SLAng: A language for defining service level agreements

TLDR

Application or web services are increasingly used across organisational boundaries, with new services emerging at network and storage levels, and languages for specifying service interfaces have been researched and adopted in industry. We investigate end‑to‑end quality of service (QoS) and highlight that QoS provision is multi‑faceted, requiring complex agreements among network, storage, and middleware services. We introduce SLAng, a language for defining Service Level Agreements that accommodates these multi‑faceted QoS needs. In a case study of image processing across multiple domains, SLAng is used to specify QoS and its effectiveness is evaluated, demonstrating its applicability.

Abstract

Application or web services are increasingly being used across organisational boundaries. Moreover, new services are being introduced at the network and storage level. Languages to specify interfaces for such services have been researched and transferred into industrial practice. We investigate end-to-end quality of service (QoS) and highlight that QoS provision has multiple facets and requires complex agreements between network services, storage services and middleware services. We introduce SLAng, a language for defining Service Level Agreements (SLAs) that accommodates these needs. We illustrate how SLAng is used to specify QoS in a case study that uses a web services specification to support the processing of images across multiple domains and we evaluate our language based on it.