Fluent Essays

Step One: Select the current chapter being covered in lecture in class about which you want to comment. (See the schedule below.) Step Two: Use the “Packback Questions” link on the Home page to access Packback. Step Three: Click on “Ask a New Question” and type in the question that you want to ask pertaining to the chapter being covered this week. Remember to use open ended questions. Step Four: Find an external source that supports your question. Step Five: Use paragraphs and don’t make spelling errors. Check your Curiosity score and make sure that it’s at least an 80. The System Development Life Cycle at Work: An Examination of a Successful Private Branch Exchange (PBX) Installation Ron Davis Auburn University Auburn, AL Tel: 334.844.6524 [email protected] Houston Carr, Ph.D. Auburn University Auburn, AL Tel: 334.844.6522 [email protected] Jeremy Stafford Auburn University Auburn, AL Tel: 334.844.6524 [email protected] mailto:[email protected] mailto:[email protected] mailto:[email protected] RUNNING HEAD: The SDLC at Work 2 Abstract This article analyzes an installation of a Private Branch Exchange (PBX) at a private medium-sized southeastern college and the role that the Systems Development Life Cycle (SDLC) played in this project. The SDLC is described and is followed by an illustration of how the steps of the SDLC were implemented in the LaGrange College PBX project. This examination reveals that following the guidelines of the SDLC is fundamental to the success of an information systems installation project. The article also asserts that the analysis and general design phase is the most important step of the SDLC and an extremely detailed model showing the requirements of the system must be developed early in the process. RUNNING HEAD: The SDLC at Work 3 Introduction Founded in 1831, LaGrange College (LC) is a southeastern liberal arts college located about sixty miles southwest of Atlanta, Georgia. Roughly 1,000 students are enrolled and approximately 200 full and part-time staff members are employed on a 120- acre campus. In the spring of 2000, the college decided to examine its existing telephone service. The college had been using BellSouth ESSX©, which is a form of centrex service, for many years. Although ESSX had performed adequately during this time, the college felt that this service would not meet the growing needs of the school. For example, due to the extra monthly expense charged for additional services, few users within the college had any features besides local and long distance access. The college wished to provide additional features such as digital and analog telephone service, direct outward dial (DOD), music on hold, and call transfer. Particularly, LC wanted each member of the faculty and staff, as well as each student living in on-campus housing, to have an individual voice mail account. The college also wanted to furnish each faculty and staff member with their own unique telephone number. Under ESSX, as many as three professors were sharing one phone line. Additionally, the college desired to bring maintenance and upgrading of the system in-house to avoid possible delays in service. In recognition of these problems, a two-man project team was formed to address the situation. One member of the team was a self-taught PC network administrator who had spent the previous year working within the administration of the school. The other member was an LC employee who served as the liaison between the school and BellSouth. Neither employee had any formal training in the Systems Development Life Cycle (SDLC), information systems, or telecommunications. RUNNING HEAD: The SDLC at Work 4 As the college considered available alternatives, the first decision to be made was whether to remain with ESSX or to install some other solution. Some more advanced technical options were eliminated immediately because the IS department was not directly involved with the project. However, the new executive management team of the college had prior experience with Private Branch Exchanges (PBX) and felt comfortable both with the technology and with making the necessary financial investment into a PBX project. For these reasons, options other than installing a PBX or remaining with ESSX were eliminated immediately from consideration. Insert table 1 here. Table 1. Comparison of a centrex system and a PBX. SDLC The Systems Development Life Cycle, routinely used by systems analysts, programmers, and other IT professionals to complete information systems projects, is a process of using a standard approach to solve a problem. A simplistic diagram of the SDLC would be as follows: Analysis → Design → Implementation. First, one must determine what the problem is, design a solution for the problem, and then install that solution The PBX project at LaGrange College utilized a more detailed SDLC model consisting of six steps. In the following sections, a technical explanation of each step will be given followed by a discussion of the actions taken during the PBX project at LaGrange College. RUNNING HEAD: The SDLC at Work 5 Step 1. Investigation. In the investigation phase of the project, the problem is identified by a user, a member of the technical staff, or a member of management. After this occurs, a team is formed to discuss the problem and any potential solutions. Teams are usually composed of a leader, technical specialists, and users. In addition, Telco or vendor representatives and consultants may also be included. A senior member of the organization usually serves as the project champion. This person needs the stature and resources to assist the project in overcoming various political hurdles within the organization. The team should address all issues affecting the project such as the project scope, technical concerns, risk issues, and geographic locations. In addition, the feasibility of various options is discussed in general terms. Accessing feasibility may cover many different areas of concern (economic, technical, behavioral, operational, time, ethical, and regulatory). Once this process has been competed, a white paper should be created describing the project and its objectives. At the onset, the investigation at LaGrange College was limited because the management team preferred to retain ESSX or acquire a PBX system. The main goals of the project were listed as a) offer a telephone system to the campus community that is reliable and offers many features, b) provide a system that is cost effective in both the short and long term, and c) maintain control over the system locally by an LC employee. Considering these three goals, ESSX was eliminated as an option. The new focus of the investigation became deciding which type of PBX system to choose and which vendor to select. The team visited several sites to examine different PBX installations and to talk to RUNNING HEAD: The SDLC at Work 6 the telecommunications specialists maintaining these systems. Potential vendors were also reviewed, and a list of five potential vendors was created. Step 2. Analysis and General Design. The second phase of the SDLC is to determine the exact specifications needed for the system. Determining the specifications is crucial because in later phases of the SDLC these specifications are used to correctly design, install, and maintain a solution. The project team must interact extensively with the users of the potential system to determine their exact needs. The information acquired during this period must be documented so it can be used by both the project team and the vendors in later phases of the SDLC. Additional aspects to be considered during this phase include system architecture, physical planning, future growth, and PBX capacity. The final result of the analysis phase is a list of system specifications. At the end of the investigation phase, LaGrange College was committed to the idea of a PBX. At the onset of the analysis phase, one of the main questions facing the team was deciding between a centralized versus a decentralized architecture for the PBX. The centralized approach concentrates most of the computing resources of the PBX into one area. All of the telephone nodes in the system connect back to this central PBX. This design connects the individual telephone extensions back to the PBX via pairs of copper wire. According to the decentralized approach, each building on campus would contain a module that would provide telephone services for the occupants of the building. The modules are interconnected by fiber optic cables. The advantage of the decentralized approach is that one does not have to worry that the number of extensions in the building exceeding the number of available copper wire pairs. One should note that each module RUNNING HEAD: The SDLC at Work 7 must be located in a climate controlled area. Since the project team felt it could not meet this requirement, it decided against using the decentralized design. The team decided to utilize a modified centralized design. The primary PBX was located on the main campus while three smaller PBXs, which supported LC facilities adjacent to campus, were located off-site. These three units were connected to the primary PBX via fiber optic cable. All extensions were connected back to one of the PBXs with copper wire pairs. The next portion of the project, the creation of the system specifications, was the most important part of the LC project. At that point, a list of specifications for the new system was created. This list became a blueprint for the system and was used extensively throughout the remainder of the project. Due to its importance, it will be discussed later in this paper in greater detail Step 3. Detailed Design, Procurement, and Installation. Once the system specifications are provided, several decisions can be considered and made during this phase of the SDLC. The first, the make-or-buy decision, refers to the decision of either building the system in-house or purchasing it from outside vendors. Other considerations include investigating what other alternatives are available and the impacts of each on the schedule, budget, and usability of the system. Potential vendors should be evaluated and ranked with a spreadsheet or matrix. After receiving proposals from all of the potential vendors, a vendor(s) should be selected. After the vendor is selected and the design is finalized, all necessary equipment is ordered. Areas must be set aside to receive and temporarily store the incoming equipment. Before installation is possible, one must adequately prepare the facilities in regards to space, cooling, electricity, and security. Once the equipment has been received RUNNING HEAD: The SDLC at Work 8 and all preparations have been made, the PBX components are installed by either the organization or by its vendors. The PBX is then tested to insure its readiness. At this point in the LC project, the systems specifications model for the college was completed. It was then used by potential vendors as a blueprint to design their proposals. Four vendors submitted PBX hardware and software proposals for consideration while only one vendor, who had years of experience with the college, submitted a proposal for the installation of fiber and copper cable. Each proposal was considered in terms of design, price, features, and service. The systems offered similar options and service agreements; however, pricing for the systems varied greatly. The difference between the least and most expensive PBX system exceeded $100,000. Based on these proposals, the project team selected two venders; one vendor, BellSouth, was used to provide the PBX and the other vendor, Telecomm, was used for cabling. After approval for these decisions was received from both the President and from the Board of Trustees of the college, the team and the vendors agreed upon the final design of the system, and orders were placed for the necessary equipment. Once all the equipment was received, installation of both the PBX and the fiber optic and copper cables occurred. Step 4. Implementation. After the system is installed and tested, implementation activities need to take place. Users are trained to effectively operate the system, and in-house technicians are taught how to maintain the equipment. Also, the project team will need to decide how the transfer, or cutover, from the old system to the new one will occur. There are several options for the cutover. One option, a pilot approach, allows the organization to test the RUNNING HEAD: The SDLC at Work 9 new system with a small group of users. Problems are then identified and corrected. Another option, a parallel approach, introduces the new system while maintaining the old one; however, both systems must be maintained if this method is adopted. A third option, the phase method, activates segments of the new system in sequence. A final option, the cold turkey approach, the most risky of them all, simply turns off the old system and turns the new one on. At LaGrange College, after the installation of the new system, both the vendor and a member of the project team trained the users. In activating the new system, LaGrange College decided to use the parallel cutover method; consequently, the old system was maintained for approximately one month after the switchover to the new PBX. No major problems were encountered during the implementation. In fact, the implementation which was scheduled to have a two-week duration occurred ahead of schedule and only required a weekend to complete. Step 5. Evaluation and Review. The focus at this point of the SDLC is on the performance of the project team, the vendors, the new system, and the organization during the project. An evaluation of the entire process is conducted at this point. The following are some questions that should be asked: How did the vendors perform? Does the new system meet expectations? What improvements may be made when the next project occurs? Both the management and the employees of the college expressed their satisfaction with the performance of the new PBX. The features offered by the new system were far superior to the services provided by their old ESSX service. The project team was also delighted with the efforts of its two vendors as the project was completed RUNNING HEAD: The SDLC at Work 10 ahead of schedule and on budget. By using the parallel cutover method, no downtime was experienced by the users during or after implementation. The PBX vendor also rated the LC project team with a 9.5 out of 10 rating with one technician calling it an “almost perfect installation.” Step 6. Maintenance and Change. In the final phase of the SDLC, the system is turned over to a maintenance group who identifies and corrects problems on an on-going basis. Modifications in terms of expansion, hardware, and software updates are continually implemented. This phase is the longest in length and lasts until the system is replaced. The LaGrange College project was completed over two years ago. Since that time, the PBX has experienced no significant downtime. A former member of the project team handles everyday maintenance and modifications. The PBX has proven to be scalable with the addition of two new dormitories to the system. Overall, the PBX has given a valuable return for its investment. System Specifications The systems specifications portion of the project was completed in the second phase of the SDLC. In retrospect, this particular part of the project was the fundamental contributor to the success of the project. The systems specifications became “the guidebook” for the project. The benefits of having such detailed plans were as follows: • Information was acquired through heavy interaction with users. Users were given a sense of participation in the project. Their involvement ensured that the PBX would deliver the desired services and features. RUNNING HEAD: The SDLC at Work 11 • Creation of the system specifications led to the discovery of isolated phone lines connected to modems, elevators, security systems, and HVAC units. • By developing the specifications, the project team had a detailed and accurate view of the hardware needed for the PBX. For example, the team knew it must purchase exactly 281 telephones. • Since the team decided to use pairs of copper wire for connectivity, the exact number of pairs of wire needed for each building was known as a result of the specifications. • The specifications served as guidelines to the vendors during the design of their proposals. These specifications were so accurate, two different vendors, using the same hardware, submitted proposals that had less than $1,000 difference in price. • During installation, a copy of the specifications was made for each vendor. Therefore everyone involved in the project was working “on the same page.” The first step in developing the system specifications was to acquire blueprints for each building on campus. If the blueprints were not available, a set was created. The head of each department on campus was interviewed to determine his/her exact needs. These requirements were recorded, and the locations of each piece of equipment (telephone, modem, security system, etc) were noted on a working copy of the floor plans. Once this step was completed, this information was transferred into an Excel spreadsheet and marked onto a floor plan. These maps and sheets were assembled into the system specifications book. RUNNING HEAD: The SDLC at Work 12 For example, figure 1 is the floor plan for the first floor of the natatorium. The telephone for the tennis coach is marked with a triangle and a “10” indicating that the jack is on east wall of the room. Table 2 contains the corresponding data for this floor plan. Using the number 10 as a key on the spreadsheet, it is noted that the extension for this telephone is 8018, the old centrex telephone number for this phone is 889-1018, it is a digital connection, it needs two active voice mail accounts, it uses a standard digital phone (D1), and it is connected to the copper pair of wires labeled 521010. Insert figure 1 here. Figure 1. Sample floor plan from the system specifications model. Insert table 2 here. Table 2. Corresponding data for the sample floor plan. Table 3 is an example of the benefits a team can gain by fully developing the system specifications of a project. By using all of the data on each floor plan and spreadsheet of the systems specifications book, it was an easy matter to determine the amount of hardware needed for the PBX. The hardware required for the system was determined by combining the data from all the floor plans for each building on campus as shown in table 3. Insert table 3 here. Table 3. Required hardware for PBX. RUNNING HEAD: The SDLC at Work 13 The final configuration of the PBX is shown in figure 2. The main campus is supported by the NEAX 2400. Connectivity to the central office and the campus LAN occurs at this point. Three PCs are connected to the NEAX 2400 to run the voice mail, 911, and systems administration functions. Three NEAX 2000s are also linked to the NEAX 2400 via fiber optic cable. Each NEAX 2000 supports a portion of the college that is not located on the main campus. Each telephone is connected to the system via copper wire into either a NEAX 2000 or into the NEAX 2400. Most of the copper wire in the interior of the buildings had been used with the ESSX system and was reconnected into the new PBX. A large portion, however, of the exterior copper wire was either replaced or supplemented with new copper pairs by the cabling vendor. Insert figure 2 here. Figure 2. Completed PBX. Conclusion LaGrange College wanted to provide its employees with high-quality and feature rich-telephone service. To accomplish these goals, the school installed a new PBX system. A group of inexperienced yet enthusiastic and hardworking members of a project team achieved this task. Without any prior training in the SDLC or systems analysis and design, this team unknowingly followed the standards of the SDLC. Using this methodical approach to search, design, and implement a solution was key to the completion and success of this project. Through this project, one can see that the analysis and general design phase of the SDLC is the most important step of the process, and RUNNING HEAD: The SDLC at Work 14 building a model of the system specifications early in the process is critical to completing the later stages of the SDLC and to the overall success of the project. RUNNING HEAD: The SDLC at Work 15 Tables and Figures Centrex Versus PBX Centrex PBX 1. Switching provided by phone company. On-site switching with purchased on leased equipment. 2. Each extension is connected to the central office. Local loops only for the number of outside lines necessary. 3. Monthly fee for each extension Up front purchase fee or monthly lease. 4. Changes made by Centrex provider. Changes made by trained employee. 5. Minimal space requirements. Floor space for equipment must be provided. 6. Maintenance provided by telephone company. Maintenance provided by vendor or by trained employees. 7. Extra features incur an additional monthly charge. Most features (such as voice mail) do not add additional monthly charges. 8. LC service entirely analog. Able to provide both digital and analog service. Table 1. Comparison of BellSouth Essx© (Centrex) and a PBX. Figure 1. Sample floor plan from the PBX requirements model. RUNNING HEAD: The SDLC at Work 16 Table 2. Corresponding floor plan data. Required PBX Equipment NEAX 2400 IMX NEAX 2000 IVS Totals Analog Phones 41 18 59 Digital Phones (8 Button) 156 41 197 Digital Phones (32 Button) 15 7 22 Speakerphones 2 0 2 Switchboard 1 0 1 Analog Cards (With Caller ID) 34 0 N/A Analog Cards (Without Caller ID) 9 7 N/A Digital Cards 11 6 N/A Table 3. Required hardware for PBX. RUNNING HEAD: The SDLC at Work 17 Figure 2. Completed PBX. RUNNING HEAD: The SDLC at Work 18 References: Allingham, P., & O’Connor, M. (1992). MIS Success: Why Does It Vary Among Users? Journal of Information Technology, 7, 160 – 168. Burton, G. F., Leitch, R. A., & Tuttle, B. M. (2001). A User’s Willingness to Adopt a New Information System: The Influence of the Decision-Making Improvements and Performance-Monitoring Dimensions of the System. Journal of Information Systems, 15(2), 61 – 79. Carr, H. H., & Snyder, C. A. (2003). Management of Telecommunications. McGraw-Hill Irwin, 2nd ed., 581 – 614. Derfler, F. J. (1987). Making connections: voice-and-data PBX systems. PC Magazine, 6(14), 307 – 325. Labriola, D. (1999). PC PBX’s Come of Age. PC Magazine, 18(1), 201 – 212. Lai, W. R., & Lin, Y. B. (1998). Resource Planning for Wireless PBX Systems. International Journal of Information Networks, 5(4), 351 – 357. Lummus, R. R., & Duclos, L. K. (1995). Implementation of EDI Systems. Journal of Systems Management, 46(5), 42 – 48. RUNNING HEAD: The SDLC at Work 19 Mahmood, M. A. (1987). System Development Methods – A Comparative Investigation. MIS Quarterly, 11(3), 292 – 311. Martin, M. (2002). RBOCs bringing new life to Centrex. Network World, September 2002, 28 – 32. Raymond, L. (1985). Organizational Characteristics and MIS Success in the Context of Small Business. MIS Quarterly, 9(1), 37 – 52. Skjellum, A., Dimitrov, R., & Angaluri, S. V. (2001). Systems Administration. The International Journal of High Performance Computing Applications, 15(2), 143 – 161.