Dimension
Chart 12 Class C Subnet Planning
NO. “BORROWED” | SUBNET MASK | NO. | NO. HOSTS PER |
HOST BITS |
| SUBNETS | SUBNET |
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|
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4 | 255.255.255.240 (/28) | 16 | 14 |
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5 | 255.255.255.248 (/29) | 32 | 6 |
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6 | 255.255.255.252 (/30) | 64 | 2 |
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7 | 255.255.255.254 (/31) | 128 | 1 |
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For class “A” and class “B” addresses the subnet mask also determines which bits are part of the network number and which are part of the host ID.
A class “B” address has two host ID octets available for subnetting and a class “A” address has three host ID octets (see Chart 1) available for subnetting.
The following table is a summary for class “B” subnet planning.Chart 13 Class B Subnet PlanningNO. “BORROWED” | SUBNET MASK | NO. | NO. HOSTS PER |
HOST BITS |
| SUBNETS | SUBNET |
|
|
|
|
1 | 255.255.128.0 (/17) | 2 | 32766 |
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2 | 255.255.192.0 (/18) | 4 | 16382 |
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3 | 255.255.224.0 (/19) | 8 | 8190 |
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4 | 255.255.240.0 (/20) | 16 | 4094 |
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5 | 255.255.248.0 (/21) | 32 | 2046 |
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6 | 255.255.252.0 (/22) | 64 | 1022 |
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7 | 255.255.254.0 (/23) | 128 | 510 |
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8 | 255.255.255.0 (/24) | 256 | 254 |
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9 | 255.255.255.128 (/25) | 512 | 126 |
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10 | 255.255.255.192 (/26) | 1024 | 62 |
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11 | 255.255.255.224 (/27) | 2048 | 30 |
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12 | 255.255.255.240 (/28) | 4096 | 14 |
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13 | 255.255.255.248 (/29) | 8192 | 6 |
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R | IP Subnetting |