I am studying for my CCNA Certification and I have a doubt about VLSM.
Take a look at the question:
R1 has configured interface Fa0/0 with the ip address 10.5.48.1 255.255.240.0
command. Which of the following subnets, when configured on another interface on
R1, would not be considered to be an overlapping VLSM subnet?
a. 10.5.0.0 255.255.240.0
b. 10.4.0.0 255.254.0.0
c. 10.5.32.0 255.255.224.0
d. 10.5.0.0 255.255.128.0
In the book, the answer to this question is as follows:
C and D. Subnet 10.5.0.0 255.255.240.0 implies range 10.5.0.0–10.5.15.255, which
does not overlap. 10.4.0.0 255.254.0.0 implies range 10.4.0.0–10.5.255.255, which
does overlap. 10.5.32.0 255.255.224.0 implies range 10.5.32.0–10.5.63.255, which
does overlap. 10.5.0.0 255.255.128.0 implies range 10.5.0.0– 10.5.127.255, which
I thought the right answer was letter A. Am I wrong? Or I didnt understand the question?
I am using ICND2, Wendell Odom, PDF VERSION.
You are right; the right answer is A.
Errors like this are typically posted in the errata file for the book. If you go to http://www.ciscopress.com/bookstore/product.asp?isbn=158720181X, and look for the "Updates" link, you'll see the errata file for this book, which includes a reference to this error. Sorry about the error.