We consider a queueing loss system with heterogeneous skill based servers with arbitrary distributions. We assume Poisson arrivals, with each arrival having a vector indicating which of the servers are eligible to serve it. Arrivals can only be assigned to a server that is both idle and eligible. We assume arrivals are assigned to the idle eligible server that has been idle the longest and deri...

We study the problem of optimally controlling a three server queueing system. Arriving customers join a single queue, which is served by three servers, 8 1 , 52 and 53. The servers are exponential, but of different rates. The total expected time a customer spends in the system is to be minimized. We show that the optimal policy can be characterized by three thresholds, m3,mb and mi, such that: ...

For popular websites most important concern is to handle incoming load dynamically among web servers, so that they can respond to their client without any wait or failure. Different websites use different strategies to distribute load among web servers but most of the schemes concentrate on only one factor that is number of requests, but none of the schemes consider the point that different typ...

Motivated by modern call centers, we consider large-scale service systems with multiple server pools and a single customer class. For such systems, we propose a simple routing rule which asymptotically minimizes the steady-state queue length and virtual waiting time. The proposed routing scheme is FSF which assigns customers to the Fastest Servers First. The asymptotic regime considered is the ...

Consider a two-server, ordered entry, queuing system with heterogeneous servers and finite waiting rooms in front of the servers. Service times are negative exponentially distributed. The arrival process is deterministic. A matrix solution for the steady state probabilities of the number of customers in the system is derived. The overflow probability will be used to formulate the stability cond...

We consider a queueing loss system with heterogeneous skill based servers with arbitrary service distributions. We assume Poisson arrivals, with each arrival having a vector indicating which of the servers are eligible to serve it. An arrival can only be assigned to a server that is both idle and eligible. Assuming exchangeable eligibility vectors and an idle time ordering assignment policy, th...

In this paper, we consider systems that can be modelled by M | M | n queues with heterogeneous servers and non informed customers. Considering any two servers: we show that the probability that the fastest server is busy is smaller than the probability that the slowest server is busy. Moreover, we show that the effective rate of service done by the fastest server is larger than effective rate o...

-The main aim of this paper is to present a model for distributing prioritized customers to heterogeneous parallel servers. A queuing optimization model is proposed in the form of a nonlinear programming problem having linear constraints, so that the average mean response time taken over all job requests is minimized. A solution procedure is developed by employing the convexity of the performan...

In the framework of the research activity performed by the Gruppo di Ricerca sull'Informatica Distribuita (GRID group), the authors are currently investigating efficient mechanisms and proper design guidelines to support the development of parallel multimedia servers in heterogeneous systems. The reference architecture for our investigations is based on clusters of workstations, interconnected ...