RFC 2753 Framework for Policy-based Admission Control January 2000 - Policy: The combination of rules and services where rules define the criteria for resource access and usage. - Policy control: The application of rules to determine whether or not access to a particular resource should be granted. - Policy Object: Contains policy-related information such as policy elements and is carried in a request or response related to a resource allocation decision. - Policy Element: Subdivision of policy objects; contains single units of information necessary for the evaluation of policy rules. A single policy element may carry an user or application identification whereas another policy element may carry user credentials or credit card information. The policy elements themselves are expected to be independent of which QoS signaling protocol is used. - Policy Decision Point (PDP): The point where policy decisions are made. - Policy Enforcement Point (PEP): The point where the policy decisions are actually enforced. - Policy Ignorant Node (PIN): A network element that does not explicitly support policy control using the mechanisms defined in this document. - Resource: Something of value in a network infrastructure to which rules or policy criteria are first applied before access is granted. Examples of resources include the buffers in a router and bandwidth on an interface. - Service Provider: Controls the network infrastructure and may be responsible for the charging and accounting of services. - Soft State Model - Soft state is a form of the stateful model that times out installed state at a PEP or PDP. It is an automatic way to erase state in the presence of communication or network element failures. For example, RSVP uses the soft state model for installing reservation state at network elements along the path of a data flow. - Installed State: A new and unique request made from a PEP to a PDP that must be explicitly deleted. Yavatkar, et al. Informational