subnetting help

irishdar

my college assignment stated 9 subnets off a / 24 address........why is it better to make 16 /28 subnets and waste 7...... instead of making 8 /27 and splitting 1 further to create 2 /28 subnets

16 /28....waste 7 subnets
7 /27 and 2 /28 ....no waste....is this possible

is the flaw in this problem that i must make a further 8 /28 addresses instead of 2 to make up the total value of the bits i borrowed

JLAW904

Is there a certain number of hosts required for each of the 9 subnets you need? Or is all you have to do is subnet it into 9 subnets? Doing it into 16 equal /28 subnets would use up all of the address space without wasting any. But if you need exactly 9 subnets, what you described in using VLSM also uses up all the space.

Example:
192.168.1.0/27
192.168.1.32/27
192.168.1.64/27
192.168.1.96/27
192.168.1.128/27
192.168.1.160/27
192.168.1.192/27
192.168.1.224/28
192.168.1.240/28

boredgamelad

You're right from a real world perspective, but exams or test questions that don't specify VLSM as a requirement are generally looking for your answer to use evenly sized subnets.

irishdar

thanks for replying....no certain number of hosts....it just wants 9 subnets...... that's the way i had my addresses structured but i was told this was incorrect......as i should have just made 16 /28 subnets and used 9 out of the 16.....that's what i meant by wasting the 7 extra subnets.....why make 7 extra subnets when you can just make 9.....so you reckon i should always use conventional subnetting in college or tests ....unless it says use vlsm... lost a good few points from my assignment over it.......crazy ay

KILLBaddy

Iono If This Is The Right Forum Or Thread To Ask This Question But I'ma Ask Anyways And Hope Someone Would Please Help Me Out.....

There's A Network Address Of 172.28.0.0/16 and needs to support 515 users on each subnet... Calculate

1. Host bits & Network bits
2. Subnet Mask
3. Generate Network Id Up to the 5th term....

NetworkVeteran

KillBady, what do you think the answers are, and why? That would help us clear up your misconceptions.

If you don't know how to do subnetting, check out this thread--

http://www.techexams.net/forums/ccna-ccent/38772-subnetting-made-easy.html