The router can also be called a gateway device. The router is the network layer relay and the third layer relay task completed in OSI/RM. It stores and packet forwards the data packets between different networks. It is mainly to separate the networks in different logics.
The data is transmitted from one subnet to another, and can be processed through the router’s routing function. In network communication, the router has the function of judging the network address and selecting the IP path. It can construct a flexible link system in multiple network environments and link each subnet through different data packets and media access methods. In operation, the router only accepts the information transmitted by the source station or other related routers. It is an interconnected device based on the network layer.