Alexander Kesselman

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We consider two types of buffering policies that are used in network switches supporting QoS (Quality of Service). In the <italic>FIFO</italic> type, packets must be released in the order they arrive; the difficulty in this case is the limited buffer space. In the <italic>bounded-delay</italic> type, each packet has a maximum delay time by which it must be(More)
We study the number of steps required to reach a pure Nash equilibrium in a load balancing scenario where each job behaves selfishly and attempts to migrate to a machine which will minimize its cost. We consider a variety of load balancing models, including identical, restricted, related, and unrelated machines. Our results have a crucial dependence on the(More)
We consider a network providing Differentiated Services (DiffServ), which allow Internet Service Providers (ISPs) to offer different levels of Quality of Service (QoS) to different traffic streams. We study two types of buffering policies that are used in network switches supporting QoS. In the FIFO type, packets must be transmitted in the order they(More)
Wireless ad hoc radio networks have gained a lot of attention in recent years. We consider geometric networks, where nodes are located in a euclidean plane. We assume that each node has a variable transmission range and can learn the distance to the closest neighbor. We also assume that nodes have a special collision detection (CD) capability so that a(More)
Several routing schemes in ad hoc networks first establish a virtual backbone and then route messages via backbone nodes. One common way of constructing such a backbone is based on the construction of a connected dominating set (CDS). In this article we present a very simple distributed algorithm for computing a small CDS. Our algorithm has an approximation(More)
Combined input and output queued (CIOQ) architectures with a moderate fabric <i>speedup</i> <i>S</i>&#62;1 have come to play a major role in the design of high performance switches. The switch policy that controls such switches must consist of two components. A buffer management policy that controls admission to buffers, and a scheduling policy that(More)
We consider buffer management policies for shared memory switches. We study the case of overloads resulting in packet loss, where the constraint is the limited shared memory capacity. The goal of the buffer management policy is that of maximizing the number of packets transmitted. The problem is online in nature, and thus we use competitive analysis to(More)
Wireless sensor networks have recently posed many new system building challenges. One of the main problems is energy conservation since most of the sensors are devices with limited battery life and it is infeasible to replenish energy via replacing batteries. An effective approach for energy conservation is scheduling sleep intervals for some sensors, while(More)