Just to elaborate on Adam's answer
If you are using CIDR (allows 0 and 255 as networks) you have a
total of 8 networks (2^3)
This leaves you with 8190 hosts per network (2^13 - 2)
The network ranges (256 - 224 = 32 ) (you get the 224 by
counting the 1's in this case 11100000)
The hosts range between the network addresses (this accounts for
the subnet address and broadcast address)
172.31.0.0 - 172.31.31.255
172.31.32.0 - 172.31.63.255
172.31.64.0 - 172.31.95.255
172.31.96.0 - 172.31.127.255
172.31.128.0 - 172.31.159.255
172.31.160.0 - 172.31.191.255
172.31.192.0 - 172.31.223.255
172.31.224.0 - 172.31.255.255
So the answer is D
Hope this helps
Dusty Harper
[EMAIL PROTECTED]
MCSE + I + DBA
CCNA, CCDA
A+, Network+, i-Net+
-----Original Message-----
From: Adam Hickey [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, March 14, 2001 5:57 PM
To: Bruce; [EMAIL PROTECTED]
Subject: Re: Sample CCNA test question..bogus?
It would appear to me that by the statement 172.16.0.0/19 they are
stating a
major net rather than one of the subnets created by the masking. If you
look
carefully at the answers, D is the only one that can be right because it
is
the only one that qualifies as a host address. A) 172.16.32.0 = a subnet
address, B) 172.16.64.0 = a subnet address, C) 172.16.63.255 = a
broadcast
address within a subnet, D) 172.16.80.255 = a host address within a
subnet.
If I am wrong, it wouldn't be the first time. but that's what I see.
Adam Hickey
[EMAIL PROTECTED]
----- Original Message -----
From: "Bruce" <[EMAIL PROTECTED]>
Newsgroups: groupstudy.cisco
To: <[EMAIL PROTECTED]>
Sent: Wednesday, March 14, 2001 9:38 PM
Subject: Re: Sample CCNA test question..bogus?
> Tom, Thanks for your response but I beg to differ. I agree that answer
D
> falls inside the range of the 64 subnet as you explain, but this is
not
the
> question. The question asks for a valid host using 172.16.0.0/19, not
> 172.16.64.0/19
> By my reckoning, the valid host range is 172.16.0.1 to 172.16.31.254
>
> Regards,
> BR.
>
> "Tom Lisa" <[EMAIL PROTECTED]> wrote in message
> [EMAIL PROTECTED]">news:[EMAIL PROTECTED]...
> > Well, since I'm not a qualified psychiatrist I don't want to comment
on
> your mental
> > health, but there is a correct answer here. If we go to binary it
all
> becomes clear.
> >
> > The /19 means that the first 19 bits are network/subnetwork bits and
the
> remaining 13
> > bits are host bits. Therefore our mask would look like this:
> > 11111111.11111111.11100000.00000000
> >
> > Since the first two octects are identical, we can dispense with them
and
> concentrate on
> > the first 3 bits of the third octet and the remaining host bits.
> >
> > Our subnet addresses would be as follows:
> >
> > X.X.00000000.00000000 = X.X.0.0 Hosts = X.X.0.1 - X.X.31.254 Bdcst =
> X.X.31.255*
> > *Assumes Subnet Zero Allowed
> > X.X.00100000.00000000 = X.X.32.0 Hosts = X.X.32.1 - X.X.63.254 Bdcst
=
> X.X.63.255
> > X.X.01000000.00000000 = X.X.64.0 Hosts = X.X.64.1 - X.X.95.254 Bdcst
=
> X.X.95.255
> > X.X.01100000.00000000 = X.X.96.0 Etcetera, Etcetera....
> > .
> > .
> > Etcetera (You get the picture)
> >
> > From this you can see that:
> > answer A is the "wire" address of the 32 subnet
> > answer B is the "wire" address of the 64 subnet
> > answer C is the Broadcast address of the 32 subnet
> > answer D falls within the valid host range for the 64 subnet and is
> correct.
> >
> > BTW, a good source for learning IP Addressing & subnetting is:
> www.learntosubnet.com
> >
> > HTH,
> > Prof. Tom Lisa, CCAI
> > Community College of Southern Nevada
> > Cisco Regional Networking Academy
> >
> >
> > Bruce wrote:
> >
> > > Q. Which one of the following is a valid host using the address of
> > > 172.16.0.0 /19?
> > >
> > > a. 172.16.32.0
> > >
> > > b. 172.16.64.0
> > >
> > > c. 172.16.63.255
> > >
> > > d. 172.16.80.255
> > >
> > > Which one and why?
> > >
> > > (I say none of them. Am I going mad?)
> > >
> > > _________________________________
> > > FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
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[EMAIL PROTECTED]
> >
> > _________________________________
> > FAQ, list archives, and subscription info:
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> >
>
>
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