Networking Concepts
Subnetworks
Table | Valid Addresses of Example Subnetwork |
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| Subnet | Address of | Decimal Value | Possible Node | Decimal Value of |
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| Subnetwork in | of Subnetwork | Address on | Rightmost Byte |
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| 1 | 001 (00000) | 32 | ||
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| 2 | 010 (00000) | 64 | ||
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| 3 | 011 (00000) | 96 | ||
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| 4 | 100 (00000) | 128 | ||
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| 5 | 101 (00000) | 160 | ||
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| 6 | 110 (00000) | 192 | ||
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By looking at the binary values of two IP addresses, it is easy to tell if nodes belong to the same subnet. If they do, all the bits that make up the subnet mask will be the same between IP addresses in the subnet.
Take, for example, two IP addresses (in decimal and in binary) of subnet number 1 from Table
192.6.12.411100 0000 0000 0110 0000 1100 0010 1001
192.6.12.551100 0000 0000 0110 0000 1100 0011 0111
The subnet mask has already been defined as:
255.255.255 224 1111 1111 1111 1111 1111 1111 1110 0000
Because the mask has all bits except the five rightmost bits set to 1, all bits except the five rightmost bits must match between nodes on the same subnet. Because the two example IP addresses from subnet 1 do match except for their five rightmost bits, they belong to the same subnet.
NOTE | Subnet addressing can be used in internetworks (networks with |
| gateways). |
30 | Chapter 2 |