What is The Difference between IPv6 and IPv4? (IPv6 vs IPv4)

TelecomAcadmey explains the difference between IPv6 and IPv4 ( IPv6 vs IPv4 ), and looks at the topic of migrating to a 128-bit address space. IPv4 contain 32-bit and IPv6 contain 128-bit. We will discuss IPv6 vs IPv4 Briefly.

What is Internet Protocol (IP)?

IP stands for Internet protocol specifies the technical format of packets and the addressing scheme for computers to communicate over a network. Most networks combine IP with a higher-level protocol called TCP, which establishes a virtual connection between a destination and a source.

IP versions

Internet Protocol have two version which we used normally and we will discuss IPv6 vs IPv4 address.

  • IPv4
  • IPv6

What is The Difference between IPv6 and IPv4? (IPv6 vs IPv4)

IPv6 vs IPv4

The basic difference between IPv6 and Ipv4 are as follows.


  • IPv6 has a larger 128-bit address space, providing (340,282,366,920,938,463,463,374,607,431,768,211,456 to be exact) This provides roughly 50 octillion addresses per person alive on Earth today, or roughly 3.7 x 1021 addresses per square inch of the Earth’s surface.
  • A lack of Internet addresses caused web programmes slow down.
  • To allow the Internet to continue to grow and spread across the world, implementing IPv6 is necessary.

Benefits of IPv6

IPv6 offers the following features:

  • Increased Address Space and Scalability – providing the absurd number of possible addresses stated previously.
  • Integrated Security – provides built-in authentication and encryption into the IPv6 network header
  • Compatibility with IPv4 – simplifies address migration, as IPv6 is backward-compatible with IPv4

IPv6 Address Representation

  • An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets, a group sometimes also called a hextet). The groups are separated by colons (:).
  • 2001:0db8:85a3:0000:0000:8a2e:0370:7334
  • The hexadecimal digits are case-insensitive.
  • The full representation of IPv6 have following techniques;
  • Leading zeroes in a group may be omitted, but each group must retain at least one hexadecimal digit.
  • Thus, the example address may be written as: 2001:db8:85a3:0:0:8a2e:370:7334

IPv6 Address Types

  • Unicast – An IPv6 unicast address uniquely identifies an interface on an IPv6-enabled device
  • Multicast – An IPv6 multicast address is used to send a single IPv6 packet to multiple destinations.
  • Anycast – An IPv6 anycast address is any IPv6 unicast address that can be assigned to multiple devices. A packet sent to an anycast address is routed to the nearest device having that address.

The IPv6 Prefix

  • IPv4 utilizes a subnet mask to define the network “prefix” and “host” portions of an address.
  • IPv6 always use CIDR notation to determine what bits notate the prefix of an address:
  • Full Address:  1254:1532:26B1:CC14:123:1111:2222:3333/64 Prefix ID:   1254:1532:26B1:CC14:     Host ID:   123:1111:2222:3333
  • The /64 indicates that the first 64 bits of this address identify the prefix.


  • IPv4 is defined and specified in IETF publication RFC 791.
  • It is used in the packet-switched link layer in the OSI model.
  • IPv4 uses 32-bit addresses for Ethernet communication in five classes: A, B, C, D and E.
  • Classes A, B and C have a different bit length for addressing the network host.
  • Class D addresses are reserved for multicasting, while class E addresses are reserved for future use.

Benefits of IPv4

  • Simpler
    • IPs a normal human might be able to remember.
    • Less programming, less memory, etc.
  • Familiarity
    • Thousands (millions?) of Network and System Administrators already know it.
    • Existing infrastructure supports it at almost every level already.

IPv4 Address Representation

  • IPv4 addresses may be represented in any notation expressing a 32-bit integer value.
  • They are most often written in the dot-decimal notation, which consists of four octets of the address expressed individually in decimal numbers and separated by periods.
  • Example

IPv4 Address type

The Internet standards define the following types of IPv4 addresses:

  • Unicast. Assigned to a single network interface located on a specific subnet on the network and used for one-to-one communications.
  • Multicast. Assigned to one or more network interfaces located on various subnets on the network and used for one-to-many communications.
  • Broadcast. Assigned to all network interfaces located on a subnet on the network and used for one-to-everyone-on-a-subnet communications.

The IPv4 Prefix

A network may also be characterized by its subnet mask or netmask, which is the bitmask that when applied by a bitwise AND operation to any IP address in the network, yields the routing prefix.

Subnet masks are also expressed in dot-decimal notation like an address.

For example, is the subnet mask for the prefix.

IPv4 and IPv6 Coexistence

There is not a single date to move to IPv6. For the future, both IPv4 and IPv6 will coexist. The IETF has created various protocols and tools to help network administrators migrate their networks to IPv6. The migration techniques can be divided into three categories:

Dual Stack –A station must run IPv4 and IPv6 simultaneously until all the Internet uses IPv6. To determine which version to use when sending a packet to a destination to the source host queries the DNS. If the DNS return an IPv4 address, the source host sends an IPv4 packet. If the DNS return an IPv6 address, the source host sends an IPv6 packet.

Tunneling: is a strategy used when two computer using IPv6 want to communicate with each other and the packet must pass through a region that uses an IPv4. To pass through this region the packet must have an IPv4 address. So the IPv6 packet is encapsulated in IPv4 packet when it enters the region, and it leaves its capsule when it exits the region. It  seems as  if the IPv6 packet enters the tunnel at one end and emerges at other end.

  • Header Translation: sender wants to use Ipv6 but the receiver does not understand Ipv6
  • Tunneling does not worked
  • Must Ipv4 format to understood
  • Header format totally changed

You may also like: What is IPv6 (Internet Protocol Version 6)?

Hamza Arif
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Hamza Arif

Hey, i hamza arif student of telecommunication from BZU, i am good in Networking, Telecommunication and Web Development working on different projects and try my best to teach them to all of you.
Hamza Arif
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