# subnetting help

Registered Users Posts: 3 ■□□□□□□□□□
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

• Member Posts: 23 ■□□□□□□□□□
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
• Member Posts: 365 ■■■■□□□□□□
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.
• Registered Users Posts: 3 ■□□□□□□□□□
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
• Registered Users Posts: 2 ■□□□□□□□□□

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
3. Generate Network Id Up to the 5th term....
• Member Posts: 2,338 ■■■■■■■■□□
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--