Networking - Subnetting - Discussion

Discussion Forum : Subnetting - Subnetting (Q.No. 4)
4.
What is the maximum number of IP addresses that can be assigned to hosts on a local subnet that uses the 255.255.255.224 subnet mask?
14
15
16
30
Answer: Option
Explanation:
A /27 (255.255.255.224) is 3 bits on and 5 bits off. This provides 8 subnets, each with 30 hosts. Does it matter if this mask is used with a Class A, B, or C network address? Not at all. The number of host bits would never change.
Discussion:
23 comments Page 2 of 3.

Yogesh said:   4 years ago
What is the maximum number of subnet and host per subnet for the 192.168.5.47 255.255.255.224 network?

Ankit Chaturvedi said:   8 years ago
Total host= 2^( use off bits) - 2.

Bijay KC said:   8 years ago
Thank you @Nikhil.

Nikhil said:   1 decade ago
255.255.255.224 i.e Binary of 255 is 11111111 and Binary number of 224 is 11100000.

Here 1 Represent On bit and 0 represents Off bit.
Then how to calculate Host Id.

See Here,

Formula Host Id = 2^off bit - 2 i.e 2^5 = 32 - 2 = 30.
And Net Id is = 2^on bit = 2^3 = 8.
That's why Answer is 30.

Nishu Kumar said:   8 years ago
(1)255.255.255.224
128+64+32=224.

2^3 =8, 2^5-2= 32 -2 =30
(2) formula;

Block size = 256 - Actual subnet mask,
=256 -224,
= 32.

Seonti said:   8 years ago
Can anyone explain why it is /27?

Dhananjay said:   8 years ago
Thanks.

Chaithanya said:   8 years ago
24|27 = 3bits on 5 bits off.
2^h-2 h=hostsbits = 5,
32-2 = 30.

Or simple total is 256 so 256-224=30.

Darth vader said:   9 years ago
Convert it to binary:

11111111.11111111.11111111.11100000.

You can't use 1s because they are mask bits, you can use 0s as host bits and they can get values between 0 to 31 (total 32 values).

2 of these 32 host values cannot be used as a host IP because one of them belong to broadcast and the other belong to the network address. There is a formula for this host calculation it is 2^(host bits)-2 For this example it is 2^5 - 2 = 32-2 = 30.

Sagar said:   9 years ago
Your answer is easy to understand, Thanks @Nikhil.


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