networking

Question

The address of a class B host is to be split into subnets with a 6 - bit subnet number. What is
the maximum number of subnets and maximum number of hosts in each subnet ?
(1) 62 subnets and 1022 hosts (2) 64 subnets and 1024 hosts
(3) 62 subnets and 254 hosts (4) 64 subnets and 256 hosts

Comments

$maximum \  subnet \ =  \ 2^n - 2$

                                 $ = 2^6 - 2$

                                 $ = 62$

$N.B \rightarrow$    The RFC 950 specification reserves the subnet values consisting of all zeros and all ones (broadcast), that's why 2 is subtracted.

$number \ of \ bits \ for \ host \ id \ in \ B: 16 \ bits$

$6$ is used as subnet, remaining $10(16-6)$ bits is used for hosts

$maximum \  hosts \ =  \ 2^n - 2$

                             $ = 2^10 - 2$

                             $ = 1022$

$N.B\rightarrow$ The address with all bits as 1 is reserved as the broadcast address and address with all host id bits as 0 is used as the network address of the subnet, that's why 2 is subtracted.

 https://en.wikipedia.org/wiki/Subnetwork#Subnet_and_host_counts

Answer 1

Class B network= 16bit.

Subnet  =6 bit.

Host= 32-(16+6)=12bit.

• No of subnet=2^n-2 =2^6-2=62 host.

• No of host=2^n-2 =2^10-2 =1022

Comments

hello Sir ,

   How 2⁶-1=62 ?                 ,it is equal to 63.

       and 2¹⁰-1=1022 ?         , it is equal to 1023.

your answer is right But Explanation is Wrong.

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