Cisco PGW 2200 Softswitch Presentation
Number Modification Feature Module
Document Release History
Publication Date
Comments
January 16, 2009
Initial release of document
Feature History
Release
Modification
9.7(3)
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:
•
Feature Description, page 1
•
Configuration, page 5
•
Obtaining Documentation, Obtaining Support, and Security Guidelines, page 8
Feature Description
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.
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Cisco PGW 2200 Softswitch Presentation Number Modification Feature Module
Feature Description
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.
Nature of Address (NOA)
Address Digits
International
442085550165
National
2085550165
For another example, a call received from the USA (country code +1) can be presented in the following
format.
Nature of Address (NOA)
Address Digits
International
12125550140
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.
Presentation Number Modification
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Cisco PGW 2200 Softswitch Presentation Number Modification Feature Module
Feature Description
PSTN-to-SIP Calls
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.
SIP-to-PSTN Calls
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 1
Examples of PSTN-to-SIP PN Conversion by the Cisco PGW 2200 Softswitch
Number Format
IAM Message Received from the PSTN Side
INVITE Message Sent to the SIP Side
National formats
Calling party number (CgPn): 2085550100
If the caller is in the UK:
Presentation number (PN): 2085550123
•
CgPn is converted to +442085550100
•
PN is converted to +442085550123
As another example, if the PGW 2200 is located in
Spain and the NOA is national:
International
formats
•
CgPn is converted to +342085550100
•
PN is converted to +342085550123
CgPn: 12125550100
CgPn is converted to +12125550100
PN: 12125550123
PN is converted to +12125550123
Mixed national and National CgPn: 2085550100
international NOA International PN: 442085550123
formats
If the caller is in the UK:
•
CgPn is converted to +442085550100
•
PN is converted to +442085550123
Presentation Number Modification
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Cisco PGW 2200 Softswitch Presentation Number Modification Feature Module
Feature Description
Table 1
Examples of PSTN-to-SIP PN Conversion by the Cisco PGW 2200 Softswitch (continued)
Number Format
IAM Message Received from the PSTN Side
INVITE Message Sent to the SIP Side
Mixed NOAs.
International CgPn: 12125550100
The PGW 2200 drops the PN parameter.
An International
number is “faking”
a National number
prefix.
National PN: 2085550123
Mixed NOAs
International CgPn: 442085550100
National PN: 2085550123
If the caller is in the UK:
•
CgPn is converted to +442085550100
•
PN is converted to +442085550123
As another example, if the PGW 2200 is located in
Spain and the NOA is mixed, the PGW 2200 drops
the PN parameter.
No CgPn
No CgPn parameter
If the caller is in the UK:
National PN: 2085550123
PN is converted to +442085550123
The PGW 2200 converts the PNs in this example
depending on the value that is set for the property
MapCLItoSipHeader.
If the property MapCLItoSipHeader = 0, the PN is
associated with the display name in the From
header. The calling party number is associated
with the user name in the From header to meet the
requirements for this feature.
If the property MapCLItoSipHeader > 0 (1, 2, or
3), the PN is mapped to both display name and
user name in the From header. The calling party
number is put in the P-Asserted-Id header or
Remote-Party-Id according to a different property
value that is the expected by the SIP protocol.
No CgPn with
international PN
No CgPn parameter
International PN: 442085550123
If the caller is in the UK:
•
CgPn: not available
•
PN is converted to +442085550123
(Conversion depends on the setting of the CLI
code of practice)
Presentation Number Modification
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Cisco PGW 2200 Softswitch Presentation Number Modification Feature Module
Feature Description
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.
Table 2
Examples of SIP-to-PSTN PN Conversion by the Cisco PGW 2200 Softswitch
Number Format
PSTN Side (IAM Message)
National format for In the UK:
UK
National CgPn is converted to 2085550100
International
format
SIP side (INVITE Message)
CgPn: +442085550100
National PN is converted to 2085550123
PN: +442085550123
International CgPn is converted to 12125550100
CgPn: +12125550100
International PN is converted to 12125550123
PN: +12125550123
Benefits
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.
Related Documents
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
http://www.cisco.com/en/US/products/hw/vcallcon/ps2027/tsd_products_support_series_home.html
Configuration
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.
Presentation Number Modification
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Cisco PGW 2200 Softswitch Presentation Number Modification Feature Module
Feature Description
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.
PSTN
Trunk Group Configuration for PSTN-to-SIP Calls
Trunk group 1000
CCOrigin = 44
PGW 2200
Trunk group 2222
ADigitCCPrefix = 1
BDigitCCPrefix = 1
SIP
273682
Figure 1
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:[email protected]>
•
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.
Presentation Number Modification
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Cisco PGW 2200 Softswitch Presentation Number Modification Feature Module
Feature Description
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.
PSTN
Trunk Group Configuration for SIP to PSTN Calls
Trunk group 1000
ADigitCCRM = 44
BDigitCCRM = 44
PGW 2200
Trunk group 2000
SIP
InhibitSipFromMapping = 3
273683
Figure 2
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.
Presentation Number Modification
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Cisco PGW 2200 Softswitch Presentation Number Modification Feature Module
Obtaining Documentation, Obtaining Support, and Security Guidelines
Obtaining Documentation, Obtaining Support, and Security
Guidelines
For information on obtaining documentation, obtaining support, providing documentation feedback,
security guidelines, and also recommended aliases and general Cisco documents, see the monthly
What’s New in Cisco Product Documentation, which also lists all new and revised Cisco technical
documentation, at
http://www.cisco.com/en/US/docs/general/whatsnew/whatsnew.html
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Presentation Number Modification
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