How does a switch handle broadcast frames and what is a broadcast storm?

• A. Switches forward broadcasts to all ports in the same VLAN; a storm occurs when excessive broadcasts overwhelm the network.
• B. Switches block all broadcast frames by default.
• C. Broadcast storms are caused by unicast traffic.
• D. Switches convert broadcasts into multicast automatically.

Answer: (A)

Broadcast frames are meant for every device in the same VLAN. When a switch receives a broadcast, it floods that frame out all ports that belong to the same VLAN, so every host in that VLAN sees it. This is how essential services like ARP and DHCP reach all devices without needing special addressing. But if there’s a loop or misconfiguration, those broadcasts can circulate endlessly, consuming bandwidth and CPU resources until the network slows or stops—this is called a broadcast storm. Spanning Tree Protocol and other loop-prevention measures exist to block redundant paths and break cycles, preventing storms from occurring. So the correct idea is that switches forward broadcasts to all ports in the same VLAN, and a broadcast storm happens when excessive broadcasts overwhelm the network. It’s not that broadcasts are blocked by default, not caused by unicast traffic, and not automatically converted to multicast.