1) the straight through type of Ethernet switch can be understood as the cross line matrix telephone switch between the ports. It is a data packet at the input port detection, check the Baotou package, to obtain the address, start the internal dynamic lookup table into the appropriate output port, connected at the intersection of the input and output of the data packets through the corresponding port, to achieve the exchange function. Because there is no need to store, the delay is very small, the exchange is very fast, this is its advantage. The disadvantage of this is that the packet content is not saved by the Ethernet switch, so it is impossible to check whether the transmitted packet is incorrect or not. Because there is no cache, the input / output ports with different speed can not be directly connected, and the packet loss can be easily lost.

2) store and forward: store and forward mode is the most widely used method in the field of computer network. The input port of the first packet stored, then the CRC (cyclic redundancy check) check, just take out the packet's destination address in the packet processing of error, through the look-up table into an output port to send packet. Because of this, the storage and forwarding method in data processing time delay is big, this is its insufficiency, but it may carry on the error detection to the data packet which enters the switch, effectively improves the network performance. In particular, it can support the conversion between ports at different speeds, and maintain the cooperative work between high speed ports and low speed ports.

Isolation: This is a solution between the former 3. It checks whether the length of the packet is 64 bytes, if less than 64 bytes, the description is false, then discard the packet; if more than 64 bytes, then send the packet. This method does not provide data validation. Its data processing speed is faster than the store and forward mode, but it is slower than the straight through.