Why Is Traffic Management Required in the ATM WAN?
For ATM applications in the LAN or campus environment, ATM performance issues can be easily addressed with additional bandwidth. In this environment, bandwidth is a relatively cheap and readily available resource. When increasing traffic patterns lead to cell loss and degraded performance, network managers add additional fiber or implement faster interface speeds. In the WAN environment, however, bandwidth continues to be a costly resource that must be used as aggressively as possible to boost network efficiency and reduce network operating costs. Thus, mechanisms that use existing capacity more efficiently are crucial, as shown in Figure 1. If those mechanisms deliver predictable performance under all circumstances and enhance application throughput significantly even better. That’s exactly what traffic management mechanisms deliver in the ATM WAN. Figure 1: ATM WAN Switch Requirements In the ATM WAN, the most constricted bandwidth, coupled with a higher overall network latency, drive
