Telecommunication Mediation Device

The main purpose of Mediation Device (MD) is to serve as the bridge between CCBS and the components of telecommunication network, allowing CCBS to access network elements thoroughly despite the complexity of the network and greatly reducing the cost of the development and maintenance of the system. MD can be divided into two categories, one being the Provisioning Mediation Device, and the other being the xDR Mediation Device which is used to provide the functions of (3) service activation and (4) management of call detail records in the framework. Fig. A.3 shows the scope of MD.

Fig. A.3: Scope of MD

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A.3.1 Provisioning Mediation Device

Whether a telecom service can operate normally depends on whether the network elements are correctly configured. For example, in order to enable provisioning in mobile phones, HLR needs to be configured first, and the provisioning of intelligent services require SCP. The main task of Provisioning Mediation Device is to handle the provisioning requests in the Order Handling Management that was mentioned in section A.2.3, which converts the requests into network component instructions in order for network to be configured. Fig. A.4 describes the main modules of Provisioning Mediation Device.

Fig. A.4: Main modules of provisioning mediation device

n Collection: Collects customer services (such as activating or terminating services) or their demands for network configuration that are listed on the order. These demands can be sent via the method of “process-to-process” to be temporarily stored in the related databases.

n Scheduling: Provisioning can be done instantly or booked in advance. Moreover, a phone number maybe configured differently within a short amount of time. A common example is the halting of service due to non-payments, and the customer makes the payment instantly and requests the service to be restored. If there is a

problem with the network, the execution of these two configurations could result in a major error that seriously undermines the customer’s rights. Thus, scheduling allows the provisioning to be appropriate and timely.

n Flow Control: The activation of a service may involve the configurations of multiple network elements. For example, the provisioning of prepaid cards requires the configuration of HLR, intelligent network elements, and SCP. However, the order of this process determines the normal operation of the network; thus, a correct flow control is needed. In actual practices, the mechanism of finite state machine is used to control the flow.

n Command Translation: The configurations of the instructions for provisioning and network elements are drastically different. They require conversion and synchronization, and the result of the configuration of network elements needs to be given to the person who demands it after conversion.

n NE Interface: Different Network Elements (NE) have different communication interfaces. The most common method of communication is TCP/IP socket programming interface, which is still used in the earlier X.25 protocol. The demands of TCP/IP socket interfaces are divided into synchronization and a-synchronization based on their degree of real-time. Considering the reusability, these interfaces can be made into driver programs.

Besides the above functions, the following functions are also developed in order to allow easy maintenance for the system:

n Error Handling Mechanism: Configurations cannot be completed if there is a problem with the content of a request or a malfunction in the network component.

The convenient Error Handling Mechanism (such as resend or reply) will reduce the probability of manual interventions, thus reducing the cost of maintenance.

n Central Monitoring System: The provisioning in mobile services needs to be

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completed within a few minutes. CMS allows maintenance personnel to monitor the system at any time.

A.3.2 xDR Mediation Device

Besides the monthly plan, communication charges are also included in the monthly bill.

The billing of the services in the earlier days that focused on voice calls was simpler since the CDR (Call Detail Record) is recorded by the switching center, and charges were calculated according to the duration of each call. As data services and value-added services develop quickly, the billing models become increasingly complex. The sources of this billing information increase rapidly, such as the CDR of GPRS Charging Gateway and the EDR (Event Detail Record) of different network events, and IPDR (Internet Protocol Detail Record). We call these records “xDR.” The main task of xDR Mediation Device is to gather the records generated in different network elements, which are then processed and provided to end application systems. This makes the network very visible in the billing system and greatly reduces the complexity of the billing system. Fig. A.5 describes the main modules of xDR Mediation Device.

Fig. A.5: Main modules xDR mediation device

n Collection: Collects the xDR from all the network elements. xDR is usually

temporarily stored in the network elements as files. The mediation system is able to actively pull out (such as the “pulling” in ftp) or passively receive (such as the

“pushing” in ftp) these files.s.

n Decode: There are no standards for the format and content of xDR. Also being a mobile switcing center (MSC), files produced by different companies are in different formats such as Binary or ASCII, the length maybe fixed or flexible, the fields also differ with different network elements. The languages that are more commonly used to define new network elements are ASN.1 and XML. The main function of decoding is to decipher files of different formats and analyze the data index.

n Filter: Filtrated data are not used by end billing system. For example, in Taiwan,

“Mobile Origination Call” needs to pay for the call, and the “Mobile Termination Call” does not. Also making a call from a mobile phone, the charges for the call are already deducted from a prepaid card. Thus, the function of filter is to filter the needed data index according to business logic.

n Reformat: The content needed by the billing system is often less then that in the data index of network elements. For example, for a Mobile Origination Call, a MSC may involve hundreds of fields, whereas billing only involves less than 20 fields.

The function of reformat is to convert the raw data into the format needed by the end application system.

n Distribution: xDR provides other functions other than billing such as preventing call-hijacking, data storage, communicating with police and official departments, and online bill settlement. The function of distribution is to send the reformatted files to end application systems through the most commonly used channel such as ftp.

n Aggregation: The actions in network elements often do not match with the needed

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data in the end application system. For example, in WAP mobile Internet services, each transaction is recorded whenever a button is pressed in WAP Gateway. From the angle of billing, it is sufficient to charge for each session. The function of aggregation is to compile the relevant call detail records that can be used by the simpler data index required by the end application system. In practice, correlated databases are used for temporary storage of compiled data that will be sent to the end application system.

n Correlation: A transaction may generate different records on different network elements. Take MMS for example, a MMS transmission generates xDR in WAP Gateway, MSC, SMSC, GPRS Charging Gateway, MMSC, MMS Terminal Gateway, or MMS Email Gateway. Correlation analysis needs to be conducted in these different CDRs in order to come up with the data index needed by the end applications. The function of correlation is to determine the correlation between CDR and provide fuller data index for the end application system. In practice, correlated databases are used for temporary storage, the processed data are then sent to the end application system.

Besides these basic functions, the mediation system in service provisioning, Error Handling Mechanism, and Central Monitoring System are also necessary tools that allow easy maintenance of the system.