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Appendix G IP subnetting
N0115789
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.
Example: four subnets
The above example illustrated using a 25-bit subnet mask to divide a class C
address space into two subnets. Similarly to divide a class C address into four
subnets, you need to borrow two host ID bits to give four possible combinations
of 00, 01, 10 and 11. The subnet mask is 26 bits
(11111111.11111111.11111111.
11
000000) or 255.255.255.192. Each subnet
contains 6 host ID bits, giving 2
6
-2 or 62 hosts for each subnet (all 0s is the subnet
itself, all 1s is the broadcast address on the subnet).
Table 54
Subnet 1
Network number
Last octet bit value
IP Address
192.168.1.
0
IP Address (Binary)
11000000.10101000.00000001.
00
000000
Subnet Mask (Binary)
11111111.11111111.11111111.
11
000000
Subnet Address: 192.168.1.0
Lowest Host ID: 192.168.1.1
Broadcast Address: 192.168.1.63 Highest Host ID: 192.168.1.62
Table 55
Subnet 2
Network number
Last octet bit value
IP Address
192.168.1.
64
IP Address (Binary)
11000000.10101000.00000001.
01
000000
Subnet Mask (Binary)
11111111.11111111.11111111.
11
000000
Subnet Address: 192.168.1.64
Lowest Host ID: 192.168.1.65
Broadcast Address:
192.168.1.127
Highest Host ID: 192.168.1.126
Summary of Contents for BCM50e
Page 18: ...18 Figures N0115789 ...
Page 22: ...22 Tables N0115789 ...
Page 28: ...28 Preface N0115789 ...
Page 38: ...38 Chapter 1 Getting to know your BCM50e Integrated Router N0115789 ...
Page 44: ...44 Chapter 2 Introducing the SMT N0115789 SMT menus at a glance Figure 6 SMT overview ...
Page 60: ...60 Chapter 4 LAN setup N0115789 ...
Page 82: ...82 Chapter 6 Remote Node setup N0115789 ...
Page 86: ...86 Chapter 7 IP Static Route Setup N0115789 ...
Page 114: ...114 Chapter 9 Network Address Translation NAT N0115789 ...
Page 136: ...136 Chapter 11 Filter configuration N0115789 ...
Page 140: ...140 Chapter 12 SNMP Configuration N0115789 ...
Page 144: ...144 Chapter 13 System security N0115789 ...
Page 172: ...172 Chapter 15 Firmware and configuration file maintenance N0115789 ...
Page 186: ...186 Chapter 17 Remote Management N0115789 ...
Page 206: ...206 Appendix B Triangle Route N0115789 ...
Page 226: ...226 Appendix D PPPoE N0115789 ...
Page 232: ...232 Appendix F N0115789 ...
Page 242: ...242 Appendix G IP subnetting N0115789 ...
Page 304: ...304 Appendix K Log descriptions N0115789 ...
Page 306: ...306 Appendix L Brute force password guessing protection N0115789 ...