156Appendix E: Understanding IP and IP addressing
Figure 33 IP addressing: class C
Class C addresses range from 192.0.0.X to 223.255.255.X (standard network mask is 255.255.255.0), therefore, we can have
32 bits
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110 | networkid |
| hostid |
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3 bit 21 bits 8 bits
Class C indicator
Field subnet in table IPNETWRK
subnet id
hostid
2 to 6 bits 2 to 6 bits
For any class, the hostid can be split into a subnet id and a hostid depending on custom- er requirements. This helps simplify routing to areas. For class C network, the subnet id can range from 2 to 6 bits.
Note 1: Network ids and host ids which are comprised of all 1’s or all 0’s are reserved, therefore, subtract 2 from the subnet id and hostid to get the actual count.
Note 2: There are also special addresses that are reserved for ‘unconnected’ networks (networks that use IP but are not connected to the Internet). Class C networks
have 256 of these special addresses ranging from 192.168.0.0 to 192.168.255.0.
Figure 34 Subnet mask: class C
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| CLASS C subnet masks |
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| IPNETWRK | ||
| No. subnets |
| No. hosts |
| netmask |
| Netmask in binary format |
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| 2 | 62 | 255.255.255.192 | (11111111.11111111.11111111.11000000) | 2 |
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| 6 | 30 | 255.255.255.224 | (11111111.11111111.11111111.11100000) | 3 |
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| 14 | 14 | 255.255.255.240 | (11111111.11111111.11111111.11110000) | 4 |
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| 30 | 6 | 255.255.255.248 | (11111111.11111111.11111111.11111000) | 5 |
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| 62 | 2 | 255.255.255.252 | (11111111.11111111.11111111.11111100) | 6 |
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| Host/Router |
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| DMS | |
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