User Manual

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Appendix B IP Addresses and Subnetting
NBG-418N v2 User’s Guide
164
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.
Exa mple : Four Subne ts
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 70 Subnet 1
IP/ SUBNET MASK NETWO RK NUMBER LAST OC TET BIT VALUE
IP Address (Decimal) 192.168.1. 0
IP Address (Binary) 11000000.10101000.00000001. 00000000
Subnet Mask (Binary) 11111111.11111111.11111111. 11000000
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 71 Subnet 2
IP/ SUBNET MASK NETWORK NUMBER
LAST O CTET BIT
VALUE
IP Address 192.168.1. 64
IP Address (Binary) 11000000.10101000.00000001. 01000000
Subnet Mask (Binary) 11111111.11111111.11111111. 11000000
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
Table 72 Subnet 3
IP/ SUBNET MASK NETWO RK NUMBER
LAST O CTET BIT
VALUE
IP Address 192.168.1. 128
IP Address (Binary) 11000000.10101000.00000001. 10000000
Subnet Mask (Binary) 11111111.11111111.11111111. 11000000
Subnet Address:
192.168.1.128
Lowest Host ID: 192.168.1.129
Broadcast Address:
192.168.1.191
Highest Host ID: 192.168.1.190
Table 73 Subnet 4
IP/ SUBNET MASK NETWORK NUMBER LAST OCTET BIT VALUE
IP Address 192.168.1. 192
IP Address (Binary) 11000000.10101000.00000001. 11000000