Cisco switches suppress broadcast storms (1)

In Enterprise Networks, broadcast data packets are a double-edged sword. On the one hand, it is a data packet necessary for normal network connection. For example, in the automatic IP address acquisition scheme, broadcast data packets must be used to find available DHCP servers. On the other hand, it is easy to be used by viruses or hackers, for example, network congestion caused by DOS attacks. Therefore, reasonable control of broadcast data packets is required in network design.

I. dangers of broadcast data packets

A very important feature of broadcast data packets is that each network device in the broadcast domain, including PCs or switches, must process broadcast data packets. It can be seen that if a broadcast domain contains a large amount of broadcast traffic, all the relevant devices will be affected because they must extract resources to process these broadcast packets. At the same time, these broadcast packets occupy valuable bandwidth resources. If too many broadcast packets exist in the network, network congestion may occur, greatly reducing the network performance and security level. Therefore, the network design should prevent abnormal function faults caused by excessive broadcast traffic, and pay attention to the potential security risks. In short, if an exception occurs in the network, the abnormal device will send a large amount of broadcast packet traffic. If too many broadcast datagram traffic occurs within one second, the CPU usage of network devices such as switches is high, and the Set utilization rate reaches 100%, leading to network interruption. To this end, a secure network design uses a variety of measures to suppress the traffic of broadcast packets.

In the traditional network design, there are also many measures to reduce unnecessary broadcast packets in the network. For example, you can design a network into multiple network segments to reduce the number of devices in the broadcast domain and reduce the number of broadcast packets. However, these traditional solutions all require additional equipment, which is not very convenient to implement. In Cisco vswitches, broadcast suppression is provided. Maybe the network administrator can solve this problem in another way.