Collision and broadcast domain

[fisnik-jashari1]

Hi everyone

I am confused a little bit about collision domain and broadcast domain. I know that each port in the switch is a singe collision, but when we connect the switch to the router is the line counted as collision domain or broadcast domain or both.

Correct me if i am wrong.  We have two broadcast domains each for router interface and  4 collision domains.

Thank you for your answers.

[Jon Marshall · Accepted solution]

Basically yes to what you say.

L3 devices separate broadcast domains (usually) so you have two broadcast domains terminating on each of the router's interfaces.

Each switch port is a separate collision domain so as you have 4 connections you have 4 collision domains.

Jon