The bridge is a simple related device. Its only purpose is to split the physical network being shared into multiple small parts. The bridge is usually only 2 ports; the bridge of more than 2 ports is called Switch. Because Ethernet is the most commonly used physical network, we will use it to explain our point of view. On an Ethernet, all access computers share the same "line" (physically not the same root, but electrical communication). When 2 computers tried to talk at the same time, they will be submerged by the other party, which is called conflict. The more computers on Ethernet, the greater the chance of conflict. The bridge splits Ethernet into many conflict domains. Unless the other side of the bridge is scheduled, all the data on the bridge 1 is left there, so that the burden on 1 segment is reduced. Bridges do not consider the protocol used online (TCP / IP, IPX, AppleTalk, ECT.) Because they work in the data link layer. This is both an advantage and is also a shortcoming; because they work on a simple layer, the bridge can blindly operate at high speed, but they will not be able to control the work of its work almost. From then on, the router is born. The router works in the network layer - they actually know the protocols that transmit data on the network. Because they know the agreement, they can decide how to handle specific data by rules. To this end, the router is useful in connection networks for different destination or different organizations. The user can apply for a rule or filter to pass a particular data without making other data. Or arrange data for a certain purpose service into a specific network connection, and other data skips this connection. This service is to charge. The router gets the description of specific data details, the longer the data is sent to the destination. Therefore, the higher the rapid router, the more expensive the hardware price. In short, in most large networks, you can find a mixture of Switch (based on multi-port bridge) and routers. With their advantages and disadvantages - but their combination is a valid combination.
