1. Introduction
In the digital area, the Internet is the foundation of global life and economy, and all networked devices need a unique IP (Internet Protocol) address, as their “identity card” to communicate. IPv4 is an earlier version of IP address while IPv6 is the latest version. In short, IP address helps devices around the world find each other correctly and then transmit data. So, IPv4 vs IPv6, what are the specific differences between them? Why do we need to transit from IPv4 to IPv6? This article will analyze the characters, development status of IPv4 and IPv6.
2. Overview of IPv4
(1) Definition and Development
IPv4 (Internet Protocol Version 4) is a widely used IP protocol currently. Since its inception in 1981, it has become the basis of global Internet communication, offering unique addresses for devices, so that data can be transmitted accurately.
(2) Address Format
IPv4 adopts 32-bit addresses, typically represented in dotted decimal format, “192.168.1.1” for example. It can provide approximately 4.3 billion unique addresses in total.
(3) Address Classification
IPv4 addresses are divided into five classes: A, B, C, D, E. In these, Classes A, B, and C are used for general networking, Class D is designed for multicast, and Class E is reserved for experiments.
3. Overview of IPv6
(1) Definition and Development
IPv6 (Internet Protocol Version 6) is a new generation internet protocol, designed to solve the exhaustion of IPv4 addresses. In 1998, IETF proposed IPv6, providing a larger address space and optimizing network performance, security and management to adapt to the future development of the Internet.
(2) Address Format
IPv6 uses 128-bit addresses, represented in hexadecimal and separated by colons, such as “2001:db8::8a2e:370:7334”. It offers 2¹²⁸ addresses, far more than IPv4.
(3) Address Classification
Unicast. Used for one-to-one communication between devices. For instance, computers request web content from servers, meanwhile the server responds only to the specific request.
Multicast. Support one-to-many data transmission. In online streaming, all views can receive the same data.
Anycast. The same address can be assigned to multiple devices, then data will be sent automatically to the nearest target, improving efficiency. When you access a website, you are next directed to the closet server to speed up loading times.
4. Transition Technologies
Since IPv4 and IPv6 can’t interoperable directly, networks require some transition technologies to ensure a smooth upgrade The key methods include Dual Stack, Tunneling, NAT/DNS
(1) Dual Stack
Concept. Devices and networks run both IPv4 and IPv6, and select the suitable protocol based on the target.
Characteristics.
- Supports both IPv4 and IPv6 without protocol translation, ensuring high communication efficiency.
- Requires network devices to support dual protocols, enhancing management complexity.
Applications. Widely used in ISPs, data centers and enterprise networks, to facilitate IPv6 migration.
(2) Tunneling
Concept. Encapsulates IPv6 data packets in IPv4 network, or encapsulates IPv4 data packets in IPv6 network, allowing networks running different IP protocols to communicate with each other.
Common Tunneling Technologies.
- Encapsulates IPv6 data packet within IPv4, automatic configuration, ideal for dynamic addressing environments.
- Teredo. Applicable for devices behind NAT, enabling IPv6 to traverse IPv4 networks.
- GRE, IP-in-IP. Used in enterprises and ISP networks, supporting customized tunnel configurations.
Advantages. No need to upgrade all network devices, enabling a gradual IPv6 deployment.
Disadvantages. Increases encapsulation cost, which may impact network performance.
(3) NAT / DNS
https://www.techtarget.com/searchnetworking/definition/domain-name-system
Concept. Enables IPv6 devices to access IPv4 resources, suitable for IPv6-only networks.
NAT, namely, Network Address Translation. By translating addresses, NAT maps IPv6 addresses to IPv4 addresses, allowing IPv6 devices to access IPv4 serves. NAT enables multiple devices on a local network to share a single public address, thus helping protect the limited IPv4 address space. IPv6 doesn’t need NAT, so it reduces translation overhead, while expanding the address space from 32 bits to 128 bits.
DNS, namely, Domain Address Translation. It translates domain names into IP addresses. In IPv6-only networks, DNS generates a synthetic IPv6 address, and access IPv4 servers via NAT.
Advantages. Ideal for IPv6-only networks, and no need for user-side configuration modification.
Disadvantages. Only supports IPv6’s access to IPv4, and reverse communication is limited.
| Technologies | Affect | Applications | Advantages & Disadvantages |
| Dual Stack | Run both IPv4 and IPv6. | Networks gradually transitioning IPv6. | Great compatibility, but complex management. |
| Tunneling | Encapsulates data packets in IPv4/IPv6 networks. | Networks crossing networks with different protocols. | No need to change the underlying network, but increases encapsulation overhead. |
| NAT / DNS | Allow IPv6-only devices to access IPv4 resources. | IPv6-only networks. | Suitable for IPv6-only development direction, but only supports one-way communication. |
5. IPv4 vs IPv6
(1) Main differences
| Feature | IPv4 | IPv6 |
| Address Length | 32-bit, approximately 4.3 billion addresses. | 128-bit, approximately 340 undecillion addresses. |
| Address Format | 4 decimal numbers, separated by dots. | 8 hexadecimal numbers, separated by colons. |
| Address Allocation | Static and dynamic allocation (DHCP). | Supports Stateless Address Auto Configuration (SLAAC). |
| Built-in Security | None, requires additional configuration. | IPsec support. |
| QoS | Limited flexibility. | Efficient and precise traffic management. |
| Routing Efficiency | Larger routing tables so complex management. | Smaller routing tables hence efficient management. |
| Compatibility | Widely compatible, supports almost all devices. | New protocol, needs transition technologies for compatibility. |
(2) Advantages and Disadvantages of IPv4
| Advantages | Disadvantages |
| Mature & Stable. Widely used with mature technology. High Compatibility. Supports almost all devices, and easy to connect with existing infrastructure. | Limited Addresses. Only provides approximately 4.3 billion addresses, insufficient for demand. Allocation Challenges. Limited addresses so complex management. No Built-in Security. Requires additional security protocols. |
(3) Advantages and Disadvantages of IPv6
| Advantages | Disadvantages |
| Vast addresses. Offers a huge address space, thus solving the address shortage problem. Built-in Security. Includes encryption and authentication, enhancing security. Automatic Configuration. Supports devices in getting addresses automatically, simplifying setup. Simplified Routing. Concise routing tables enable higher efficiency. | Compatibility Issues. Not compatible with IPv4.requiring transition technologies. Complex Deployment. Need time and resources for upgrading. Learning Time. New technology and address format require adaptation. |
(4) Why IPv4 Is Still in Use?
Compatibility. IPv4 is widely used, consequently needing time and resources for replacement.
Cost & Complexity. IPv6’s employment involves high costs and complex technologies.
Address Management. Through NAT, IPv4’s short-term address shortages can be alleviated.
Transition Issues. IPv4 and IPv6 are not directly compatible, and transitioning requires additional technologies.
Existing Demands. Various devices and applications still can run properly within IPv4.
6. Summary
IPv4 and IPv6 are two core protocols in global internet communication. IPv4 is stable with great compatibility, but addresses are limited. In contrast, IPv6 offers a larger address space and built-in security, meeting future development. Although IPv6 is becoming more popular, IPv4 is still dominant. Furthermore, the two protocols need to be used in parallel during the transition process.
IPv4 guarantees the stable operation of networks, while IPv6 provides a solution for future network expansion. As the number of devices grows, understanding their differences and transition technologies is crucial to the continued development of the network.
