Contents
1 Introduction
This document describes how to configure the SIP Trunking Application Server (ST AS) Carrier Select Rn (CSRn) and Carrier Pre-Select Rn (CPSRn) services in MTAS. It describes how to configure the Managed Objects (MOs) for the ST CSRn and CPSRn services, how these services are collocated with other services in the ST AS, and the interaction between them.
This document is intended for personnel configuring and fine-tuning the ST AS.
1.1 Prerequisites
It is assumed that the user of this document is familiar with the Operation and Maintenance (O&M) area, in general.
1.1.1 Licenses
No service license is required for the ST CSRn or CPSRn services.
1.1.2 Documents
Before starting any procedure in this document, ensure that the following documents are available:
1.1.3 Conditions
The following condition must apply:
- An Ericsson Command-Line Interface (ECLI) session in Exec mode is in progress.
2 Overview
The ST CSRn service allows an end user in a Private Branch Exchange (PBX) to choose which carrier to select for a particular call. The main functions of the ST CSRn are as follows:
- Check if the user is allowed to use a carrier identified from a dialed Carrier Select Code (CSC) prefixed to the dialed number
- Take the appropriate action that includes the addition of the rn parameter.
The ST CPSRn service allows calls from each served user to be handled by a carrier other than the default carrier, depending on whether the call is local or remote.
The ST CSRn overrides the ST CPSRn. They are both originating services normally executed for the originating session case.
After the ST Communication Diversion (CDIV) on a terminating ST AS, when AS chaining is disabled, the ST AS continues to execute ST CSRn or CPSRn on behalf of the diverted PBX.
When AS chaining is enabled, the INVITE is routed back to the Serving Call Session Control Function (S-CSCF) after ST CDIV is executed. The S-CSCF can then initiate triggering of ST CSRn or ST CPSRn for the originating session case.
2.1 ST CSRn and CPSRn Subfunctions
This section describes the main subfunctions in the ST CSRn and ST CPSRn.
2.1.1 ST Carrier Pre-Select Rn
The ST Carrier Pre-Select Rn subfunction provides the ST CPSRn service, which allows the operator to choose, for each end user, which carrier is to be used for all calls made to local and remote phone numbers.
2.1.2 Check Local Rn
The Check Local Rn subfunction determines whether a call type is local or remote. It uses the Country Code (CC) and Area Code (AC) stored in the subscription data to determine if the Called Party Numbers are local or remote.
If a match is found for the CC and AC of the caller in the Called Party number, the call is considered local, otherwise, it is considered remote.
2.1.3 ST Carrier Select Rn
The ST Carrier Select Rn subfunction provides the ST CSRn service, which allows an end user to choose which carrier to be used for a particular call.
2.1.4 Destination Validation Rn
The Destination Validation Rn subfunction checks if calls to the destination address are not allowed to use Carrier Select.
2.1.5 Configure Service
Both ST CSRn and ST CPSRn services are enabled at node level. For more information, refer to Managed Object Model (MOM).
2.2 Interaction with Other Services
This section describes how the ST CSRn and the ST CPSRn interact with other services.
2.2.1 ST CSRn and ST CPSRn
The ST CSRn service has precedence over the ST CPSRn service. That means, if a user provisioned with both ST CSRn and ST CPSRn starts call-by-call Carrier Select, then the call is routed using the ST CSRn service.
Both ST CSRn and ST CPSRn preserve the received rn parameter. This means that these services are bypassed, and the rn parameter is forwarded if received from the PBX. It is the same behavior in Multimedia Telephony (MMTel). The standard CS and CPS parameters (cic, dai, npi) are deleted by ST CSRn or ST CPSRn, if provisioned for the PBX.
2.2.2 ST Communication Diversion
If the target address of a diversion contains a phone number, the INVITE to the target is subject to the same ST CSRn or ST CPSRn logic as if the served user originated the call to the target.
After the ST CDIV, either terminating ST AS continues to trigger ST CSRn (or ST CPSRn) for the terminating session case, or the INVITE is routed back to the S-CSCF, in which case the originating ST AS is started from the S-CSCF, and triggers originating services (like ST CSRn or ST CPSRn) for the originating session case.
For more information, refer to MTAS Communication Diversion Management Guide.
2.2.3 ST Communication Barring
The original domain name in the incoming request is only overwritten with the domain name of the Carrier, after Originating Communication Barring service (OCB) interaction has been carried out.
It is possible to create OCB rules that bar or allow calls based on carrier selected by the caller. For more information, refer to ST AS Communication Barring Service Management Guide.
3 ST CSRn and ST CPSRn Configuration
The ST CSRn and ST CPSRn services are controlled by the MtasStCsCpsRn MO. An overview of the ST CSRn and ST CPSRn MO structure is shown in Figure 1.
Configurable MOs and attributes related to the ST carrier selection services are defined in Managed Object Model (MOM).
3.1 ST Carrier Selection Reason Codes Configuration
The Q.850 Reason code value that arrives for a congestion situation in 4xx or 5xx is set by the mtasStCsCpsRnReasonCodes attribute in the MtasStCsCpsRn MO.
3.2 ST CSRn Administrative State Configuration
The ST CSRn service is enabled by setting the mtasStCsRnAdministrativeState attribute in the MtasStCsRn MO to 1. If the mtasStCsRnAdministrativeState is set to 0 (Locked), no ST CSRn service is provided by the ST AS.
3.3 ST CSRn Carrier Access Code Configuration
The code to be dialed by the user to use an alternative carrier is set by the mtasStCsRnCarrierAccessCode attribute in the mtasStCsRn MO.
3.4 ST CSRn Carrier Select Code Configuration
The code to be dialed by the user pointing out the specific carrier is set by the mtasStCsRnCsc attributes in the mtasStCsRn MOs. The string consists of the Carrier Access Code (CAC) followed by the Carrier Identification Code (CIC) as received in the Request-URI.
3.5 ST CSRn Carrier Identity Configuration
Each carrier identity is set by the mtasStCsRnCscCarrierId attribute in the mtasStCsRnCsc MO. It is a key to an existing instance of MtasStCarrierRn MO.
3.6 ST CSRn Carrier Name Configuration
The alias name for each carrier is represented by the mtasStCsRnCscCarrierName attribute in the mtasStCsRnCsc MO.
3.7 ST Carrier Rn Configuration
The CarrierId in the MtasStCarrierRn MO is defined by its attribute MtasStCarrierRn.
3.8 ST Carrier Rn Domain Configuration
The domain associated with the carrier is set by the MtasStCarrierRnDomain attribute in the MtasStCarrierRn MO.
3.9 ST Carrier Rn Disallowed Destinations Configuration
The destination telephone numbers not allowed to be routed over a specific carrier are configured by the mtasStCarrierRnDestDisallowed attribute of the carrier MtasStCarrierRn MO. This attribute is a list specifying the leftmost part of global numbers, starting with a + sign followed by 0–31 digits.
3.10 ST CPSRn Administrative State Configuration
The ST CPSRn service is enabled by setting the mtasStCpsRnAdministrativeState attribute in the MtasStCpsRn MO to 1. If the mtasStCpsRnAdministrativeState is set to 0 (Locked), no ST CPSRn service is provided by the ST AS.
3.11 ST CPSRn Test Number Local Configuration
The test numbers that a user can dial to test the local preselection are set by the mtasStCpsRnTestNumLocal attributes in the MtasStCpsRn MO. Each value in the local test number list must be different from each value in the mtasStCpsRnTestNumRemote.
3.12 ST CPSRn Test Number Remote Configuration
The test numbers that a user can dial to test the remote preselection are set by the mtasStCpsRnTestNumRemote attributes in the MtasStCpsRn MO. Each value in the remote test number list must be different from each value in the mtasStCpsRnTestNumLocal.
3.13 Service Data Configuration
This section describes how to configure the service data.
3.13.1 Operator Subscription Level Service Configuration
The operator part of the subscriber data is set through the Customer Administration Interface Third Generation (CAI3G) protocol. As a prerequisite for activating ST Carrier Select Rn or ST Carrier Pre-Select Rn, the Country Code and Area Code of the PBX must be set in the ST Common Data.
For more information, refer to MTAS CAI3G Interface for ST AS.
3.13.2 Subscriber Subscription Level Service Configuration
No service data for the ST CSRn, nor ST CPSRn services are configured in the subscriber part of the subscriber data.
4 Performance Management
For information on measurements related to the ST CSRn and ST CPSRn services, refer to Managed Object Model (MOM).
5 Fault Management
There are no alarms related to the ST CSRn and ST CPSRn services.