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Appendix B IP Addresses and Subnetting
VMG4380-B10A / VMG4325-B10A User’s Guide
317
The following figure shows the company network after subnetting. There are now two sub-
networks, A and B.
Figure 186
Subnetting Example: After Subnetting
In a 25-bit subnet the host ID has 7 bits, so each sub-network has a maximum of 2
7
– 2 or 126
possible hosts (a host ID of all zeroes is the subnet’s address itself, all ones is the subnet’s
broadcast address).
192.168.1.0 with mask 255.255.255.128 is subnet A itself, and 192.168.1.127 with mask
255.255.255.128 is its broadcast address. Therefore, the lowest IP address that can be assigned to
an actual host for subnet A is 192.168.1.1 and the highest is 192.168.1.126.
Similarly, the host ID range for subnet B is 192.168.1.129 to 192.168.1.254.
Example: Four Subnets
The previous example illustrated using a 25-bit subnet mask to divide a 24-bit address into two
subnets. Similarly, to divide a 24-bit address into four subnets, you need to “borrow” two host ID
bits to give four possible combinations (00, 01, 10 and 11). The subnet mask is 26 bits
(11111111.11111111.11111111.11000000) or 255.255.255.192.
Each subnet contains 6 host ID bits, giving 2
6
- 2 or 62 hosts for each subnet (a host ID of all
zeroes is the subnet itself, all ones is the subnet’s broadcast address).
Table 118
Subnet 1
IP/SUBNET MASK
NETWORK NUMBER
LAST OCTET BIT
VALUE
IP Address (Decimal)
192.168.1.
0
IP Address (Binary)
11000000.10101000.00000001.
00000000
Subnet Mask (Binary)
11111111.11111111.11111111.
11000000
Summary of Contents for VMG4325-B10A
Page 4: ...Contents Overview VMG4380 B10A VMG4325 B10A User s Guide 4 Troubleshooting 283 ...
Page 14: ...Table of Contents VMG4380 B10A VMG4325 B10A User s Guide 14 ...
Page 15: ...15 PART I User s Guide ...
Page 16: ...16 ...
Page 24: ...Chapter 1 Introducing the Device VMG4380 B10A VMG4325 B10A User s Guide 24 ...
Page 69: ...69 PART II Technical Reference ...
Page 70: ...70 ...
Page 178: ...Chapter 10 Quality of Service QoS VMG4380 B10A VMG4325 B10A User s Guide 178 ...
Page 204: ...Chapter 13 Interface Group VMG4380 B10A VMG4325 B10A User s Guide 204 ...
Page 220: ...Chapter 15 Firewall VMG4380 B10A VMG4325 B10A User s Guide 220 ...
Page 226: ...Chapter 17 Parental Control VMG4380 B10A VMG4325 B10A User s Guide 226 ...
Page 236: ...Chapter 19 Certificates VMG4380 B10A VMG4325 B10A User s Guide 236 ...
Page 240: ...Chapter 20 Log VMG4380 B10A VMG4325 B10A User s Guide 240 ...
Page 244: ...Chapter 21 Traffic Status VMG4380 B10A VMG4325 B10A User s Guide 244 ...
Page 250: ...Chapter 24 IGMP Status VMG4380 B10A VMG4325 B10A User s Guide 250 ...
Page 254: ...Chapter 25 xDSL Statistics VMG4380 B10A VMG4325 B10A User s Guide 254 ...
Page 256: ...Chapter 26 User Account VMG4380 B10A VMG4325 B10A User s Guide 256 ...
Page 262: ...Chapter 29 TR 064 VMG4380 B10A VMG4325 B10A User s Guide 262 ...
Page 266: ...Chapter 30 Time Settings VMG4380 B10A VMG4325 B10A User s Guide 266 ...
Page 272: ...Chapter 32 Logs Setting VMG4380 B10A VMG4325 B10A User s Guide 272 ...
Page 290: ...Chapter 36 Troubleshooting VMG4380 B10A VMG4325 B10A User s Guide 290 ...
Page 344: ...Appendix D Wireless LANs VMG4380 B10A VMG4325 B10A User s Guide 344 ...