Sharmistha Chatterjee 82349D 82349D Helsinki University of Technology Instant Messaging and Presence with SIP

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

SIMPLE  Origin  Originated from SIP (Session Initiation Protocol).  Internet Engineering Task Force’s 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).

Features of SIMPLE 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.

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.

SIMPLE PRESENCE SERVER

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

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.

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

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.

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.

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

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).

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

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.

R eferences 1.Agile Mobile. 2.SIP Communicator. 3.Day, M., Rosenberg, J., and H. Sugano.,. A Model for Presence and Instant Messaging.,. RFC 2778, The Internet Engineering Task Force, February Rosenberg. Optimizing Federated Presence with View Sharing. Internet-draft, The Internet Engineering Task Force, July sharing-01.txt. 5.Rosenberg. Models for Intra-Domain Presence and Instant Messaging (IM) Federation. Internet-draft, The Internet Engineering Task Force, July drafts/draft-ietf-simple-intradomain-federation-01.txt. 6.Schulzrinne, H.,. CIPID: Contact Information in Presence Information Data Format., draft-ietf-simple-cipid-04. Rfc, The Internet Engineering Task Force, October

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