Action Referral in the Session Initiation Protocol (SIP)
Avaya
Cisco Systems
Avaya
Skype
This specification defines action referral that allows an application to make a high level request to a User Agent to perform an action, and let the the User Agent execute the action as it sees fit. Action referral uses the SIP REFER method with a Refer-To header field containing a URN, which indicates the requested action. This specification also defines the option tag 'action-ref' to allow the UA to indicate its support for action referral.