Collision domains and switches When a network is segmented with a 12-port Ethernet switch, how many collision domains are created?

Introduction / Context:
A collision domain is a network segment where data packets can collide with each other during transmission. The use of hubs, switches, and routers affects how many collision domains exist in a network. Switches are designed to reduce collision domains.

Given Data / Assumptions:

• The device in question is a 12-port Ethernet switch.
• Each port on a switch operates independently.
• We are discussing traditional Ethernet with CSMA/CD in mind.

Concept / Approach:

Unlike hubs, which forward frames to all ports and thus create a single collision domain, switches create a separate collision domain for each port. Therefore, a 12-port switch creates 12 collision domains.

Step-by-Step Solution:

Verification / Alternative check:

Standard networking references confirm that switches eliminate collisions by dedicating a collision domain to each port.

Why Other Options Are Wrong:

• 1: true only for hubs, not switches.
• 2 or 5: arbitrary incorrect numbers.
• 24: double the actual number of ports.

Common Pitfalls:

• Confusing collision domains with broadcast domains. A switch still maintains a single broadcast domain unless VLANs are used.

Final Answer:

12