Multiple-Server ModelWith the multiple-server model, customers form a single line and choose one of s servers when one is available. The service system has only one phase; consequently, we are focusing our discussion on multiple-channel, single phase systems. We make the following assumptions in addition to those for the single-server model: There are s identical servers, and the service distribution for each server is exponential, with a mean service time of 1>m. It should always be the case that sm exceeds l.