A two-level queueing network model with blocking and non-blocking messages

We analyze a novel two-level queueing network with blocking, consisting of N level-1 parallel queues linked to M level-2 parallel queues. The processi ng of a customer by a level-1 server requires additional services that are exclusively offered by level-2 servers. These level-2 servers are accessed through blocking and non-blocking messages issued by level-1 servers. If a blocking message is issued, the level-1 server gets blocked until the messa ge is fully processed at the level-2 server. The queueing network is analyz ed approximately using a decomposition method, which can be viewed as a gen eralization of the well-known two-node decomposition algorithm used to anal yze tandem queueing networks with blocking. Numerical tests show that the a lgorithm has a good accuracy.