10.3 Background

10.3 Background

To make the design process more straightforward, I have separated the design of the network into making technology choices and determining interconnection mechanisms. At this point in the process, we should have the requirements specification, with its user, application, device, network, and other requirements; the requirements map, which shows the locations of applications and devices; the flow specification, with its performance characteristics for individual and composite flows, flow models, and data sources and sinks; and the component architectures for performance, security and privacy, network management, and addressing and routing. We will use all of this information as input to the network design.

Network design consists of determining your design goals for the network and translating these goals into evaluation criteria for making technology choices for the design. The network is then segmented into small, workable areas, and technology choices are made for each area based on the evaluation criteria. After making our technology choices, we will determine how to interconnect areas of the design. We will also look at various interconnection mechanisms and where they may apply in the design.

The technologies that will be discussed in this chapter may be at different stages of development, testing, or deployment based on when this material is applied to the design. When evaluating and selecting technologies for your design, check the current (or expected) state of each candidate technology before applying it to the design to ensure that your technology choices can be implemented.

Figure 10.1 shows the process model for making technology choices for a network design. Input to the design comes from the results of the requirements specification and map, the flow specification and map, and the reference architecture. This information is used to establish design goals for the network and to develop criteria to evaluate candidate technologies. Guidelines for technology evaluation, presented in this chapter, are used in conjunction with the evaluation criteria to make technology selections.

Figure 10.1: Process for selecting technologies for the network design.

One of the results of the design process will be one or more diagrams describing where each of the technologies applies within the network. These diagrams will be combined with diagrams describing the network architecture and interconnection mechanisms for a complete description of the network. This complete set of diagrams will then be used to prepare and plan for the network, including, for example, writing a request for proposal (RFP), ordering equipment, deploying cable, and writing the transition plan for the network.