System expandability in respect of Ethernet in vehicle

The invention discloses a system expandability in respect of Ethernet in a vehicle and a packet switching unit. The packet switching unit is configured as a data packet for receiving different information through an Ethernet interface; the data switching unit can be configured to change a target which is stated in the data packet or an Ethernet address/ a network address/ and interface combination, which enables one of the Ethernet address/ the network address/ terminal combination to correspond to the Ethernet address/ the network address/ terminal combination which corresponds to a second information packet having another information identifiers; if the two Ethernet address/the network address/ the terminal combination are different before change; or after the change, one of the Ethernet address/ the network address/ the terminal combination is different from the Ethernet address/ the network address/ the terminal combination which corresponds to the second information data packet having other information i