Subsystem number


subsystem numbers are used to identify applications within network entities which use SCCP signalling.

GSM and UMTS SSNs

In Global System for Mobile Communications and Universal Mobile Telecommunications System, subsystem numbers may be used between Public land mobile networks, in which case they are taken from the globally standardized range or the part of the national network range reserved for GSM/UMTS use between PLMNs. For use within a PLMN, numbers are taken from the part of the national network range not reserved for GSM/UMTS use between PLMNs.
The following globally standardized subsystem numbers have been allocated for use by GSM/UMTS:
0 Not used/Unknown
1 SCCP MG
6 HLR
7 VLR
8 MSC
9 EIR
10 is allocated for evolution.
The following national network subsystem numbers have been allocated for use within GSM/UMTS networks:
249 PCAP
250 BSC
251 MSC
252 SMLC
253 BSS O&M
254 BSSAP
The following national network subsystem numbers have been allocated for use within and between GSM/UMTS networks:
142 RANAP
143 RNSAP
145 GMLC
146 CAP
147 gsmSCF or IM-SSF
148 SIWF
149 SGSN
150 GGSN
241 INAP

North American (ANSI) SSNs

232 CNAM
247 LNP
248 800 number translation
254 800 number translation