collision domains confusion.

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I'm studying for my network + and i'm just not catching the information. I'm taking multiple practice exams that are asking me how many collision domains do I have if I have a router, switch and a hub with a certain number of connections to the devices, etc.

@cody-hulin said in collision domains confusion.:

I'm studying for my network + and i'm just not catching the information. I'm taking multiple practice exams that are asking me how many collision domains do I have if I have a router, switch and a hub with a certain number of connections to the devices, etc.

First you must know what a collision domain is. When multiple devices have access to the same wire. Only 1 device device can speak at any one given moment in time. If 2 devices try to do this at the same time. The signal will "collide" causing the traffic to not arrive at its destination. To handle this, we tend to use CSMA/CD. We deal with collisions after the fact to insure that communication is possible.

The more devices on the same wire, the more collisions are likely because more devices can talk at the same time.

Collisions are limited different technologies like what you mentioned. Those limitations are collision domains.

• Hubs, all ports on a hub is in a collision domain.

• Routers, each port on a router creates a collision domain

• Switches, each port on a switch is it's own collision domain. Usually there are none because there is usually only a single device on a single port.