Broadcast Storm Caused by Network Loops | Generated by AI
Question: In a switched network, what causes a broadcast storm?
Answer:
The correct answer is B) Network loops without STP.
Explanation
In an Ethernet switched network, broadcast frames (such as ARP requests) are forwarded out of all ports except the incoming port by every switch. If there is a loop in the network topology (e.g., two switches connected by multiple links without proper controls), a broadcast frame can circulate indefinitely:
- The frame enters the loop, gets flooded by each switch, and keeps looping around.
- Each iteration multiplies the number of broadcast frames, rapidly consuming bandwidth and CPU resources on switches and end devices.
This phenomenon is known as a broadcast storm.
Spanning Tree Protocol (STP) prevents this by detecting loops and logically blocking redundant paths, ensuring a loop-free topology while maintaining redundancy for failover.
Why not the other options?
- A) Too many unicast frames: Unicast floods can occur with unknown destinations, but they do not multiply exponentially like broadcasts in a loop, and do not typically cause a “broadcast” storm.
- C) Misconfigured VLANs: This can cause issues like unintended traffic leakage or isolation problems, but it does not create endless frame multiplication leading to a broadcast storm.
- D) High bandwidth usage: This is a symptom or result of various problems (including a broadcast storm), but it is not the root cause of a broadcast storm itself.
Thus, the primary cause of a broadcast storm in a switched network is the presence of network loops without STP (or another loop-prevention mechanism).