RFC 2753 (rfc2753) - Page 2 of 20


A Framework for Policy-based Admission Control



Alternative Format: Original Text Document



RFC 2753      Framework for Policy-based Admission Control  January 2000


   of-day/week. Similarly, diff-serv mechanisms also need to take into
   account policies that involve various criteria such as customer
   identity, ingress points, and so on.

   This document is concerned with specifying a framework for providing
   policy-based control over admission control decisions. In particular,
   it focuses on policy-based control over admission control using RSVP
   as an example of the QoS signaling mechanism. Even though the focus
   of the work is on RSVP-based admission control, the document outlines
   a framework that can provide policy-based admission control in other
   QoS contexts. We argue that policy-based control must be applicable
   to different kinds and qualities of services offered in the same
   network and our goal is to consider such extensions whenever
   possible.

   We begin with a list of definitions in Section 2. Section 3 lists the
   requirements and goals of the mechanisms used to control and enforce
   access to better QoS.  We then outline the architectural elements of
   the framework in Section 4 and describe the functionality assumed for
   each component.  Section 5 discusses example policies, possible
   scenarios, and policy support needed for those scenarios. Section 6
   specifies the requirements for a client-server protocol for
   communication between a policy server (PDP) and its client (PEP) and
   evaluates the suitability of some existing protocols for this
   purpose.

2. Terminology

   The following is a list of terms used in this document.

   -  Administrative Domain: A collection of networks under the same
      administrative control and grouped together for administrative
      purposes.

   -  Network Element or Node: Routers, switches, hubs are examples of
      network nodes. They are the entities where resource allocation
      decisions have to be made and the decisions have to be enforced. A
      RSVP router which allocates part of a link capacity (or buffers)
      to a particular flow and ensures that only the admitted flows have
      access to their reserved resources is an example of a network
      element of interest in our context.

      In this document, we use the terms router, network element, and
      network node interchangeably, but the should all be interpreted as
      references to a network element.

   -  QoS Signaling Protocol: A signaling protocol that carries an
      admission control request for a resource, e.g., RSVP.



Yavatkar, et al.             Informational