PDIOO Methodology


In this section, I’m going to introduce you to what’s known as the PDIOO methodology. PDIOO is an acronym that stands for planning, design, implementation, operation, and optimization. It reflects the various phases of a typical network’s life cycle—you’ll come across each phase in the regular operation of all networks. Though each phase is important, network design is a vital phase of PDIOO methodology.

There’s an innate, contingent connection between network design and each of the other PDIOO phases because design essentials are found in each phase and each phase is critical to consider when making network design decisions.

The following is a description of each individual yet correlated PDIOO life cycle phase, plus there’s one more phase (retirement) that I’ll cover in this section as well.

Planning The network requirements are what you need to pinpoint in the planning phase. Important considerations for this phase include determining exactly where you plan to install the network, its objectives, and the types of services it will provide and to whom, etc. Once you’ve established these specifications, you’ve clarified your fundamental network requirements.

Design The set of network requirements identified in the planning phase is the basis of what you’ll use to design the network. It’s also important to consider any information obtained though discussions with managers and administrators as well as any data gained through the analysis and audits of the existing network if you’re upgrading. With a solid network design model in hand, you’re ready to move on to the implementation phase.

Implementation With an approved design—and any additional equipment the design requires—the next step is to implement the new network. This is where you’ll get to test the design and see if it’s valid or if you’ll need to tweak it a bit to get it there.

Operation The operation phase is where the true viability of the network design is tested. Any weaknesses discovered are addressed here, and the network’s actual performance levels that are monitored during day-to-day operations supply the information you need to move into the optimization phase.

Optimization This phase hinges upon solid, practical network management that’s objectively directed toward detecting and working out any glitches before they evolve into serious problems. The optimization phase is highly significant because if issues can’t be troubleshot effectively or if the network’s performance breaks down over time, redesigning the network is probably necessary. Major changes in service requirements due to growth, restructuring, etc., can also make redesigning the network essential. This last scenario is where having a clear, accurate picture about throughput, responsiveness, and the types and frequency of resources accessed provides an invaluable tool with which to create a new and viable network design.

Retirement Although not technically part of the PDIOO process, the retirement of the network—or parts of the network—is a natural progression in the life cycle of a network. As new technology develops and needs evolve, all or part of the network often becomes obsolete. The outdated equipment is then either retired or repositioned somewhere else in the network where the demands on it won’t overwhelm its limited capacity.




CCDA. Cisco Certified Design Associate Study Guide
CCDA: Cisco Certified Design Associate Study Guide, 2nd Edition (640-861)
ISBN: 0782142001
EAN: 2147483647
Year: 2002
Pages: 201

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