Using standard, universally accepted data transfer protocols is essential for exchanging information on the internet. The huge number of subscribers and both stationary and mobile devices must be identified, which is why IPv4 and the more advanced IPv6 protocols are used. When a request is sent, identification takes place via the IP address, and then a connection is established between the hosts.
What Are IPv4 and IPv6?
According to standard conventions, a device’s IP address in IPv4 consists of four numbers separated by periods. When data is sent, the packet header always contains both the sender and recipient addresses, and routing decisions are made based on this information.
The differences between IPv4 and IPv6 are significant. IPv4 was first implemented back in 1983 and uses 32 bits for addressing, yielding a maximum address space of around 4.3 billion end devices.
However, as digital technology expanded rapidly, this address space became insufficient. Toward the end of the last century, the IPv6 protocol was actively developed. It uses a 128-bit address space, making the maximum number of client devices practically unlimited, at least for the foreseeable future.
IPv4 Features
Despite the differences between IPv4 and IPv6, both protocols remain in active use on today’s data networks. The main characteristics of IPv4 include:
- Origins in ARPANET: IPv4 was first used in the ARPANET. Today, it still underpins the internet and is considered the primary protocol.
- Address Format: Addresses are binary numbers (0 or 1), but for ease of use, they are typically expressed as four decimal, three-digit numbers separated by periods.
- 32-Bit Address Space: This is split into four bytes, giving a maximum of 2^32 possible IP addresses.
When IPv4 was designed, 4.3 billion addresses were considered more than enough. However, it quickly became clear that this limitation was too restrictive.
IPv6 Features
IPv6 is an improved version of IPv4 and is being actively rolled out across the internet. Key features include:
- 128-Bit Address Space: The theoretical maximum number of IP addresses is 2^128—an extremely large number that is hard to comprehend.
- Address Segmentation: The first 64 bits carry the network address information for routing, while the remaining 64 bits identify the host’s network interface.
- Notation: Instead of periods, IPv6 addresses use colons to separate sections, and the addresses themselves use hexadecimal notation.
Visually, IPv4 addresses are in a 32-bit format (often displayed as four dotted decimal sections), whereas IPv6 uses a 128-bit format (often displayed as eight groups of hexadecimal digits separated by colons).
Key Differences Between the Protocols
The primary difference between IPv4 and IPv6 is the size of the address space. The newer protocol allows for an enormous number of devices to be uniquely identified, with no foreseeable limits. Several other fundamental differences also merit consideration:
Differences in Data Security
When IPv4 was developed, digital technology was still at an early stage, and security was not a major focus. Most security measures were left to application-level software. IPv6, on the other hand, was designed with a fundamentally different approach:
- End-to-End Encryption: IPv6 supports this feature to ensure secure connections.
- IPsec Extension: Encrypts the data channel using cryptographic protocols.
- AH and ESP Protocols: Check and maintain data integrity and authenticity within the IPv6 stack.
- IKE Extension: Handles security attribute configuration when exchanging data between devices.
While IPsec can also be used in IPv4, it is optional. With IPv6, IPsec is one of the core components, making it clearly superior in terms of information security.
Packet Header Compression
In IPv4, the packet header contains a 32-bit address. Additional service-related information inflates the header to around 40 bytes because there are 13 mandatory fields. As a result, parsing and routing these packets consumes considerable resources.
IPv6 uses only 8 fields in the packet header, reducing it to about 20 bytes. This slimmer header makes data transfer more efficient and faster, easing the burden on routing and improving overall network throughput.
Reduced Need for NAT
With IPv4, the main difficulty is the limited number of available addresses. NAT (Network Address Translation) is often used to make one IP serve multiple devices—for example, a home or office network can have internal (private) IPs behind a router that holds one external IP address visible to the internet.
Thanks to its vast address range, IPv6 largely eliminates the need for NAT. Every device can receive an IP address directly visible online—a major advantage for systems that require such addressing. It boosts speed and does away with extra hardware in the communication path, while IPv6’s built-in security features compensate for the lack of NAT-based protection.
No Geographical Restrictions
Because of the massive address space, there is no regional binding of address ranges in IPv6. You can use any available IP anywhere in the world. This means each user can effectively have a large number of available IPv6 addresses.
High QoS Performance
Both IPv4 and IPv6 can leverage QoS (Quality of Service), but the structure of packet headers differs. In IPv4, the DS field is 8 bits and classification occurs at intermediate nodes.
With IPv6, packets are processed much faster thanks to a 20-bit field in the header. This larger field improves QoS by enabling more efficient traffic handling.
Convenient Automatic Protocol Configuration
When IPv6 was developed, an important feature was introduced: devices can automatically obtain an IP address and communicate it to nearby devices. This capability allows for “stateless” address autoconfiguration, with neighbor discovery as a potential complement (or even alternative) to DHCP in the future.
Why the Transition to IPv6 Is Inevitable
The constantly growing number of network-connected devices and the inherent address limitations of IPv4 make a switch to IPv6 unavoidable. Over 20% of internet users already have some access to IPv6, and this share is set to rise. More providers are offering IPv6 support alongside their standard IPv4 service.
For IPv4 to remain serviceable, NAT must be used—an interim solution that will persist only until large-scale adoption of IPv6. Methods exist to translate IPv6 addresses to IPv4 ones, but they are neither optimal nor fast.
In summary, IPv6 has been around for more than a decade but is not yet universally adopted. Beyond the advantages listed above, the new technology supports multipath data transmission, packet fragmentation, excellent compatibility with mobile networks, and higher effective payload capacity.
If you have the technical means to switch to IPv6, it’s best to do so sooner rather than later. Switching protocols is inevitable, and the benefits of IPv6 become apparent almost immediately. With each passing day, more devices support the new addressing and exchange data using IPv6.