ZyXEL Communications VFG6005, User Manual

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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 nee
d 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. 11 000000) 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).
Subnet 1
IP/SUBNET MASK NETWORK NUMBER
LAST OCTET BIT
VALUE
IP Address (Decimal) 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