The SVI-IWF supports the 3GPP IMS component the IM-Service Switch Function (IM-SSF) 3GPP 23.278 providing a seamless bridge between an IMS network (SIP) and a CAMEL based SS7 Intelligent Network via Squire Technologies integrated SVI-TAS Telephony Application Server.
When an operator initially deploys an IMS network they are unlikely to be able to enable all the revenue services available to their existing legacy subscribers. To insure continuity of service the IMS network can leverage the existing Intelligent Network through the IM-SSF component.
In “reverse” the IM-SSF allows legacy subscribers to access the new services available in an IMS network. It is the glue that allows legacy subscribers to access new services run from SIP application servers – i.e Mobile PBX, OTT etc.
Unstructured Supplementary Services Data (USSD) is a session based protocol used in 2G/3G networks to send text between a mobile phone and an application program in the network. Unlike SMS there is no store and forward as USSD transactions only exist for the length of a session. USSD applications are generally menu driven as able to push text in menu format to subscriber handsets.
Working with a 4G mobile operator rolling out roaming services they needed to insure that pre-paid subscribers credit checks operate correctly in 3G networks.
Some 3G networks perform credit checks via USSD. The SVI-TAS integrated with a DIAMETER SVI-IWF product is deployed in the clients 4G network to deliver the required USSD to DIAMETER messaging inter-operability. In a subsequent phase of the project the client decided to provide their subscribers with a full USSD driven menu application. This was interfaced and configured using the SVI-TAS to provide the HTTP interface to their OCS platform. This flexibility and ease of deployment allows our clients to rapidly evolve and extend functionality according to their requirements.