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PSX Globalization Summary

A globalized number in PSX SIP URI can be represented as global number or as combination of local number and phone-context parameter.

Currently, the R-URI header received in an INVITE message is used for populating the Called Number and the Called-URI structures in a policy request. Called-URI structure is populated as it is from the Request URI wherein the user-part of URI is copied to the user-part and the phone-context value is copied to the phone-context part of called-URI structure. However, for populating called number structure, only the user-part of URI is used, wherein the user-part is copied as the called number in Called number structure.

When the SBC Core receives a globalized number in Request-URI, it uses that number to populate the called number in the policy request. The PSX uses the received number for call processing. However, when the Request-URI contains a number in "local number + phone-context" format, only the local number (represented by the user part of SIP URI ) is populated as the called number in policy request which the PSX uses for call processing. In this scenario the phone-context received in the incoming SIP message is not honored and hence not used for call processing. The SBC honors phone-context received in R-URI using the honorPhoneContext flag configurable in the Feature Control Profile. When this flag is enabled, phone-context received in R-URI is honored and local number+phone-context is used for call processing.

Currently, a local number is globalized from the PSX using the globalization profile. When the “Globalize Flag” in the Globalization profile is enabled, the PSX copies the country code to the policy response and indicates to the SBC that number is globalized, and to prepend the CC to called number before sending out the message to next hop. The SBC uses the country-code received in policy response and appends to it a '+' followed by the called number and sends the global number is Egress Request-URI and To Header.

The SBC allows the configuration of a phone-context parameter length (phoneContextParameterLength in IP Signaling Profile) in an Egress message when the number is globalized in PSX. If the phoneContextParameterLength is configured for value "n", then first "n" digits of the number are used as phone-context, and the remaining digits are used as local number in egress message. A default value of "0" means this parameter is not used.

In summary, the SBC honors the phone-context parameter for globalization of the local number at the PSX (i.e. converting the local number to E.164 number) before using it for call processing, and provided a mechanism to configure phone-context parameter length for inclusion in the egress message.

SBC Behavior

When the phoneContextParameterLength flag is configured in the SBC for a length greater than "0" for the globalized called number, the PSX sends the configured value in a policy response to the SBC. The SBC, in turn, uses this configured value to insert phone-context parameter of received length in RURI and To headers.

When the SBC flag honorPhoneContextParameter is enabled, the SBC uses the country-code received in policy response and appends to it a '+' followed by the called number and sends the global number is Egress Request-URI and To Header.

useIpProtocol flag must first be enabled in order to enable honorPhoneContextParameter flag.

 

For configuration details, refer to the following pages:

Honor Phone Context Parameter:

Phone Context Parameter Length:

 

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