Subsystem number

Signalling Connection Control Part (SCCP) subsystem numbers are used to identify applications within network entities which use SCCP signalling.

In Global System for Mobile Communications (GSM) and Universal Mobile Telecommunications System (UMTS), subsystem numbers may be used between Public land mobile networks (PLMNs), in which case they are taken from the globally standardized range (1 - 31) or the part of the national network range (129 - 150) reserved for GSM/UMTS use between PLMNs. For use within a PLMN, numbers are taken from the part of the national network range (32 - 128 & 151 - 254) not reserved for GSM/UMTS use between PLMNs.

The following globally standardized subsystem numbers have been allocated for use by GSM/UMTS:

The following national network subsystem numbers have been allocated for use within GSM/UMTS networks:

The following national network subsystem numbers have been allocated for use within and between GSM/UMTS networks:

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