How many subnets and hosts per subnet? Question

mohamedshajid

Hello guys I'm Shajid basically i finished All the class of subnetting now i can find everything but except this question is confuse me.

They are asking from the Subnettingquestions.com

Question: How many subnets and hosts per subnet can you get from the network 10.0.0.0 255.255.240.0?
Answer: 4096 subnets and 4094 hosts

Actually I don't know how to find the subnets and all. So can anybody help me? Thanks in advance

control

Your address is a Class A address... (default Mask 255.0.0.0)

So with the given mask you have the 8 default bits, plus another 12 "borrowed" bits (255.240).

2^12 - gives you the 4096

This then leaves 12 bits left over for the host bits - again 2^12 (-2) gives you 4094

mohamedshajid

control wrote: »

Your address is a Class A address... (default Mask 255.0.0.0)

So with the given mask you have the 8 default bits, plus another 12 "borrowed" bits (255.240).

2^12 - gives you the 4096

This then leaves 12 bits left over for the host bits - again 2^12 (-2) gives you 4094

Hey Control, You such a brainer you saved my time dude, Now i did more than 50 Subnetting Question even in reverse Engineering So i'm glad like to move to "IOS And Configuration" As well but This Forum Helps me a lot

Reck_

With this kind of question, I use this as a guide.

2 ^(NSM-DSM) = # of Subnet

2 ^(32-NSM) -2 = # of Host

where:
NSM= New Subnet Mask
DSM= Default Subnet Mask
32 = IPv4 in bits

How many Subnets ?
2 ^(NSM-DSM) = # of Subnet
2 ^(20-= 2 ⁽¹²⁾ =4096 Subnets

How many Host ?
2 ^(32-NSM) - 2 = # of Host
2 ^(32-20) - 2 = # of Host
2 ⁽¹²⁾ - 2 = 4096-2= 4094 Host

Subnettingquestions.com is my breakfast as I prepared for myCCNA exam, so I think you are in the right track.
The foundation of subnetting in my opinion, relies ondefault subnet masks, so make sure you know them by heart. Good luck.

mohamedshajid

Reck_ wrote: »

With this kind of question, I use this as a guide.

2 ^(NSM-DSM) = # of Subnet

2 ^(32-NSM) -2= # of Host

where:
NSM= New Subnet Mask
DSM= Default Subnet Mask
32 = IPv4 in bits

How many Subnets ?
2 ^(NSM-DSM) = # of Subnet
2 ^(20-= 2 ⁽¹²⁾ =4096 Subnets

How many Host ?
2 ^(32-NSM) - 2= # of Host
2 ^(32-20) - 2= # of Host
2 ⁽¹²⁾ - 2= 4096-2= 4094 Host

Subnettingquestions.com is my breakfast as I prepared for myCCNA exam, so I think you are in the right track.
The foundation of subnetting in my opinion, relies ondefault subnet masks, so make sure you know them by heart. Good luck.

OMG Reck this is great formula to define the answer correctly. Thanks bro

Ivanjam

mohamedshajid, this "great formula" can be found in almost every CCNA/CCENT book. Which one(s) are you currently reading?

mohamedshajid

Ohhh. But i'm reading Todd lammle's 7th Edition CCNA But there is no formula that i've encountered.

Ivanjam

mohamedshajid wrote: »

Ohhh. But i'm reading Todd lammle's 7th Edition CCNA But there is no formula that i've encountered.

I have the first edition of Lammle's CCENT book and the formula is on page 123 (granted, there is a typo there and he has number of subnets = 2x instead of 2^x and number of hosts = 2y-2 instead of 2^y-2). So I doubt very much that he doesn't have the formula in his CCNA book.

kanugeete

Hey guys i read somewhere that no of subnets are 2^n-2 for n bits taken from host id.
Is it wrong??
and if right,then how? thnx in advance