of calls; however, instead of the media being hairpinned at the enterprise location, it is optimized in the network. This optimization leads to better call quality (lower latency) and lower bandwidth utilization. Phase IV: SNR services enabled at the SP. This phase is more controversial because it changes the place in the network where the forking occurs from the enterprise con- trol to the SP. At this phase, the SP knows that a certain cellular phone is the same as a certain enterprise phone number and rings both. This service is popular among smaller deployments in which the power and control of the enterprise dialing plan is easy to move into the SP, but as companies grow larger, it is controversial as to whether to allow the SP to make the decision to fork the call before it comes into the enterprise. In summary, the use of cellular phones as an alternative to desk phones will continue, and the major effect on the trunking solutions is how this SNR capability will be imple- mented. Endpoint Trends in Enterprises and Their Effects on SIP Trunk The changes in the endpoints at enterprises will have a direct and significant impact on the SIP trunking services that SPs will offer and customers will consider purchasing. Table 2-1 summarizes these trends. 20 SIP Trunking Table 2-1 Endpoint Trends and Effects on SIP Trunking Endpoint Trend Effect on SIP Trunking Service Offered by SPs Desktop Advanced functionality and new features Advanced services need to be offered to handset that take advantage of the faster CPU and take advantage of the advanced capabili- advanced screen capabilities. Color ties of the endpoints. Calls with subject phones, touch screens, and more PC-like lines, video calls, and wideband codecs. capabilities have become the norm in desktop phones. Softphones Softphones become more widely New features are offered that take advan- adopted because of lower cost and tage of these capabilities. Codec selec- wide availability of PCs. tion based on available bandwidth, location-based services, and wide 