RFC 2216 (rfc2216) - Page 2 of 22

Network Element Service Specification Template

RFC 2216            Network Element Service Template      September 1997


   specifies parameters used to invoke the service, the relationship
   between those parameters and the service delivered, and the end-to-
   end behavior obtained by concatenating several instances of the
   service.

   Each service definition also specifies the interface between that
   service and the environment. This includes the parameters needed to
   invoke the service, informational parameters which the service must
   make available for use by setup, routing, and management mechanisms,
   and information which should be carried between end-nodes and network
   elements by those mechanisms in order to achieve the desired end-to-
   end behavior. However, a service definition does not describe the
   specific protocols or mechanisms used to establish state in the
   network elements for flows that use the described service.

   Services defined following the guidelines of this document are
   intended for use both within the global Internet and private IP
   networks. In certain cases a concatenation of network element
   services may be used to provide a range of end-to-end behaviors, some
   more suited to a decentralized internet and some more appropriate for
   a tightly managed private network. This document points out places
   where such distinction may be appropriate.

   This document is comprised of three parts.  The first defines some
   terms used both in this document and in the various service
   specification documents.  The second discusses data formats and
   representations.  The third portion of the document describes the
   various components of the service specification template.

Definitions

   The following terms are used throughout this document. Service
   specification documents should employ the same terms to express these
   concepts.

 o Quality of Service (QoS)

   In the context of this document, quality of service refers to the
   nature of the packet delivery service provided, as described by
   parameters such as achieved bandwidth, packet delay, and packet loss
   rates. Traditionally, the Internet has offered a single quality of
   service, best-effort delivery, with available bandwidth and delay
   characteristics dependent on instantaneous load. Control over the
   quality of service seen by applications is exercised by adequate
   provisioning of the network infrastructure. In contrast, a network
   with dynamically controllable quality of service allows individual
   application sessions to request network packet delivery
   characteristics according to their perceived needs, and may provide



Shenker & Wroclawski         Informational