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Appendix A - IP Addresses, Netmask etc.
A.1. IP Addressing
An IP address is a 32-bit value, divided into four octets of eight bits each. The standard
representation is four decimal numbers (in the range of 0..255), divided by dots.
Example: 192.2.1.123
This is called decimal-dot notation.
The IP address is divided in two parts: network and host. To support different needs,
three ”network classes” have been defined. Depending on the network class, the last one,
two or three bytes define the host, while the remaining part defines the network. In the
following, ‘x’ stands for the host part of the IP address:
A.2. Class A Network
IP address 1.x.x.x to 127.x.x.x
Only 127 different networks of this class exist. These have a very large number of
potential connected devices (up to 16,777,216)
Example: 10.0.0.1, (network 10, host 0.0.1)
A.3. Class B Network
IP address 128.0.x.x to 191.255.xxx.xxx
These networks are used for large company networks. Every network can
consist of up to 65,534 devices.
Example: 172.1.3.2 (network 172.1, host 3.2)
A.4. Class C Network
IP address 192.0.0.xxx to 223.255.255.xxx
These network addresses are most common and are often used in small companies. These
networks can consist of a maximum number of 254 hosts.
Example: 192.7.1.9 (network 192.7.1, host 9).
IP Addresses, Netmask etc.
The remaining addresses 224.x.x.x - 239.x.x.x are defined as ”class D” and
are used as a multicast addresses.
The addresses 240.x.x.x. - 254.x.x.x are defined as "class E" and are
reserved addresses.
A.5. Network Address
The host address with all host bits set to "0" is used to address the network
as a whole (in routing entries, for example).
