INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY


Rec. No. : E.430

Title :	Quality of service framework

Study Group : II - Network Operation

Version : New

Date of adoption : 1992

Notes :	


A typical user is not interested in how a particular service is 
implemented, but he is interested in comparing one service with 
another in terms of certain universal performance parameters which 
apply to any service. Quality of Service (QOS) is expressed by 
parameter which:

	-   do not depend on assumptions about the network internal 
	    design;

	-   are referred to in terms of user-perceivable effects and 
	    not by their causes in the network;

	-   are described in network independent terms and create a 
	    common language understandable by both the user and the 
	    provider;

	-   take into account all aspects of the service which can be 
	    objectively measured at the service access point.

A network provider is concerned with the efficiency and effectiveness 
of the network. From the network providers point of view, network 
performance is best expressed by parameters which give information 
for:

	-   system development;

	-   network planning;

	-   operation and maintenance.

The user orientated QOS parameters provide a valuable framework for 
network design, but they are not necessarily usable in specifying 
network performance requirements for particular connections.

Similarly, the network performance (NP) parameters primarily determine 
the Quality of Service, but they do not, necessarily, describe that 
quality in a way that is meaningful to users.

The purpose of Recommendation E.430 is to identify a relationship 
between Quality of Service and network performance parameters.



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