Frequent Questions      

    CCNA (200-120) Exam Practice Questions


Host, and subnet calculation


Up             Previous              Next

Q2. You have an IP of with a subnet mask of 7 bits. How many hosts and subnets are possible?

A. 126 hosts and 510 subnets

B. 128 subnets and 512 hosts

C. 510 hosts and 126 subnets

D. 512 subnets and 128 hosts

  Correct Answer: C



Class B network has the form N.N.H.H, the default subnet mask is 16 bits long.

There is additional 7 bits to the default subnet mask. The total number of bits in subnet are 16+7 = 23.

This leaves us with 32-23 =9 bits for assigning to hosts.

7 bits of subnet mask corresponds to (2^7-2)=128-2 = 126 subnets.

9 bits belonging to host addresses correspond to (2^9-2)=512-2 = 510 hosts.

Up               Previous              Next

Disclaimer: All Simulation Exams practice tests, study guides and/or material are neither sponsored by, nor endorsed by, nor affiliated with Cisco® Systems, Inc., Microsoft® Corporation, Inc., CompTIA® , Check Point Software Corp., Prosoft® or any other company. All trademarks are trademarks of their respective owners and duly  acknowledged. MCSE ™, MCSE+I ™ are registered trademarks of Microsoft® Corporation and CCNA™, CCNP™, CCIE™ are registered trade marks of Cisco® Systems. A+™, Network+™, i-Net+™, Server+™ are registered trade marks of CompTIA®. CCSA™, CCSE™ are registered trademarks of CheckPoint® Software Corp. CIW™ is a trade mark of Prosoft®. Thank-you for your interest in Simulation Exams. Please see read me file before you download, install, and/or use any software from  For any information or questions regarding this Website, please e-mail webmaster at

Copyright © 2000-2015 All rights reserved

Website design by