LAN Design for CPA Firm
When designing a LAN for a company, the designer must first consider the needs of that company. In this case, the CPA firm has several basic needs they have already expressed, and these needs will form the basis for the LAN that will be designed for them.
First off, the company has five departments locate in one building with a total of 560 employees. As they did not specify, it should be fairly safe to assume they will want all the employees’ computers to be able to access the network. This means that the network itself will be fairly large, and may require a more complex structure.
Their stated needs state that they want the network to be easily expandable, without much expense. They want fast access to the network on all computers, and, finally, they want the LAN to be up at all times. The basic design will be reached by analyzing the needs and requirements of the company, and choosing a topography and design accordingly.
First, they want the network to be easily expandable, with minimal expense. This requirement suggests the need for a star or tree topology, as these topologies both allow the network to be easily expandable. In the case of a star topology, however, the network will have an eventual limit to the number of connections it has. Given the number of employees they already have, the requirement then suggests the use of a tree topology, which links several star networks, and allows more connections because of this. The use of the tree topology also allows the network to be expanded at less cost, since it will use less cable for new additions to the network, and saves additional costs in that it requires less amplification along those cables to ensure connectivity and speed. Each department will essentially be several star networks combined into a tree network, combined into a larger tree to link the departments with each other.
The company’s next requirement is fast access to the network. This is a common requirement, but one that can be taken for granted. This requirement can be fulfilled by any of the basic topographies, and the tree network is still able to maintain this. However, should a decentral network node have a large volume of traffic, the network will experience low connectivity through that node. The introduction of a backbone into the tree network, will ensure the speed of the network, by routing the traffic into a high-speed central node to ensure high speed between all segments within the structure. We now have tree networks for each department, all connected to a backbone, and this ensures the second requirement of the company.
The last requirement is that the LAN is up at all times. Also a requirement that can be taken for granted, this can be very essential to the functioning of the network, and the business itself. Of the backbone types, a collapsed backbone will provide all the requirements so far discussed, but should the central node fail, the company will lose access to the entire network. The design then needs to implement a distributed backbone, where the central node is actually not one specific part, but several components on the network. The distributed backbone ensures that the network stays up even should one or more components fail, or should the network need maintenance.
Given the analysis of the requirements of the company then, the basic LAN design is one incorporating a distributed backbone central node, itself a resembling a star or tree network connected to the tree structures of each department. This basic design fulfils the need for expandability, speed, and continuous function of the network.