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4.3.2 ENG.2 System requirements analysis

Process ID

ENG.2

Process Name

System requirements analysis

Process Purpose

The purpose of the System requirements analysis process is to transform the defined customer requirements into a set of desired system technical requirements that will guide the design of the system.

Process Outcomes

As a result of successful implementation of this process:

  1. a defined set of system requirements is established;

  2. system requirements are categorized and analyzed for correctness and testability;

  3. the impact of the system requirements on the operating environment is evaluated;

  4. prioritization for implementing the system requirements is defined;

  5. the system requirements are approved and updated as needed;

  6. consistency and bilateral traceability are established between customer requirements and system requirements;

  7. changes to the customer’s requirements baseline are evaluated for cost, schedule and technical impact; and

  8. the system requirements are communicated to all affected parties and base lined.

NOTE 1: System requirements may be categorized in terms of feasibility and risk.

NOTE 2: System requirements may typically include functional, performance, interface, design requirements and verification criteria. Verification criteria define the qualitative and quantitative criteria for verification of a requirement. Verification criteria demonstrate that a requirement can be verified within agreed constraints.

NOTE 3: Analysis of system requirements for testability includes development of verification criteria.

Base Practices

ENG.2.BP1: Identify System Requirements. Use the customer requirements as the basis for identifying the required functions and capabilities of the system and document the system requirements in a system requirements specification. [Outcome 1]

NOTE 1: System requirements include: functions and capabilities of the system; business, organizational and user requirements; safety, security, human-factors, engineering (ergonomics), interface, operations, and maintenance requirements; design constraints and qualification requirements (ISO/IEC 12207) as well as application parameters influencing system functions and capabilities.

ENG.2.BP2: Analyze system requirements. Analyze the identified system requirements in terms of technical feasibility, risks and testability. [Outcome 2]

NOTE 2: Verification criteria for all system requirements should be defined for further development of system test cases.

NOTE 3: The results of the analysis may be used for categorization of the requirements (see also ENG.2.BP.4).

ENG.2.BP3: Determine the impact on the operating environment. Determine the interfaces between the system requirements and other components of the operating environment, and the impact that the requirements will have. [Outcome 3]

ENG.2.BP4: Prioritize and categorize system requirements. Prioritize and categorize the identified and analyzed system requirements and map them to future releases of the system. [Outcomes 2, 4]

NOTE 4: Refer to the process SPL.2 Product Release.

ENG.2.BP5: Evaluate and update system requirements. Evaluate system requirements and changes to the customer’s requirements baseline in terms of cost, schedule and technical impact. Approve the system requirements and all changes to them and update the system requirements specification. [Outcome 5, 7]

ENG.2.BP6: Ensure consistency and bilateral traceability of customer requirements to system requirements. Ensure consistency of customer requirements to system requirements including verification criteria. Consistency is supported by establishing and maintaining bilateral traceability between the customer’s requirements and system requirements including verification criteria. [Outcome 6]

ENG.2.BP7: Communicate system requirements. Establish communication mechanisms for dissemination of system requirements, and updates to requirements to all relevant parties. [Outcome 8]

Output Work Products

01-51 Application parameter [Outcome 1]

08-16 Release Plan [Outcome 4, 5]

13-04 Communication record [Outcome 8]

13-21 Change control record [Outcome 7]

13-22 Traceability record [Outcome 6]

15-01 Analysis report [Outcome 2, 3, 4, 7]

17-08 Interface requirements specification [Outcome 3]

17-12 System requirements specification [Outcome 1, 5]

17-50 Verification criteria [Outcome 2]

NOTE: For system requirements specifications, the IEEE-Standard 1233- 1998, Guide for Developing System Requirements Specifications might be used.

 

5.Process Capability Indicators

Level 2: Managed process

Level 3: Established process

Level 4: Predictable process

Level 5: Optimizing process