imum latencies and losses. CBR is the highest QoS you can get, and it is for very demanding applications, such as live media, streaming media, streaming audio, streaming video, and VOD. Initially, CBR was to be used for applications such as voice and videoconferencing, but we have found that those applications do not necessarily need the continuous band- width. As mentioned previously, much of a voice conversation is silence. If we were carrying that voice over CBR service, whenever there was silence, the ATM switches would be stuffing in empty cells to maintain that continuous bandwidth, and of course that would be overkill and a waste of network resources. Variable bit rate (VBR)-VBR has two subsets: real-time (VBR-RT) and non-real-time (VBR-NRT). VBR provides a fair share of available bandwidth according to a specific allocation policy, SO it has a maximum tolerance for latencies and losses. VBR is the highest QoS in the data realm, and it is also an adequate QoS for real-time voice. VBR-RT can be used by native ATM voice with bandwidth compression and silence suppression. So when some- body is silent, VBR-RT makes use of the available bandwidth to carry some- body else's cells, and therefore, VBR is also appropriate for multimedia functions such as videoconferencing. VBR-NRT can be used for data trans- fer where response time is critical (e.g., transaction-processing applications such as airline reservations, banking transactions). The Next-Generation Network Infrastructure Available bit rate (ABR)-ABR supports VBR data traffic with average and peak traffic parameters (e.g., LAN interconnection and internetworking ser- vices, LAN emulation, critical data transfer that requires service guaran- tees). Remote procedure calls, distributed file services, and computer process swapping and paging are examples of applications that would be appropriate for ABR. Unspecified bit rate (UBR)-You could call UBR poor-man's ATM. It pro- vides best-effort service. UBR offers no service guarantee, SO it is used for text data a