Collision domain

[lucad7846]

Hi everyone

Just a quick question please. 

Given the attached screenshot, I believe there is 4 broadcast domains and 11 collision domains. It looks like 11 collision domains is not the correct answer. Do we counts the ports on the devices to determine the number of collision domains? 

Can someone help with this please? 

Many thanks in advance

[lucad7846]

here is the network diagram

[Kasun Bandara · Accepted solution]

its 10 collision domains

[lucad7846]

Hi 

Thanks so much

Just to clarify so that I can learn - is it 10 because you count the hub with the 2 pc's connected to it as just 1? 

Many thanks 

[MHM Cisco World]

all user and router connect to Hub count as ONE collision domain.

https://study-ccna.com/collision-broadcast-domain/

[lucad7846]

Hi Thanks for your reply

So based on the screenshot I posted isn't there 11 collision domains? I am bit confused 

Thanks 

[MHM Cisco World · Accepted solution]

No there is 10 only.

[lucad7846]

Thanks for letting me know cheers 

[MHM Cisco World]

Friend hub connect to 100 host/routers represent one collision domain, in such if one host/router need to send traffic all other need to wait otherwise collision happened.

[lucad7846]

I see. Thanks so much for letting me know

Cheers 

[Joseph W. Doherty]

There can be a many as 11 collision domains, or as few as just one.  11, 1?

Collisions cannot happen on ports running full duplex, which might be the case for all the ports except those connected to the hub.  I.e. that would (usually - see next paragraph) be the "just one" collision domain.

If the hub in question is dual speed, i.e. 10/100, it could then have two collision domains; which would also increase the possible maximum number of collision domains to 11.  (NB: I've worked with dual speed hubs, basically they bridge traffic between 10 and 100.)

Regarding number of broadcast domains, that would depend on whether switches are using VLANs (dashed line between sw-1 and sw-2, trunk?); also whether routers are bridging (that's very unusual - but another dashed line between routers, trunk?), not routing.