IMG 1010 - SUBCRIBE/NOTIFY Methods

Overview

The ability to request asynchronous notification of events proves useful in many types of SIP services for which cooperation between  end-nodes is required.  Examples of such services include automatic callback services (based on terminal state events), buddy lists (based on user presence events), message waiting indications (based on mailbox state change events), and PSTN and Internet Interworking (PINT) [2] status (based on call state events).

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