Network design is getting more complex with complexity of our network with different type of multimedia and data traffic, so it is necessity that we have a proper design methodology that support out plan. In this article we will see some network design methodology. Some of the design approaches are as follows:
Designing topology with Top-Down Approach
After selecting the network design methodology, you need to design you network topology. You can use the top-down design approach for designing the network topology. Top-down design just means starting your design from the top layer of the OSI model and working your way down. Top-down design adapts the network and physical infrastructure to the network application’s needs. With a top-down approach, network devices and technologies are not selected until the applications’ requirements are analyzed. To complete a top-down design, the following is accomplished:
- Analysis of application and organization requirements (As discussed in Eight steps design )
- Design from the top of the OSI reference model
- Define requirements for upper layers (Application, Presentation, Session)
- Specify infrastructure for lower OSI layers (transport, network, data link, physical)
- Gather additional data on the network
Network prototype or Pilot test:
Pilot or prototype is the simple implementation or testing network solutions that you have implemented in your network deployment. A pilot site is small live test site before the solution deployed. This is the real world approach for discovering problems before you deploy the network design solution for rest of network. Pilot test can be implemented on sub module, some campus or remote office site. With pilot or prototype you can perform the testing and experiment that you can’t do on the real environment so it is good way for testing things before deployments. Successful test will prove your design and in case of any failure you can go back to previous phase and can modify the plan and design phase.
Network Design document:
The design document describes the business requirements, old network architecture, network requirements; and design, plan, and configuration information for the new network. The network designers, architects and analysts use it to document the new network changes, and it serves as documentation for the enterprise. The design document should include the following sections:
- Introduction
- Design requirement
- Existing network infrastructure
- Design selection Logical design, routing protocols, IPv6 etc
- Proof of concepts
- Implementation plan
- appendix
Introduction: describes all the information related to project’s purpose and the reasons for the network design.
Design Requirements is an important part of the network design document which includes the lists of organization’s requirements, constraints, and goals.
Existing Network Infrastructure define the current network including Layer 3 topology diagrams, physical topology diagrams, audit results, routing protocols, a summary of all applications, a list of network routers, switches, and other devices configurations and a description of issues. Design contains the specific design information, such as logical and physical topology, IP addressing, routing protocols, and security configurations.
Proof of Concept is the results from live pilot or prototype testing.
Implementation Plan includes the detailed steps for the network staff to implement the new installation and changes.
Appendixes contains list of exiting network devices, configurations, and additional information used in the design of the network.
