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References:
IETF RFC 2778 and 2779

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Posted by george99

• In the group of protocols known as Instant Messaging and Presence (IMP)
• “A presence and instant messaging [IMP] system allows users to subscribe to each other and be notified of changes in state, and for users to send each other short instant messages.” (IETF 2778)
• Uses Subscribe and Notify SIP methods to update a database
Terms
• Presentity – Provides presence information to be stored and distributed
• Watcher – receives information from the service
• Fetcher – Requests current values from the Presentity
• Poller – Special case of a fetcher, requests information on a regular basis
• Subscriber – Requests notification of a future change in status (usually a UAC)

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Posted by yogendra

In computing, SIMPLE (Session Initiation Protocol for Instant Messaging and Presence Leveraging Extensions) is an instant messaging (IM) and presence protocol suite based on Session Initiation Protocol (SIP). Like XMPP, and in contrast to the vast majority of IM and presence protocols used by software deployed today, SIMPLE is an open standard. Both are IETF standards or proposed standards.

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Posted by sagitraz