INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY


Rec. No. : I.121

Title :	Broadband aspects of ISDN

Study Group : XVIII - ISDN

Version : Revised

Date of adoption : 1991

Notes :	


Recommendation I.121states the basic principles of broadband aspects 
of integrated services digital network (B-ISDN) and indicates further 
developments of the ISDN network capabilities in order to support more 
advanced services and applications.

The B-ISDN Recommendations were written taking into account the 
following:

	-   the emerging demand for broadband services;

	-   the availability of high speed transmission, switching and 
	    signal processing technologies;

	-   the improved data and image processing capabilities 
	    available to the user;

	-   the advances in software application processing in the 
	    computer and telecommunication industries;

	-   the need to integrate both interactive and distribution 
	    services;

	-   the need to integrate both circuit and packet transfer mode 
	    into one universal broadband network;

	-   the need to provide flexibility in satisfying the 
	    requirements of both user and operator;

	-   the need to cover broadband aspects of ISDN in CCITT 
	    Recommendations.

The main feature of the ISDN concept is the support of a wide range of 
audio, video and data applications in the same network. A key element 
of service integration for an ISDN is the provision of a wide range of 
services to a broad variety of users utilizing a limited set of 
connection types and multipurpose user/network interfaces.



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