Protocol-level reconfigurations for autonomic management of distributed network services

The paper describes a service model for the autonomic management of distributed networked systems. In this model, a service provider (SP) maintains multiple protocol modules to exercise the infrastructure resources under various environment conditions. Each protocol exhibits a certain degree of performance optimality and service resilience in distinct operating regions of the network infrastructure and the environment. During run-time, the SP selects one of the protocol modules that can meet the application-requested Quality of Service (QoS) obligation against the prevailing operating conditions. Under normal conditions when the external disturbances are benign (e.g., low packet loss in the network), an optimal usage of the network resources is important. Under adverse conditions however (such as prolonged sub-system outages and failures), a sustained access to the network service at some minimum acceptable level becomes more important than a resource-optimal service offering. Often, a resilient protocol incurs more resource usage to tackle the hostile environment conditions than a performance-conscious protocol tuned for the normal case operations (dasiaa single shoe does not all sizespsila !!). Accordingly, a protocol selection by the SP considers the trade-off between dasiaservice availabilitypsila under extreme operating conditions and dasiaresource optimalitypsila under normal operations. Our model allows a dasiadynamic switchingpsila from one protocol module to another at run-time based on the changing environment conditions. The paper advocates dasiaprotocol switchingpsila as a foundation for building autonomic network services with the twin goals of service-level availability and performance.