CS 578 – Software Architectures Spring 2010 Homework Assignment #1 Due: Thursday, February 18, 2010 – see course websites for submission details – The Call Center Customer Care (C4) Case Study provided as an appendix to this assignment presents an initial high level (“Level 1”) architectural breakdown for the system used by a large telecommunications company. This system comprises several subsystems, one of which is C4 itself. 1. By now, you have read about the architectural design process, including the selection of architectural styles. Not all styles are applicable to all systems and any choice of style will involve making trades on various system attributes. Pick any two styles that you have read about and design two different architectures for the C4 system, one that adheres to each style. In order to apply a style, you will need to create a detailed architectural breakdown (a “Level 2” architectural breakdown) for C4. In other words, “expand” the C4 box shown the figure present on page 1 in the Case Study into an architecture. It is, of course, difficult to decide on the exact degree of detail to be provided in a “Level 2” architecture, such as the one required for this assignment. Make sure to show all the connectors inside the C4 architecture as well as those which interconnect the C4 to the other parts of the system. Moreover, you should graphically distinguish different types of the connectors used in your design. Also, there is no such thing as the “correct” or “optimal” architecture. However, as a granularity guideline, your decomposition of C4 should consist of no less than 10 distinct components.1 Note that you are not required to select a style from the course text book, but you must let us know what style you are attempting to apply and provide a reference if the style in not one from the course text. Submit one diagram for each architecture you design. 2. Give a brief rationale for your architecture: why did you select the styles that you did? Weigh the pros and cons of each architectural style. We will not grade you based on how accurately you apply each style so much as your rationale for selecting a particular style and understanding its limitations. Please limit your answer to 2 paragraphs. 3. Compare each of your architectures: give one example of a system property/requirement described in the Case Study that is addressed in a superior manner by one of your architectures. Be sure to not only name the property/requirement, but explain how each architecture addresses the property/requirement and give rationale for why you think one system in superior to the other. Please limit your answer to 2 paragraphs. 4. Since C4 is a very large system with many different, possibly conflicting, requirements, your architecture may only directly address a subset. To demonstrate this, for one of your architectures, select two of the key architectural challenges and requirements (listed in bulleted items on page 4 of the Case Study) and argue/discuss how your architecture DOES NOT support them in an acceptable fashion. Please limit your answer to 2 paragraphs. 5. Modify one of your architectures to address the shortcomings discussed in Q4. Can you do so without violating the chosen architectural style? Give rationale for why you think this change is nonetheless appropriate to make. Please limit your answer to 2 paragraphs and a new diagram. 1 This is only a guideline. There is nothing magical about this number, nor do we have a specific solution in mind.Call Center Customer Care System(a case study)Note: this is a simplified and generalized description of a real systemIntroductionThe Call Center Customer Care System has been developed by Andersen Consulting for a large UStelecommunication company. The primary function of the system is to support interactions with thecustomers that request new services (ex: new phone lines), changes in the configuration of the existingservices (ex: phone number changes, long-distance company changes, or relocation), or report problems.The phone company has over 19Mil customers. Considering how often, on average, a customer changeshis/her service configuration, the system has to support up to 400 company representativessimultaneously at near 7X24 availability level. However, these representatives are not the only means bywhich a customer can request a change or report problems. For example, there exists a phone service(Quick Service) by which customers can communicate with the system. This is discussed in more detaillater.System InteractionsThe C4 (Call Center Customer Care System) system interacts with a number of other systems, inparticular with:• A network provisioning system that makes physical changes to the network configurations andsupports network management• A Billing system• A host of corporate DBs, and• A number of downstream systems.A high level structure of the system interactions is show in Fig. 1. Collectively, this is a big thing andrather complicated.C4 ASOSDownstreamSystemsP/S......Corp. DBsBillingBatchOn-lineQui ServiceInteractions with NOSSNOSS (Network Operations Support System) is the network management and provisioning system. It isbeing developed concurrently by a large 3rd party hardware/software company specializing incommunication networks. Its functionality contains:• Work force management - management of maintenance crews• Provisioning - putting physical network components in place such as connections from the curb tothe house• Network creation - an peculiar name for maintaining information about new and existing physicalnetwork• Activation - automatic turning on/off of services• Network management that contains:• status monitoring and measurements• proactive maintenance• diagnostics, and• problem reporting, and• Field access - a subsystem providing up-to-the-minute information for field technicians.The NOSS architecture is based on the OSI CMIS (Common Management Information Service). Theinterface between C4 and NOSS is a large set of messages in the named-tag/value format. Each messageinter-change is technically a synchronous pair of messages composed of a request and a reply. At theapplication level there are two types of interactions: 1) a request followed by a response that contains therequested information and/or confirmation of NOSS action, and 2) an overall interaction consisting oftwo message pairs; a) initial