IPv4 vs IPv6: Differences That You Need to Know

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IPv4 vs IPv6: Differences That You Need to Know

Vinay Khatri
Last updated on December 11, 2022

    When we talk about internet protocols, there are two basic ones, IPv4 and IPv6, that we use to represent the IP addresses. In this article, we will provide brief introductions of both the IP versions and compare them - IPv4 vs IPv6 - to highlight all the key differences that they have. Moreover, we will also look into their similarities.

    What is IP?

    IP or internet protocol is a set of rules that defines how the communication between a client and the server occurs. Also, IP makes it possible to route data packets correctly from the source device to the destination device.

    What is an IP Address?

    In general, IP delivers data packets from the source to the destination using the IP address, and each device that can access the internet comes with a unique IP address. Also, it's the IP addresses of devices that make it possible to identify the destination system among millions of systems present on the network.

    What is IPv4?

    With the introduction of the internet, IPv4 was the first IP version introduced and deployed for the production of the ARPANET in 1983. If we compare it with its successor version IPv6, most devices today still use IPv4. It uses a 32-bit(4 bytes) addressing mode, which means that it can allocate 4 billion unique addresses. While 4 billion could sound too much, the rapid increase in the number of devices that can access the internet has already resulted in the exhaustion of the IPv4 addresses.

    However, as each internet-enabled device needs to be assigned a unique IP address, there's the need to switch to the newer version of IP known as IPv6 that offers much more IP address combinations.

    History of IPv4

    IPv4 is the fourth version of the Internet Protocol. Introduced in 1983, IPv4 is currently the most popular internet protocol. At the time of its release, it was considered very fast and it can have, theoretically, 4.3 billion IP addresses. The internet during the 1980s was not widespread, and hence IPv4 was sufficient at that time.

    Features of IPv4

    • Provides support for about 4.3 billion IP addresses.
    • IPv4 uses a 32-bit address.
    • It is developed by ARPANET.
    • It supports the variable Length Subnet Mask (VLSM).
    • The protocol uses Dynamic Host Configuration Protocol (DHCP) to configure the network manually.
    • It represents the address in decimal form.

    Advantages of IPv4

    • A major portion of internet-enabled devices uses IPv4.
    • It is less complex than IPv6.
    • IPv4 has security measures to encrypt data in its address packets.
    • The protocol is easily supported by most network topologies .
    • Easy to handle by most systems.
    • Guaranteed data delivery.

    Disadvantages of IPv4

    • Less secure than IPv6.
    • Manual configuration via DHCP is complex.
    • It has inefficient mobility nodes.
    • Depletion of Public address.

    Applications of IPv4

    • Routing and addressing packets of data.

    What is IPv6?

    IPv6 was developed by the Internet Engineering Task Force (IETF) in 1994, and on 14 th July 2017, it was ratified as a Draft Standard for the IETF. It uses a 128-bit address, which means it can allocate approx. 3.4×10 38 unique addresses. One of the major limitations of both versions is that they are not interoperable, thus we cannot perform direct communication between IPv4 and IPv6.

    History of IPv6

    During the 1990s, the internet started running out of IP addresses due to the explosion of the web. It was getting everywhere, and everyone was looking to put up a website on the internet, whether students or companies. This led to the introduction of the sixth version of the Internet Protocol, i.e., IPv6 in 1994.

    Features of IPv6

    • It is the most recent version of the internet protocol.
    • IPv6 provides support for 3.4 x 10 38 IP addresses.
    • IPv6 uses a 128-bit address.
    • IETF developed IPv6.
    • IPv6 represents the address in a hexadecimal form.

    Advantages of IPv6

    • All devices will gradually adopt IPv6.
    • Automatic network configuration.
    • It has a much larger address space.
    • Virtually unlimited host addresses for each prefix.

    Disadvantages of IPv6

    • Shifting to IPv6 is a costly affair.
    • It is harder to fit prefixes on Topology Drawings.
    • Long addresses.

    Applications of IPv6

    • Routing and addressing packets of data.

    IPv4 vs IPv6: Head-to-Head Comparison

    The following IPv4 vs IPv6 table highlights all the key differences between the two based on a wide range of parameters.

    IPv4 IPv6
    Address size IPv4 uses a 32-bit address. IPv6 uses a 128-bit address.
    Addressing representation It represents the address in decimal form. It uses the hexadecimal form to represent the address.
    Header fields It has 12 header fields. It uses 8 header fields (version, Traffic class, flow label, payload length, next header, hop limit, source address, destination address).
    Header Field Length IPv4 header field length is 20. IPv6 header field length is 40.
    Checksum IP4 requires checksum fields. It does not require a checksum field.
    Address type IPv4 supports Unicast, broadcast, and multicast. IPv6 supports Unicast, multicast, and anycast
    Virtual Length Subnet Mask IPv4 supports VLSM. It does not support VLSM.
    Fragmentation Sender and forwarding routes perform the fragmentation. Only the sender performs the fragmentation.
    Network Configuration In IPv4, we use DHCP to configure the network manually. In IPv6, the network is configured automatically.
    Security IPv4 security can be compromised. The security measures employed by IPv4 are more effective.
    Device compatibility Compatible with all devices, but is not ideal for mobile devices. It is also compatible with all devices, including mobile devices.
    MAC address Mapping To map MAC addresses, it uses Address Resolution Protocol (ARP). To map MAC address, it uses Neighbour Discovery Protocol (NDP).
    Optional Fields It has many optional fields. It does not provide an optional field.
    Encryption In IPv4, we do not have an encryption facility. IPv6 provides an encryption facility to ensure better security.
    Address Generate It can generate approx. 4.3 billion unique addresses It can generate approx. 3.4×10 38 Unique address
    Example Ac90::a9c4:ac5e:4ac5:eee8%5

    Similarities Between IPv4 and IPv6

    Despite their differences, both IPv4 and IPv6 share several similarities. Beyond being internet protocols, both:

    • Can transmit fragmented packets.
    • Have the Packet Header part.
    • Provide support for manual IP assignments.
    • Support broadcasting and multicasting features.


    Despite IPv6 being better than IPv4, only 20 to 22% of the devices have adopted IPv6 and the rest uses IPv4. This is so because shifting to IPv6 from IPv4 is expensive. For an enterprise to move to IPv6, it has to make a significant investment. However, with time, all devices will shift to IPv6, and there is no doubt that one day the IPv4 addresses will cease to exist.

    Hopefully, this article helped you understand all the crucial differences between IPv4 and IPv6. Also, if you have any queries or suggestions, feel free to share them with us in the comments section below.

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    IP stands for Internet Protocol. An IP address is a combination of characters and numbers that uniquely identifies any device on the internet or local network.

    The primary difference between IPv4 and IPv6 is that IPv4 has an address size of 32 bits, while IPv6 has a hexadecimal address of size 128-bit.

    IPv6 has an address size of 128 bits. Therefore, it supports 2 to the power 128 addresses. The number of addresses in IPv4 is 1028 times large than the number of addresses in IPv4.

    IPv6 is the next generation and the most recent version of IP that provides a vast collection of addresses than IPv4. When using IPv6, more people and devices would be able to be connected to the internet.

    The primary drawback of IPv4 is its limited address space, i.e., it can support the limited number of devices for connection.

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