Service Cluster: A New Framework for SLA-Oriented Provisioning in WDM Mesh Networks

A service level agreement (SLA) typically specifies the availability a service provider (SP) promises to a customer. Current schemes usually employ backup resources to achieve high SLA satisfaction. We propose a new provisioning framework, called service cluster (SC), which uses no explicit backup resources. By grouping several services with (typically) different availability specifications, an SC can dynamically re-allocate resources to avoid SLA violations. Services that can tolerate additional down time lend resources to services that need to be kept running. We first analyze a condition for admission control. We then propose a dynamic resource allocation scheme (ADT¹ balancing scheme, SC-ABS) and apply it to the SC framework. The dynamic management of SC-ABS is realized by novel SLA-violation estimation in an event-driven manner without continuous monitoring. We compare SC-ABS with shared-path protection, and numerically show its various advantages in terms of: 1) higher SLA satisfaction (up to 30% more); 2) lower service blocking ratio; 3) higher tolerance of failures; 4) more balanced SLA satisfaction; and 5) consuming no explicit backup (or standby) resources. Our scheme can meet the SLA of significantly more services than protection-based schemes, thus providing more profit for the SP and lower cost for the customer.