Formalization of Network Quality-of-Service Requirements

Abstract

Abstract. The provision of network Quality-of-Service (network QoS) is a major challenge in the development of future communication systems. Before designing and implementing these systems, the network QoS requirements are to be specified. Existing approaches to the specification of network QoS requirements are mainly focused on specific domains or individual system layers. In this paper, we present a holistic, comprehensive formalization of network QoS requirements, across layers. QoS requirements are specified on each layer by defining QoS domain, consisting of QoS performance, reliability, and guarantee, and QoS scalability, with utility and cost functions. Furthermore, we derive preorders on multi-dimensional QoS domains, and present criteria to reduce these domains, leading to a manageable subset of QoS values that is sufficient for system design and implementation. The relationship between layers is formalized by two kinds of QoS mappings. QoS domain mappings associate QoS domains of two abstraction levels. QoS scalability mappings associate utility and cost functions of two abstraction levels. We illustrate our approach by examples from the case study Wireless Video Transmission.

NQSL - Formal Language and Tool Support for Network Quality-of-Service Requirements

“…In previous work [1], we have introduced a formalization of network QoS. In particular, we have formalized the notions of QoS domain, QoS scalability, QoS mapping, and QoS requirements.…”

“…A detailed description of the three mapping subfunctions is given in [1]. In general, the QoS mappings are neither injective nor surjective.…”

“…A QoS scalability mapping sm is a set of four mapping functions sm Util , sm Cost , sm Up and sm Down , translating the different scalability domains into each other [1].…”

“…NQSL is directly derived from the formalization of network QoS in [1], which we have outlined in Section 3. It supports the specification of QoS domains and subdomains, QoS scalability, QoS mappings, and QoS requirements.…”

“…In Section 3, we summarize our formalization of network QoS requirements (cf. [1]). Section 4 introduces NQSL, the Network QoS Specification Language.…”