rn, be delay is the jitter buffer: Incoming audio is passed expressed in terms of users, applications, the time of day, through the jitter buffer and some amount of audio in- and monitor real-time applications. Policy-based network formation (PCM samples, say) is buffered up before rules configure (and reconfigure from time to time, as playing the samples out. If an incoming packet is delayed necessary) the network SO that its behavior carries out somewhat, then the information already in the buffer can the business needs. It implements the rules by config- be played out until either the buffer empties or the in- uring individual network devices to behave in accordance formation arrives. Because the packets are presumably with the network policies, typically utilizes a variety of coming at a fixed rate, when one or more packets arrive protocols, such as telnet/Command Line Interface, late, some subsequent packets should arrive "early" (or COPS, and SNMP, to communicate with network de- on time) to refill the buffer. If the buffer runs dry, some vices to achieve the desired configuration. The way type of audio fill-in must be supplied. As network jitter policy-based network management works, the rules are gets worse, the size of the jitter buffer must be increased generally stored in a directory with a schema designed to to avoid too many under-runs. Unfortunately, the use of support rule-based policy management. Each IP switch a jitter buffer introduces a delay proportional to the and router in the converged enterprise network should be buffer's target size. Some products (e.g., Microsoft able to be configured to provide a variety of services. NetMeeting) create an extremely large jitter buffer on These services provide low latency and constant delay as the order of 200-300 ms in order to handle jitter from is required for good voice quality. This service is generally virtually any type of connection, which introduces configured by assigning a particular queue(s) in the a "fixed" delay degradation of the conversa