While the roles of a network designer are indeed varied, and different general approaches to network design exist, the entire concept of designing a network is greatly simplified through the use of structured design methodologies. Although it sounds rather fancy, a structured design methodology is really nothing more than a set of distinct steps that help to ensure that all of the necessary tasks in the network design process are completed.
Cisco uses a methodology known as PDIOO as part of designing networks. PDIOO is an acronym that describes some of the major elements in a network design process, namely:
Instead of concentrating on memorizing these elements, you should instead focus on recognizing them as the key elements to any network design project. More than anything, PDIOO represents a theme that comes up again and again over the course of designing not only a network, but also just about any system you can think of.
For the purpose of designing networks, Cisco recommends an 8-step process that constitutes the structured network design methodology mentioned earlier. Each of these 8 steps represents a specific network design task that much be completed as part of a project. The specific steps involved in any network design project include:
- Identifying customer requirements
- Identifying and analyzing the current network
- Designing network topologies and services
- Planning the network implementation
- Proof of concept (building pilots or prototypes)
- Documenting the network design
- Implementing and verifying the network design
- Monitoring and revising the network design
Each of these elements is looked at in more detail in upcoming articles.