Đang chuẩn bị liên kết để tải về tài liệu:
Thực hiện chất lượng dịch vụ trong các mạng IP (P5)

Mapping Service Requirements to Network Resources The ability to properly map services to network resources in a multi-service network is highly important both for making the initial configuration of a network domain, and also as a basis for performing network configuration optimization. The basic task in both cases is the same, although in the latter case there is an initial configuration to start with, as well as potentially a larger number of existing boundary conditions for the new configuration. Resource allocation is an optimization problem where the available network resources, SLAs for different parties, and requirements of service types are examples. | 5 Mapping Service Requirements to Network Resources The ability to properly map services to network resources in a multi-service network is highly important both for making the initial configuration of a network domain and also as a basis for performing network configuration optimization. The basic task in both cases is the same although in the latter case there is an initial configuration to start with as well as potentially a larger number of existing boundary conditions for the new configuration. Resource allocation is an optimization problem where the available network resources SLAs for different parties and requirements of service types are examples of boundary conditions. The SLA interfaces relevant to resource allocation are illustrated with an example configuration in Figure 5.1. The responsibility of end-to-end service quality can be thought to be by default with service providers who use SLAs towards network transport providers to implement the service quality. Alternatively an access network operator may provide a set of services from outsourced Application Service Providers ASPs such that the access network operator is responsible for end-to-end service quality. There may be more than one service provider involved for example in using IP telephony services in such a way that the Implementing Service Quality in IP Networks Vilho Raisanen 2003 John Wiley Sons Ltd ISBN 0-470-84793-X 134 MAPPING SERVICE REQUIREMENTS TO NETWORK RESOURCES Service subscriber J SLA SLA SLA Transport operator Service operator SLA k Transport operator SLA SLA Figure 5.1 SLA reference model for the present chapter caller and callee use different IP telephony service providers. In the general case there may be also transit operators involved. As to services both external service operator transport operator and operator-internal service transport interfaces are illustrated in Figure 5.1. In general there is no need to have a one-to-one relationship between service and transport .