OSI Model, Switching Systems, Network Channel Processors, and Media
Supporting Activities: Introduction to Network Channels, Processors, and Media
•A switch is a Data Link layer device, which means it's able to look into the packets that pass through it to examine a critical piece of Data Link layer information: the MAC address. With this information in hand, a switch can keep track of which computer is connected to each of its ports.
Supporting Activity: Introduction to Circuit Switching
A packet is a message that is sent over the network from one node to another node. The packet includes the address of the node that sent the packet, the address of the node the packet is being sent to, and data.
Supporting Activity: Introduction to Packet Switching
•In a hub, every packet that arrives at the hub on any of its ports is automatically sent out on every other port. The hub has to do this because it is a Physical layer device, so it has no way to keep track of which computer is connected to each port.