ON POOLING IN QUEUING-NETWORKS

We view each station in a Jackson network as a queue of tasks, of a pa rticular type, which are to be processed by the associated specialized server. A complete pooling of queues, into a single queue, and server s, into a single server, gives rise to an M/PH/1 queue, where the serv er is flexible in the sense that it processes all tasks. We assess the value of complete pooling by comparing the steady-state mean sojourn times of these two systems. The main insight from our analysis is that care must be used in pooling. Sometimes pooling helps, sometimes it h urts, and its effect (good or bad) can be unbounded. Also discussed br iefly are alternative pooling scenarios, for example complete pooling of only queues which results in an M/PH/S system, or partial pooling w hich can be devastating enough to turn a stable Jackson network into a n unstable Bramson network. We conclude with some possible future rese arch directions.