INTERNATIONAL  TELECOMMUNICATION  UNION

		     ITU-T RECOMMENDATION SUMMARY

Rec. No. : I.324

Title :	Architecture of ISDN

Study Group : XVIII - ISDN

Version : Revised

Date of adoption : 1991

Notes :	


The objective of Recommendation I.324 is to provide a common 
understanding of the CCITT studies on the general architecture of an 
ISDN from the functional point of view. The model is not intended to 
require or exclude any specific implementation of an ISDN, but only to 
provide a guide for the specification of ISDN capabilities.

It presents a basic architectural model of an ISDN, with its eight 
main switching and signalling functional capabilities:

	-   ISDN local connection related functions;

	-   64 kbit/s circuit switched functional entities;

	-   64 kbit/s circuit non-switched functional entities;

	-   packet switching functional entities;

	-   frame mode functional entities;

	-   common channel inter-exchange signalling functional 
	    entities;

	-   switched functional entities at rates greater than 
	    64 kbit/s;

	-   non-switched functional entities at rates greater than 
	    64 kbit/s.



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