What is Internet Protocol Version 4 (Pv4)

IP stands for Internet Protocol version v4 stands for Version Four (IPv4), is the most widely used system for identifying devices on a network. It uses a set of four numbers, separated by periods (like 192.168.0.1), to give each device a unique address. This address helps data find its way from one device to another over the internet.

An IP address (Internet Protocol address) is a unique identifier assigned to each device connected to a network that uses the Internet Protocol for communication. It serves two main purposes:

• Identification: It uniquely identifies a device on a network.
• Location Addressing: It indicates where a device is located within a network, making data routing possible.

Note: It was Introduced by ARPANET in 1983

Understanding IPv4 Addressing

An IPv4 address consists of series of four eight-bit binary numbers which are separated by decimal point. Although any numbering system can be used to represent a unique 32- bit number, most commonly you see IP address expressed in dot decimal notation. Some of the examples are:

IPv4 Address Format

An IPv4 address consists of 32 bit (binary digit), grouped into four section of known as octets or bytes. Each octet has 8 bits and this bits can be represented only in 0 or 1 form, and when they grouped together, they form a binary number. Since each octet has 8 bits, it can represent 256 numbers ranging from o to 255. These four octets are represented as decimal numbers, separated by periods known as dotted decimal notation. For example IPv4 address 185.107.80.231 consists of four octets.

Binary Representation

IPv4 is basically converted into binary form by computer although these are usually seen in decimal form for human readability. Each octet is converted into 8 bit binary number . For instance 185.107.80.231 in binary looks like:

• 185: 10111001
• 107: 01101011
• 80: 01010000
• 231: 11100111

So 185.107.80.231 in binary is: 10111001.01101011.01010000.11100111

Parts of IPv4

IPv4 addresses consist of three parts:

• Network Part: The network part indicates the distinctive variety that's appointed to the network. The network part conjointly identifies the category of the network that's assigned.
• Host Part: The host part uniquely identifies the machine on your network. This part of the IPv4 address is assigned to every host. 
  For each host on the network, the network part is the same, however, the host half must vary.
• Subnet Number: This is the non obligatory part of IPv4. Local networks that have massive numbers of hosts are divided into subnets and subnet numbers are appointed to that.

Types of IPv4 Addressing

IPv4 basically supports three different types of addressing modes:

• Unicast Addressing Mode: This addressing mode is used to specify single sender and single receiver. Example: Accessing a website.
• Broadcast Addressing Mode: This addressing mode is used to send messages to all devices in a network. Example: sending a message in local network to all the devices.
• Multicast Addressing Mode: This addressing mode is typically used within a local network or across networks and sends messages to a group of devices. Example: Streaming audio to multiple devices at once.

IPv4 Datagram Header

These fields together ensure the proper delivery, routing, fragmentation, and reassembly of IP packets across the network.

• VERSION: Version of the IP protocol (4 bits), which is 4 for IPv4 
• HLEN: IP header length (4 bits), which is the number of 32 bit words in the header. The minimum value for this field is 5 and the maximum is 15. 
• Type of service: Low Delay, High Throughput, Reliability (8 bits) 
• Total Length: Length of header + Data (16 bits), which has a minimum value 20 bytes and the maximum is 65,535 bytes. 
• Identification: Unique Packet Id for identifying the group of fragments of a single IP datagram (16 bits) 
• Flags: 3 flags of 1 bit each : reserved bit (must be zero), do not fragment flag, more fragments flag (same order) 
• Fragment Offset: Represents the number of Data Bytes ahead of the particular fragment in the particular Datagram. Specified in terms of number of 8 bytes, which has the maximum value of 65,528 bytes. 
• Time to live: Datagram’s lifetime (8 bits), It prevents the datagram to loop through the network by restricting the number of Hops taken by a Packet before delivering to the Destination.
• Protocol: Name of the protocol to which the data is to be passed (8 bits) 
• Header Checksum: 16 bits header checksum for checking errors in the datagram header 
• Source IP address: 32 bits IP address of the sender 
• Destination IP address: 32 bits IP address of the receiver 
• Option: Optional information such as source route, record route. Used by the Network administrator to check whether a path is working or not.

Characteristics of IPv4

• IPv4 could be a 32-bit IP Address.
• IPv4 could be a numeric address, and its bits are separated by a dot.
• The number of header fields is twelve and the length of the header field is twenty.
• It has Unicast, broadcast, and multicast-style addresses.
• IPv4 supports VLSM (Virtual Length Subnet Mask).
• IPv4 uses the Post Address Resolution Protocol to map to the MAC address.

Advantages of IPv4

• IPv4 security permits encryption to keep up privacy and security.
• IPV4 network allocation is significant and presently has quite 85000 practical routers.
• It becomes easy to attach multiple devices across an outsized network while not NAT.
• This is a model of communication so provides quality service also as economical knowledge transfer.
• IPV4 addresses are redefined and permit flawless encoding.

Limitations of IPv4

• IP relies on network layer addresses to identify end-points on the network, and each network has a unique IP address.
• The world's supply of unique IP addresses is dwindling, and they might eventually run out theoretically.
• If there are multiple hosts, we need the IP addresses of the next class.
• Complex host and routing configuration, non-hierarchical addressing, difficult to re-numbering addresses, large routing tables, non-trivial implementations in providing security, QoS (Quality of Service), mobility, and multi-homing, multicasting, etc. are the big limitations of IPv4 so that's why IPv6 came into the picture.