Quality Of Service Implementation Research Articles

End-to-end quality of service for high-end applications

High-end networked applications such as distance visualization, distributed data analysis, and advanced collaborative environments have demanding quality of service (QoS) requirements. Particular challenges include concurrent flows with different QoS specifications, high-bandwidth flows, application-level monitoring and control, and end-to-end QoS across networks and other devices. We describe a QoS architecture and implementation that together help to address these challenges. The General-purpose Architecture for Reservation and Allocation (GARA) supports flow-specific QoS specification, immediate and advance reservation, and online monitoring and control of both individual resources and heterogeneous resource ensembles. Mechanisms provided by the Globus Toolkit are used to address resource discovery and security issues when resources span multiple administrative domains. Our prototype GARA implementation builds on differentiated services mechanisms to enable the coordinated management of two distinct flow types—foreground media flows and background bulk transfers—as well as the co-reservation of networks, CPUs, and storage systems. We present results obtained on a wide area differentiated services testbed that demonstrate our ability to deliver QoS for realistic flows.

A novel approach for providing quality of service in multi service IP networks

Considering specific operational and corporate service requirements, this article proposes an approach for providing quality of service (QoS) in multi service networks based on the IP (Internet Protocol) technology. The basic elements of the proposed approach encompass DiffServ - aware QoS architecture, proposal for traffic classification, proposal for configuration of the data plane QoS implementation mechanisms, as well as the model of QoS control and management. Particularly, the proposed approach is applicable to private networks with specific operational and corporate needs (power utilities, traffic and transport, etc), which mandatory require different levels of QoS in order to assure stable and reliable system operation.

Using UML to specify QoS constraints in ODP

This paper is concerned with Quality of Service (QoS) specification in distributed system design. The specification and implementation of QoS is increasingly important in distributed systems due to the need to address questions of performance, particularly for systems involving multimedia. To ensure correct implementation of QoS requirements, statements of QoS need to be introduced early in the design process, and in terms of design we consider the use of the Unified Modelling Language (UML), which has quickly become the de facto standard for object-based designs. The framework we use for distributed system construction is that provided by the open distributed processing reference model, and we focus in particular on its computational viewpoint. The aim of this paper is to construct a UML model of the computational viewpoint focusing on the description of QoS within that viewpoint. To specify the QoS aspects of computational objects in the UML model, we use a real-time logic called QL. In order to express further constraints on the UML model of the computational viewpoint, we use the Object Constraint Language to express invariants that each instance of our model must satisfy. The purpose of our UML model of the computational viewpoint is to act as a template via which specific distributed system designs can be constructed and we illustrate this with the specification of a lip synchronisation mechanism.

Quality of service – technology and implementation

This paper discusses various facets of quality of service (QOS), a technology that allows network managers to prioritize data to optimize bandwidth use and maintain data quality. Given the wide variety and high volume of data as well as bandwidth limitations on networks today, QOS has gained great importance in recent years. Successful implementation of QOS requires selecting from the wide array of models and algorithms available and careful consideration of other technical and organizational issues. Different QOS models and algorithms have been discussed to provide the network manager with an insight into these technologies that can aid in the selection of QOS models and algorithms. Various technical and organizational implementation issues, including how QOS is implemented in routers, have been discussed to assist the network manager to be aware of these issues and properly implement QOS.

Enhanced ATM for satellite laser communication networks

Satellite networks are one of the most emergent areas in commercial communication. Today about twenty serious consortiums (such as Iridium, Teledesic, Globstar, and Celestri) develop satellite communication networks. In the new generation of satellite networks, laser will be used as a communication link between the satellites in order to get wider bandwidth for the network backbone. One of the main problems of a satellite laser link is dramatic reduction of the communication performances for up to several milliseconds due to deviation of the pointing direction of the very narrow laser beam. The satellite mechanical vibrations cause this deviation. This fact is an obstacle in implementation of high QoS (quality of service) application in satellite network. In this research we propose the use of the diversity concept in order to overcome the vibration effect. A communication diversity means using a number of independent propagation paths for transmitting the same information. This concept increases the probability of receiving the information. We derive the diversity algorithm based on standard ATM (synchronic transfer mode). A practical satellite communication network performance based on our algorithm is presented.

Logistical quality of service in NetSolve

From its inception a principal goal of the Next Generation Internet (NGI) has been to find a way to provide reliable, scalable, cost effective, and deployable delivery of data with quality of service (QoS) guarantees as a foundation for innovative NGI applications. But while schemes to provide reliable end-to-end QoS are being actively pursued on a number of fronts, the well known problems with the scalability, cost, and deployability of end-to-end QoS continue to obstruct progress toward achieving this end. Our research focuses on the nature and potential value of an approach to providing QoS that builds on a strategy for allowing NGI applications to dynamically manage remote storage resources in order to stage data locally for later delivery. We call this strategy logistical Quality of Service ( logistical QoS). The concept of logistical QoS is a generalization of the typical end-to-end model for reserving QoS, permitting much more flexible use of buffering of messages in order to achieve QoS delivery without difficult end-to-end requirements. Whenever data is available to be sent well before it needs to be received, it can be staged, i.e. moved in advance to a location close to the receiver for later delivery. Isolating the act of buffering data as a distinct operation, independent of delivery to the receiver, opens up a new dimension of freedom in the management of communication and storage resources that can offer NGI application developers a wide variety of new opportunities to innovate. Our project focuses on the development of logistical QoS as enabling network functionality for application-driven staging and scheduling of distributed computation on NGI. It is divided into two parts: (1) research on the basic network functionality that is required to support logistical QoS that is reliable, scalable, cost effective, and easy to use; and (2) research that investigates the integration of logistical QoS and the basic network technology that underlies it with the scheduling of distributed computations using NetSolve and the Network Weather Service. Our work on logistical QoS focuses on the Internet Backplane, as providing a mechanism for managing remote storage resources, and the Internet Backplane Protocol, as enabling technology for using that mechanism. The idea underlying the concept of the Internet Backplane is that NGI will enable us to consider the global network as an extension of the processor backplane, if only we have a low overhead mechanism for fine grained naming and access to data, analogous to physical addresses and bus transfers. By this analogy the Internet Backplane is a common namespace for fine-grained management of distributed resources. The IBP provides a flexible interface to enable this functionality, allowing reliable and flexible control of remote storage buffers through a general scheme for naming, staging, delivering and protecting data. We will test logistical QoS as an enabling technology for NGI computing using NetSolve. NetSolve is a software environment for networked computing designed to transform disparate computers and software components into a unified, easy-to-access computational service; it is being used by NSF's Partnerships for Advanced Computational Infrastructure to build high-performance systems for distributed computation on leading edge networks. We will investigate the implementation of logistical QoS within NetSolve and the integration of IBP with the Network Weather Service (used to monitor and forecast the performance of network and computational resources) to build a scheduling capability that maximizes the performance of NetSolve across next generation networks.

Family assessment and its relation to hospice care.

It is proposed that a family system evaluation be added to the initial medical and social history used during a hospice assessment. The family evaluation should assess the family through a functional/dysfunctional framework in addition to assessing the role structure of each of its members. This additional data can offer insight into the internal workings of the family while adding important information as to the compliance level of the family in accepting hospice and the services that hospice has to offer. This may assist in not only the quality of service implementation but in assisting hospice personnel in lessening their potential for stress and burnout as well.