An important problem associated with virtual paths is to determine the bandwidths that should be allocated to the set of virtual paths in the network. The bandwidth allocation to virtual path has strong impact on network throughput, signaling and call blocking QoS. There exist many algorithms in the literature which attempt to assign bandwidth to the virtual paths. However, to the best of the author's knowledge, no work takes into consideration the adverse impact of over allocation of network bandwidth to the virtual paths. In this paper we discuss various tradeoffs such as throughput, signaling and QoS and show that there exist a unique set of bandwidths beyond which the performance of the network deteriorates rapidly with respect to all the three measures. It is shown in this paper that this upper bound can be computed distributively in real time using run time estimates. We use this result in designing a dynamic bandwidth allocation algorithm. This dynamic algorithm provides the flexibility of adjusting QoS, network throughput and the signaling load on the switches to the desired level in real time.