Table Of Contents
Cisco PGW 2200 Softswitch Presentation Number Modification Feature Module
Document Release History
The Presentation Number Modification feature was introduced on the Cisco MGC software.
This document describes the Presentation Number (PN) Modification feature and includes the following sections:
The Presentation Number Modification feature enables a service provider to configure the Cisco PGW 2200 Softswitch to modify the presentation number (PN) for calls between a PSTN network on one side and a SIP server on the other. The feature modifies PN prefixes. Before the introduction of this feature, the Cisco PGW 2200 Softswitch could modify a calling party number (A-number). The PGW 2200 also could modify a PN but only if an A-number was present. This feature enables the PGW 2200 to modify a PN when no A-number is present.
ISUP messages can contain numbers presented in two different formats, national and international. A national number format does not include a country code. A national number also does not include a national-access-code prefix (the digit 0). An international number format looks similar to the national number format but it does include a country-code prefix.
Calls that the PGW 2200 receives from the PSTN contain the Nature of Address (NOA) parameter, which is specified as either national or international, for the calling party number (CgPn) and the PN. If the NOA is national, the number does not contain a country code. If the NOA is international, the number includes a country code.
For example, a call from the PSTN that contains a country code (for instance the UK-country-code +44) can be presented in one of the following two formats.
For another example, a call received from the USA (country code +1) can be presented in the following format.
In the case of a service provider whose PGW 2200 is located in the UK, a call received from the US cannot present the calling party number in national format because it is not a UK number. A SIP server located in the UK cannot present the international calling party number in its national format.
Devices on a SIP network may require digits in the international format regardless of the origin. Therefore, if configured, if a call originates on the PSTN and it includes a national NOA, the PGW 2200 must insert the appropriate country code when it sends the call to a device running the SIP protocol (for example, 44 in the UK).
Note You can configure the Cisco PGW 2200 to insert the appropriate country code for the country in which the PGW 2200 is located.
Occasionally, a call originating on the PSTN includes a PN but no A-number. The PN might be presented in national or international format.
Calls originating on a SIP network and sent through the PGW 2200 to the PSTN are presented in international format. If the PN or A-number included in the call is from a phone in the UK (a call from a phone in the UK would include +44), the PGW 2200 must present the number in national number format and set the NOA to national before it passes the call to the PSTN.
In this document, calls sent from the PSTN through the PGW 2200 to a SIP network are called break-in calls. Calls sent from a SIP network through the PGW 2200 to the PSTN are called break-out calls.
Note The examples provided in the following sections are of a Cisco PGW 2200 Softswitch located in the UK. However, it is possible to configure the Cisco PGW 2200 Softswitch for any country code, to match the country in which the PGW 2200 is located.
When the PGW 2200 receives a break-in call from the PSTN that is intended for a SIP network, it inspects the call for an A-number and PN. If there is no A-number, the PGW 2200 identifies the NOA of the PN. If the NOA of the PN is national, the PGW 2200 converts the NOA to international and adds the appropriate country code prefix.
For example, if a PGW 2200 receives a call from the PSTN that is intended for a subscriber on a SIP network in the UK, the PGW 2200 converts the number from a national format to international format by adding the prefix +44 to the PN.
Note For the example in this section, the PGW 2200 manages calls according to requirements of the British Telecommunications network.
When the PGW 2200 receives an break-out call from a SIP network that is intended for the PSTN, if the PN includes a country-code prefix, and the PGW 2200 is located in the country identified by the prefix, the PGW 2200 converts the PN NOA to national and removes the country-code prefix.
Note In this context, the PGW 2200 manages calls according to requirements of the British Telecommunications network.
Number Conversion Examples
Table 1 lists examples of how the PGW 2200 manages the number conversions required when it receives incoming calls from the PSTN that are intended for a subscriber on a SIP network and that include numbers presented in various formats.
Table 2 provides examples of how the PGW 2200 converts PNs when it receives outgoing calls from a SIP network that are intended for a subscriber on the PSTN and that include numbers presented in various formats.
The Presentation Number Modification feature enables the Cisco PGW 2200 Softswitch to manipulate a presentation number, which improves its ability to connect elements on a PSTN network to elements on a SIP network.
This document contains information that is strictly related to this feature. The documents that contain additional information related to the Cisco PGW 2200 Softswitch are at
This section describes the configuration required to enable the PN Modification feature on the Cisco PGW 2200.
Note The information in this section pertains specifically to configuring the Cisco PGW 2200 Softswitch to manage PN modification for PSTN-to-SIP and SIP-to-PSTN calls according to requirements of the British Telecommunications network.
Configuring PSTN to SIP Calls
Figure 1 presents a diagram that shows the PGW 2200 properties that the service provider must configured on trunk groups to enable the PN Modification feature to convert PNs properly for PSTN-to-SIP Calls.
Figure 1 Trunk Group Configuration for PSTN-to-SIP Calls
In Figure 1, the incoming PSTN trunk group is 1000. The outgoing SIP trunk group is 2222. The SIP side always requires an international number. For this example, assume that country code is 44 (for the UK).
On the originating side, the service provider sets the trunk group property CCOrigin to 44
(CCOrigin = 44).
On the terminating side, the service provider sets the trunk group property ADigitCCPrefix to 1 (ADigitCCPrefix = 1). The ADigitCCPrefix property enables the PGW 2200 to add the prefix country code to both the PN and CgPn.
Also on the terminating side, the service provider sets the trunk group property BDigitCCPrefix to 1 (BDigitCCPrefix = 1). The BDigitCCPrefix property enables the PGW 2200 to add the prefix country code to the called number.
In addition, the service provider configures the required country code digit strings for B-number modification in DIGMODSTRING. The service provider adds the result type CC_DIG to the dial plan (identified as t001 in this example). The following MML sample commands show how to add the DIGMODSTRING and result type CC_DIG to the dial plan t001:numan-add: digmodstring: custgrpid="t001", name="ccUK", digstring="44"numan-add: resulttable: custgrpid="t001", name="result2", resulttype="CC_DIG", dw1=UK, setname="set5"
On the terminating side, if the service provider sets the property MapCLItoSipHeader to 0 (MapCLItoSipHeader = 0), the PGW 2200 maps the PN to the display name and the CgPn to the user name in the From Header of the SIP message.
Also, the service provider might be required to set the property cgpnInclude to either 0 or 1 to alter number display behavior when the presentation indicator is ''presentation restricted.''
Note A service provider sets the property cgpnInclude to meet the requirements of its network.
•If you set cgpnInclude = 0, and the SIP network is not trusted, the From header has SIP URI as: Anonymous <sip:Anonymous@anonymous.invalid>
•If you set cgpnInclude = 1, and the SIP network is trusted, and honors the anonymous setting by not passing the CLI to the SIP end point, the From header has URI as Anonymous <sip:CGPN@PGW_HOST>
If you set the property MapCLItoSipHeader to 3 (MapCLItoSipHeader = 3), the PGW 2200 maps the PN to the display name and user name in the From header of the SIP message and the CgPn to the P-Asserted-ID header.
Configuring SIP-to-PSTN Calls
Figure 2 presents a diagram that shows the PGW 2200 properties that the service provider must configure on trunk groups to enable the PN Modification feature to convert PNs properly for SIP-to-PSTN calls.
Figure 2 Trunk Group Configuration for SIP to PSTN Calls
In Figure 2, the incoming SIP trunk group is 2000. The outgoing PSTN trunk group is 1000. The SIP side always requires an international number. For this example, assume that country code is 44 (for the UK).
On the originating side, the service provider sets the property InhibitSipFromMapping to 3 (InhibitSipFromMapping = 3).
See the Cisco Media Gateway Controller Software Release 9 Provisioning Guide (Table A-75 in Appendix A) for a full description of the InhibitSipFromMapping property.
On the terminating side, the service provider sets the properties ADigitCCRm and BDigitCCRm to 44 (the country code for the UK in this example). The following sample MML commands show how the trunk groups might be configured to support SIP to PSTN calls:prov-ed:trnkgrpprop:name="2000", custgrpid="DP00", InhibitSipFromMapping="3", ADigitCCPrefix="1"prov-add:trnkgrpprop:name="1000", adigitccrm="44", bdigitccrm="44"
You specify a value for the trunk group property CliSelectionForCodeOfPractice3 to provision the level of calling line identity (CLI) that you want the PGW 2200 to use when sending the calling line identities (such as Calling Party Number or Generic Number parameter) to the next exchange. Valid values for this property are in the range 0-2 (Default 0).
Valid values for the property CliSelectionForCodeOfPractice3:
0—Indicates no specific CLI selection (default)
1—Indicates single CLI selection. Sends only the CLI.
2—Indicates dual CLI selection. Sends the CLI; or the PGW 2200 send the CLI and the PN.
3—Indicates CBI bit transparency over DSS1.
Set the property CliSelectionForCodeOfPractice3 to 0 or 2 to meet your service-provider requirements.
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