Signalling Connection Control Part (SCCP) subsystem numbers are used to identify applications

Application software

Application software, also known as an application or an "app", is computer software designed to help the user to perform specific tasks. Examples include enterprise software, accounting software, office suites, graphics software and media players. Many application programs deal principally with...

 within network

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

 entities which use SCCP signalling.

GSM and UMTS SSNs

In Global System for Mobile Communications

Global System for Mobile Communications

GSM , is a standard set developed by the European Telecommunications Standards Institute to describe technologies for second generation digital cellular networks...

 (GSM) and Universal Mobile Telecommunications System

Universal Mobile Telecommunications System

Universal Mobile Telecommunications System is a third generation mobile cellular technology for networks based on the GSM standard. Developed by the 3GPP , UMTS is a component of the International Telecommunications Union IMT-2000 standard set and compares with the CDMA2000 standard set for...

 (UMTS), subsystem numbers may be used between Public land mobile network

Public land mobile network

A public land mobile network is a regulatory term in telecommunications. A PLMN is a network that is established and operated by an administration or by a recognized operating agency for the specific purpose of providing land mobile telecommunications services to the public.A PLMN is identified...

s (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 standardised subsystem numbers have been allocated for use by GSM/UMTS:
0 Not used/Unknown
1 SCCP MG
6 HLR

Network Switching Subsystem

Network switching subsystem is the component of a GSM system that carries out call switching and mobility management functions for mobile phones roaming on the network of base stations...

 (MAP

Mobile Application Part

The Mobile Application Part is an SS7 protocol which provides an application layer for the various nodes in GSM and UMTS mobile core networks and GPRS core networks to communicate with each other in order to provide services to mobile phone users...

)
7 VLR (MAP)
8 MSC (MAP)
9 EIR

EIR

EIR may refer to:* Effective interest rate, a banking term* Entrepreneur In Residence or Executive In Residence, a term in venture capital and business education* Environmental Information Regulations 2004, a UK Statutory Instrument...

 (MAP)
10 is allocated for evolution (possible Authentication Centre).

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

249 PCAP
250 BSC

BSC

BSC is a three-letter abbreviation that may refer to:Science and technology* Bachelor of Science , an undergraduate degree* Base Station Controller, part of a mobile phone network; see: Base Station subsystem...

 (BSSAP-LE)
251 MSC (BSSAP-LE)
252 SMLC

SMLC

Serving Mobile Location CenterThe SMLC is a network element in GSM Networks that resides in the BSC which calculates network-based location of mobile stations . The SMLC may control several LMUs which measure radio signals to help find mobile stations in the area served by the SMLC...

 (BSSAP-LE)
253 BSS

Base Station Subsystem

The base station subsystem is the section of a traditional cellular telephone network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem...

 O&M (A interface)
254 (A interface)

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

142 RANAP

RANAP

RANAP protocol is used in UMTS signaling between the Core Network, which can be a MSC or SGSN, and the UTRAN. RANAP is carried over Iu-interface....

143 RNSAP
145 GMLC

GMLC

The Gateway Mobile Location Centre contains functionality required to support LCS . In one PLMN , there may be more than one GMLC. The GMLC is the first node an external LCS client accesses in a GSM or UMTS network. The GMLC may request routing information from the HLR or HSS...

 (MAP)
146 CAP
147 gsmSCF (MAP) or IM-SSF (MAP)
148 SIWF (MAP)
149 SGSN (MAP)
150 GGSN (MAP)

North American (ANSI) SSNs

232 CNAM (Calling Name)
247 LNP

Local number portability

Local number portability for fixed lines, and full mobile number portability for mobile phone lines, refers to the ability to transfer either an existing fixed-line or mobile telephone number assigned by a local exchange carrier and reassign it to another carrier...

248 800 number translation (AIN0.1

Intelligent network

The Intelligent Network , is the standard network architecture specified in the . It is intended for fixed as well as mobile telecom networks...

)
254 800 number translation (TCAP

Transaction Capabilities Application Part

Transaction Capabilities Application Part, from ITU-T recommendations Q.771-Q.775 or ANSI T1.114 is a protocol for Signalling System 7 networks. Its primary purpose is to facilitate multiple concurrent dialogs between the same sub-systems on the same machines, using Transaction IDs to differentiate...

)