CONTENTS

Page

1.	SECTION 1 - NETWORK FUNCTIONAL PRINCIPLES....................... 3

1.1	Recommendation I.310 - ISDN network functional principles....... 3

2.	SECTION 2 - REFERENCE MODELS....................................	35

2.1	Recommendation I.320 - ISDN protocol reference model............	35

2.2	Recommendation I.324 - ISDN network architecture................	49

2.3	Recommendation I.325 - Reference configurations for ISDN

connection types.................................................	64

2.4	Recommendation I.326 - Reference configurations for	relative.network resource requirements..........................	73

3.	SECTION 3 - NUMBERING, ADDRESSING AND ROUTING...................	76

3.1	Recommendation I.330 - ISDN numbering and addressing	principles......................................................	76

3.2	Recommendation I.331 - Numbering plan for the ISDN era.......... 85

3.3	Recommendation I.332 - Numbering principles for interworking

between ISDNs and dedicated networks with different

numbering plans................................................. 85

3.4	Recommendation I.333 - Terminal selection in ISDN...............	90

3.5	Recommendation I.334 - Principles relating ISDN

numbers/subaddresses to the OSI reference model network layer	addresses........................................................	112

3.6	Recommendation I.335 - ISDN routing principles.................. 118

4.	SECTION 4 - CONNECTION TYPES....................................	145

4.1	Recommendation I.340 - ISDN connection types.................... 145

5.	SECTION 5 - PERFORMANCE OBJECTIVES..............................	166

5.1	Recommendation I.350 - General aspects of Quality of Service

and network performance in digital networks, including	ISDNs...........................................................	166

5.2	Recommendation I.351 - Recommendations in other services

including network performance objectives that apply at

T reference point of an ISDN.................................... 180

5.3	Recommendation I.352 - Network performance objectives for

connection processing delays in an ISDN......................... 180

1.	SECTION 1 - NETWORK FUNCTIONAL PRINCIPLES

1.1	Recommendation I.310

ISDN-NETWORK FUNCTIONAL PRINCIPLES

FIGURE 1/I.310

ISDN network series of Recommendations

1.2	Services supported by an ISDN

The concepts and the principles of an ISDN are described in Recommendation I.120. The services supported by an ISDN are given in the

I.200-Series of Recommendations. A classification and the tools for the description of telecommunication services are specified in Recommendation I.210 according to the description method as given in Recommendation I.130. The network capabilities to support these services are defined in the I.300-Series of Recommendations. The relationship between these Recommendations and some other relevant I-Series Recommendations is shown in Figure 1/I.310.

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-	the low-layer functions (LLF) relate to the bearer services;

-	the high-layer functions (HLF) together with the lower layer functions relate to the teleservices.

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Recommendation I.324 introduces the functional grouping CRF (Connection Related Functions). The CRF can be local, national transit or international transit. EFs can be associated with each of these.

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-	Basic EFs: For each connection type, there are up to 8 BFGs to implement (see Table 1). Therefore each BFG is composed of basic EFs related to this connection type. However some basic EFs may be common to several connection types (e.g. "called number analysis" belonging to the BGF "routing").

-	Additional EFs: Additional EFs form a common set of functional elements available to build up the various AGFs, and so to implement supplementary services.

This grouping of EFs into sets of BGFs and AGFs is illustrated in Figure 6/I.310.

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