Calculating the Subnets.
Calculating the Subnets.
I am using the online Subnet Calculator. Some Data displayed on the calculator and indicated by the Red arrows on the screenshot below need some explanation:
example:
how did they come with subnet bits: 12
Maximum subnets 4096
host per subnets :14
subnet ID :172.16.1.0
Broadcast address : 172.16.1.15
Thank you
![subnet.JPG]()
I am using the online Subnet Calculator. Some Data displayed on the calculator and indicated by the Red arrows on the screenshot below need some explanation:
example:
how did they come with subnet bits: 12
Maximum subnets 4096
host per subnets :14
subnet ID :172.16.1.0
Broadcast address : 172.16.1.15
Thank you
how did they come with subnet bits: 12
You start with an address that has a 16-bit mask. You extend the mask to accommodate the number of subnets/hosts and you end up with a 28-bit mask.
28-16=12.
Actual mask minus the original (or starting) mask will give the size of the subnet field. Which in this case is 12.
You chose class B network mask, so your results of a /28 is 12 bits in from the /16. Now if you go back and choose class C network, you will only be 4 bits from the /24.
Sr. Network Engineer
CERTIFIED EXPERT
jsk -
Sorry - should say
Your first usable subnet will be 172.16.0.0/28.
First address in the subnet is 172.16.0.0
Last address in the subnet is 172.16.0.15
First address in a subnet is always the network address and unusable (subnet ID)
Last address in a subnet is always the broadcast address and unusable (Broadcast Address)
Does that clarify?
Sorry - should say
Your first usable subnet will be 172.16.0.0/28.
First address in the subnet is 172.16.0.0
Last address in the subnet is 172.16.0.15
First address in a subnet is always the network address and unusable (subnet ID)
Last address in a subnet is always the broadcast address and unusable (Broadcast Address)
Does that clarify?