ZyXEL Communications 650 Series Manuel D’Utilisation

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Prestige 650 Series User’s Guide 
IP Subnetting 
 
B-5 
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 
(11111111.11111111.11111111.11000000) or 255.255.255.192. Each subnet contains 6 host ID bits, giving 
2
6
-2 or 62 hosts for each subnet (all 0’s is the subnet itself, all 1’s is the broadcast address on the subnet).  
Chart B-7 Subnet 1 
 
NETWORK NUMBER 
LAST OCTET BIT VALUE 
IP Address 
192.168.1. 
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 
Chart B-8 Subnet 2 
 
NETWORK NUMBER 
LAST OCTET 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 
Chart B-9 Subnet 3 
 
NETWORK NUMBER 
LAST OCTET 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