more info about broadcast domains

[sumabhat]

dear sir,


could you please help me with differentiation between broadcast domain and collision domain? i am not able to get the exact picture of this concept in mind. and also how to calculate the number of collision domain. u can say it with ref to written lab 1.3

[alexus009]

Hello,

The definition of braodcast and collision domain is defined precisely on page 3 and 4 but the "Real World Scenario" on page 6 of chapter 1 on the Update Deluxe Edition is not clear. Todd or colleagues', please clarify?

Thank you,

alexus009

[tobyvere]

Hello,

Just getting into the new book and do agree, it is not clear how you determine how many collision domains there are such as in Fig 1.4 Chapter 1.

I am a bit confused as initially you say "The Bridge breaks up collision domains, but all hosts connected to both hubs are still crammed into the same broadcast domain. Also the Bridge only created two collision domains"

Then the paragraph below when you ask us to count how many collision and broadcast domains there are you tell us there are three collision domains in the hub bridge internetwork?

Sorry I do not get this and I am unsure how you get 5 from the switched internetwork as well? You have explained what the qtys are but not how you get these numbers.

Again for the example in Fig 1.5 I see 9 collision domains and 1 Broadcast domain not 10 collision domains?

Sorry I just need further clarification, I am new to this and do not want to get lost at the start

Thank you for your help.

Toby

[avinash]

Hi Toby,

Bridges and switches basically do the same thing - break up collision domains on LAN. Each port on the switch / Bridge breaks up collision domains.

"The Bridge only created two collision domains".The bridge has segmented the network into two collision domains instead of one (using only hubs). Last paragraph on Page No 10. talks about figure 1.4 again "The bridge network equals three collision domains" (this includes the port connected to router).

Example in Fig 1.5, perhaps you are not counting the switch port connected to Router.


Regards

A.

[aguilera]

Thanks again avinash!

d. aguilera

[tobyvere]

Great stuff, cheers mate I didn't realise the switch port to the router was a collision domain as well ; )

[avinash]

Hi Toby,

Glad the post was able to help out.

A.

[bs_kwaj]

OK, just to clarify, does Fig. 1.5 on Page 10 show 3 or 4 broadcast domains?

The first paragraph at the top of Page 11 says that each VLAN is a separate broadcast domain?

Is that one per switch or just one per VLAN, which are only defined for the 3 bottom switches? Based on the way the other collision and broadcast domains are counted then, I count 4 broadcast domains. Is that right?

Thanks...

[dbeare]

It depends on how the network is set up. If it is set up without setting up any VLAN's, everything past the router is 1 broadcast domain. If, however, we set up each of the host PC's on a VLAN, each individual VLAN is a broadcast domain as well. So, if the two computers on each switch were on VLAN1 and VLAN2 respectively, then there would be 3 broadcast domains, 1 from the router, and 1 each for the VLANs. I wouldn't worry too much about this at this point, you'll get into how VLANs work and why they are their own broadcast domains in later chapters.

[bs_kwaj]

Thanks dbeare. I see what you're saying. I was just getting caught up in the counting in that part of the chapter.
:cool:

The key point is 'virtual' and not 'physical' in this case.

[Joel]

:) pls i need ur help, i want to write this exam b4 april,iam a computer science student 200Level