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PPDIOO Stages
Understanding what is supposed to happen at each stage is vital in order for a company (or consultant) to properly use the lifecycle approach and to get the most benefit from it. We’ll review the different stages, what happens at each stage, and what deliverables are generally produced from each stage (keep in mind that the names of these documents change from company to company, but the general content is the same).
Prepare
The way that the Prepare phase is used depends on the current state of the company. The first way assumes that the company has done little-to-no research on establishing their business requirements, technology vision, and technology strategy (among others). The second way assumes that the company has these already established, and this iteration through the Prepare phase is done as an update to these existing plans.
Generally, in the Prepare phase, a company will develop their business requirements, technology vision and technology strategy. It is very important that these are established before going forward to ensure that the network is developed to be as close with the business requirements as possible.
If this is not the first iteration of the prepare phase, then a review of the current business conditions must be matched against what was previously developed; if any changes are found, the technology vision and strategy should change to meet these new conditions.
What comes out of this analysis is then used to develop a very high-level conceptual architecture of the proposed network. The recommended features and functionality proposed in this conceptual architecture should then be validated through proof-of-concept testing.
The typical deliverables from this phase include:
- High-level design (HLD)
- Customer Requirements Documents (CRD)
- Current state assessment Survey and Results (CSAS).
Plan
Like the Prepare phase, the way in which the Plan phase is used depends on the current state of the company’s network. A project plan is the next thing to be developed. If no current network exists, then this project plan should include a number of pieces of information that are required before the next phase, including the allocation of the resources (financial and physical) for the design and implementation phases, the development of a network security plan, and the development of a project schedule to match the business requirements found in the Prepare phase.
If there is an existing network in place, then the project plan is developed (or updated), but only after an audit of the existing infrastructure, sites and operational environment is completed. It is vital that a thorough audit is completed to ensure that any changes to the network will not influence network usability, will reduce network resource redundancy, and ensure an easier upgrade experience.
The typical deliverables from this phase include:
- Site Requirements Specifications (SRS)
- Solutions Test Plan (STP)
- Site Survey Form (SSF)
- Customer Requirements Document Response (CRDR)
Design
During the Design phase, the company develops (or updates) a comprehensive network design. It is important that the information gathered from the first two phases is used to ensure that the design meets all of the business and technical requirements that were previously developed. If everything has been completed correctly, the design will provide a network that is able to manage the everyday tasks that are required of it and meet or exceed all expected availability, reliability, security, scalability, and performance metrics.
There are also a number of different documents that are developed during this phase that guide the deployment, configuration, and commission of network devices and services.
The typical deliverables from this phase include:
- Low Level Design (LLD)
Implement
There are a number of different methods of implementation that are used. Generally, it is good to setup and configure a test bed that will be used to simulate the different parts (or additions) of the network design. Using this method allows the implementers the ability to find any potential problems; if found, these problems are resolved inside this test bed before full scale implementation continues. Once any issues are worked out in the test bed, a full scale implementation can start; of course, depending on the size of the implementation, there can be a number of logistical issues to work out during this time. For example, it needs to be determined who is in charge of deployment, configuration, testing, and operations of the network during these different steps. The company must also ensure that any integration tasks with the current network are handled carefully so ongoing operations are affected as little as possible.
Once the network has been implemented, a series of tests should be run to ensure that the operation of the new network is as expected and designed. If any issues are found, it is best that they are handled as early in the implementation as possible to ensure the issue impacts as few parts of the network as possible.
The typical deliverables from this phase include:
- Network Ready For Use (NRFU) Test
- NRFU Test Report
- Implementation Log
Operate
The Operate phase is by far the longest of the PPDIOO phases; this is because in this phase a company is operating without making major changes to the network. During this phase, the company spends the majority of their funds managing the network which includes proactive and reactive monitoring, performance management, trouble management, security management, and capacity planning and monitoring, among others. Any minor moves, adds, or changes (MAC) also occur during this phase.
The typical deliverables from this phase include:
- Root Cause Analysis Reports
- MAC Reports
- Support Contract Analysis (SMARTnet)
Optimize
The Optimize phase can happen at any time after a network is operational; typically it happens either when there has been a minor or major change in the business or technical requirements of the network or is scheduled as a “check-up.”
During this phase, the current business and technical requirements will be compared to those used when the network was initially designed. If any changes are recommended, then the phases start again from the beginning to ensure consistency and an ongoing good design.