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Network Performance

In order to illustrate the use of various network devices, there is an assumption that the small organization runs its network based on the Ethernet 10BaseT standard. There are about 40 PCs and other network nodes connected to three hubs that form a single logical repeater using the proprietary expansion connectors (Spurgeon, 2009, p. 271). As the UTP Cat 5 cable is used to connect PCs to hubs, the network cabling is appropriate for the star topology. However, the logic of a current setup effectively represents a bus topology, as hubs do not isolate any PC’s traffic from all other network nodes. The whole network is a single collision domain where only one PC can transmit at a time. If two or more network nodes start transmitting simultaneously, a collision occurs and all nodes wait for some time before the next transmission attempt. Due to these features of a shared environment, the network performance has steadily degraded as more powerful PCs succeeded the obsolete ones.

The situation can be improved by replacing hubs with Ethernet switches. The cabling part is capable of supporting 100 Mbps network speed (Gupta, 2006, p. 367), thus the most appropriate solution would be to use the 100BaseTX Fast Ethernet standard. Compared to the shared environment, the switches allow simultaneous transmission of many network nodes using the MAC (Media Access Control) addressing. All traffic designated to a specific PC is forwarded only through the switch port to which that PC is connected. A single 48-port Fast Ethernet switch could suffice but there might be implications related to the network scalability. As the company plans to occupy a few additional offices located at the far end of the very long floor, the better solution would be to use several switches interconnected via 1 Gbps ports. In this way, a 100 meter length limitation will not prevent the network growth because switches could be distributed along the corridor.