IPv6 Explained: What It Is and Why It Matters
The Scarcity of IPv4 and the Rise of IPv6
The available pool of IPv4 addresses for use on the public Internet is dwindling rapidly. This scarcity has driven up costs significantly, as evidenced by Microsoft’s $7.5 million acquisition of 666,624 IP addresses from Nortel during its 2011 bankruptcy proceedings.
This equates to a price exceeding $8 per individual IP address, highlighting the economic pressures stemming from limited availability.
Technical Limitations of IPv4 and the IPv6 Solution
Beyond the issue of scarcity, IPv4 also presents inherent technical challenges. IPv6 was developed as a direct response to these limitations, offering a more robust and scalable solution for the future of internet addressing.
The core purpose of IPv6 is to overcome the shortcomings of its predecessor and provide a sustainable infrastructure for continued internet growth.
Delayed IPv6 Deployment
Despite its advantages, the widespread adoption of IPv6 has faced considerable delays. A more proactive implementation of IPv6 in prior years would have facilitated a far less disruptive transition from IPv4.
Postponing the rollout has complicated the process and created challenges for a seamless migration.
Image Credit: Bob Mical on Flickr
A smoother transition would have minimized disruption and allowed for a more gradual integration of the new standard.
IPv4: Addressing Technical Limitations
The Internet Protocol version 4 (IPv4) was initially defined in 1980 utilizing 32-bit addresses. This allocation resulted in a total address space of 232, equating to 4,294,967,296, or 4.2 billion, unique addresses. While this quantity appeared substantial at the time of its inception, the current number of network-connected devices globally far surpasses this figure.
Furthermore, the proliferation of internet-connected devices is projected to continue its upward trajectory. Compounding this issue, a portion of the IPv4 address space is designated for specific, reserved purposes. Consequently, the number of publicly routable IPv4 addresses available for general use is less than the theoretical 4.2 billion.
The Scarcity of Public IPv4 Addresses
The existing pool of publicly routable addresses is demonstrably insufficient to provide a unique address for every device connected to the internet. Network Address Translation (NAT) has served as a crucial mitigating factor, particularly within home network environments.
Most home networks employ NAT through their routers. A single public IPv4 address, obtained from the Internet Service Provider (ISP), is then distributed among multiple devices within the home network. This is achieved by establishing a local area network (LAN), where each device receives a private, local IP address.
However, this approach introduces complexities when hosting server software and necessitates the configuration of port forwarding.
Potential Solutions and Their Drawbacks
Carrier-grade NAT represents one proposed solution. This would involve placing all users of an ISP on a local network managed by that ISP. The ISP would then implement NAT, mirroring the functionality of a home router.
Under this model, individual users would not possess publicly routable IP addresses. This limitation would preclude the operation of certain server applications that require incoming connections.
Image Credit: Jemimus on Flickr
Addressing Limitations: The Solution of IPv6
The development of IPv6 began in 1995 as a proactive measure to prevent the eventual depletion of IPv4 addresses. IPv6 utilizes 128-bit addressing, allowing for a theoretical maximum of 2128 unique IPv6 addresses.
This translates to approximately 3.402 × 1038 possible addresses – a significantly greater quantity than IPv4 can provide.
Benefits Beyond Address Space
Beyond simply resolving the issue of IPv4 address exhaustion, the expansive address space of IPv6 introduces several key benefits.
Notably, the sheer volume of available addresses enables the possibility of assigning each internet-connected device a globally routable, public IP address.
This, in turn, would remove the need for Network Address Translation (NAT), which currently adds complexity to network configurations.
NAT introduces layers of indirection, and its elimination simplifies network architecture.
Image Credit: Justin Marty on Flickr
The Lingering Question of IPv6 Adoption
IPv6 was completed in 1998, over two decades ago. It’s reasonable to expect a resolution to the addressing issue by now, yet progress has been remarkably slow.
Despite its longevity, widespread implementation has faced significant hurdles. A portion of existing software remains incompatible with IPv6, although updates are continually being released to address this. Certain network infrastructure components may also lack IPv6 support.
Manufacturers sometimes prioritize the sale of new, IPv6-capable hardware over providing firmware updates for older devices. Furthermore, a number of websites still operate exclusively on IPv4, lacking both IPv6 addresses and corresponding DNS records.
Challenges Hindering Full Deployment
The process of testing, updating software, and replacing hardware has understandably not been a top priority for many organizations. Sufficient availability of IPv4 address space has allowed for deferral of IPv6 implementation.
However, the approaching depletion of the IPv4 address pool is intensifying the urgency of this matter. Currently, deployment is actively occurring, with a “dual-stack” approach facilitating a more seamless transition.
Modern operating systems are increasingly capable of utilizing both IPv4 and IPv6 addresses concurrently, which simplifies the upgrade process. This coexistence minimizes disruption during the shift to the new protocol.
- IPv6: The next generation Internet Protocol.
- IPv4: The current, but limited, Internet Protocol.
- Dual-Stack: A deployment method supporting both IPv4 and IPv6.
The continued availability of IPv4 has, in effect, delayed the inevitable. Now, with IPv4 exhaustion looming, the need for comprehensive IPv6 adoption is undeniable.