Service provider functionality with policy enforcement functional layer bound to SIP

A system comprising:

• a communication network;
• a first communication node communicatively coupled with the communication network and adapted to send messages via the communications network;
• a second communication node communicatively coupled with the communication network and adapted to receive the messages from the first communication node;
• and
• a policy enforcer communicatively coupled with the communication network and adapted to identify a type of communication represented by the messages, determine one or more policies applicable to the communication represented by the messages based on the type of communication, and enforce the policies to provide one or more enhanced features, wherein the type of communication comprises one or more of a session control message, a routing message, a call control message, and a media exchange, wherein the one or more enhanced features include features for providing security, identity management, and telephone functions to a Voice Over Internet Protocol (VoIP) service, wherein enforcing the policies on exchanges between the parties to provide the one or more enhanced features includes modifying a target address for the exchanges, and wherein enforcing the policies delegating at least one enforcement task to the first communication node or the second communication node.

A system comprising:

• a communication network;
• a first user agent of a first endpoint device communicatively coupled with the communication network and adapted to send messages via the communications network;
• and
• a second user agent of a second endpoint device communicatively coupled with the communication network and adapted to receive the messages from the first user agent, wherein the second user agent includes a policy enforcer adapted to identify at least one of the first user agent and the second user agent, identify a type of communication represented by the messages, wherein the type of communication comprises one or more of a session control message, a routing message, a call control message, and a media exchange, determine one or more policies applicable to the communication represented by the messages based on the type of communication, and enforce the policies to provide one or more enhanced features wherein the one or more enhanced features include features for providing security, identity management, and telephone functions to a Voice Over Internet Protocol (VoIP) service, wherein enforcing the policies on exchanges between the parties to provide the one or more enhanced features includes modifying a target address for the exchanges, and wherein enforcing the policies on the exchanges between parties comprises delegating at least one enforcement task to the first user agent.