MadeEasy Workbook: Computer Networks - Subnetting

Question

A class B network address 130.50.0.0 is submitted as follows. The last 10 bits of the host I'd are allotte for host number and the remaining 6 bits are reserved for subnet number.

Q- what are the first hosts address of 1st and 4th subnets?

1. 130.50.4.1 and 130.50.16.1
2. 130.50.1.1 and 130.50.4.1
3. 130.50.0.0 and 130.50.3.0
4. None of these

Comments

No,we don't count first as 0000 because it is used as subnet id.It is not host.Host always starts from 0001.

Answer will be definitely A).

---

Host always starts from 0001.

 130.50.0.1 ---- isn't it starts with 1

 

Answer will be definitely A).

it is actually lead to Option D. (  130.50.0.1 and 130.50.12.1 )

But it is a non-standard question, i mean the question is not well formed... no need of further discussion

---

https://gateoverflow.in/274106/subnet-addresses

Answer 1

Ans: Option D) None of the Above

A class B network address given:  130.50.0.0

Class B = 16 Bits NID (Network ID) and 16 bits HID (Host ID).

Given, 6 bits are reserved for subnet number. Therfore, total subnets = 2^6. 

Remaining 10 bits for HID. So, _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _  (are last 16 bits) , in which the least significant 10 bits will be 0 0. 0 0 0 0 0 0 0 1 (as we need the 1st valid host address of both 1st and 4th subnets), and the most significant 6 bits are for SIDs (Subnet IDs) [not marked in BOLD Places] 

Now the weights of last 4 bits in 3rd Octet = 8 , 4, 2 & 1. Out of which, 2 & 1 are in Host Address. So remaining Subnet ID weights to be filled are for 8 and 4 with combinations : (00, 01, 10, 11) 

Now filling the SIDs (Subnet IDs) [ → 

For subnet 1 : 0 0 0 0 0 0 (and rest bold ones) → 130.50.0.1 (Ans)

For subnet 2 : 0 0 0 0 0 1 (and rest bold ones) → 130.50.4.1

For subnet 3 : 0 0 0 0 1 0 (and rest bold ones) → 130.50.8.1

For subnet 4 : 0 0 0 0 1 1 (and rest bold ones) → 130.50.12.1 (Ans)