Connection splitting: an efficient way of reducing call blocking in ATM

In this paper, we propose a technique for reducing ATM call blocking which is achieved by splitting wideband connections into multiple low-bandwidth subconnections and routing them independently through the network. The essence of the mechanism is to use fragmented network bandwidth for supporting calls which are otherwise blocked by conventional routing. ATM bandwidth fragmentation may take place in a situation when a connection occupies a part of a link bandwidth and the rest of it is not sufficient for another connection. The unused bandwidth becomes fragmented. We provide a detailed cell-level design for the split scheduling algorithms which use a special type of ATM resource management (RM) cell for maintaining cell ordering. The analysis and simulation of the scheduling algorithms show that connection splitting is capable of delivering acceptable cell-level quality of service to multiple traffic classes. We also deliver a solution for implementing splitting without requiring any protocol changes within the network. We show that it is sufficient to modify the data and control plane protocols only within the end-stations. Finally, a set of routing level simulations for splitting demonstrate that splitting can reduce blocking by up to 45% for high bandwidth calls in a moderately loaded network. Considering that it does not incur any network expenses and protocol changes, we propose splitting as an efficient means for reducing connection blocking.