uni- cate. In this case, you might have a trunking solution between the high-security devices and the lower-security devices. Different Features: Finally, the largest difference that occurs within an enterprise is the features required by various groups. These diverse features necessitate differing call control environments and, as such, a trunking solution between them is required. Trunking solutions are always required in an enterprise. As a result, a number of trends in these trunking solutions are important to understand. One trend that occurs in an enter- prise is the trend toward trunking different UC solutions with SIP trunks. SIP trunks pro- vide a widely acceptable and standardized method to get at least basic connectivity between a wide range of different call control solutions including both voice and video. The trend toward utilizing SIP within the enterprise as the default method to trunk differ- ent call control mechanisms is replacing both TDM trunks and H.323 trunks between these devices. A second major trend for trunking in enterprise is the more extensive use of video. Video solutions range from desktop video, to low-cost room-based video, to high-end Telepresence solutions. These video solutions have developed at different stages with the earliest H.320-based ISDN solutions still used in many cases today. Because of this wide variety of video solutions, there is a requirement for a method to interconnect these together. This is a major trend in enterprise SIP trunking as a method for interconnecting disparate video communications technologies. One of the major challenges that exists today is that these technologies do not natively use SIP; therefore, a great deal of inter- working with older technologies occurs, such as H.320 and H.323 that is required. Finally, the third major trend for enterprise trunking solutions is the nonvoice/video traf- fic between different areas of call control that need to be interconnected. These areas include traffic such as instant messaging traffic and presence i