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 =?Utf-8?B?RUVXYXNoaW5ndG9u?= 02-01-2006 02:44 AM

Subnetting problem

I had a problem where I'm supposed to find subnets using the equation 2n-2
with n being the number of bits I borrow from the original subnet mask. If I
wanted to borrow 3 bits, using traditional algebra it would be 2(3)-2 which
equals 4 (subnets). But their example came up with 8 subnets so is that
equation a misprint and should be 2 to the 3rd power (2x2x2 which equals 8)?
And if that is true then I'm assuming I can ignore the (-2) part of the
equation
--
MCSA is just the beginning...

 LRM 02-01-2006 03:04 AM

Re: Subnetting problem

"EEWashington" <EEWashington@discussions.microsoft.com> wrote in message
news:FD476302-5616-4DD7-9F57-8FC7CCE5C1E5@microsoft.com...
>I had a problem where I'm supposed to find subnets using the equation 2n-2
> with n being the number of bits I borrow from the original subnet mask. If
> I
> wanted to borrow 3 bits, using traditional algebra it would be 2(3)-2
> which
> equals 4 (subnets). But their example came up with 8 subnets so is that
> equation a misprint and should be 2 to the 3rd power (2x2x2 which equals
> 8)?
> And if that is true then I'm assuming I can ignore the (-2) part of the
> equation
> --
> MCSA is just the beginning...

2^x-2 is to determine host bits. So lets say you have a class C subnet mask,
which gives you 8 bits for the hosts, the equation would work, 2^8-2 which
is 254. The reason you subtract to 2 is that one is a network IP and one is
a broadcast IP neither of which can be assigned to a host. So your subnet is
lets say 192.168.1.0/24. 192.168.1.0 is network and 192.168.1.255 broadcast.
The IPs in between can be assigned to nodes on your subnet.

For Subnets, however, you wouldn't subtract the 2, it would be just 2^x. In
your example above it is 2^3 which does equal 8.

If the question was asking for subnets you would not use -2 in your
equation.

--
LRM
MCNGP 7^2

 PC LOAD LETTER 02-01-2006 04:19 AM

Re: Subnetting problem

"LRM" <Fskspam@friedspam.com> wrote in message
news:%232uVAxtJGHA.2012@TK2MSFTNGP14.phx.gbl...

> 2^x-2 is to determine host bits. So lets say you have a class C subnet
> mask, which gives you 8 bits for the hosts, the equation would work, 2^8-2
> which is 254. The reason you subtract to 2 is that one is a network IP and
> one is a broadcast IP neither of which can be assigned to a host. So your
> subnet is lets say 192.168.1.0/24. 192.168.1.0 is network and
> 192.168.1.255 broadcast. The IPs in between can be assigned to nodes on
>
> For Subnets, however, you wouldn't subtract the 2, it would be just 2^x.
> In your example above it is 2^3 which does equal 8.
>
> If the question was asking for subnets you would not use -2 in your
> equation.

Why the 4377 would I ever want to do math? That's what calculators are for.

function domath(x)
domath = 2^x-2
end function

there. Now I have a calculator for it. I can put it in a text file and never
use it. AND, as an added bonus, I can spend 10 hours looking for the file at
some point in the future, because I know I figured this out somewhere
before.

MCSB

 LRM 02-01-2006 04:29 AM

Re: Subnetting problem

news:OTDOoauJGHA.3272@tk2msftngp13.phx.gbl...
>
> "LRM" <Fskspam@friedspam.com> wrote in message
> news:%232uVAxtJGHA.2012@TK2MSFTNGP14.phx.gbl...
>
>> 2^x-2 is to determine host bits. So lets say you have a class C subnet
>> mask, which gives you 8 bits for the hosts, the equation would work,
>> 2^8-2 which is 254. The reason you subtract to 2 is that one is a network
>> IP and one is a broadcast IP neither of which can be assigned to a host.
>> So your subnet is lets say 192.168.1.0/24. 192.168.1.0 is network and
>> 192.168.1.255 broadcast. The IPs in between can be assigned to nodes on
>>
>> For Subnets, however, you wouldn't subtract the 2, it would be just 2^x.
>> In your example above it is 2^3 which does equal 8.
>>
>> If the question was asking for subnets you would not use -2 in your
>> equation.

>
> Why the 4377 would I ever want to do math? That's what calculators are
> for.
>

Because math is the most fun you can have by yourself, well at least for me,
I don't have an outy.

> function domath(x)
> domath = 2^x-2
> end function
>
> there. Now I have a calculator for it. I can put it in a text file and
> never use it. AND, as an added bonus, I can spend 10 hours looking for the
> file at some point in the future, because I know I figured this out
> somewhere before.
>
> MCSB
>

You should be able to do the calc in your head, and not rely on a piece of
code to do it for you.

Please don't do math if it makes you angry. Continue the beautiful Interneil

--
LRM
MCNGP 7^2

 PC LOAD LETTER 02-01-2006 05:07 AM

Re: Subnetting problem

"LRM" <Fskspam@friedspam.com> wrote in message
news:uWC5LguJGHA.1028@TK2MSFTNGP11.phx.gbl...

> Because math is the most fun you can have by yourself, well at least for
> me, I don't have an outy.

Well, that ruins all of the myths guys ever have about girls. Waitaminute,
don't girls have TWO outies?

> You should be able to do the calc in your head, and not rely on a piece of
> code to do it for you.

What? Do things by myself? That's a horrible idea!

> Please don't do math if it makes you angry. Continue the beautiful

Breathing makes me angry. Thinking makes me angry. I can't stop thinking. I
can't stop breathing, I can't avoid math. I'm in 4377. DAMMIT. This is
making me angry.

Well, maybe. Maybe I'll just teach the Interneil to do math for me.

Actually, maybe the Interneil should learn math on it's own, because now
that I've figured out that I have an outy, and you don't, why would I ever
want to do anything related to the InterNeil?

MCSB

 LRM 02-01-2006 04:03 PM

Re: Subnetting problem

news:eV9f01uJGHA.2696@TK2MSFTNGP14.phx.gbl...
>
>
> Breathing makes me angry. Thinking makes me angry. I can't stop thinking.
> I can't stop breathing, I can't avoid math. I'm in 4377. DAMMIT. This is
> making me angry.
>

Ok, now that we've established a base line for your anger we need to

--
LRM
MCNGP 7^2

 TechGeekPro 02-01-2006 04:29 PM

Re: Subnetting problem

On Jan 31, 2006 at 11:19pm "PC LOAD LETTER" blathered:

>
> "LRM" <Fskspam@friedspam.com> wrote in message
> news:%232uVAxtJGHA.2012@TK2MSFTNGP14.phx.gbl...
>
>> 2^x-2 is to determine host bits. So lets say you have a class C subnet
>> mask, which gives you 8 bits for the hosts, the equation would work,
>> 2^8-2 which is 254. The reason you subtract to 2 is that one is a
>> network IP and one is a broadcast IP neither of which can be assigned
>> to a host. So your subnet is lets say 192.168.1.0/24. 192.168.1.0 is
>> network and 192.168.1.255 broadcast. The IPs in between can be assigned
>> to nodes on your subnet.
>>
>> For Subnets, however, you wouldn't subtract the 2, it would be just
>> 2^x. In your example above it is 2^3 which does equal 8.
>>
>> If the question was asking for subnets you would not use -2 in your
>> equation.

>
> Why the 4377 would I ever want to do math? That's what calculators are
> for.
>
> function domath(x)
> domath = 2^x-2
> end function
>
> there. Now I have a calculator for it. I can put it in a text file and
> never use it. AND, as an added bonus, I can spend 10 hours looking for
> the file at some point in the future, because I know I figured this out
> somewhere before.
>
> MCSB

YCMU

--
TGP MCNGP #100100

mcngp.com is better than mcngp.co.uk with updates and a 99% uptime
guarantee

Choke me in the shallow water before I get too deep.

 Robert Williams 02-01-2006 06:26 PM

Re: Subnetting problem

[snip]
>
> Because math is the most fun you can have by yourself, well at least for me,
> I don't have an outy.
>

Since when do you need an outy to have fun by yourself LRM?

[snip]

> You should be able to do the calc in your head, and not rely on a piece of
> code to do it for you.
>

Precisely LRM. At least learn to do it in your head before you start to use a
calc.

> Please don't do math if it makes you angry. Continue the beautiful Interneil
>

I love watching people get annoyed at math....it's fun to watch them pull their
hair out.

 LRM 02-01-2006 06:38 PM

Re: Subnetting problem

"Robert Williams" <RobertW@I.DONT.WANT.YOUR.SPAM.danjonengineering.c om>
wrote in message news:e%23SQ%23z1JGHA.420@tk2msftngp13.phx.gbl...
> [snip]
>>
>> Because math is the most fun you can have by yourself, well at least for
>> me,
>> I don't have an outy.
>>

> Since when do you need an outy to have fun by yourself LRM?
>

I don't, but I am not as easily distracted by this sort of activity as say
someone with an external object would be. I felt a caveat was necessary when
I originally posted, because I couldn't proclaim that math would be more fun
than something I am not completely familiar with. And I didn't want to speak
for those who may find auto-outy activity more satisfying than math.
I was being sensitive to outy-owners' needs as it were.

--
LRM
MCNGP 7^2

 Robert Williams 02-01-2006 07:01 PM

Re: Subnetting problem

> > Since when do you need an outy to have fun by yourself LRM?
> >

> I don't, but I am not as easily distracted by this sort of activity as say
> someone with an external object would be.
>

Yes, it does seem we "outy havers" get a little more distrated in times like
this.

> I felt a caveat was necessary when
> I originally posted, because I couldn't proclaim that math would be more fun
> than something I am not completely familiar with.
>

Had no idea, I'm learning something new about you everyday LRM. If only I

> And I didn't want to speak
> for those who may find auto-outy activity more satisfying than math.
>

Unfortunately there are too many of us...I mean them

> I was being sensitive to outy-owners' needs as it were.
>

Sensitivity can be overrated at times

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