Fill in the blanksQuestion 1 · Recall
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By the end you can explain what Ethernet is, why collisions happen, and describe how CSMA/CD detects them and stops them repeating.
Six people at a table, one conversation. Polite people listen before speaking. But sometimes two people start at exactly the same moment, both stop ("sorry, you go"), and then... both start again together. Awkward.
The fix is to wait a random moment before trying again. That's CSMA/CD in a nutshell.
Ethernet
The most widely used set of protocols (standards) for wired LANs. Data is sent in frames, each containing the destination and source MAC addresses, the data, and an error check.
Collision
When two devices transmit on a shared medium at the same time, their signals overlap and both frames are corrupted.
Early Ethernet ran on a bus: one shared cable. Only one device can transmit at a time, but nothing physically stops two from trying.
Even devices that listen first can collide. A signal takes time to travel along the cable, so two devices far apart can both hear silence and start transmitting a split second apart.
CSMA/CD
Carrier Sense Multiple Access with Collision Detection: the method Ethernet uses on a shared medium. Devices listen before transmitting, detect collisions while transmitting, and wait a random time before trying again.