In Figure 2, each server is on the segment on which it gets the most use. Bridges don't retransmit packets that don't need to pass through them, so this configuration reduces network traffic without introducing routing overhead onto the servers. Bridges occasionally crash, and a bridge failure would prevent users on each segment from accessing the other segment. But most bridges crash far less often than servers crash, and in the event of a bridge crash, users on each side of the network can access the server on their segment. Switched Environments Suppose your network has grown to the point that you don't want to keep all your devices on one physical segment anymore.
Switches provide the easiest and most common way to segment traffic.
The primary difference between a switch and a bridge is that switches work on a larger scale. Switches usually have at least a dozen ports, but bridges usually have only two ports. Unlike switches and bridges, a hub transmits packets to all of its active ports. Many people refer to hubs as shared media because every device that connects to the hub has to share its bandwidth with all the other devices that connect to the hub. If you connect too many hubs, you end up with a shared network too large to let users work effectively.