Ring Back Tones
The figure below shows the overall solution architecture with required integration points:
The service allows subscribers to select their personal Ring Back Tones to be played to a calling party when their Service Phone number is called.
The content i.e. the Ring Tone files shall not be provided by Media Routes. They may be provided by the operator through a third party content provider.
The following features and use cases are supported by the service:
- Tones are stored as .wav files in the Media Server which is an integral part of the RBT server.
- Users can select their tones from an online content portal by going to an operator supplied URL
- Users may also select their Tones from an IVR based portal by calling an Access Number. The hierarchy of IVR tree is constructed based on structure of the content e.g. folders and will be customized in collaboration with Service Provider and Operator’s team.
- Calling parties may also select their Tones while hearing them during a call if they are also a customer of the Phone Service by pressing a Hot-Key combination, for which they shall be prompted while the one is being played.
- Users may change their Tones by any of the methods mentioned above.
- One single global ring back tone can be selected for all incoming calls while up to 5 different tones can be selected on per caller Identifier basis. The global tone will be played to all callers except if a Caller Identifier matches a Caller Identifier specific tone in the subscriber profile.
- Subscribers may also subscribe to RBT via USSD short codes. The RBT web-service, which is an integral part of RBT Application Server, shall receive those codes from Operator’s USSD gateway and pass them to the RBT Application for interpretation.
- Users may cancel their subscription to Ring-Back Tones by either a web-based portal or calling an IVR number
- Every time a user receives an incoming call, the calling party shall hear the user selected Ring Back Tone till the user picks up the call. The tone shall stop playing as soon as the user picks up the call.
Required Integrations and Call Flow
The Ring Back Tones Service described above requires the following critical integrations with the Operator’s Network Elements depending upon the network architecture:
Integration with Mobile Switching Center
If the operator deploys this service in an existing 2G or 3G (CDMA) fixed or mobile network, then integration is required with Operator’s Mobile Switching Center (MSC) or core Soft-Switch that handles the Call Signaling and Media.
Note that if this service is deployed in an NGN or 4G network such as LTE which is all IP till the last mile i.e. local loop is also IP, then this integration is not required.
RBT service shall integrate with the MSC to handle call signaling of the calling party before the subscriber picks up. The Call flow is described below:
- On receiving an incoming call for a subscriber, the MSC shall look for an indication in the subscriber’s profile defined in Home Location Register (HLR) for the subscription to RBT Service.
- If the subscription to RBT Service is indicated in the HLR, the MSC shall put the Calling Party’s call on Hold in the MSC and forward the call on SIP interface to RBT server.
- Two options exist when the call leg to be directed to RBT server:
- The call may not be terminated by the RBT and just stay in signaling phase while the Ring Back tone is played in Early Media phase of SIP signaling.
- The call is terminated by the RBT server i.e. put in fully parked mode by the MSC, and then Media is played by RBT server after terminating the SIP signaling.
- RBT Server shall retrieve the subscriber’s service profile from its database, which includes the RBT file name the subscriber has selected.
- RBT Server shall play the RBTone either as early Media or by completing the call leg, as the case may be, after retrieving the tone file from the Media Server attached as an integral component of the RBT server. The selected tone will either be the global tone set by the customer or a Caller ID specific tone if any such tone is set by the subscriber.
- Media shall be played from the Media Server and sent to the Media Gateway address sent by MSC to RBT server in the initial SIP signaling.
- At the end of the played tone, RBT server may play an IVR prompting the user to select the just played RBT as his or her own RBT by pressing a Hot-Key combination, if he or she is also a Phone Service customer.
- If the user presses the hot-key combination, the RBT server shall set the tone just played as the RBT of the calling party by updating the calling party’s service profile in the database.
- When the subscriber picks up the phone, the MSC sends either a SIP BYE message (if the call was terminated by the SIP server) or a SIP Cancel Message (if tone was played in Early Media Phase) to the RBT server. RBT server shall disconnect the call leg connected to its side.
- MSC will take the call leg off the hold condition and join the calling and called party call legs together to start conversation.
Integration with Customer Provisioning/CRM
The RBT server needs to integrate with Operator’s customer provisioning system. When a customer subscribes to RBT via CRM and/or Subscriber Management System, the provisioning system shall use the web-services based API exposed by RBT platform to provision the subscriber on RBT platform. Similarly, the Provisioning shall invoke RBT platform API to de-provision the subscriber on RBT platform as and when required in the Subscriber Management business processes.
Integration with HLR
The RBT server needs to integrate with HLR associated with the MSC. RBT shall use the interface and the API exposed by HLR to indicate in the Subscriber’s profile that RBT service has been enabled for this subscriber. Similarly, when a subscriber is de-provisioned in RBT, the platform shall indicate to the HLR about this event using the same API.
Integration with USSD gateway
The RBT server may need integration with the Operator’s USSD gateway to receive and interpret USSD short codes and interpret them. The short codes may be used by subscribers to select particular Ring Tones and subscriber or un-subscriber to the service. USSD gateway shall send the codes in SOAP/XML or other web-based interface supported by it. The RBT web-service shall receive the short code and pass it on to the RBT server application logic for interpretation and further action.