ANSI T1.671-2000 pdf download Signaling System Number 7 (SS7) – Carrier Service Provider ldentification (CSPI)
Scope, Purpose, and Application
1.1 Scope Carrier Service Provider ldentification (CSPI) information is intended to identify to intermediate switches all presubscribed carriers associated with a calling party. ldentifiable carrier service providers include the preferred intraLATA toll carrier, the preferred interLATA carrier, and the international carrier. Other carrier types may be included as the need arises.
1.2 Purpose CSPI may identify one carrier that had been selected to transport a call as dialed. CSPI should identify all other associated presubscribed carriers as potential carriers. A potential carrier may become the selected carrier if the called party number is changed at an intermediate switch. For appropriate call types, an originating switch should include CSPI information in a call setup message sent to an intermediate switch.
1.3 Application CSPI should be used for PSTN, non-ISDN and ISDN circuit mode (Basic and Primary Rate) calls.
Normative Reference
The following standard contains provisions, which, through reference in this text, constitute provisions of this American National Standard. At the time of publication, the edition indicated was valid. All standards are subject to revision, and parties to agreements based on this American National Standard are encouraged to investigate the possibility of applying the most recent edition of the standard indicated below:
T1.113 – 2000, American National Standards for Telecommunication Signaling System No. 7 (SS7) Integrated Services Digital Network (ISDN) User Part.
Definitions
Carrier: used in this standard to represent the network transporting a call. However, as a distinction under this usage, if the carrier is a local service provider, that information is conveyed by the Local Service Provider ldentification (L SPI) information rather than the CSPI information.
4 Acronyms ANSI American National Standards Institute