10. 4. Determine number of subnets and hosts: Solve for subnets: 2 borrowed -2 2 3= 8-2 = 6 subnets Solve for hosts: 2 retained – 2 2 5= 32-2 = 30 hosts 5. Establish the least significant subnet bit: x.x.x.11 1 00000 The least significant bit is 32, therefore our subnets should increment by 32. 6. List the first and last subnet in the series, as well as the first and last host on each subnet. Let’s look at how that looks in Binary. 128 64 32 16 8 4 2 1 2 7 2 6 2 5 2 4 2 3 2 2 2 1 2 0 128 64 32 16 8 4 2 1 0 0 1 0 0 0 0 0
11. With a Class “C” Network we have 8 host bits: In our example, we have borrowed 3 bits to create additional networks so, our bits has to be divided as follows: List out the first and last subnet, and first and last host on each subnet: This is where understanding binary, and how to list a series is important. Remember that the first in a series is all zeros and a one, and the last in a series is all ones and a zero. Bit # 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1 Network Bits Host Bits Bit# 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1
12. Let’s look at how we list out our first subnet, remember the first in a series is all zeros and a one. Our first subnet in binary is “ 32 ” because we borrowed 3 bits, which also is our least significant bit. Our first subnet is 209.168.19.32. Let’s look at how we find the first host on the first subnet, remember the rule? Our first host on our first subnet is “33” (32+1) because that is the value of all of the bits in this octet. Our first host on the first subnet is 209.168.19.33. Network Bits Host Bits Bit# 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1 0 0 1 0 0 0 0 0 Network Bits Host Bits Bit# 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1 0 0 1 0 0 0 0 1
13. The last host on our first subnet is “62” (32+16+8+4+2). The last host on the first subnet is 209.168.19.62. Our first subnet looks like this 209.168.19.32 First host 209.168.19.33 Last host 209.168.19.62 How would you figure out the last host on the first subnet? The last in a series is all ones and a zero. Let’s look at how we would determine the last subnet, remember the last in a series is all ones and a zero. The last subnet is 209.168.19.192 Tip: Use the custom subnet mask minus the LSB (224 – 32 = 192) Network Bits Host Bits Bit# 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1 0 0 1 1 1 1 1 0 Network Bits Host Bits Bit# 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1 1 1 0 0 0 0 0 0
14. The first host on the last subnet? The first host on the last subnet is 209.168.19.193 . The last host on the last subnet? The last host on the last subnet is 209.168.19.222. The last subnet is 209.168.19.192 First host 209.168.19.193 Last host 209.168.19.222 Network Bits Host Bits Bit# 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1 1 1 0 0 0 0 0 1 Network Bits Host Bits Bit# 8 7 6 5 4 3 2 1 Value 128 64 32 16 8 4 2 1 1 1 0 1 1 1 1 0