Introduction To Addressing

What is a Network Address?

A computer network is a collection of several interconnected computers that share one or more resources that are made available on or by network nodes. A set of guidelines or network protocols governs the sharing or communication between the machines. Network addresses are used to identify these machines, which may also have hostnames.

A host or machine in a communications network is uniquely identified by a network address, which can be logical or physical. A network may not be entirely unique and may include details about the structure and hierarchies of the network’s nodes. Some fundamental examples of network addresses include phone numbers, media access control (MAC) addresses, and Internet protocol (IP) addresses. It may be numerical, symbolic, or even both in some circumstances.

The assignment of distinctive addresses to various nodes in a network falls primarily under the purview of the network layer. They can be physical or logical addresses, as was already mentioned, but typically they are logical addresses or addresses that are based on software. An IP address is the most frequently used network address. It gives a node in an IP network a unique identification. An IP address is a 32-bit long numerical address that is written in a dot-decimal notation with a period separating each byte’s decimal representation. For instance, the IP address 196.32.216.9 has the values 196 for the first 8 bits, 32 for the following 8 bits, and so on. An IP address’s first three bytes identify the network and its final byte identifies the host on the network. Subclasses are further divisions of an IP address:

Classful Addressing

An IP address is 32-bit long. An IP address is divided into sub-classes:

• Class A
• Class B
• Class C
• Class D
• Class E

An IP address is divided into two parts:

• Network ID: It represents the number of networks.
• Host ID: It represents the number of hosts.

We can see that each class has a particular range of IP addresses in the diagram above. The number of bits used in a class, as well as the number of networks and hosts available in the class, are all determined by the IP address class.

Class A

An IP address is given to networks with a lot of hosts or Class A in them.

• The network ID is 8 bits long.
• The host ID is 24 bits long.

In Class A, the first bit of the first octet’s higher-order bits is consistently set to 0 and the network ID is determined by the remaining 7 bits. In any network, the host ID is determined by the 24 bits.

The total number of networks in Class A = 27 = 128 network address

The total number of hosts in Class A = 224 – 2 = 16,777,214 host address

Class B

An IP address is given to networks in Class B that range in size from small to large networks.

• The Network ID is 16 bits long.
• The Host ID is 16 bits long.

The first octet’s higher-order bits are always set to 10 in Class B and the network ID is determined by the remaining 14 bits. The Host ID is decided by the remaining 16 bits.

The total number of networks in Class B = 214 = 16384 network address

The total number of hosts in Class B = 216 – 2 = 65534 host address

Class C

Only small networks in Class C are given IP addresses.

• The Network ID is 24 bits long.
• The host ID is 8 bits long.

In Class C, the first octet’s higher-order bits are always set to 110 and the network ID is determined by the final 21 bits. The host in a network is identified by its 8-bit host ID.

The total number of networks = 221 = 2097152 network address

The total number of hosts = 28 – 2 = 254 host address

Class D

An IP address in Class D is set aside for multicast addresses. It is devoid of subnetting. The first octet’s higher-order bits are always set to 1110 and the remaining bits in any network determine the host ID.

Class E

An IP address is used in Class E for foreseeable use or for future research and development. There is no subnetting present. In any network, the host ID is determined by the remaining bits of the first octet, which are always set to the value 1111.

Norms to assign Network ID

1. Share the same network ID across all hosts connected to the same network.
2. It cannot start with 127 as 127 is used exclusively by Class A.
3. The network ID cannot be assigned if all of its bits are set to 0 because it identifies a specific host on the local network.
4. Since the network ID is reserved for multicast addresses, it cannot be assigned if all of its bits are set to 1.

Norms to assign Host ID

1. It must be unique within any network.
2. The host ID cannot be assigned if all of its bits are set to 0 because it serves as the IP address’s network ID.
3. All of the bits on the host ID that are not zero are reserved for multicast addresses.

Classful Network Addressing

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