Abstract : The premise of Quality of Security Service is that system and network management functions can be more effective if variable levels of security services and requirements can be presented to users or network tasks. In this approach, the "level of service" must be within an acceptable range, and can indicate degrees of security with respect to various aspects of assurance, mechanistic strength, administrative diligence, etc. These ranges result in additional latitude for management functions to meet overall user and system demands, as well as to balance costs and projected benefits to specific users/clients. With a broader solution space to work within the security realm, the underlying system and network management functions can adapt more gracefully to resource shortages, and thereby do a better job at maintaining requested or required levels of service in all dimensions, transforming security from a performance obstacle into an adaptive, constructive network management tool.