Networking - Subnetting - Discussion
Discussion Forum : Subnetting - Subnetting (Q.No. 6)
6.
You have a network that needs 29 subnets while maximizing the number of host addresses available on each subnet. How many bits must you borrow from the host field to provide the correct subnet mask?
Answer: Option
Explanation:
A 240 mask is 4 subnet bits and provides 16 subnets, each with 14 hosts. We need more subnets, so let's add subnet bits. One more subnet bit would be a 248 mask. This provides 5 subnet bits (32 subnets) with 3 host bits (6 hosts per subnet). This is the best answer.
Discussion:
16 comments Page 2 of 2.
Manu Ratheesh said:
10 years ago
In order to get 2 sub-networks, we have to borrow 1 bit from the host id part.
Similarly, to get 4 subnets, we have to borrow 2 bits form the host id, to get 16 subnets, borrow 4 bits from the host id part.
If we borrow 5 bits from the HID part, we will get 2^5 = 32 subnets. Hence, minimum 5 bits should be borrowed to obtain 29 subnets. Answer (D).
Similarly, to get 4 subnets, we have to borrow 2 bits form the host id, to get 16 subnets, borrow 4 bits from the host id part.
If we borrow 5 bits from the HID part, we will get 2^5 = 32 subnets. Hence, minimum 5 bits should be borrowed to obtain 29 subnets. Answer (D).
Noel Gates said:
10 years ago
There needs to be a better explanation to this!
Rinju said:
1 decade ago
How we will get 240 and 248 and how it related to 29?
Anand Mohan said:
1 decade ago
No of hosts: 2^n-2.
2^5 = 32.
32-2 = 30 subnets.
255.255.255.11100000.
255.255.255.248.
2^5 = 32.
32-2 = 30 subnets.
255.255.255.11100000.
255.255.255.248.
Rodo said:
1 decade ago
Should be B. You need 5 SUBNET bits to achieve the subnet requirement of 29.
Rahul said:
1 decade ago
Please anybody clarify me. Am confused.
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