Solved

Selecting a network prefix - Study/Exam help

Posted on 2014-03-17
5
628 Views
Last Modified: 2014-03-17
I'm looking for help on a practice question regarding network.
Am wondering someone could dumb down the answer for me and explanation because I'm really trying to get a better understanding of this.

The question goes:

Your company has a main office that contains 255 client computers.
The client computers are located on a subnet that uses the network ID of 10.10.1.0/24.

The company plans to open two branch offices. The offices will be configured as follows:

Branch1: 100 client computers
Branch2: 50 client computers

You need to select a network prefix for each office to ensure that there are enough IPv4 addresses for each client computer.

The solution must minimize the number of unused IP addresses.

Which network prefixes should you select?




The available choices are:

/24
/25
/26
/27
/28
0
Comment
Question by:garryshape
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
5 Comments
 
LVL 35

Accepted Solution

by:
Joseph Daly earned 250 total points
ID: 39934421
I dont really like this question because it seems like bad info.

The main office has 255 clients and only a /24 subnet. This is incorrect because with a /24 you have only a maximum usable IPs of 254 not 255.

For the 50 person office the probably want you to say /26 since that will give you 62 usable addresses and the 100 office you would want to use a /25 since it gives you 126 usable addresses.

In a real life situation for these two remote offices you would probably just use a /24 on each of them for future growth.
0
 
LVL 4

Expert Comment

by:Kent Fichtner
ID: 39934469
I Agree with Joe.  If your question is what does /24 mean and why then you would want to look up subnetting.  it is a topic that can drive you nuts.

Basically if you think of a IPv4 address in binary, then it is made up of 8  ones or zeros per period

10.10.1.0 would then be 00001010.00001010.00000001.00000000

The slash notation is where (starting from the left) is left as static.

In the case above /24 wouldn't allow for the first 24 numbers to change, and only the last 8 can.  Since 11111111 in binary is 255 (-1 for broadcast) you can get a max of 254 per octet.  To answer your question just take the number of users, convert to binary, and see how many numbers it would take to make it:

100 clients is written as 01100100.  Since that the largest digit is in the 64's place, you can static everything to the left.  In this case, as Joe stated above, that would be 25 digits or /25 notation.

Hope that helps a little.
0
 

Author Comment

by:garryshape
ID: 39934484
Thanks, how do you calculate usable addresses based on the /#?
Do you have to convert to binarY?
0
 
LVL 4

Assisted Solution

by:Kent Fichtner
Kent Fichtner earned 250 total points
ID: 39934505
The best idea is to convert to binary.  That way you can count the number for the slash notation.

Cisco has a good way of looking at it.

I would type out the answer, but subnetting is a long topic, not too difficult once you get it, but takes a while to understand.
0
 

Author Comment

by:garryshape
ID: 39934530
ok thanks, yeah this is for a microsoft windows exam which seems complicated. Half the exam is IPv4 and IPv6 stuff. Better take my networking exam at the same time I guess.
0

Featured Post

Don't Cry: How Liquid Web is Ensuring Security

WannaCry is just the start. Read how Liquid Web is protecting itself and its customers against new threats.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Meet the world's only “Transparent Cloud™” from Superb Internet Corporation. Now, you can experience firsthand a cloud platform that consistently outperforms Amazon Web Services (AWS), IBM’s Softlayer, and Microsoft’s Azure when it comes to CPU and …
During and after that shift to cloud, one area that still poses a struggle for many organizations is what to do with their department file shares.
This video gives you a great overview about bandwidth monitoring with SNMP and WMI with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're looking for how to monitor bandwidth using netflow or packet s…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

724 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question