Setup guide

Page 124 Dedicated Micros
Classes of Networks
There are three ‘available’ classes of networks. There other classes of networks that are
reserved and therefore are not ‘available’ to the general public.
Class A
The Class A network allocates the first octet to the Network ID and the remaining three octets
are the Host ID’s. There is also an address range that has been defined for a Class A network.
As we use the first octet as the Network ID, we can see from the subnet mask that a Class A
subnet ‘masks’ out the network portion of the address.
Class A Address Range
This identifies the range of network address that are within the Class A address range; 0 – 126.
Subnet Mask
This shows that the first octet masked by the subnet which identifies the Network ID and the
remaining 3 octets are the Host ID’s. Which means that we can have 127 (0 to 126) networks
each with up to 16,777,216 hosts.
Alternative Format
There are two ways an IP address can be written;
10.1.1.23 255.0.0.0.
10.1.1.23/8 - which identifies that the first 8 bits (octet) is the Network ID.
Both addresses are the same they are just written in a different format.
Class B
A Class B network can be seen as being a medium sized network offering more network ID’s
than a Class A but less host ID’s, we can see that the subnet ‘masks’ out the network portion of
the IP address.
Class A Address Range Subnet Mask Alternative Format
0.x.x.x 255.0.0.0 0.x.x.x/8
126.x.x.x 255.0.0.0 126.x.x.x/8