In earlier papers, we proposed the PCC (parallel connection control) algorithm for the setup and release of on-demand ATM (asynchronous transfer mode) connections. This paper describes an implementation and analysis of PCC. The PCC algorithm is implemented on a testbed of three types of ATM switches from which service time measurements (software execution times) are obtained. These measured service times are used as input data for an analytical queueing network model to characterize the PCC end-to-end setup delay and maximum throughputs. Assuming all connections pass through ten switches, for this measured data, PCC has a theoretical maximum throughput of 343 calls/sec/switch, and at about 90% of this maximum limit (i.e., at 310 calls/sec/switch), the mean end-to-end connection setup delay is only 43 ms. We also compare PCC performance against an equivalent sequential connection setup/release approach. We observe that PCC end-to-end setup delay is much smaller than the sequential setup delay (34% at low load and even smaller at higher load). Also, the per-switch maximum throughput of the PCC approach is 80% more compared to the sequential approach.

A common approach used for decreasing end-to-end connection setup delay in ATM networks is to provision partial segments a priori using virtual path connections (VPCs). In this paper, we present an analysis to study the effect of such provisioning. The analysis demonstrates that significant savings in bandwidth, and hence network costs, are achieved if the number of provisioned VPCs are minimized, especially if there is uncertainty in the traffic pattern characterization. For a given example, we show that to achieve a 0.1% blocking probability requirement, if link capacities are shared (i.e., not partitioned a priori to provisioned VPCs), resource savings of 14.4%, 47.9% or 80% are possible under exact, approximate and poor traffic characterizations, respectively. If the above bandwidth savings are to be achieved in networks that use traditional node-by-node connection setup approaches, end-to-end connection setup delay will increase. In this paper, we propose a new connection setup algorithm that allows the savings in bandwidth obtained through sharing while at the same time controlling the connection setup delay.