IPv4 vs IPv6: What’s the Difference?

What is the difference between these two IP versions? Before discussing IPv4 vs IPv6, let’s understand IP a bit.

The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries.

IP is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. It delivers packets from the source host to the destination host solely based on the IP addresses. The first major IP version is IPv4, and IPv6 is the next version after IPv4.

What is IPv4?

IPv4 was the first IP version to be used and is also the most well-known version. It uses a 32-bit address space and provides nearly 4.3 billion unique addresses, although many are used for special networking purposes.

IPv4 addresses are 32-bit binary numbers that must be represented as decimal numbers. Therefore, the IPv4 addresses that we see are made up of four digits in the range of 0-255, separated by dots.

Here is an example of an IPv4 address:

What is IPv6?

IPv6 is the successor to IPv4 and uses a 128-bit address format that includes numbers and letters.
This is an example of an IPv6 address:

Why do we need a new version of IP?

IPv4 is insufficient, so a new version of IPv6 is needed to augment it. Although IPv4 provides what already seems like a lot of IP addresses, we need more with the rapid growth of the Internet. For example, the RIPE NCC announced on November 25, 2019, that it had run out of IPv4 addresses and called for more progress in adopting IPv6.

IPv4 vs IPv6: what is the difference?

Item	IPv4	IPv6
Full Name	Internet Protocol version four	Internet Protocol version six
Address Length	IPv4 has a 32-bit address length	IPv6 has a 128-bit address length
Address configuration	It Supports Manual and DHCP address configuration	It supports Auto and renumbering address configuration
Connection Integrity	In IPv4 end to end, connection integrity is Unachievable	In IPv6 end-to-end, connection integrity is Achievable
Address Space	It can generate 4.29×ninth power of 10 address space	The address space of IPv6 is quite large. It can produce 3.4×thirty-eighth power of 1 address space
Security	The Security feature is dependent on the application	IPSEC is an inbuilt security feature in the IPv6 protocol
Representation	Address representation of IPv4 is in decimal	Address representation of IPv6 is in hexadecimal
Fragmentation	Fragmentation performed by Sender and forwarding routers	In IPv6, packet flow identification is Available and uses the flow label field in the header
Flow Identification	In IPv4, Packet flow identification is not available	In IPv6, packet flow identification is Available and uses the flow label field in the header
Requires address translation	Yes, for example, through Network Address Translation (NAT)	No
Address Types	Unicast, broadcast, and multicast.	Unicast, multicast, and anycast.
Security	In IPv4, Encryption and Authentication facility not provided	In IPv6, Encryption and Authentication are provided
Head Size	IPv4 has a header of 20-60 bytes.	IPv6 has a header of 40 bytes fixed
Convert	IPv4 can be converted to IPv6	Not all IPv6 can be converted to IPv4
Field	IPv4 consists of 4 fields, which are separated by addresses dot	IPv6 consists of 8 fields, which are separated by a colon (:)
Class	IPv4’s IP addresses are divided into five classes: Class A, Class B, Class C, Class D, and Class E	IPv6 does not have any classes of the IP address
SNMP	SNMP is a protocol used for system management	SNMP does not support IPv6
VLSM	IPv4 supports VLSM( Variable Length subnet mask )	IPv6 does not support VLSM
Mobile support	Requires Mobile IP	Built-in
Optional extras	Limited support for optional controls	Numerous extension headers are available to enhance routing, fragmenting, quality of service, Neighbor Discovery Protocol (NDP), and so on
Mapping	Uses ARP(Address Resolution Protocol) to map to MAC address.	Uses NDP(Neighbour Discovery Protocol) to map to MAC address.
DNS resolution	A records	AAAA records

Here’s a more detailed description of these two differences between IPv4 and IPv6.

IPv4 header vs IPv6 header

IPv4 header

The IPv4 packet header consists of 14 fields, 13 of which are required. The 14th field is optional and aptly named options. The standard IPv4 header is shown below:

IPv6 header

The IPv6 header consists of 8 fields. The address size used in the IPv6 header is approximately four times that of the IPv4 header, but the header size is only twice that of the IPv4 header. The standard IPv6 header is shown below:

Comparison

IPv4 Field	IPv6 Field	Function
Fields that have the same functionality and the same name in IPv4 and IPv6
Version	–	Indicates the version of the IP protocol in use.
Source Address	–	The network layer identifier of the sender of the packet. 32-bit in IPv4 and is increased to 128-bit in IPv6.
Destination Address	–	The network layer identifier of the receiver of the packet. 32-bit in IPv4 and is increased to 128-bit in IPv6.
Fields that have the same functionality but their names were changed
Total Length	Payload Length	Indicates the length of the IP packet. In IPv4, the length includes both the IP header and the data. In IPv6, the length includes the data plus any extension headers but does not include the main IP header.
Time to Live	Hop Limit	Both fields have the same function. They ensure that packets do not loop around the network indefinitely.
Protocol	Next Header	Indicates the protocol being transported in the payload portion.
DSCP+ECN	Traffic Class	Both protocols are used for traffic classification and marking. Nowadays, they use the 6-bit Differentiated Services technique (DSCP).
Fields that exist in IPv4 and have been removed from IPv6
Internet Header Length（IHL)	None	This field is used in IPv4 cases when the header is variable length. It is not needed in IPv6 because the v6 header is fixed-length 40 bytes.
Fragment Offset	None	These fields are used when fragmenting IPv4. In IPv6, only the packet source performs fragmentation using the Fragmentation extension header.
Header Checksum	None	The designers of IPv6 decided that this field is redundant and no longer necessary because there are checksum fields in the upper-layer protocols.
Options	None	Options are now handled using the extension headers in IPv6, so this field is unnecessary.
Fields that are new in IPv6 and do not exist in IPv4
None	Flow Label	A new field in IPv6 identifies that a packet is part of a sequence and must be handled the same way as the entire traffic flow.

IPv4 vs IPv6 DNS

What is DNS?

DNS is the acronym used for Domain Name System. A primary purpose of DNS is to translate IP addresses into hostnames (alphabetic names) inside a local network and vice versa. DNS primarily aims to translate IP addresses into hostnames (alphabetic names inside a local network and vice versa.) This IP translation allows users to have a better online experience.

For a simple example, our company OPTCORE’s hostname is optcore.net. One of the IPv4 addresses associated with optcore.net is 172.67.74.226. DNS for IPv4 and IPv6.

IPv4 vs IPv6 DNS

Two types of lookup zones are used in DNS: Forward Zone and Reverse Zone.

Forward lookup zones translate hostnames to IP addresses, while reverse lookup zones translate IP addresses to hostnames. In IPv4, forward lookup areas are represented by “A records.” An “A record” can only hold a 32-bit IP address. Since IPv6 addresses are 128-bit, DNS needed a solution to accommodate larger IP addresses.

One such solution is the “AAAA” record. The “AAAA” record is a simple extension of the “A” record. Since the IP address is expanded 4 times from 32 bits to 128 bits, the resource record is extended from “A” to 4 “A.” “AAAA” is used to indicate the correspondence between domain names and IPv6 addresses and does not support address hierarchy.

Reverse zone lookups convert hostnames to IP addresses. The IPv6 reverse resolution record is a “PTR” like IPv4.

Benefits of IPv6 over IPv4

• Routing efficiency: IPv4 headers are more complex, which may slow down data processing and routing. IPv6 has a simpler header structure than IPv4, simplifying the task for routers.
• Advantage: IPv6 includes stronger, more reliable support for QoS features, which helps increase Web site traffic and improve the quality of audio and video on the page.
• Improved Security: IPv6 has some enhanced security built in. IPv6 provides security such as data authentication, data encryption, and more. Here, Internet connections are more secure.
• Improved support for mobile devices: IPv6 is more compatible with mobile networks than IPv4.
• High Load: IPv6 allows for a larger payload than IPv4.
• Ample address space: Less than 1% of networks use IPv6, while 99% still use IPv4.

How to convert IPv4 to IPv6

There are several strategies for switching from IPv4 to IPv6.

• Dual Stacking: Dual-stack technology allows devices to utilize IPv4 and IPv6 concurrently, ensuring compatibility between the protocols and enabling a seamless migration process. 
• Tunneling: This method allows IPv6 users to send data through an IPv4 network to reach other IPv6 users.
• Network Address Translation (NAT): NAT helps devices using different versions of IP addresses (IPv4 and IPv6) communicate by translating the addresses to understand each other.

FAQ

Q. Is IPv6 better than IPv4?
A. Yes, IPv6 is better than IPv4 because IPv6 is more advanced and has more features than IPv4.

Q: Can IPv4 and IPv6 coexist?
A: Yes, IPv4 and IPv6 can coexist in the same network. In this case, it is called a dual-stack network, where devices support IPv4 and IPv6 protocols and can handle IPv4 and IPv6 traffic through their respective protocol stacks.

Q. If I deploy IPv6, will all my systems be exposed to the public IPv6 Internet?
A. No, deploying IPv6 does not automatically expose all systems to the public IPv6 Internet. For example, in an IPv4 network, an IPv6 firewall can be deployed to control access and enforce filtering policies. By configuring the firewall to allow only outgoing traffic (similar to an IPv4 NAT setup), you can control the level of host exposure in an IPv6 network.

Q. Should I use IPv6 at home?
A. Yes, it can be beneficial to use IPv6 at home, as it offers many benefits over IPv4. If your ISP supports IPv6, and your devices and router are compatible, it’s worth considering shifting to IPv6.

However, if your current setup with IPv4 is working without any issues, and you don’t need the additional address space at home, the transition to IPv6 might not be necessary.

Conclusion

Through this article, you have gained an initial understanding of IPv4 and IPv6, including the concepts of the two protocols, the differences, and how to transition from IPv4 to IPv6, among other things crucial for you.

The proliferation of the Internet and the growing demand for IP addresses have made IPv6 an essential element of our digital presence. The future of IPv6 is optimistic, as it offers the potential to improve the security, performance, and adaptability of our communications.

However, IPv6 is unlikely to replace IPv4 anytime soon completely, so we don’t have to worry about failing to keep up with the technology’s iterations.

Read more

• How To Set a Static IP Address
• What is Optical Transceiver: A Beginner Guide (2024)

Reference

• IPv4 vs IPv6 – Understanding the differences
• Difference Between IPv4 and IPv6
• IPv4 DNS Vs. IPv6 DNS – Implementation and Predictions