As computer networks work well, and we hope, is the most time, the inner workings of the system modules transparent for the average user. The most common components on a computer network, cable not included are "router", "hubs" and "switch". Many of these modules may be similar cosmetically. Each module typically has Ethernet ports (RJ45, which looks like an oversized phone plug) and LED displays. However, do these modulesdifferent, and it is important to understand the differences.