Admission control for hard real-time connections in ATM LAN's

A CAC algorithm must efficiently determine if a new connection can be admitted by verifying that its QoS requirements can be met without violating those of previously admitted connections. In hard real-time systems, the QoS requirements are specified in terms of end-to-end cell deadlines and no cell loss due to buffer overflow. A CAC algorithm must account for interdependencies among connections caused by sta-tzstical multiplexing of cells in ATM networks. Arbi-trarity of network topology may lead to cyclic depen-dencies among various connections. We present an eficient CAC algorithm that addresses the above is-sues. The algorithm uses a traffic descriptor called the maximum traffic rate function to effectively com-pute bounds on end-to-end delays of connections and buffer requirements within the network. Our work dif-fers from most previous work in that it does not require traffic restoration inside the network.