WAN: Dedicated Circuit Network Essay

3. WAN- Dedicated Circuit Network
This type of WAN network is leasable from the common carrier and can provide exclusive service for 24/7 within the company. It can help us to connect all the devices from one city's branch to another by using point to point connection in the company. As a result, each branch will use different devices to support this connection based on their required needs and capacity, such as switches, routers or multiplexers. The selection of these devices depends on what the workplace prefers. The amount of capacity and devices (transition rate) that is needed has to be carefully specified, because when the contract is signed with the common carriers about the amount of circuits needed, it is advisable not to alter as it will be costly because additional capacity and devices has to be installed.
At the dedicated circuit networks, different architectures are available. For XYZ's network, we will go with the partial mesh architecture that connects not all but many computers together. It could be perhaps expensive because each computer has to do its routing by itself. However, it can handle the traffic better than other types and the message and have several and shorter pathways to go through to reach its required destination. Moreover, if one stop in the pathway faces a failure, the message can still use the other pathways by traveling through other stops.
The partial mesh connection will be organized by making the 3 main servers on the specified three departments at the Headquarters in Los Angeles. Since the Financial department has limited access to its employees, it will be a local server, which means that it will not be connected across the WAN network between the other three branches. On the other hand, the Marketing and Human Resources department's information can be available to all the employees in each department, so the employees in these two departments will have an access to its servers. Therefore, the Marketing and HR department will be connected widely across the network.
Figure 1 WAN network diagram
As shown in figure 1, each branch will have a switch and a router to support the network connection. As mentioned, just several computers will be connected widely through the network and some will have limited access to its employees. So those computers that need wide connection will be connected first to the switches that are used for connecting the devices inside the building and enable the messages to switch to and from the devices. Moreover, they will receive all the messages and send them to their destination based on the data link layer address, and because switches function at the data link layer, the networks should use the data link layer protocol and address. Furthermore, the switches are connected to the routers, which will work at the network layer and can accept connections from the same or different lines. Thus, their main functionality is to select the best path for the message to travel through the network.