devices plugged into that hub. As illustrated in Figure, your visibility window is limitless when your sniffer is connected to a hub-based network.
Unfortunately for hub-based networks are pretty rare because of the headaches they cause network administrators. Because only one device can communicate at any one time, a device connected through a hub must compete for bandwidth with the other devices trying to communicate through the hub. When two or more devices communicate at the same time, packets collide, as shown in Figure 2. The result may be packet loss, and the communicating devices will compensate for that loss by re transmitting packets,which increases network congestion and collisions. As the level of traffic and number of collisions increase, devices may need to transmit a packet three or four times, decreasing network performance dramatically. It’s easy to understand why most modern networks of any size use switches.