Scott Jordan

Throughput in multiple service, multiple resource communication networks

Communication networks that integrate multiple services using multiple resources are considered. In particular, the authors pose resource allocation problems, present a sensitivity analysis, and provide a glimpse of the possible behavior of such networks. The simplest discipline is assumed: a service request is accepted if the necessary resources are available; otherwise it is rejected. Two results are obtained. The first gives the sensitivity of throughput of service requests of type i with respect to offered traffic and service rates of type j. The second result is that the set of vectors of achievable throughput rates is a convex polyhedron given by an explicit set of linear inequalities. >

Access control to two multiserver loss queues in series

We consider admission policies to two multiserver loss queues in series with two types of traffic. Both are generated according to independent Poisson processes with constant arrival rates. The first type requires service at the first queue and with a positive probability enters the second queue; the second type requires service at only the second queue. The service time distribution is exponential at either station. We show that under appropriate conditions the optimal admission policy that maximizes the expected total discounted reward over an infinite horizon is given by a switching curve. We characterize the form and shape of this curve and its variation with system parameters.

Control of multiple service, multiple resource communication networks

The authors focus upon communication networks that integrate multiple services using multiple resources. In particular, the authors address the decision of whether to accept or deny service requests in such a system. A conjecture for the optimal policy for a related system introduced by G.J. Foschini and B. Gopinath (1983) is proved, and the optimal coordinate convex policy for a multiple service, multiple resource system is characterized.<<ETX>>

Access control of parallel multiserver loss queues

This paper considers access control in a target multiserver loss queue fed by a set of upstream parallel multiserver loss queues and by a stream of new customers. The target queue faces a choice of how many servers to reserve for each stream. Revenue is gained by each station when it serves a customer, but the amount of revenue at the target queue depends on the source of the customer. We prove that the policy that maximizes total discounted revenue consists of a set of monotonically decreasing thresholds as functions of the occupancy of each queue. We prove monotonicity properties with respect to system parameters. We show that there exists an ordering of the thresholds based on the relative revenue paid at the target queue. Finally, we compare this system with a tandem queue model.

Near optimal admission control for multiserver loss queues in series

This paper considers access control policies in multiserver loss queues in series such as might arise in the context of computer and telecommunication networks. Each queue is presented with both served upstream customers and Poisson arrivals from outside the network, and it may route serviced customers out of the network or to the downstream queue. Service times of each customer are i.i.d. and exponentially distributed. Revenue is earned by each station when it serves a customer, but the amount of revenue depends on whether the customer entered the network at this station or was routed from an upstream station. We propose a simple recursive method to solve the problem using dynamic programming on a set of reduced state spaces. This approach includes a rate estimation technique for upstream stations, and a revenue estimation technique for downstream stations. Numerical results demonstrate the performance of these near-optimal policies under light, moderate, and heavy traffic.

A continuous state space model of multiple service, multiple resource communication networks

The merging of telephone and computer networks is introducing multiple resources into networks, and information is becoming increasingly distributed across the network. Related services are being integrated onto a single network rather than being offered on separate uncoordinated networks. We focus upon communication networks that integrate multiple services using multiple resources. In previous work, such networks have been modeled by multidimensional Markov chains with product form distributions. We approximate the distribution on the original discrete state space by a similar product form distribution on a continuous state space. We consider access control of such a system and prove that the resulting optimal coordinate-convex control policy is convex. Based on this result, we suggest an algorithm for ending a near-optimal policy for the discrete problem that has much less complexity than existing methods for finding optimal or near-optimal policies. >

Classic conditioning: the FCC’s use of merger conditions to advance policy goals

Federal regulators routinely impose conditions on companies seeking to complete a merger or acquisition. Under standard circumstances, the Federal Communications Commission (FCC) must justify significant policy decisions by explaining assumptions underlying the decision; key alternatives; the rationale for that particular policy tactic; and how the new policy dovetails with agency precedent (Yoo, 2007). Critics contend, however, that merger negotiations lack transparency and are too far-reaching. In fact, the FCC may negotiate with companies under review to extract conditions that have minimal connection to actual concerns surrounding the transaction, and that circumvent established policymaking processes (Koutsky and Spiwak, 2010; Noah, 1997; Tramont, 2001; Weiser, 2009). Critics also assert that by engaging in closed-door negotiations and “arm-twisting” (Noah, 1997), the FCC is able to evade judicial scrutiny—partially because companies in regulated industries fear repercussions if they challenge agency demands. For these reasons, members of Congress have sponsored legislation aimed at severely limiting—and even stripping—FCC regulators of their power to review acquisitions (Borland, 1999; Telecommunications Merger Review Act of 2000). Despite their controversial nature, merger negotiations often do result in a set of conditions that benefit the public. While this study focuses on U.S. deals, European merger obligations can also be used to achieve industry-wide policy goals (Voight and Schmidt, 2005).

Sensitivity of optimal quality of service to bandwidth and buffer prices

Congestion-based pricing of network resources is a common approach in evolving network architectures that support quality of service (QoS). Resource usage and QoS will thus fluctuate in response to changes in price, which must be dynamically controlled through feedback. Here, we investigate the sensitivity of QoS to resource prices in a reservation-based QoS architecture. Such sensitivities are crucial to guide development of price adjustment algorithms. We derive necessary and sufficient conditions for resources to act as normal goods. We then show that the minimum total cost is a decreasing convex function of loss. Finally, we prove that if a resource is a normal good, then an increase in the price of that resource causes the loss on that link to increase, the loss on all other links to decrease, and the total loss to increase.

A recursive algorithm for bandwidth partitioning

We consider complete partitioning of bandwidth among multiple services. When class bandwidth is an integer multiple of the next lower class and total bandwidth is an integer multiple of the largest class bandwidth, we develop a recursive algorithm that determines the optimal complete partitioning policy with a significantly lower complexity than that of known dynamic programming or mixed integer programming approaches.