-----SIMPLE holds a promising future
  in next generation Instant Messaging.
• Better performance than XMPP.

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References

• Agile Mobile. http//www.agilemobile.com/simple.ht
  ml.
• SIP Communicator. http//sip-communicator.org/.
• Day, M., Rosenberg, J., and H. Sugano.,. A Model
  for Presence and Instant Messaging.,. RFC 2778,
  The Internet Engineering Task Force, February
  2000. http//ietf.org/rfc/rfc2778.txt.
• Rosenberg. Optimizing Federated Presence with
  View Sharing. Internet-draft, The Internet
  Engineering Task Force, July 2008.http//www.ietf.
  org/internet-drafts/draft-ietf-simple-view-sharing
  -01.txt.
• Rosenberg. Models for Intra-Domain Presence and
  Instant Messaging (IM) Federation.
  Internet-draft, The Internet Engineering Task
  Force, July 2008.http//www.ietf.org/internet-draf
  ts/draft-ietf-simple-intradomain-federation-01.txt
  .
• Schulzrinne, H.,. CIPID Contact Information in
  Presence Information Data Format.,
  draft-ietf-simple-cipid-04 . Rfc, The Internet
  Engineering Task Force, October 2005.
  http//tools.ietf.org/html/draft-ietf-simple-cipid
  -04.

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• Thank You
• Questions?