?
Solved

How to do subnetting in Cisco ?

Posted on 2011-10-08
7
Medium Priority
?
262 Views
Last Modified: 2012-12-16
Hello Expert , I am doing  A ccna course , and really intrest me , now we got to the subnetting chapter and I find it hard one , I have got a book , and there are many ways finding soluations to ne problem , my question is is there a simple way where u can answer the most common question like , what network certain IP address is on? what is the subnet mask , the broadcast address and the range , pls I gt exam on monday and I want to do all I can to understand and pass the exam , what confuse me the most is the no of bits that r needed to design a network , or when they say for example you got 37.0.0.0 and ur requirement is at least 500 hosts per network however as many subnets as possible without exceeding 1000 subnets , I need explaining pls and not throw a website and I need to deal with it , I need to understand more than anything else . thks alot
0
Comment
Question by:hnael
  • 2
  • 2
5 Comments
 
LVL 6

Expert Comment

by:jgibbar
ID: 36936707
If you have already registered with Cisco, the learning center helped me to understand this topic a whole lot better. Check out https://learningnetwork.cisco.com/docs/DOC-2574
0
 

Author Comment

by:hnael
ID: 36938258
Sorry , I could not view the vedios because I gt a probelm with registration, since I was registered in the past and it seems I gt 2 registration and I tried 20 times to register with no luck , can you send me a direct link pls without going throw registration, thks
0
 
LVL 12

Accepted Solution

by:
Fidelius earned 2000 total points
ID: 36938260
I'll try to explain as simple as I can.
All about subnetting is related to understanding of binary representation of adresses and masks and calculating with with 2^x.
So you have 37.0.0.0. Mask for this network is 255.0.0.0 or /8 (255 is equal to eight 1 in binary representation of subnet mask).
To have 500 hosts in one subnet, you have to find smallest "x" in 2^x > 500
2^1 = 2
2^4 = 4
2^3 = 8
...
2^9 = 512

So subnet you need should have last 9 zeroes: 255.255.254.0 or /23 (maximum nuber of 1's is 32, so 32-9=23).
That is for hosts.

To calculate number of subnets which contains 1000 /23 networks, do the following:
- first find suitable supernet mask:
2^x >= 1000
By same system as above x=10, so you need to add 10 zeros to existing 9, to have 19 in total.
Converting it to mask: 255.248.0.0 or /13.

To calculate final number of networks with 1000 subnets consisted of 500 hosts each, you have to find how many /13 networks are in /8.
2^(13-8)=2^5=32

I hope this clears things a bit, and I hope I understood your question well. If not please post original question from your test.

Regards!


0
 

Author Comment

by:hnael
ID: 36984416
Any more easiar way to find the no of bits needed for subnetting ?
0
 
LVL 12

Expert Comment

by:Fidelius
ID: 36984516
One thing to remember: All 1's and 0's in subnetting must be continuous.

Easiest way is to memorize all 2^x, where x is 1 to 10. In converting that to subnets, x defines number of 0's at the end of subnet mask.

In my previous post, whole process is described in more detail, but in essence it is just finding closest bigger 2^x (example: for 200 hosts, first bigger is 2^8=256).

Regards!
0

Featured Post

Prepare for your VMware VCP6-DCV exam.

Josh Coen and Jason Langer have prepared the latest edition of VCP study guide. Both authors have been working in the IT field for more than a decade, and both hold VMware certifications. This 163-page guide covers all 10 of the exam blueprint sections.

Question has a verified solution.

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

AWS has developed and created its highly available global infrastructure allowing users to deploy and manage their estates all across the world through the use of the following geographical components   RegionsAvailability ZonesEdge Locations  Wh…
Data center, now-a-days, is referred as the home of all the advanced technologies. In-fact, most of the businesses are now establishing their entire organizational structure around the IT capabilities.
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…
After creating this article (http://www.experts-exchange.com/articles/23699/Setup-Mikrotik-routers-with-OSPF.html), I decided to make a video (no audio) to show you how to configure the routers and run some trace routes and pings between the 7 sites…

807 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