Basic Subnetting Examples

Basic Subnetting Examples

Subnetting FAQs

  • Q. What is subnetting?
    A. Subnetting is a networking technique that allows a network administrator to split up one large group of network address on a single network into multiple networks with fewer numbers of host addresses.
  • Q. What is the difference between the network addresses and host addresses?
    A.The network address is the first address in certain network address range or subnet. For example the network address 192.168.1.0 with a subnet mask of 255.255.255.0 is the network address and is not usable by devices on the network. Similarly the network address 192.168.1.255 in this example is the broadcast address for this network and is not usable/assignable to devices on the network. A host address is any address inbetween the network and broadcast address and is assignable to devices such as servers, computers, routers, other tablets and cellphones that use wifi connections. Basically host addresses are used by any device that connects to your network.
  • Q. Why do I need to learn subnetting?
    A.Subnetting is unneeded in many situations when you are dealing with devices and servers that all need to connect to the same network. However for larger or more complex networks subnetting is very useful. In situations when you are assigned a certain range of IP addresses from and internet provider and would like to break them into multiple networks, or need to have a completely separate network for your servers. You might not need a full 254 IP addresses for your server network and only want to use 62 for future servers and devices. These are a few situations where subnetting is usefull.

 


 

*** Example #1 - Not Subnetted ***
Original Network Address & Subnet Mask: 192.168.1.0 255.255.255.0
Bits Borrowed (None Full Octet Used): 192.168.1.|00000000
# of possible networks: 1
Number of usable Host IP addresses: 254
Each Network address increments by 256 (counting 0)

1st Network 192.168.1.0
1st Usable 192.168.1.1
Last Usable 192.168.1.254
Broadcast

192.168.1.255


*** Example #2 ***
Original Network Address & Subnet Mask: 192.168.1.0 255.255.255.0
New Subnet Mask: 255.255.255.128
Bits Borrowed: 192.168.1.1|0000000
# of possible networks: 2
Each Sub-Network address increments by 128

1st Network 192.168.1.0
1st Usable 192.168.1.1
Last Usable 192.168.1.126
Broadcast

192.168.1.127

2nd Network 192.168.1.128
1st Usable 192.168.1.129
Last Usable 192.168.1.254
Broadcast

192.168.1.255



*** Example #3 ***
Original Network Address & Subnet Mask: 192.168.1.0 255.255.255.0
New Subnet Mask: 255.255.255.192
Bits Borrowed: 192.168.1.11|000000
# of possible networks: 4
Each Sub-Network address increments by 64

1st Network 192.168.1.0
1st Usable 192.168.1.1
Last Usable 192.168.1.62
Broadcast

192.168.1.63

2nd Network 192.168.1.64
1st Usable 192.168.1.65
Last Usable 192.168.1.126
Broadcast

192.168.1.127

3nd Network 192.168.1.128
1st Usable 192.168.1.129
Last Usable 192.168.1.190
Broadcast

192.168.1.191

4nd Network 192.168.1.192
1st Usable 192.168.1.193
Last Usable 192.168.1.254
Broadcast

192.168.1.255