 3G-324M. The modifications were made mainly in codec requirements, the network interface, and call control. Among other things, interoperability will be required to enable cus- tomers with new SIP phones to call customers using the older 3G-324M handsets. The migration to SIP is now inevitable, thanks to the introduction of three new ingredients for packet-based high-quality mobile live video: IMS-As discussed earlier in this chapter, IMS will provide a more efficient IP backbone to support real-time and multimedia applications, including video over IP. High-Speed Downlink Packet Access (HSDPA)-As discussed in Chapter 14, HSDPA vastly improves the access link. Mobile phone chipsets-Mobile phone chipsets capable of processing video at 30fps make the video-viewing experience akin to what we are used to with movies and television. However, there remains the major issue of latency in the IP network itself. The key factor for live video is the round-trip time (RTT), which ideally should be less than 80 milliseconds. Currently, average response times range from 100 to 500 milli- seconds (depending on the world region), which means that during busy times, latencies can easily be over 1,000 milliseconds. The Internet Traffic Report Web site (www.internettrafficreport.com/main.htm) contains reports on the current per- formance of major Internet routes around the world and includes statistics on latencies and packet loss. The future of mobile video goes far beyond video telephony. Live video is expected to become the basis for a wide range of potential 3G revenue producers, including security camera feeds, video chat, video-enabled call centers, video shar- ing, and music videos. In support of these advanced services, operators need to measure not just QoS but the quality of the experience. Mobile TV Many analysts see a strong market for mobile TV, provided that it is packaged and priced correctly, but others offer a much more conservative viewpoint. Mobile TV broadcasts have started in South Korea, Japan, and the United 