The Logical and Physical Design of a Network When a network is being designed, the architect must first think about the logical layout and that should be enforced. When he figures out what devices need to communicate and how, a physical design of the network can be implemented. A logical design is the reasoning of a network, with no particular devices or locations chosen. The physical design of the network is when the devices are picked and their actual location determined. When the logical design of a network is planned, an engineer will generally map out the logical layout and addressing of the network. This allows the person to picture the topology of the network and the addressing scheme that will be used amongst the network devices.
Information must be gathered about several important factors before the logical design of the network is started. For example, depending on the services that will be provided to users, you may need to analyze the possible traffic patterns that might result from your plan. Locate potential bottlenecks and, where possible, alleviate them by providing multiple paths to resources or by putting up servers that provide replicas of important data so that load balancing can be provided. You need to determine who the clients are and what their actual needs will be. Distinguish between novice and power users. The services that will be provided on the network should also be determined during the logical planning stage.
They may be limited by a scope, such as a firewall between LANs. And if so, that still doesn’t account for configuring a firewall to enable access to the Internet. You may also need to determine if an Internet connection will be needed for internal network’s users and outside vendor. Will all users need to access email-both within the internal network and through the firewall on the Internet? The same goes for what sites users will be allowed to access using a network browser and other network applications. Will you have users who work from home and require dial-in or VPN access through the Internet? The problem is that not everyone follows certain rules, bypassing important rules and questions that the person should ask when the design is in progress. A proper logical network design must be able to foresee future requirements, growth, security, capacity and efficiency.
There are books and manuals that analyzes these topics in hundreds of pages, and it is impossible to include them here. One big mistakes that usually occur, and I have seen in many companies I have consulted, is squeezing as many computers and network devices possible, in one logical network, which is a big mistake. I always find myself telling people to break their network into smaller, easier manageable pieces that will help maintain a certain level of security, and avoid the network being flooded with unnecessary broadcasts and multi casts. My suggestion to you, if your planning to design a network is to take a look around for documents, white papers and books that cover the above mentioned topics and read through them.
You will find some pretty good ideas and tactics to conquer all of the problems and questions you might be facing. o After you ” ve decided on the network protocols and the services you need to offer on the network, identified potential bottlenecks, and evaluated the security problems associated with your network needs, you can then design the physical aspects of the network. o The preceding chapter discussed different physical network topologies. There are tools you can use, such as Visio, to draw a physical network diagram. Tools such as these are expensive but make a much better presentation to management than hand-drawn network layouts.
Whichever tool you decide to use to create the actual network drawings, just be sure that the drawings are clear and concise. Looking back at your network application requirements, bandwidth requirements, and the like, you can then start designing the physical network, deciding where to place important servers and redundant devices. Write a 3 – 4 page (350 words per page) paper that explains the difference between logical design and physical design of a network. Illustrate an example of a logical design for a network. Illustrate an example of the physical design of the network in the logical design.