Broadcast knowledge Simple Q &

Broadcast knowledge Simple Q & A first, how does one network card know the MAC address of another network card? The answer is: there is an ARP protocol that can solve this problem. This will be introduced later. Here, you only need to know that the Ethernet packet must know the MAC address of the receiver before it can be sent. Second, even if the MAC address is available, how can the system send the packets to the receiver accurately? The answer is: Ethernet adopts a very "primitive" method. Instead of sending data packets to the receiver accurately, it sends data packets to all computers in the network so that each computer can determine for itself, whether it is the receiver. Computer 1 sends a data packet to computer 2. computers on the same subnet, such as computer 3, computer 4, and computer 5, will receive the packet. They read the "Header" of the package, find the MAC address of the receiver, and then compare it with their own MAC address. If the two are the same, they will accept the package for further processing, otherwise, the package will be discarded. This sending method is called broadcasting ). With the definition of data packets, the MAC address of the network card, and the broadcast transmission method, the "link layer" can transmit data between multiple computers.