Allalaghatta Pavan

Resource Management for Ad-Hoc Wireless Networks with Cluster Organization

Boosted by technology advancements, government and commercial interest, ad-hoc wireless networks are emerging as a serious platform for distributed mission-critical applications. Guaranteeing QoS in this environment is a hard problem because several applications may share the same resources in the network, and mobile ad-hoc wireless networks (MANETs) typically exhibit high variability in network topology and communication quality. In this paper we introduce DYNAMIQUE, a resource management infrastructure for MANETs. We present a resource model for multi-application admission control that optimizes the application admission utility, defined as a combination of the QoS satisfaction ratio. A method based on external adaptation (shrinking QoS for existing applications and later QoS expansion) is introduced as a way to reduce computation complexity by reducing the search space. We designed an application admission protocol that uses a greedy heuristic to improve application utility. For this, the admission control considers network topology information from the routing layer. Specifically, the admission protocol takes benefit from a cluster network organization, as defined by ad-hoc routing protocols such as CBRP and LANMAR. Information on cluster membership and cluster head elections allows the admission protocol to minimize control signaling and to improve application quality by localizing task mapping.

Controlling the process with distributed multimedia

The process control industry has many uses for multimedia, from incorporating diverse imaging sensors to visualizing, monitoring and controlling time-critical processes. A distributed client-server architecture, together with specialized image-processing hardware and a number of commercial products, demonstrates the effectiveness of using multimedia data in a simulated film-coating process. >

Real-time adaptive resource management

Distributed mission-critical environments employ a mixture of hard and soft real-time applications that usually expect a guaranteed range of quality of service (QoS). These applications have different levels of criticality and varied structures ranging from periodic independent tasks to distributed pipelines or event-driven modules. The underlying distributed system must evolve and adapt to the high variability in resource demands that competing applications impose. The current industry trend is to use commercial off-the-shelf (COTS) hardware and software components to build distributed environments for mission-critical applications. The paper considers how adding a middleware layer above the COTS components facilitates consistent management of system resources, decreases system complexity, and reduces development costs.

Hierarchical feedback adaptation for real time sensor-based distributed applications

The paper presents an innovative hierarchical feedback adaptation method that efficiently controls the dynamic QoS behavior of real time distributed data flow applications, such as sensor based data streams or mission-critical command and control applications. We applied this method in the context of the Real Time Adaptive Resource Management system, a middleware integrated services, developed at the Honeywell Technology Center. We present the analytical model for Automatic Target Recognition pipeline application and the impact of hierarchical feedback adaptation on the application behavior and its QoS parameters.

Hierarchial architecture for real-time adaptive resource management

This paper presents the Real Time Adaptive Resource Management system (RTARM 1), developed at the Honeywell Technology Center. RTARM supports provision of integrated services for real-time distributed applications and offers management services for end-to-end QoS negotiation, QoS adaptation, real-time monitoring and hierarchical QoS feedback adaptation. In this paper, we focus on the hierarchical architecture of RTARM, its flexibility, internal mechanisms and protocols that enable management of resources for integrated services. The architecture extensibility is emphasized with the description of several service managers, including an object wrapper build around the NetEx real-time network resource management. We use practical experiments with a distributed Automatic Target Recognition application and a synthetic pipeline application to illustrate the impact of RTARM on the application behavior and to evaluate the system performance.

A network architecture for distributed high performance heterogeneous computing

Network computing has the potential for dramatically increasing the amount of computing power available to large scale compute intensive applications. The authors describe a network architecture upon which a high performance distributed computing environment may be constructed. The architecture uses a specially designed time and wavelength division multiplexed (TWDM) optical passive star as the underlying high speed network. The network architecture is flexible enough to support the many different communication patterns of distributed applications by embedding a computation directly within the system hardware.<<ETX>>

Experiments with video transmission over an asynchronous transfer mode (ATM) network

Abstract.We present end-to-end performance of digital coded video (JPEG, MPEG-1, and MPEG-2) over a local asynchronuous transfer mode (ATM) network. We discuss performance in terms of both delay (jitter) and frame loss as a function of load. The experimental data reveal that the burstiness of the variable bit-rate-coded video streams degrades the performance significantly when the hosts and the network are stressed. Our results show that traffic smoothing decreases frame loss significantly while maintaining acceptable jitter and loss bounds. We also discuss requirements for system components, such as the network interface and switch, which are necessary to support video services efficiently.

Topological embedding into WDM optical passive star networks with tunable transmitters of limited tuning range

Wavelength Division Multiplexing (WDM) has been widely used for studying the performance of optical networks, especially those employing optical passive star couplers. Many models have been proposed for WDM on an optical passive star coupler, such as each station equipped with a single tunable transmitter and a single fixed wavelength receiver, and each station with multiple tunable transmitters and multiple tunable receivers. The current technology only allows the transceivers to be tunable in a small range, a fact ignored in previous studies. In this paper, we focus on the design of WDM optical passive star networks with tunable transmitters of limited tuning range and fixed wavelength receivers. The limited tuning range has effects on the maximum delay, the total number of wavelengths which can be used, and the topological embedding. Complete graphs, meshes, and hypercubes are the three topologies studied in this paper. The relationship between the total number of wavelengths which can be utilized and the embedded topology is established. The bound for the maximum delay is analyzed. The optimal embedding algorithms are given for the systems embedded with one of the three topologies.

Experimental evaluation of real-time support on the Mercuri wide area ATM testbed

ATM has been widely accepted as the key enabling technology for emerging multimedia applications. We at the Honeywell Technology Center are investigating the application of this technology to real-time control systems. The Mercuri wide area ATM testbed is a collaborative research effort in this direction. In this paper we describe our experiences from a series of performance evaluation experiments on the Mercuri testbed. Besides measuring application level throughput and round-trip delay, we investigated the support for real-time provisions like priority and deadline guarantees, which are especially important for control applications. We also measured delay and jitter for remote video transfer under no-load and loaded conditions. The major conclusion of our experiments is that the end systems remain a major bottleneck for high speed communications. We point out possible causes of performance degradation in this paper and outline some issues that need to be resolved for ATM to become a viable alternative for real-time multimedia based control applications.

Reverse channel augmented multihop lightwave networks

The idea of providing reverse channels with minimal hardware costs in Shuffle-nets to reduce the network diameter improve mean delay, and provide other advantages is discussed. The reverse channel idea can be applied to any multistage network with wrapped around connections. The advantages of reverse channels are demonstrated by providing a simple reverse connection between adjacent stages of the Shuffle-net. It is shown how a time- and wavelength-division-multiplexed media access protocol for the Shuffle-net can be easily adapted for the reverse channel augmented Shuffle-net (RC-Shuffle-net). The performance of the RC-Shuffle-net and its advantages over the Shuffle-net are shown.<<ETX>>