erconnection SBC or enterprise session manager (discussed previously) within an enterprise. This application interconnection SBC has a function similar to a peering SBC in an SP. However, most of the requirements, when deployed in an enterprise, focus on intercon- necting the disparate signaling aspects of the various UC applications, and there is less of a concern around security between the applications because all the applications are under the control of the same information technology infrastructure. Generally, an application interconnection SBC connects internal applications such as an Interactive Voice Response (IVR) or voicemail system to the internal call agent that controls endpoints that create media steams. Chapter 5: Components of SIP Trunks The roll of an application interconnection SBC is generally being taken over by the enter- prise session manager. This is because a session manager can be optimized to deal with only the signaling issues that occur between the different UC components and can pro- vide the additional feature of the ability to invoke supplementary services. Enterprise Networks-Intercompany Media Engine A new technology that has recently been developed by Cisco is the Cisco Inter-Company Media Engine (IME). This technology allows for enterprises to connect to each other directly across the Internet with the use of the PSTN or a SP SIP Trunk as a backup con- nection and the use of the PSTN as a validation method for ensuring the correct routing. This technology takes advantage of new development techniques including peer-to-peer networking and advanced cryptography to ensure that as customers can deploy advanced UC applications within their enterprises, there is an secure and reliable method to extend these applications to other enterprise customers who have deployed similar technology across the Internet. The Cisco IME is shown in Figure 5-9. As of press time, the Cisco IME is still in the early deployment stage. Summary The components that make up a SIP trunk solution deployed by S