What is IPv4 Exhaustion?

IPv4 Exhaustion Calls for Carrier-grade NAT (CGNAT) and IPv6 Migration

IPv4 exhaustion, a problem resulting from the unanticipated popularity of the internet at the time of its creation, is the depletion of available IPv4 addresses for connected devices. Beginning in the early 1980s, each computer was assigned a unique public IP address consisting of four groups of eight bits, or 32 bits total. This standard, called IPv4, resulted in 4,294,967,296 different values. At the time, this supply seemed inexhaustible, but by the late 1980s, it was already clear that even a pool this large would inevitably run out. With the rapid expansion of internet users, always-on devices, mobile devices, and IoT, that time is now upon us. The free pool of IPv4 addresses managed by regional internet registries (RIR) have been fully allocated. The American Registry of Internet Numbers (ARIN), the regional internet registry (RIR) serving the U.S., Canada, and several Caribbean and North Atlantic islands, was fully depleted in September 2015. Réseaux IP Européens Network Coordination Centre (RIPE NCC), the RIR serving Europe, West Asia, and the former U.S.S.R., reached IPv4 exhaustion in November 2019. Other RIRs, APNIC (Asia Pacific) and LACNIC (Latin America) have also reached IPv4 exhaustion beginning in 2011.

Beginning in the 1990s, a series of new technologies were developed to address the looming problem of IPv4 exhaustion. IPv6, a successor to IPv4, went live globally in June 2012. Using a 128-bit address, IPv6 offers a pool dozens of orders of magnitude larger than IPv4 and is for practical purposes inexhaustible. However, IPv6 is not backward compatible with IPv4, making direct communication between the two impossible without some intervening technology. As a result, IPv6 migration can be a challenging process.

In the meantime, IPv4 exhaustion poses critical problems for internet users and service providers that depend on IPv4. Any shortage or delay in IP address assignment to a device from a network can result in the degradation or even outright denial of service to the subscribed device. With extensive investments in IPv4, organizations also need to be able to extend the value of their existing infrastructure while making a staged IPv6 migration over time. One approach, network address translation (NAT), involves remapping an IP address space into another, making it possible for a single IPv4 address to be used for an entire private network rather than having a separate IPv4 address assigned to each device within the network. Carrier-grade NAT (CGNAT), also known as large-scale NAT (LSN), serves a similar function on a carrier level, making it possible for a small pool of public IP addresses to be shared across a large number of end sites.

How A10 Networks Addresses IPv4 Exhaustion

A10 Networks helps customers address IPv4 exhaustion through both CGNAT and IPv6 migration. The A10 Networks Thunder® Carrier Grade Networking (CGN) solution enables simple, cost-efficient CGNAT with high availability and superior performance to ensure critical applications and services are available and reliable while extending the life of existing IPv4 investment. By enabling translation and tunneling between IPv4 and IPv6 networks, the A10 Networks solution also enables a smooth, managed migration to IPv6 infrastructure.

IPv4 Exhaustion Articles and Assets of Interest


Uber Solves IPv4 Exhaustion at Scale (Case Study)

Uber maximizes finite IPv4 addresses while simplifying service creation and troubleshooting with A10 Networks Thunder CGN for large-scale network address translation.

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