2,198 views
2 votes
2 votes
If we have 3 bits in the subnetid then how many subnets we have..??

6 or 8?

4 Answers

13 votes
13 votes
it is 8 subnets only.. we will not assign the first and last addresses in a network/subnet  to any host. you guys are removing 2 subnets from total which is not correct. inside the subnet two host addresses has to be removed for network address and broadcast address
4 votes
4 votes

no of subents for n bits is 2n−2 

here n= 3 bits

so 2n-2

=23-2

=8-2

=6 subnets 

Why subtracting 2 .. ?

In any netwrok  say class B netwrok  NID : 192.168.0.0

First Address => 192.168.0.0  => This is Network Address
Last Address => 192.168.255.255 => This is broadcast address

These two address cannot be assigned to HOST .

Hence we subtract 2 from total Network address

edited by
3 votes
3 votes
I have given the computer networks test today and Bikram sir has said 2^n -2 is old concept and now we use all 2^n subnets.
1 votes
1 votes

Ans is 8 

if subnet ID bit is n then , max no of possible subnets are 2^n

In our case subnet ID bits are 3 therefore total subnet possible are 8 .

We can use all the subnets no restriction on it , In gate we should pay more attention to the question wordings if there is some supposition or rules or convention they are mentioned in the question if not then stick to the concept

Yeah per subnet no of usable IP =  no of IP address possible -2 

Related questions

0 votes
0 votes
2 answers
2
3 votes
3 votes
2 answers
3
radha gogia asked Apr 6, 2018
1,431 views
Interface $A - 255.255.255.128$Interface $B -255.255.255.192$Interface $C -255.255.255.224$ 1) which one of the following IP addresses belong to interface $B$ ?$200.200.2...
1 votes
1 votes
1 answer
4
Chaitanya Kale asked Feb 13, 2023
449 views
Consider the following table with subnetsSubnetSubnet IdSubnet Mask$ A$150.60.160.0255.255.240.0$B $150.60.164.0255.255.252.0$C $150.160.168.0255.255.252.0 Can we say sub...