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New Member

collision domain

i have a this network design:

Router === BR-Root ----- BR-Cleint === BR-AP ----- WGB

What is the collision domains for this network design ?

1 ACCEPTED SOLUTION

Accepted Solutions
New Member

Re: collision domain

That's not entirely true...

This whole scenario is one broadcast domain, but is multiple collision domains. All of the components are layer 2 bridges which means they build forwarding tables for each interface, similar to an ethernet switch.

In this scenario, you will have one collision domain between the router and the root bridge, another collision domain between the root bridge and the client bridge, another between the client bridge and the AP, another collision domain between the AP and the WGB, and a final outside the WGB.

However, since this is a csma/ca (collision avoidance) topology, 'collisions' don't occur. Instead, a device wishing to transmit will 'listen' to the carrier and will transmit if the medium is available. Unlike a collision detection network, which attempts to transmit and then senses a collision, wireless devices will not attempt to transmit if another device is currently transmitting.

3 REPLIES
Cisco Employee

Re: collision domain

BR and AP / WGB are layer 2 device , does not look at layer 3 so till you hit the router you are in one collision domain .

Remeber this is 11 meg shared bandwidth . it works on similar concept like

wired ethernet

Wired ethernet is csma/cd

wireless is csms/ca

Nilesh

New Member

Re: collision domain

That's not entirely true...

This whole scenario is one broadcast domain, but is multiple collision domains. All of the components are layer 2 bridges which means they build forwarding tables for each interface, similar to an ethernet switch.

In this scenario, you will have one collision domain between the router and the root bridge, another collision domain between the root bridge and the client bridge, another between the client bridge and the AP, another collision domain between the AP and the WGB, and a final outside the WGB.

However, since this is a csma/ca (collision avoidance) topology, 'collisions' don't occur. Instead, a device wishing to transmit will 'listen' to the carrier and will transmit if the medium is available. Unlike a collision detection network, which attempts to transmit and then senses a collision, wireless devices will not attempt to transmit if another device is currently transmitting.

New Member

Re: collision domain

thank you very much. I guessed about this, but was not sure.

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