tailieunhanh - Thực hiện chất lượng dịch vụ trong các mạng IP (P2)

Service Quality Requirements In this chapter, means of assessing and specifying service quality requirements are described. To lay the foundation for discussion, the following questions need to be answered: • What is a service? • What kind of services are there? • What does it mean to provide quality support for a particular service type? • Which form of representation of service quality requirements is the best one? Background for answering the first question will be sought by first studying a few typical Internet services, and then proceeding to define suitable concepts for service definition. The second and third questions will. | 2 Service Quality Requirements In this chapter means of assessing and specifying service quality requirements are described. To lay the foundation for discussion the following questions need to be answered What is a service What kind of services are there What does it mean to provide quality support for a particular service type Which form of representation of service quality requirements is the best one Background for answering the first question will be sought by first studying a few typical Internet services and then proceeding to define suitable concepts for service definition. The second and third questions will be answered by studying the factors affecting service quality as well as the means of measuring service quality. Finally the means of specifying service quality requirements are reviewed. First it is in order to discuss the relation of service quality support to the commonly used term Quality of Service QoS . QoS is an overarching term which different schools of thought relate to Implementing Service Quality in IP Networks Vilho Raisanen 2003 John Wiley Sons Ltd ISBN 0-470-84793-X 10 SERVICE QUALITY REQUIREMENTS different parts of end-to-end service quality including user experience and service quality support mechanisms. International Telecommunication Union s Telecommunications branch s ITU-T s related definitions are as follows Quality is the totality of characteristics of an entity that bear on its ability to satisfy stated and implied needs. Quality of service is the collective effect of service performances which determine the degree of satisfaction of a user of service. Different viewing angles on Quality of Service are listed as following QoS requirements of user or customer are a statement of the level of quality required by the applications of customers users of a service which may be expressed non-technically. QoS offered or planned by provider is a statement of the level of quality expected to be offered to the customer by the .