Understanding unicast, multicast, and broadcast

I. Communication modes are classified in IPv4 networks. There are three communication modes available for the host: 1. unicast: data communication between a single host and a single host 2. Broadcast: A single host sends data packets to all hosts in the network. 3. Multicast: A single host sends data packets to a selected group of hosts for different unicast, broadcast, and multicast purposes, and uses different IP addresses as the destination address. 2. unicast refers to the communication between a single device and a single device. Both the source address and destination address are single IPv4 addresses, and the communication of unicast data packets can be forwarded between networks. In actual network communication, most of the communication is unicast. Www.2cto.com 3: broadcast is a host that sends data packets to all hosts in the network. The Broadcast Destination Address is different from the unicast single address. There are two types of broadcast: Targeted broadcast and limited broadcast. 1. Targeted broadcast sends data packets to all hosts in a specific network. The destination address of targeted broadcast is the broadcast address of the targeted network, if the current network is 192.168.0.0/24 and you want to send a targeted broadcast to the network of 192.168.1.0/24, the destination address of the targeted broadcast is 192.168.1.255. You can configure a vro to forward the broadcast. 2. Finite broadcast refers to sending data packets to all hosts on the local network. The destination address of finite broadcast is 255.255.255.255.255. The Router does not forward the broadcast. 4. multicast refers to the communication between a single device and a single device. Broadcast refers to a single device that sends data to all hosts in the network, multicast sends hosts to a specified group of hosts. Compared with unicast, this improves the efficiency of packet sending and reduces network traffic compared with broadcast. Different from broadcast, to implement multicast, you must install the corresponding client program on the client that receives multicast. V. unicast and broadcast IP address classification address block address range multicast 224.0.0.0/24224.0.0.0 ---- 239.255.255.255 broadcast www.2cto.com targeted broadcast address + limited address targeted broadcast address: the broadcast address of each network is limited: 255.255.255.255 6: Impact of multicast and broadcast on performance network devices have different processing methods for unicast, multicast, and broadcast data packets. The host NIC and network device can identify the target MAC address of the frame and determine whether it is unicast. If it is unicast, the NIC can correctly determine whether to send frames to the CPU or discard frames. However, for multicast and broadcast, the NIC cannot determine whether the computer needs to process multicast and broadcast. For any broadcast or multicast NIC, it must be sent to the CPU, but cannot be processed by the NIC itself. This significantly consumes the CPU resources of network devices and hosts. Compared with unicast, multicast, especially broadcast, not only occupies a large amount of network resources, but also seriously affects the performance of each device in the network. Therefore, for networks with high broadcast traffic, you can consider dividing subnets to improve network performance. Author: My son, zhenshuai