given below: • Interface to SIP-enabled endpoints, such as SIP hard phones, SIP softphones, personal data assistants (PDAs), and wireless phones. • Call/session control, for example, interface to media gateway controllers, softswitches, proxies. • Media service control, for example, interface to media gateways and media servers. • Service control, for example, interface to application servers and services mediation functions. • Service creation/authoring, for example, support of call processing language (CPL), common gateway interface (CGI), and servlets [16, 26]. • Intelligent network/Internet protocol (IN/IP) internet-working, for example, the SIP-based Services in the PSTN/IN Requesting Internet Services The session initiation protocol (SIP) is a unifying protocol for providing integrated telephony and Internet types of services, such as Web, presence, instant messaging, and chat. To provide for the integration of these disparate types of services, considerations must be given from a network point of view. However, little attention has been given in the literature to identify the network elements required to provide these services or the mechanisms for integrating these different types of services for end users. This paper describes a network-level services architecture for SIP, including network functions and entities needed to support the services integration. We will discuss how services can be incorporated at different levels in the network, and the types of services typically created at each of these levels. We will also describe a service access and mediation function, which blends disparate types of services in creating a seamless and rewarding user experience.