1. Diameter Signaling Router Mobile Number Portability User Guide
  2. vSTP G-Flex Feature

6 vSTP G-Flex Feature

The GSM Flexible Numbering (G-Flex) feature enables efficient Home Location Register (HLR) management in ITU networks, ANSI networks, Global System for Mobile communications (GSM) networks, and IS-41 networks. G-Flex optimizes the use of subscriber numbers and number ranges by providing a logical link between any MSISDN number or IMSI and an HLR. This arrangement allows subscribers to be moved easily from one HLR to another.

The GSM Flexible Numbering (G-Flex) feature enhances the vSTP capabilities, by allowing operators to flexibly assign individual subscribers to HLRs and route signaling messages, based on MSISDN or IMSI number.

Upon receiving a message, G-Flex performs a G-Flex selector search in the database using the SCCP Cdpa parameters available in the message. Existence of the selectors in the G-Flex databse triggers G-Flex processing. Number conditioning is supported for the incoming messages that are destined for G-Flex processing.

The G-Flex functionality can be considerd as an enhancement to Global Title Transpotation (GTT) functionality in vSTP. The following are the G-Flex enhancements over GTT:
  • Increased Number of Translations: The transalation limit for GTT is 1 million. This limit is enhanced when G-Flex feature is used. However, the G-Flex translations are supported only from international MSISDNs and IMSIs to HLRs.
  • Number Conditioning: Since the G-Flex DataBase (GDB) stores MSISDNs and IMSIs as international numbers, and does not store Mobile Global Titles (MGTs), G-Flex provides the capability to condition incoming numbers to be international MSISDNs or IMSIs for the database look up.
  • Discrimination of Messages: Since G-Flex is used only for HLR translations, it provides a method to identify, which messages should receive G-Flex Relay or GTT. This is provided via a G-Flex service selector table, which defaults back to the GTT selector table if a match is not found.
  • Variable Number of Digits: There is no fixed number of digits for MSISDNs or IMSIs. For example, a 12-digit MSISDN can coexist with a 15-digit one. However, the number of digits of the stored numbers must be 8-15.