1. A system for use in a network connected to the Internet that provides streaming media in a plurality of media sessions between a media source connected to the Internet and a corresponding plurality of client devices connected to network, the system comprising: at least one computer processor; at least one network interface under the control of the at least one computer processor; and at least one memory, comprising: computer-executable instructions for implementing a policy repository, wherein the instructions for implementing the policy repository, when executed by the at least one computer processor, cause the at least one computer processor to store a plurality of media-centric policies; computer-executable instructions for implementing a media policy decision point, coupled to the network and the policy repository, wherein the instructions for implementing the media policy decision point, when executed by the at least one computer processor, cause the at least one computer processor to: receive media session data corresponding to one of the plurality of media sessions; determine a plurality of media session and non-media session attributes, based on the media session data; evaluate a plurality of media-centric policies; determine, based on evaluation of the plurality of media-centric policies, a proper subset of the plurality of media-centric policies that apply to the one of the plurality of media sessions, wherein each of the plurality of media-centric policies include a rule that includes a logical expression that defines when the rule is satisfied and an action, associated with the rule; and distinguish between attributes of the plurality of media session attributes that include a plurality of session-static attributes versus attributes of the plurality of media session attributes that include a plurality of session-dynamic attributes; and computer-executable instructions for implementing a media policy enforcement point, coupled to the network and to the media policy decision point, wherein the instructions for implementing the media policy enforcement point, when executed by the at least one computer processor, cause the at least one computer processor to enforce the proper subset of the plurality of media-centric policies to control the one of the plurality of media sessions based on changes in the at least one of the media session attributes and the outcome of the distinguishing between the attributes.