RFC 1193 (rfc1193) - Page 1 of 24


Client requirements for real-time communication services



Alternative Format: Original Text Document



Network Working Group                                         D. Ferrari
Request for Comments: 1193                                   UC Berkeley
                                                           November 1990



        CLIENT REQUIREMENTS FOR REAL-TIME COMMUNICATION SERVICES

Status of this Memo

   This memo describes client requirements for real-time communication
   services.  This memo provides information for the Internet community,
   and requests discussion and suggestions for improvements.  It does
   not specify any standard.  Distribution of this memo is unlimited.

Abstract

   A real-time communication service provides its clients with the
   ability to specify their performance requirements and to obtain
   guarantees about the satisfaction of those requirements.  In this
   paper, we propose a set of performance specifications that seem
   appropriate for such services; they include various types of delay
   bounds, throughput bounds, and reliability bounds.  We also describe
   other requirements and desirable properties from a client's
   viewpoint, and the ways in which each requirement is to be translated
   to make it suitable for lower levels in the protocol hierarchy.
   Finally, we present some examples of requirements specification, and
   discuss some of the possible objections to our approach.

   This research has been supported in part by AT&T Bell Laboratories,
   the University of California under a MICRO grant, and the
   International Computer Science Institute.  The views and conclusions
   in this document are those of the author and should not be
   interpreted as representing official policies, either expressed or
   implied, of any of the sponsoring organizations.

1.  Introduction

   We call real-time a computer communication service whose clients are
   allowed to specify their performance requirements and to obtain
   guarantees about the fulfillment of those requirements.

   Three terms in this definition need further discussion and
   clarification: clients, performance, and guarantees.

   Network architecture usually consists, at least from a logical
   viewpoint, of a stack of protocol layers. In the context of such an
   architecture, the notions of client and server apply to a number of



Ferrari