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P-2000W_V2 User’s Guide
Note: In the following charts, shaded/bolded last octet bit values indicate host ID bits “borrowed” to form network ID bits. The number of “borrowed” host ID bits determines the number of subnets you can have. The remaining number of host ID bits (after “borrowing”) determines the number of hosts you can have on each subnet.
Table 35 Subnet 1 |
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| NETWORK NUMBER | LAST OCTET BIT |
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IP Address | 192.168.1. | 0 |
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IP Address (Binary) | 11000000.10101000.00000001. | 00000000 |
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Subnet Mask | 255.255.255. | 128 |
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Subnet Mask (Binary) | 11111111.11111111.11111111. | 10000000 |
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Subnet Address: 192.168.1.0 | Lowest Host ID: 192.168.1.1 |
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Broadcast Address: | Highest Host ID: 192.168.1.126 |
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192.168.1.127 |
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Table 36 Subnet 2
| NETWORK NUMBER | LAST OCTET BIT VALUE |
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IP Address | 192.168.1. | 128 |
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IP Address (Binary) | 11000000.10101000.00000001. | 10000000 |
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Subnet Mask | 255.255.255. | 128 |
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Subnet Mask (Binary) | 11111111.11111111.11111111. | 10000000 |
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Subnet Address: | Lowest Host ID: 192.168.1.129 |
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192.168.1.128 |
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Broadcast Address: | Highest Host ID: 192.168.1.254 |
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192.168.1.255 |
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The remaining 7 bits determine the number of hosts each subnet can have. Host IDs of all zeros represent the subnet itself and host IDs of all ones are the broadcast address for that subnet, so the actual number of hosts available on each subnet in the example above is 27 – 2 or 126 hosts for each subnet.
192.168.1.0 with mask 255.255.255.128 is the subnet itself, and 192.168.1.127 with mask 255.255.255.128 is the directed broadcast address for the first subnet. Therefore, the lowest IP address that can be assigned to an actual host for the first subnet is 192.168.1.1 and the highest is 192.168.1.126. Similarly the host ID range for the second subnet is 192.168.1.129 to 192.168.1.254.
114 | Appendix B IP Subnetting |
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