Sub netting Class B – Question 1

Ex- IP address block – 172.108.10.20/16

To Create 4 subnetworks

• Total no of network bits : ………………
• Total No of subnet bits: …………….
• No of Sub networks – …………….
• No of Hosts per subnet: …………….
• Subnet Mask: …………….
• Block Size : …………….

Answer

• Total no of network bits : 18
• Total No of subnet bits: 18-16 = 2

11111111.11111111.11000000.00000000

• No of Sub networks : 2²=4 (Because No of Subnet Bits are 2)

• ……… .11000000.00000000
• No of Host Bits: 14
• No of Hosts per subnet: 2¹⁴ – 2

• No of IP per subnet: 2¹⁴

Subnet Mask

• 255.255.192.0

Block size = 256 – Subnet Mask

= 256 – 192
= 64

That means 64 of IPs are in 1 Block

Answer Summary – Ex- IP address block – 172.108.10.20/18

• Total no of network bits : 18
• Total No of subnet bits: 2
• No of Sub networks – 4
• No of Hosts per subnet: 2¹⁴-2
• Subnet Mask: 255.255.192.0
• Block Size : 64