DESIGN AND DEVELOPMENT OF INTELLIGENT NETWORK FOR TELETALK BANGLADESH LIMITE

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1 Daffodil International University Institutional Repository Proceedings of NCCIS November DESIGN AND DEVELOPMENT OF INTELLIGENT NETWORK FOR TELETALK BANGLADESH LIMITE Dey, Ajoy Kumar Daffodil International University Downloaded from Copyright Daffodil International University Library

2 DESIGN AND DEVELOPMENT OF INTELLIGENT NETWORK FOR TELETALK BANGLADESH LIMITED Ajoy Kumar Dey, Khandakar Hayet Mahmud, Atanu Deb Nath, A.K.M Fazlul Haque Department of Electronics and Telecommunication Engineering, Daffodil International University Abstract In this paper, the design of Intelligent Network of Teletalk Bangladesh Limited has been proposed. In our analysis, we see that Teletalk Bangladesh uses the Intelligent Network (IN) Statistics tickets. A ticket is a set of binary data that contains the information generated when a call is set up between a calling party and a called party. These tickets are usually big in size, necessitating a convenient tool to interact with the huge amount of binary data. The task is to create a graphical interface that allows searching for specific tickets by parameters to be defined. In our experiment we use the Java applets to create the Graphical User Interface. The Graphical User Interface has some searching parameter to search specific parameters to get specific data. The output is in text mode. This interface will be implemented by GUI (Graphical User Interface). Keywords: Intelligent Network, Tickets, Protocol, GUI. 1 Introduction All Intelligent Network for telecommunication involves the concept of a Billing system and also involves the concept of a Query/Response system. The system entails the notion of distributed intelligence where in is queried for information necessary for call processing [1]. For example, a mobile communication switch or Mobile Switching Center (MSC) that equipped with mobile intelligence network call logic, can launch a message or query to a database hosted by a network element called a service control point (SCP). The SCP processes the request and issues a response to the MSC so that it may continue call processing as appropriate. The Intelligent Network characteristics are given below. Modulator divided into functional entities. Uniform became standard architecture Service independent. Programmable network operable by either user or carrier provider, or both Supplier transparent- Open system architecture (OSA) Capable of rapid introduction of new services Accessible for other services providers Common channel signaling (CCS)- using out of band signaling. Service logic- invokes IN service logic programs (SLPs) In uses CCS to deliver the call set-up signaling and the network information. In this case, the traffic channels are never tied up for signaling [2]. For example, if the called party line is detected as busy by the signaling channel, the network would not assign a traffic channel to the calling party. Thus the efficient use of the traffic channels increases. Also the use of CCS can increase the speed of process for call process and information delivery. The CCS network uses digital channels with the SS7 protocol at a rate of 56 Kbps. Here we discuss about what is Intelligent Network and it s characteristics. Now for the better discussion for IN we discuss the IN interfaces. 1.1 Intelligent Network Interfaces The interfaces between intelligent network elements are: 1. Between the switching system and SCPs or adjunct systems using SS7 signaling. 125

3 2. Between the switching system and IPs or service nodes using ISDN. 3. In Intelligent Network, between SCP and SMS using the X.25 protocol. 4. Between end users AIN services; may be either conventional analog or ISDN interface [3]. The Intelligent Network general architecture with the indicated Intelligent Network interfaces is shown in the figure 1. In cellular system the channel ling between the mobile switching system and the user does not use ISDN. Because a 64 Kbps ISDN channel needs a bandwidth of 64 KHz for radio transmission. In cellular systems, the data rate of a channel is 16 kbps or less, and needs only a bandwidth of 25 khz or less. Using less channel bandwidth increases more spectrum efficiency. Service control point- The SCP invokes service logic programs. The common channel signaling network allows the SCP to fully interconnect with AIN switching systems through a signaling transport point (STP) [4]. The SCP supports 800 toll-free phone calls, area number calling, or personal location services. Adjunct system- A direct link to the AIN switching system with a high-speed interface. Communications with AIN switch via the integrated services digital network (ISDN) access link and supports user interaction. Intelligent peripheral- Controls ad manages resources such as voice synthesis announcement, speech recognition, and digit collection. AIN switch- Routes a call to an IP to ask for a function. When the IP completes the function, it also collects the user s information and sends it to AIN service logic (resides in SCP) via the AIN switch. Operational system (OS)- Provides memory administration, surveillance, network testing, and network traffic management maintenance and operation. Signaling Transport Point (STP)- The pint that interconnects the SCP and AIN switching system. 2 Literature Survey Here we discuss about the Billing Interface Protocol and Structure of the Bill File Directory, and how a bill file creating, and then call data record type. There are two BAU (Billing Administration Unit) in one MSC/SSP, one of them is master, another is back up, corresponding two IP address should be set in one bill pick-up computer [6]. BAU in MSC/SSP1 can be connected to bill pick-up computer directly by HUB because they are located in the same LAN. BAU in MSC/SSP2 should be connected to bill pick-up computer by IP router because they are not located in the same LAN. BAU can support both these two physical connection schemes. 2.1 Billing Interface Protocol FTP and FTAM protocols are both supported by BAU, but we recommend to adopt FTP protocol for its simplicity and compatibility with Windows NT. When connection between BAU and BC (Billing Center) is based on FTP protocol, BAU can act as FTP server, or as FTP Client, and FTP server is recommended. When connection between BAU and BC is based on FTAM, BAU acts as FTAM responder. Two lower layer protocol stacks are supported by FTAM: a. UTS-TCP (FTAM over TCP/IP); b. UTS-LAN (FTAM over IEEE802.3) 2.2 Bill File Directory Structure The file structure on BAU (Billing Administration Unit) is organized as following: Figure 1: Bill File Directory Structure on BAU In the Indian version, four types of new bills are added, including MTP, MTP_CFM, SCCP, and SCCP_CFM4. The new bills have a format different from the original bills. To avoid the impact of new bills on the original bills, the 126

4 above four types of bills must be saved in their own directory to separate them from the original bills in the igwb. Hence, the structure of the directory must be modified accordingly. As shown in Figure 1, one bill file is saved for three parts in three directories. One is in back data directory, one is in backdatabak directory and the other is in removable disk (MO). Bill files in backdatabak directory are provided for BC (Billing Center). When bill pick-up computer fetches one bill file from BAU, the bill pick-up computer should delete the bill file in backdatabak directory. Bill files in backdata directory are saved for backup. By the way, bill file in backdata directory is saved by date. For example directory, which is in Backup directory, would save bill file that is generated by May 26, BAU is responsible for deleting these files when they are out of date. The date is between 7 days and 20 days. The date can be configured in config.exe. Bill files in removable disk are provided for BC for long-time preservation. 2.3 Bill File Creating When BAU receives bills from SM, bill file will be created. But at first BAU save bills in temporary bill file. For normal billing, the temporary file is naming as E:\BillBack\tmp\bxxxxxxxx.dat. Here the symbol xxxxxxxx stands for bill file sequence number that can cycle from to Bill file has two creating conditions [5]. One is file length; the other is file-creating time. File length can be choosing between 200kB and 1MB. Files creating time is unlimited and can be configured according to requirement. But we recommend you adopt file length is 1MB and file creating time is 10 minutes. Bill file can be created for the first condition, or for the second condition, or for both. Both these two conditions can be configured in config.exe. Bill pick-up computer should pick up the bill files automatically. If bill pick-up computer doesn t pick up a bill file when it has been generated exceeds 30 minutes, alarm will be generated by BAU. The time slot also can be configured in config.exe. 2.4 Call Data Record (CDR_type) (Bill Type) Type of bill record (CDR), 1 byte, Hexadecimal Integral number [6], valid value defined as below while other value reserved: 0 (' ') MOC //mobile originating call 1 (' ') MTC //mobile terminating call 2 (' ') GWI //incoming GWMSC call 4 (' ') TRANSIT //transit call 6 (' ') MT_SMS* //mobile terminating SMservice 7 (' ') MO_SMS* //mobile originating SMservice 9 (' ') CALL_ATTEMPT* //attempt call 10 (' ') GWO //outgoing GWMSC call 11 (' ') ISDN_OC* //PRA originating call 12 (' ') ISDN_TC* //PRA terminating call 17 (' ') INCH //Intelligent No Charge call 18 (' ') CFW //forwarding call 19 (' ') MOI //CDR for caller instead 22 (' ') MT_INCH* //Intelligent No Charge mobile terminating call 23 ( ) CFW_INCH // Intelligent No Charge mobile forwarding call MOI is generated only in SSP when deal with overlay incoming IN call The called is an intelligent subscriber, the caller is a non-intelligent subscriber in this network, and the Call is not forwarded before incoming, the principle of charging used in some country for 127

5 particular demand can be controlled, and then the MOI bill can be generated for other network user INCH is generated in SSP when: PPS - non_charged number PPS - recharge/query number MT_INCH is generated for called subscriber and CFW_INCH for forwarding subscriber in case of freecall in MSC that is an IN-call when signal link between SCP and SSP is abnormal. The non_charged number above must be defined in SCP database. If a number just is defined as non_charged number in a terminal office, SSP will generate MOC same as calls to charged number. The bill type added with the symbol * only can be generated in the VMSC not in the GMSC. The Raw CDR Data in MSC is given below. It is totally in binary form and undistinguished to read. 3 Simulation and Testing The tool was implemented to run on a DOS Environment and written in Java Applets. The tool worked in accordance to the requirements. It has been successfully tested for the TeleTalk Bangladesh Limited using the data they provided. The following Figure 3 shows the system simulation for some test cases. In Figure 4 the left text area shows the data in one output format and in the right and bottom of the interface there are the text boxes for the parameters to be input. This figure shows the output in text of the tool for this particular input. Figure 2: Call Data Record in MSC 128

6 Figure3: Tool Interface Figure 4: Total Interface displaying the output in text 129

7 4 Conclusion In the above discussion, we have seen that one binary file consumes around 50 MB. If we convert it into a text file, it will take several GBs. So, the server needs a huge capacity to store all the binary files. It is physically impossible to store this kind of huge amount of data in a server. Because the server has a limited capacity. With the program developed, we are now able to convert some specific binary data to text data, indicated by specific parameters so that the data needs reduced server space. Thus we search the binary file and store data into a file format in accordance with some procedure defined by the algorithm. The actual goal is to solve the problem of irrelevant storage capacity for conversion from a binary file to a text format. The text format it is very much important for billing or to find any particular data. Because the binary data are undistinguishable. Though this particular work was developed specifically for the Teletalk Bangladesh Limited, similar solutions would be applicable for any such IN systems. 5 References [1] Gerry Christensen Mobile Intelligent Network. [2] D. A. Pezzutti, Operations Issues for Intelligent Networks, IEEE Communications magazine [3] H. Rarig, ISDN Signal Distribution Network, IEEE Communications Magazine, vol. 32, pp [4] R. K. Berman, J. H. Brewster, Perspective on the AIN Architecture, IEEE Communications Magazine, vol. 31, pp [5] Zhangzhimin, Modifying for INCH_CDR, The CDR document of the Huawei Technologies co., Ltd, Published on 2004/11/14, Revised version V1.06. [6] Guo Jin, GSM_MSC_BILL_INTERFACE, The CDR document of the Huawei Technologies co., Ltd, Published on Dec 25,2002, Revised version V