Module 03
Ethernet, MAC and switching
How devices on the same network find each other. Send frames through a switch, watch it learn which MAC address lives behind which port, and see when it has to flood.
Start lesson 1
What does a MAC address tell you? · 8 min · free, no account
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What you'll operate
- Frames and MAC addresses
- How a switch learns where things are
- Flood, forward or filter
- lessons
- 6
- minutes
- 51
Lessons in this module
- 1What does a MAC address tell you?Take a MAC address apart: who assigned it, and whether it names one device or a group.Free, no account8 min
- 2What is inside an Ethernet frame?Open a frame field by field, then work out its smallest and largest size.Plus8 min
- 3How does a switch learn where devices are?Watch a switch fill its MAC address table from the frames passing through it, then see entries age out.Plus8 min
- 4Flood, forward or filter?Take the switch's place: read its table and decide which ports each frame leaves by.Plus9 min
- 5Collision domain or broadcast domain?See what a hub, a switch and a router each keep apart, and count the domains in a network.Plus9 min
- 6What breaks a switched network?Follow a broadcast around a loop, see how spanning tree stops it, and watch an attacker turn a switch into a hub.Plus9 min
Lesson 1 is open to everyone, with no account. The other lessons in this module are part of Plus.