It takes
2 bits
to provide four possible subnets; therefore, 2 bits are borrowed from the host bits. 3. This means the process of creating the 4 subnets reduces the number of bits available for host IP addresses.
How many bits are in a 4 subnet?
For every host-bit we borrow we can double the number of subnets we can create, so by borrowing
2 host bits
we can create 4 subnets. Every host bit you “borrow” doubles the amount of subnets you can create. Calculate it from binary to decimal: 128+64 = 192. The new subnet mask will be 255.255.
How many bits are to be borrowed for creating the subnets?
This means that to create at least 18 subnets,
5 host bits
must be borrowed. To calculate the number of possible hosts per subnet, use the formula 2h – 2, where h equals the number of host bits. The reason two addresses must be subtracted is because of the network address and the broadcast address.
How many hosts can be addressed with 4 host bits?
A /28 CIDR notation indicates 4 bits are left for hosts (32 – 28 = 4). Using the 2
n
-2 formula, or 2
4
– 2, or 16 – 2, you see the answer is
14
. In other words, /28 supports 14 hosts, which isn’t enough to meet the need of 24 addresses in the question.
How many usable host addresses are available for each subnet when 4 bits are borrowed from a Class C IP address?
Answer: 4 bits or 2^4-2=
14 hosts
per subnet. What are the subnet addresses? Answer: 256-240 =16, 32, 48, 64, 80, 96, 112, 128, 144.
How many subnets are in a 24?
| Addresses Netmask | / 27 32 255.255.255.224 | / 26 64 255.255.255.192 | / 25 128 255.255.255.128 | / 24 256 255.255.255.0 |
|---|
How do you calculate the number of subnets?
The number of subnets is found by
counting the number of bits by which the initial mask was extended
, also known as the subnet bits. Our initial address allocation was 192.168. 0.0 with a mask of 255.255. 0.0.
What is the minimum number of subnets required?
So back to answer our initial question of the minimum subnet size to accommodate 20 hosts, the minimum number of host bits required is 5 bits (2^5 = 32). 4 bits (2^4 = 16) will be too small. So 5 bits used for the host IDs leaves us with 32 – 5 = 27 network bits. Therefore, the minimum subnet size we can use is
/27
.
What is the last usable host IP address?
The address just before the broadcast address is
the last address that you can allocate to a host. The wildcard mask is the subnet mask with the bits inverted, therefore selecting the host part of the IP address.
What is a 24 bit subnet mask?
A class C network would have a subnet mask of
255.255. 255.0
which means that 24 bits are used for the network. In CIDR notation this is designated by a /24 following the IP address.
How many hosts are in a 8 subnet?
| Network Bits Subnet Mask Number of Hosts | /8 255.0.0.0 16777214 | /9 255.128.0.0 8388606 | /10 255.192.0.0 4194302 | /11 255.224.0.0 2097150 |
|---|
How many host bits are left?
There are
16 host bits
because, when you convert 255.255. 0.0 to binary, there are 16 binary 0s—the last 16 bits in the mask.
What is a 16 subnet?
The number 16 is
the first subnet and also your block size
. … The valid subnets in this example are 16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224. As another example, if you had a Class A subnet mask of 255.255. 240.0, you’d use the mask on the second and third octets minus 256.
What is the valid host range for the 255.255 255.248 subnet?
| Prefix size Network mask Usable hosts per subnet | /27 255.255.255.224 30 | /28 255.255.255.240 14 | /29 255.255.255.248 6 | /30 255.255.255.252 2 |
|---|
How many subnets are in a class B?
Example 6: The Class B 255.255. 255.128 subnet mask: 2-2=
510 subnets
.
