Black Box LR5200A-R2, LR5100A-T manual 2 Defining an IP Subnet Mask, Applications, Location Main

Applications

The router allows mask sizes from 8 to 32 bits. The subnet mask size determines how many bits of the host field of the original IP network address will be used for the creation of subnets. In this example, specifying a mask size of 26 will produce a subnet size of 2 bits. Two bits gives 4 possible sub-network addresses from the original IP network address. Two of the resulting sub-networks will have either all zeros or all ones as the subnet address; these addresses are reserved for network functions and hence are invalid addresses. The subnet mask for the above example networks will be 255.255.255.192:

So setting a subnet mask size of 26 will generate two sub-networks with up to 62 host addresses each (64 potential addresses minus the all zero and all one addresses). The new IP sub-network addresses will be: 199.169.100.64 and 199.169.100.128.

Original IP Network Address 199.169.100.0

Subnet IP Network Address		Subnet IP Network Address
199.169.100.64	Subnet Mask is	199.169.100.128
Subnet Mask Size 26		Subnet Mask Size 26
	255.255.255.192

Router IP Address	Router IP Address
199.169.100.65	199.169.100.129
LAN #1	LAN #2
IP Computers	IP Computers

Host IP Address Host IP Address 199.169.100.66 199.169.100.67

Host IP Address Host IP Address 199.169.100.130 199.169.100.131

Figure 2 -2 Defining an IP Subnet Mask

7	1. IP Address
	Location: Main
	Ä Configuration
	Ä LAN Set up
	Ä LAN IP Set up
	Ä IP Address / Size of Subnet Mask

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