Supporting preemption in wormhole networks

When a computer network is used to support real time applications, meeting delay requirements is a key issue that has to be addressed. We study high performance networks with wormhole routing and investigate their performance in terms of meeting message delay constraints. We found that in this kind of network, preemption control performed at each node plays an important role in supporting real time traffic. In wormhole networks, this may result in unbounded packet blocking time, making it very difficult to efficiently support real time applications. To overcome this problem, we propose both transparent and non-transparent preemption schemes. Simulations show that combining proposed preemption schemes with other priority based schemes can outperform the conventional priority based schemes by a large margin, and the schemes have stable performance in large scale networks.