Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

  • Congratulations Mike Lewis on being selected by the Tek-Tips community for having the most helpful posts in the forums last week. Way to Go!

Subnetting shortcuts

Status
Not open for further replies.

NahRamp2

MIS
May 24, 2007
33
US
I know that many of you are actually instructors, and I am reaching out to you now. I noticed that there are many different tips and tricks to subnetting. Could you wise guys out there please provide me with some of you subnetting tricks to help shorten the time spent on subnetting during the exam? Doing binary conversions can't be the only way to coming up with network/broadcast ip addys, and finding what network an ip addresses belongs to.
 
NahRamp2,

You will find as you work with subnetting ..... the easier it gets!

If you read nothing else - read the subnetting chapter from the Sybex CCNA Study Guide - in more then 8 years of teaching CCNA at a Cisco Academy I have never seen a better explanation of subnetting!

As for hints - when I did the CCNA before I started I did 2 ranges of subnets on my white board/erase board they give you. I did 255.255.255.240 (/28) and 255.255.255.224 (/27)

240 is a range of 16 (256-240=16) so my subnets are:

0, 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240
- these are my subnets and the broadcast is 1 less then the next subnetwork, eg. the broadcast for 192 is 207 and 193, 194, 195, 196, 197, 198, 199, 200, 201, 202, 203, 204, 205 and 206 are all nodes on the 192 subnet!

224 is a range of 32, so my subnets are;

0, 32, 64, 96, 128, 160, 192 and 224

For the subnetwork 192 - 223 is the broadcast and 193-222 are the useable addresses on that subnet.

These 2 ranges helped answer most of my subnetting questions on the CCNA exam :)

I hope this helps


E.A. Broda
CCNA, CCDA, CCAI, Network +
 
I agree, Sybex CCNA study guide subnetting chapter, it was like someone turned on the light switch!
 
Just remembered that you can download the Sybex Subnetting chapter (PDF) from Bookpool to sample the Sybex CCNA Study Guide - this is also a GREAT website to buy cheap tech books! I have bought here many times and have never had any issues :)



Something also just reminded me of the "Learn to Subnet" website - good website!


Hope this helps!

E.A. Broda
CCNA, CCDA, CCAI, Network +
 
Status
Not open for further replies.

Part and Inventory Search

Sponsor

Back
Top