Broadcast Domain and Collision Domain

[vaibhavjaim]

hello everyone
i am new user in this forum...

i need to know that how to calculate broadcast domain and collision domain in a particular network...

anyone is there who help me regarding this...

[dbeare]

What do you mean by calculate broadcast domain and calculate collision domain? Routers break up broadcast domains and switches break up collision domains, but i'm not sure what you are asking for information on doing in your question. Can you be more specific in what you are wanting to know?

~Dustin

[dbeare]

Maybe here is an example of what you are wondering about:

Router A has three 12-port switches plugged into it. Each switch is its own broadcast domain. Each port on each switch is an individual collision domain as well. You can break up the broadcast domains by using VLAN's as well, which creates separate broadcast domains on a switch.

Is this more of what you were asking about?

[Mian]

Hi

debeare is right but also study the fig 1.4 page no.9 of the sixth edition it will really help and if VLANs are confusing you, forget about them for a while until you reach that topic and understand well ... one step at a time will make the things much clearer and easier.

an example

11 PCs connected to 11 ports of a switch A(which has total 12 ports)
A router R 1 is connected to the 12th port of the switch.

there are 12 collision domains and one broadcast domain

if the same router 1 is also connected to the other switch B to the 12th port and the remaining 11 ports of switch B are connected to 11 Pcs then altogether there will be 24 collision domains and two broadcast domains.


Broadcast is like mail(advertisement of pizza shop through leaflets) destined to all the address of a specific postcode but if you need to send say 100 pizza leaflets to all the addresses reside in one postcode and 100 advertisement of drycleaning (leaflets) to all the addresses reside in the different postcode you need a router in the middle which will look at the postcode (broadcast address) and deliver the mail to the right postcode
(two broadcast domains).

I hope it will help you to understand

Regards


Mian

[jmgern]

Thanks for that info Mian, that may have been the easiest explanation of the whole subject. I think I understand now!

[!DSeva]

Thanks for this info.

[khawshik]

so for one connected switch port one collison domain and one connected router port one broadcast domain. is it right?

[ngoni]

spot on kwakshik, one switch port - one collision domain. one router port - one broadcast domain..