Simple Object Access Protocol, is a protocol specification for exchanging structured information in VoIP computer networks. It relies on Extensible Markup Language (XML) as its message format, and usually relies on other Application Layer protocols (in this case, HTTPS message negotiation and transmission). SOAP is used to periodically monitor the data retained by the Cisco Unified Call Management application.

As with any HTTPS implementation, VoIP Availability Manager requires device access credentials to be entered by the user. Passwords are always encrypted and along with the entered user ID are provided to the Cisco Call Manager prior to requesting its data. VoIP Availability Manager repeatedly requests IPPhone registration status data from the Cisco Call Manager and stores it to monitor IP phone availability.