Question

Using the IPv4 network in the below table. You will subnet it to provide IP addresses to two subnets (Subnet A and Subnet B) that will support the required number of hosts. No subnet calculators may be used. All work must be shown using the IP Addressing worksheet below.

Network	Number of Hosts in Subnet A	Number of Hosts in Subnet B
192.168.10.0/24	100	50

IP Addressing Worksheet

Specification	Subnet A	Subnet B
Number of bits in the subnet	blank	blank
IP mask (binary)	blank	blank
New IP mask (decimal)	blank	blank
Maximum number of usable subnets (including the 0th subnet)	blank	blank
Number of usable hosts per subnet	blank	blank
IP Subnet	blank	blank
First IP Host address	blank	blank
Last IP Host address	blank	blank

Answer 1

Question : To subnet the IP address into two subnets.

Solution : To obtain 2 subnets from the IP address in the question 1 bit from the Host ID is being taken.

192.168.10.0/24 means 24 bits are the Network ID and the remaining 8 bits are the Host ID.  And 1 bit is being taken from the Host ID to divide the Original Network into 2 Subnets.

Specification	Subnet A	Subnet B
Number of bits in the subnet	1	1
IP mask ( Binary )	11111111.11111111.11111111.00000000	11111111.11111111.11111111.10000000
New IP mask ( Decimal )	255.255.255.0	255.255.255.128
Maximum number of usable subnets (including the 0th subnet )	2	2
number of usable hosts per subnet	126	126
IP subnet	192.168.10.0	192.168.10.128
First IP Host Address	192.168.10.1	192.168.10.129
Last IP Host address	192.168.10.126	192.168.10.254

IP Mask is obtained from /24 where 24 represents the Network ID . So put all 1's in those 24 bits and the subnet bit for A is 0 and subnet bit for B is 1.

Maximum number of usable subnets = the bits borrowed from the host id part.

= 1 , so number of usable subnets is 2¹

= 2.

Number of usable hosts = 2^{Number of zeroes} - 2

= 2⁷ - 2

= 126

First IP Host Address is the address followed by the Subnet ID .

Last IP Host address is the second last address of the block.