| 摘要 |
<p>Session Initiated Protocol (SIP) is used to communicate with Network-capable appliances by leveraging SIP capabilities to directly communicate with appliances, even when they are behind firewalls (116), Network Address Translators or other entities that prevent direct end-to-end communication. A remote user agent client (UAC) (100) sends a message over the Internet via proxy servers (116) to a user agent server (204) at the location of the appliances, e.g., the client's home. This communications channel allows the client to control the appliances and to determine their status. In order to enable this operation, conventional SIP messages are extended to a DO message that includes a universal resource locator (URL) without location information otherwise specific in the SIP message and a generalized payload body with control and/or query instruction specific to networked appliances. When the command message is a SIP INVITE type, it includes a description of the appliance.</p> |
