Many companies offer a variety of switches, while other companies make a wide range of NICs. Despite these obstacles, almost all of the Ethernet switches work with each other, as do the Ethernet NICs. Why? They work together because they all have to (at a minimum) conform to the IEEE 802.3 specification. The switch manufacturer can add additional features once the switch meets minimum requirements as long as the new features do not cause any of the mandatory features to stop working. Since switches all work minimally at Layer 2, any switch will offer improved security over a hub. Whereas a hub sends traffic to all workstations regardless of the intended recipient, switches only send data where they need to go. This makes sniffing a switched network much harder than sniffing a nonswitched network. Once we accept this one-switch commonality, we then need to look at what makes each different so that we can choose the right switch for each environment. The following sections describe different types of switches, including:

• Which type of switch is right for your needs?

• Physical footprint

• Speed

• Distance

• Duplex mode

• Spanning Tree Protocol

• Content Addressing Mechanism

• Backplane and Switching Fabric

• Optional Features