 much more sophisticated com- pression techniques that can allow us to make use of the even more limited wire- less spectrum to carry information. We will also need to move forward with Chapter 10 Next-Generation Networks introducing new generations of wireless technologies geared toward the support of multimedia capacities-a combination of intelligent spectrum use and highly effective compression-with support for the requisite variable QoS environment and strong security features. We will also need better compression techniques. Improvements in compression are on the way, as Table 10.1 illustrates. Delay and Jitter Along with their demands for SO much capacity, video and other real-time applica- tions such as audio and voice also suffer from delay (i.e., latency) and bit errors (e.g., missing video elements, synchronization problems, complete loss of the pic- ture). Delay in the network can wreak havoc with video traffic. The delay in a net- work increases as the number of switches and routers in the network increases. The ITU recommends a maximum delay of 150 milliseconds, and evolving agree- ments promise packet loss of 1% or less per month and a round-trip latency guar- antee of 80 milliseconds. However, the public Internet has as much as 40% packet loss during peak traffic hours and average latencies of 800 to 1,000 milliseconds. Although we really can't control the delay in the public Internet, we can engineer private IP backbones to provide the levels we're seeking. Jitter is another impairment that has a big impact on video, voice, and SO on. Jitter is introduced when delay does not remain the same throughout a network, SO packets arrive at the receiving node at different rates. Video can tolerate a small amount of delay, but when congestion points slow the buffering of images, jitter causes distortion and highly unstable images. Reducing jitter means reducing or avoiding the congestion that occurs in switches and routers, which in turn means having as many priority queues as the network QoS levels requir