ANSI T1.671:2000 pdf download.Signaling System Number 7 (SS7) -Carrier Service Provider ldentification (CSPI).
Carrier Service Provider Identification (CSPI) information is intended to identify to intermediate switches all presubscribed carriers associated with a calling party. Identifiable 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 presubscnbed 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.
2 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.1
3 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 Identification (LSPI) information rather than the CSPI information.
4 Acronyms
ANSI American National Standards Institute
5 Description of Network Capability
5.1 General Description
When a calling party dials a called party number, the originating switch determines which carrier should handle the call as dialed. The originating switch then routes the call within or toward, that carrier’s network. Certain network services, such as operator services, allow a network service operating at an intermediate switch to change the called party from that which had been originally dialed.
In support of such network services, the CSPI Information Identifies the carrier selected for the call as dialed, if other than the local service provider. Where the carrier for the call as dialed is the local service provider, Local Service Provider Identification (LSPI) information will allow proper identification of the carrier. CSPI also identifies any other known carriers associated with the calling party.ANSI T1.671 pdf download.