ATIS 1000671-2000 Signaling System Number 7 (SS7) - Carrier Service Provider Identification (CSPI).pdf

1、 AMERICAN NATIONAL STANDARD FOR TELECOMMUNICATIONS ATIS-1000671.2000(R2015) Signaling System Number 7 (SS7) Carrier Service Provider Identification (CSPI) As a leading technology and solutions development organization, ATIS brings together the top global ICT companies to advance the industrys most-p

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11、r the others would be identified as potential carriers. CSPI has been developed for use between U.S. networks to meet the anticipated needs and applications of those entities. This standard is the result of extensive work by members of the T1S1.3 Working Group on U.S. Standards for Common Channel Si

12、gnaling. This standard is intended for use in conjunction with American National Standard for Telecommunications - Signaling System Number 7 (SS7) - ISDN User Part (ISUP) - T1.113-2000, which includes an overview, messages and signals, protocol formats, procedures, and a chapter on performance. Foot

13、notes are not officially part of this standard. Future control of this document will reside with Accredited Standards Committee on Telecommunications, T1. This control of additions to the specification, such as protocol evolution, new applications, and operational requirements, will permit compatibi

14、lity among U.S. networks. Such additions will be incorporated in an orderly manner with due consideration to the ITU-T layered model principles, conventions, and functional boundaries. Suggestions for improvement of this standard will be welcome. These should be sent to the Alliance for Telecommunic

15、ations Industry Solutions, T1 Secretariat, 1200 G Street, NW, Suite 500, Washington DC 20005. This standard was processed and approved for submittal to ANSI by the Accredited Standards Committee on Telecommunications, T1. Committee approval of this standard does not necessarily imply that all commit

16、tee members voted for its approval. At the time it approved this standard, the T1 Committee had the following members: G. H. Peterson, Chair E. R. Hapeman, Vice-Chair S. C. Carioti, T1 Disciplines S. D. Barclay, Secretary C. A. Underkoffler, Chief Editor R. W. Hemmeter, T1 Technical Editor EXCHANGE

17、CARRIERS Organization Represented Name of Representative Ameritech Fred Kujawski Cathy Lazzaro (Alt.) AT Model 2 shows a local exchange connected to an operator services system via a transit exchange; Model 3 shows a local exchange connected to a second operator services system via a first operator

18、services system. LEOSSOSSLETROSSLEOSSModel 1Model 2Model 3The originating switch includes CSPI information in its call setup message. If the carrier for the call as dialed is the local service provider, all carriers identified in the CSPI information will be marked as potential; otherwise, one of th

19、e carriers in the CSPI information will be marked as selected while the other carriers will be marked as potential. An intermediate switch that supports a network service that uses CSPI information will provide the information to that network service. The network service will apply the CSPI informat

20、ion and determine whether the CSPI information should be signaled if an outgoing connection is desired. An intermediate switch that does not support a service that uses CSPI information will pass the CSPI information along in its subsequent call setup message. 5.2 Procedures 5.2.1 Provision/Withdraw

21、al Call processing at the originating switch will determine whether to include CSPI information in the call setup message of a specific call. An end user cannot explicitly request or restrict the inclusion of CSPI information in the call setup message. An end user will implicitly request CSPI inform

22、ation by dialing the 0 prefix, by dialing a service-related number, or by dialing from a screened or otherwise restricted station. ATIS-1000671.2000 5.2.2 Normal Procedures 5.2.2.1 Activation/Deactivation The inclusion of CSPI information is activated or deactivated on a per trunk group basis. The e

23、xtraction of CSPI information is activated or deactivated on a per switch basis. 5.2.2.2 Invocation and Operation Call processing invokes the inclusion and extraction of CSPI information. If the inclusion of CSPI information is active and call processing determines that the call is of a type that re

24、quires CSPI information, e.g., operator services, CSPI will be included in the call setup message. Similarly, if an intermediate switch supports a network service that requires CSPI information, and extraction of CSPI information is active, call processing will pass the received CSPI information, if

25、 any, to the network service. Call processing determines whether carriers are active or potential. For example, for 0- calls2, all CSPI carriers should be marked as potential; LSPI information will identify the local carrier. For 00- calls3, the interLATA carrier in CSPI should be marked selected wh

26、ile all other carriers are marked potential. For calls dialed with a called party number, the relationship between the calling and called party numbers should be used to determine whether carriers are marked as selected or potential. 5.2.3 Exceptional Procedures If an intermediate switch supports a

27、network service that requires CSPI information but no CSPI information is received, the network service may be able to obtain comparable data from another source. The network service at the intermediate switch may specify that CSPI be included in a subsequent setup message. 5.2.4 Alternate Procedure

28、s Under business agreements, a 0- call may result in the intraLATA Toll carrier being marked as selected; however, this will make it impossible to distinguish 0- and 00- calls if they are carried over a common trunk group served by a single carrier. 5.3 Interworking Considerations Inband signaling i

29、s not expected to support the CSPI network capability. If interworking is encountered for a call whose setup message includes CSPI information, the CSPI information will be deleted following the procedures for unsupported signaling information in T1.113. 5.4 Network Capabilities for Charging None id

30、entified. 5.5 Interactions with Supplementary Services The CSPI network capability is provided in support of supplementary services such as operator services and intelligent network capabilities. These network services would have to be modified if there were a need to use CSPI information received o

31、r to determine whether received CSPI 2A 0- call is a call for which only 0 was dialed. 3A 00- call is a call for which only 00 was dialed. ATIS-1000671.2000 information should be signaled onward. The nature of such modifications is beyond the scope of this document. A network service that had not be

32、en modified to use CSPI information should ignore it following the procedures for unrecognized optional parameters in the normative reference. No other interactions with supplementary services or network capabilities have been identified. Supplementary services and network capabilities need not be c

33、hanged if they do not make use of CSPI. 6 Functional Capabilities and Information Flows 6.1 Functional Entity Model The CSPI network capability adds functional entities to the existing basic call functional entities (FE) BC-O and BC-I for originating and intermediate nodes. There is no application o

34、f the CSPI information at a destination node; hence, there is no CSPI destination node functional entity. Supplementary services FEs may exist at an intermediate node (SS-I) that will accept information provided by the CSPI network capability. The FEs that comprise the CSPI network capability are th

35、e CSPI originating FE (CSPI-O) and the CSPI intermediate FE (CSPI-I). Figure 1 illustrates the relationship of the CSPI FEs and the basic call FEs. Figure 1 - FE Model for Service Provider Information 6.1.1 CSPI Originating Node Functional Entity CSPI-O is a FE that determines from call processing s

36、ervice logic that CSPI information should be included in the outgoing signaling to identify the potential carriers and possibly the selected carrier associated with a call as dialed. The CSPI information may be associated with the calling party based on switch provisioning or may be obtained from an

37、other network node. If BC-O determines that a call requiring CSPI information is to be handled by the local service provider, CSPI-O will mark all carriers identified in the CSPI information as potential carriers. If BC-O determines that a call requiring CSPI information is being handled by an intra

38、LATA toll carrier, an interLATA carrier, or an international carrier, CSPI-O will mark that carrier as the selected carrier and will mark the other carriers as potential carriers. ATIS-1000671.2000 6.1.2 CSPI Intermediate Node Functional Entity CSPI-I is a FE that determines whether received CSPI in

39、formation is to be passed to a resident supplementary service, for example, SS-I. Under the direction of SS-I, CSPI-I may include CSPI information in subsequent signaling. If there is no applicable SS-I at a given intermediate node, CSPI information is signaled forward unchanged. 6.2 Information Flo

40、w Model Figure 2 shows the proposed information flow model for including CSPI information in call setup messages. Figure 2 - Information Flow Model for SPI 6.2.1 Invoking CSPI-O CSPI-O is invoked by call processing at an originating node when the call is identified as requiring a supplementary servi

41、ce provided by another node that requires CSPI information. 6.2.2 Invoking CSPI-I CSPI-I is invoked by call processing at an intermediate node when a call setup message is received that requires a supplementary service provided by that node and that uses CSPI information. If an intermediate node doe

42、s not support a supplementary service that uses CSPI information, the CSPI information will be sent without change in the outgoing call setup message by the BC-I FE. 6.2.3 Activation and Deactivation of the CSPI Network Capability Activation and deactivation of the CSPI network capability is done on

43、 a per functional entity, per node basis. 6.2.4 Exceptional Procedures If CSPI information cannot be obtained for a given call, CSPI-O will route the call without CSPI information. If an intermediate node providing a supplementary service that expects CSPI information receives a call without CSPI in

44、formation, the BC-I FE will provide the available received ATIS-1000671.2000 information without the CSPI information. The supplementary service may be able to obtain comparable data from another source, such as an operator asking the calling party to provide the name of the preferred carrier to rea

45、ch the current called party number. If an intermediate node has not received CSPI information in the call setup message, it will not include CSPI information in a subsequent call setup message, except when a supplementary service explicitly provides the CSPI information from another source. Such pro

46、vision is not required by this protocol. 6.2.5 Allocation of Functions to Equipment An originating node supports BC-O and CSPI-O. An intermediate node supports BC-I and may support SS-I and CSPI-I. Table 1 identifies different scenarios for allocating FEs to specific network elements. LE represents

47、a local exchange and TR represents a transit exchange or intermediate switch. Table 1 - Allocation of Functions to Equipment Scenario LE TR TR 1 BC-O, CSPI-O BC-I, SS-I, CSPI-I 2 BC-O, CSPI-O BC-I BC-I, SS-I, CSPI-I 7 Protocol and Procedures 7.1 Protocol and Procedural Assumptions CSPI information r

48、elated to a particular calling party can be obtained from exchange provisioning data or from interactions between an exchange and another network node. The actual source of these data is beyond the scope of this protocol. CSPI information is carried as an optional ISDN User-Part (ISUP) parameter in

49、the Initial Address Message (IAM). The CSPI parameter may provide information about multiple carriers associated with the calling party. Inclusion of the CSPI parameter by an exchange capable of originating the CSPI parameter depends on supplementary service characteristics of a specific call, e.g., CSPI information would be included if a 0 prefix is dialed. The decision criteria to include the CSPI parameter are beyond the scope of this protocol. Initially, a single CSPI parameter identifying three carriers of four Binary Coded Decimal (BCD) digits each is expected to suffice. However