6 Network Characteristics

29.0073GPPGeneral requirements on interworking between the Public Land Mobile Network (PLMN) and the Integrated Services Digital Network (ISDN) or Public Switched Telephone Network (PSTN)Release 17TS

6.1 Key Characteristics of Networks Concerned

Table 1: Key Characteristics of Networks Concerned

Characteristic	PLMN	ISDN	PSTN
Subscriber Interface	Digital	Digital	Analogue
User‑network signalling	3GPP TS 24.008	DSS1, other UNIs	loop‑disconnect and DTMF
User‑terminal equipment supported	see 3GPP TS 24.002	Digital TE (ISDN NT, TE1 or TE2+TA) see e.g. I.411	Analogue TE (e.g. dial pulse telephones PABXs modem equipped DTEs)
Inter‑exchange signalling	SS No.7 ISUP TUP+, MAP	SS No.7 ISUP TUP+, TUP, NUP	Channel associated (e.g. R2, No.4, No.5) or common channel (e.g. No.6)
Transmission facilities	Digital	Digital	Analogue
Exchange types	Digital	Digital	Analogue/digital
Information transfer mode	Circuit	Circuit	Circuit
Information transfer capability	Speech, digital unrestricted, alternate speech/ group 3 fax etc.	Speech, digital unrestricted, 3,1 kHz audio, video etc.	3,1 kHz audio (voice/voice‑ band data)

6.1.1 Characteristics of PLMNs

The PLMN is fully defined in the Technical Specifications summarised in 3GPP TS 41.003 for a 2^nd generation PLMN (A/Gb mode) or in 3GPP TS 21.103 for a 3^rd generation PLMN (Iu mode).

6.1.2 Characteristics of PSTNs

Because of the efforts at an early stage to standardize ISDNs in different countries, the differences between any two ISDNs will be small compared with the differences between PSTNs, which have evolved in different ways in different countries. In some cases the evolution has occurred over many decades, and therefore each PSTN is distinct, and for a recommendation on interworking, it is necessary to make certain assumptions about a generalized PSTN.

Whilst the key characteristics of PSTNs are given in table 1 above, the specific MSC/IWFs needed to allow interworking between a PLMN and a PSTN will depend on the nature of the PSTN concerned.

Table 2 gives a number of categories that can be used to classify PSTNs and a number of possibilities within each category.

Table 2: Characteristics of PSTNs

Category	Possibilities within Category
Type of subscriber	a) PSTN with loop disconnect subscriber signalling (10 pps)
signalling	b) PSTN with DTMF subscriber signalling
Type of interexchange	a) PSTN with channel‑associated signalling
signalling	b) PSTN with common‑channel signalling
Type of interexchange	a) Analogue
transmission	b) Digital
Type of exchange	a) PSTN with electro‑mechanical switching
switching	b) PSTN with electronic (non‑digital) switching
	c) PSTN with electronic digital switching
Type of exchange	a) Non‑SPC
control	b) SPC
NOTE: Under each category, it is possible that a PSTN will have a combination of the possibilities rather than only one.

6.1.3 Characteristics of ISDN

For the "standardized ISDN" in principle taken into account here, these are defined in the ETS/ITU-T‑series.