Distributed resource allocation mechanism for SOA service level agreements

Enterprise computing facilities, such as data centers or server farms typically employ service-oriented architectures (SOA) to support multiple, XML-based Web Services. They are typically architected in multiple computing tiers, in which one tier is used for, say, offloading the CPU-intensive XML processing onto a cluster of (potentially virtual) middle-ware appliances. Service differentiation in enterprise networks addresses the issues of managing the enterprise network resources in order to achieve desired performance objectives. In this paper, we define a dynamic algorithm that manages allocation of CPU time in the appliance tier. We evaluate the service differentiation capabilities of this algorithm via simulations

Dynamic CPU scheduling for QoS provisioning

Distributed, large-scale, enterprise applications are commonly supported in multi-tier data-center environments. In this paper, we study a scheduling problem for sharing CPU time in a cluster of servers among a number of enterprise customers. Such sharing is typically mandated by service differentiation requirements and QoS guarantees. Our main contribution is the formal definition of a CPU allocation/scheduling problem with respect to QoS quarantees and evaluation of scheduling policies that address the following design criteria: they have provable performance, they do not require a priori knowledge of service statistics and their overhead is adjustable. We provide the necessary mathematical framework for policies that satisfy the above criteria and evaluate proposed algorithms via theoretical analysis and extensive simulations. © 2013 IFIP

An Efficient Delay-Constrained Minimum Spanning Tree Heuristic

Many distributed real-time applications require broadcasting information to all participants. This information must be received within some delay bound, and at the lowest possible cost. We formulate the problem of constructing broadcast trees for real-time traffic with delay constraints in networks with asymmetric link loads as a delay-constrained minimum spanning tree (DCMST) problem in directed networks. Then we prove that this problem is NP-complete, and we propose an efficient heuristic to solve the problem based on Prim's algorithm for the unconstrained minimum spanning tree problem. This is the first heuristic designed specifically for solving the DCMST problem. Simulation results under realistic networking conditions show that our heuristic's performance is close to optimal when the link loads are symmetric as well as when asymmetric link loads are used. Delay-constrained minimum Steiner tree heuristics can also be used to solve the DCMST problem. Simulation results indicate th..

Service differentiation in multitier data centers

In this paper, we study the problem of resource allocation in the setting of multitier data centers. Our main motivation and objective is to provide applications hosted in the data center with different service levels. In such centers, there are several mechanisms the designer can use to achieve such objectives. We restrict our attention to CPU time at the service tier as the resource; the objective we consider is service differentiation, expressed as allocating prespecified percentages of this resource to applications. Then, mechanisms at the designer's disposal to provide desired service differentiation include the triplet of load balancing through the switch fabric, enqueueing at a server and scheduling at a server. We focus on the enqueueing component of control mechanisms. We provide, through analysis and simulations 'rules of thumb' for situations where simple enqueueing policies can provide service differentiation. © 2013 IEEE

CPU provisioning algorithms for service differentiation in cloud-based environments

This work focuses on the design, analysis and evaluation of Dynamic Weighted Round Robin (DWRR) algorithms that can guarantee CPU service shares in clusters of servers. Our motivation comes from the need to provision multiple server CPUs in cloud-based data center environments. Using stochastic control theory we show that a class of DWRR policies provide the service differentiation objectives, without requiring any knowledge about the arrival and the service process statistics. The member policies provide the data center administrator with trade-off options, so that the communication and computation overhead of the policy can be adjusted. We further evaluate the proposed policies via simulations, using both synthetic and real traces obtained from a medium scale mobile computing application. © 2004-2012 IEEE

Optimal server assignment in multi-server queueing systems with random connectivities

In this paper, we provide complementary results on delay-optimal server allocation in multi-queue multi-server (MQMS) systems with random connectivities. More specifically, we consider an MQMS system where each queue is limited to get service by at most one server during each time slot. It is known that maximum weighted matching (MWM) is a throughput-optimal server assignment policy for such a system. In this paper, using dynamic coupling argument we prove that for a system with i.i.d. Bernoulli arrivals and connectivities, MWM minimizes, in stochastic ordering sense, a range of cost functions of the queue lengths such as total queue occupancy (which implies minimization of average queueing delay). Finally, we propose a low complexity heuristic server assignment policy for MQMS systems namely least connected server first/longest connected queue (LCSF/LCQ) and through simulations we show that it performs very closely compared with the optimal policy in terms of average queueing delay

PRACTICAL ASPECTS OF MOBILITY IN WIRELESS SELF-ORGANIZING NETWORKS

International audienceWireless and mobile computing have advanced significantly in the last decade. In particular, we now face the challenge to spontaneously establish wireless self-organizing networks, such as ad hoc, disruption-tolerant, sensor, and wireless mesh networks. These spontaneous self-organizing networks have been the focus of intensive research activity in recent years. Spontaneous networks arise from the cooperation of mobile devices in an ad hoc fashion requiring no previous infrastructure in place. A key point to couple research and real-life applications in this context is to understand how mobility (of devices, users, and applications) impacts practical networking aspects