ays due concerns arise when data networks are business critical, to loading can be reduced by giving audio packets priority such is true for a bank teller or online book ordering. service over other network traffic. Various methods of There can be little doubt that the quality of the network prioritization are in use by vendors: explicit priority is very important, almost as important as quantity in labeling (e.g., 802. 1p or DiffServ), or via address rec- some cases. The lack of adequate QoS can rapidly ognition (source/destination address preferences or port become a business inhibitor. Why then is there a sudden number preferences). Audio compression and packeti- interest in dynamic QoS management for enterprise zation also contribute to latency. Most coders operate on networks? Nothing about the traffic or its value has an audio sample interval or frame, typically 10 ms. One changed, although new forms of digitized traffic (such as or more encoded frames is then assembled into a packet video) have become available. What is different is that for transmission (multi-frame packets reduce overhead). the underlying enterprise network technology is changing This represents a delay of one or more frame times. So it (to the TCP/IP architecture pioneered by the Internet) is crucial to monitor and control latency on your con- and the desire is now to "converge" all forms of traffic verged network. onto a single TCP/IP-based infrastructure. Convergence is aimed at reducing costs and complexity, increasing operational and managerial efficiency, and opening the Quality of service door for innovative new multimedia applications. The Virtually all modern networks use a layered protocol original TCP and IP protocols were designed for appli- structure with each higher layer taking on more re- cations such as e-mail distribution, basic file transfer, and sponsibility for successful end system interworking. QoS remote terminal access, none of which were particularly mechanisms can be incorporated at any layer (or, in fact, time