CHAPTER FIVE: NETWORK
DESIGN
2.16. 5.0. Definition
Dictionaries generally define design as planning how to create
something, or the actual plans themselves. However, when you think of designing
something, whether it is a product, an addition to a house, or a network, you
likely contemplate a broader use of the word design.
2.17. 5.1. Design principals
Cisco has developed the Plan-Design-Implement-Operate-Optimize
(PDIOO) network life cycle to describe the multiple phases through which a
network passes. This life cycle phases are briefly described as follows:
ü Plan phase: The detailed network
requirements are identified, and the existing network is reviewed.
ü Design phase: The network is designed
according to the initial requirements and additional data gathered during
analysis of the existing network. The design is refined with the client.
ü Implement phase: The network is built
according to the approved design.
ü Operate phase: The network is operational
and is being monitored. This phase is the ultimate test of the design.
ü Optimize phase: During this phase, issues
are detected and corrected, either before problems arise or, if no problems are
found, after a failure has occurred. Redesign might be required if too many
problems exist.
ü Retirement phase: Although not part of
the PDIOO acronym, this phase is necessary when part of the network is outdated
or is no longer required.
Figure 5.1: illustration of PDIOO
Network design should include the following tasks,
· Determine requirements
· Analyze the existing network, if one exists
· Prepare the preliminary design
· Complete the final design development
· Deploy the network
· Monitor, and redesign if necessary
· Maintain documentation (as a part of all the other
tasks)
Figure 5.2: illustrate the tasks
Note: The Campus LAN Design addresses four primary wired LAN
requirements shared by organizations, including the need to:
· Offer reliable access to organization resources
· Minimize time required to absorb technology
investments
· Provide a productive and consistent user experience
· Reduce operation costs
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