r Edition) since late 2009 to fulfill this particular role. Session managers are similar to SBCs; however, they generally interact only with the sig- naling layer and not the media layer and can be used to invoke supplementary services independent of the final UC application. This area of session management is a growing area in the field of SIP trunks and is important because it provides a level of abstraction where each individual UC component can point to the session manager and the session manager can take advantage of the additional features of the session border controller as required. Figure 5-9 describes how a session manager is deployed in an enterprise UC network. Generally, Enterprise Session Management is only required for a large or medium network and is not a component that is deployed in SMB networks. 78 SIP Trunking Border Elements are always deployed in front Cisco IME allows for of SIP Trunk providers SIP Trunk Business to secure connections to and are optionally Providers Business other enterprises, UC deployed in front of IP infrastructure over the PBXs if media interworking Internet. Cisco IME is required. Enterprise Collaboration Platform (ECP) Session CUCU, Session Manager Manager edition, connects to various IP PBXs including Microsoft Enterprise Social and Avaya, as well as Networking Cisco and interworks with applications using Web 2.0 protocols and to the IP PBX from IP PBX from Enterprise Collaboration Vendor A Vendor B Platform (ECP). (for example, (for example, Avaya) Microsoft) Figure 5-9 The Role of Session Management in a Unified Communications Network Enterprise Networks-Application Interconnection Session Border Controller As enterprises grow larger, they typically have more than one UC application that can take advantage of SIP trunks. These applications can in some cases peer directly to one another; however, as the number of applications starts to increase, the number of peered connections also increases dramatically. One method to avoid this is the use of an appli- cation int