Security - broadcast-multicast storm

In networking, a "broadcast storm" or "multicast storm" refers to a network condition where there are a large number of broadcast or Multicast packets circulating in the network at the same time, which causes congestion and a significant slowdown of the network.

Broadcast packets are packets sent to all devices in a network segment, while multicast packets are sent to a specific group of devices on the network. When a network device (typically a switch receives a broadcast or multicast packet, it processes the packet and then forwards it out of all its interfaces (except the one it came from).

A storm occurs when there are too many of these packets being forwarded in the network, causing a high level of congestion. This can be due to a loop in the network, where packets keep circulating endlessly, or simply because there is a very high level of broadcast or multicast traffic.

A broadcast or multicast storm can severely impact the performance of a network, causing delays in data transmission, increased load on network devices, and sometimes even network outages.

Network administrators use various tools and techniques to prevent broadcast and multicast storms, such as configuring storm control to limit broadcast and multicast traffic, implementing broadcast and multicast filtering, and using protocols like Spanning Tree Protocol (STP) to prevent loops in the network.

IPv4 networks use broadcast communication to send data packets to all devices in a network segment. IPv6, on the other hand, does not use broadcast communication and instead relies on multicast and anycast communication. However, IPv6 networks are still susceptible to multicast storms, which occur when there is an excessive amount of multicast traffic.