scheduled test for 8-22-08, 1 quick question?

First of all I would like to thank all of the moderators of this site for putting this very informational website together. I visit this site at least 5x a day. Whenever I ask a question or questions I get a reply/answer faster from you guys quicker than if I were to research it on the net!! (thanks Dynamik!!)

Now for my question? I feel very confident with all of the info I have retained in preparation for this test. I am using the Technotes from this site, ExamCram 2 and some measure up test questions (also wikipedia, how stuff works etc...) I have been studying for more than 90+ days. I still fell unsure about subnetting. I have read the info posted on this site but I am a still a novice. I understand the basic concepts until.... I get a question like,

"Find the broadcast address of 192.168.2.0 /27"

which totally blows my mind. I understand everything until I see the "/" at the end of a subnet address.

how would I answer this question (please in very basic terms) and should I worry about the test getting any more complex than this with subnetting .i.e CIDR etc...?

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dvalenzuela

the Subnet is 192.168.2.0
The Subnet Mask: 255.255.255.224
The BroadCast ADdress : 192.168.2.31

Well this is the point.

u need to know /24 means 255.255.255.0. If u use /27 you are borrowin 3 bits (27-24)
This 3 will be used for network ids. The rest 5 for hosts. Anyways, the way that I do is the Following I use this small table
2^7=128,2^6=64,2^5=32,2^4=16,2^3=8,2^2=4,2^1=2,2^0=1

AAAAAAAA.BBBBBBBB.CCCCCCCC.xxxyyyyy

Since xxx(3bits) are used for Network Ids, the yyyyy(5bits) are used for host ids. Well This 5 bits needs to be filled with 1s in order to get the broadcasts for that subnet and compared with the small table above that I mentioned before. In this case
16 + 8 + 4 + 2 + 1 =31
y y y y y

This is how we get the 31. Theere are other different ways.. Goog luck on it.

dynamik

mjones wrote:

I visit this site at least 5x a day.

Why would you ever leave

mjones wrote:

I understand the basic concepts until.... I get a question like,

"Find the broadcast address of 192.168.2.0 /27"

which totally blows my mind. I understand everything until I see the "/" at the end of a subnet address.

how would I answer this question (please in very basic terms) and should I worry about the test getting any more complex than this with subnetting .i.e CIDR etc...?

/27 just tells you how many bits are used for the subnet mask.

11111111.11111111.11111111.11100000 which is simply 255.255.255.224

I'm not sure how in-depth the exam gets into subnetting. It seems a little beyond the scope of it, but you never know.

Check out www.learntosubnet.com and www.subnettingquestions.com

You'll have to learn it eventually, might as well do it now and be over-prepared for your exam

It's actually quite easy once you get the hang of it.

nicklauscombs

I think it's safe to say you will not see any questions on subnetting like that

i could however see a question on why you would subnet a network

TravR1

You will have to know default subnets (255.255.255.0 = Class C) and maybe why you would need to subnet a network, but that's it. Don't worry about what you posted being on the test. But yeah, know it anyway because it's only to your benefit.

mjones

Thanks to all of you guy's for making subnetting easy for me to understand

L0gicB0mb508

Yeah I don't think you'll see any questions about actually doing any subnetting on the test.

dvalenzuela

I did the test yesterday. I had a couple of questions like that one........ Be carefull

Barrypr

Second that, did exam yesterday few subnetting questions.

evoxdc

Barrypr wrote:

Second that, did exam yesterday few subnetting questions.

Third that, subnetting was involved with a few of the questions I had with 2 or 3 looking similar to what was posted.

TravR1

Well there is some that aren't graded. I hope those aren't on the test, I'm taking it soon and I don't know that stuff. There is nothing what was on the first test in any of my Network+ study guides. That will be lame if I get one of those

pLuhhmm

Net+ doesnt really have much of any of this on it so dont worry, but nice question tho overall.

Slowhand

dynamik wrote:

Why would you ever leave

About that, dynamik. We're going to call an intervention if you don't back away from the keyboard, get some rest. . . and come back with buffalo wings. Seriously, man, those Clockwork Orange eyelid-holders are going to give you some kind of cancer.

SamCarter

Wow, dvalenzuela, I just had to say thanks for that. I took some classes that touched on subnetting and the teacher did not explain it that way. I know there are a million ways to do it, but that one actually makes sense to me!

dvalenzuela

I learned Subnetting from this Forum......... It 's awesome...

TravR1

I learned the little I know about custom subnetting so far from learntosubnet.com