About this interactive
From the lesson:
- **Redundancy creates loops.** We want spare links between switches, but a switch sends a broadcast out every port except the one it came in on.
- **With two paths, the broadcast comes back** and is sent out again, over and over, multiplying until the network crawls or stops: a broadcast storm.
- **Spanning Tree Protocol** keeps the redundancy but blocks enough ports to leave one path, and brings a blocked link back if the active one fails.
- **Easy to cause by accident:** a cable plugged into two jacks on one switch is a loop.
What you'll learn
- Recognize when redundant Layer 2 links between switches form a loop that spanning tree must break by blocking a port
- Explain why a loop floods a network: a broadcast goes out every port but the one it came in on, so it circles and multiplies
Aligned to
Cisco CCNA
2.5
Interpret basic operations of Rapid PVST+ Spanning Tree Protocol
1.13
Describe switching concepts
Key terms
- Spanning Tree Protocol
STP
- A network protocol that prevents loops in Ethernet networks by creating a loop-free logical topology.
- Broadcast Storm
- A network condition in which excessive broadcast traffic overwhelms switch resources, preventing normal communication from occurring.
- Redundant Network Path
- An alternate physical or logical route between network sites that maintains connectivity if the primary link or router fails.
- Bridge
- A network device that connects two or more network segments and filters traffic based on MAC addresses.
- Blocking Port
- A non-designated port placed into a blocking state by STP to prevent network loops.
Topics
Stp
Switching Loops
Broadcast Storm
Redundancy
Interactive
Streak Sort
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