The MESCAL Internet QoS-based service model lays down the concepts, notions and relationships between them, pertinent to definition and provisioning of QoS-based services in the Internet, across multiple provider domains. In other words, the MESCAL service model presents the informational architecture, the basic 'service vocabulary', for building/defining QoS-based services in the Internet. From another angle, the MESCAL service model outlines the requirements of Internet QoS-based services from an informational viewpoint. It sets the functional targets of the service offering and provisioning functionality, while it also presents the necessary abstractions in the service layer around which this functionality needs to be designed. The MESCAL model extends the TEQUILA model of QoS-based intra-domain services to cover QoS-based services spanning the whole Internet, rather than the domain of a particular provider.

Specifically, the model specifies the notions of and relations between QoS-based services, QoS guarantees and c/pSLSes, outlining also different styles in requesting and establishing c/pSLSes. It then introduces the concept of ‘QoS Class’ (QC), the nucleus of QoS-based services, and specifies the notions of local and external QoS classes (l-QCs, e-QCs). Different types of QCs are defined depending on how they can obtain their values and the span of their meaning, introducing the concepts of meta- and global-QoS classes. Ordering (comparison) relationships between QCs are also defined as well as aspects of their offering/use in connection to pSLSes. Finally, the operations required for building external QCs and therefore QoS-based inter-domain services are defined and discussed in relation to the supporting service management and TE functionality: QC advertisement and discovery, classification, mapping, binding and their implementation in DiffServ IP networks.

Further reading:

M.P. Howarth, P. Flegkas, G. Pavlou, N. Wang, P. Trimintzios, D. Griffin, J. Griem, M. Boucadair, P. Morand, H. Asgari and P. Georgatsos, "Provisioning for Inter-domain quality of service: the MESCAL approach," IEEE Communications Magazine, June 2005. [pdf document]

MESCAL deliverable D1.3, "Final specification of protocols and algorithms for inter-domain SLS management and traffic engineering for QoS-based IP service delivery", Chapter 4. [link]