According to the 7 layer network model of OSI, the switches can be divided into layer 2 switch, layer 3 switch, layer 4 switch and so on, all the way to the layer 7 switch. The layer 2 switch based on MAC address is the most common, which is used for the network access layer and the convergence layer.
The layer 3 switch based on IP address and protocol is commonly applied to the core layer of the network, few of which is also applied to the convergence layer. Some layer 3 switches even share the exchange function with the layer 4 switches, which can be used to determine the target ports according to the protocol port information of the data frames. The layer 4 or above switches are called content switches, which are mainly used in the Internet data center.
According to the manageability of the switch, it can be divided into the manageable network switch
and unmanaged switch. The difference between them is the support of network management protocols such as SNMP and RMON. Managed switches are convenient for network monitoring, but the cost is relatively higher.
As for large and medium-sized networks, the convergence layer should use manageable network switches, the access layer, depending on the application needs, and the core layer, managed switches. The characteristics of switches and concentrators are fastened on the star structure, the middle node of the connection, its function is amplifying the signals. All devices share the bandwidth of Hub, that is, if hub's bandwidth is 10M, it connects 10 devices, each device takes 1M, and all ports of the Hub share the same MAC address.