In total, Akamai estimates these 800+ million IPv4 addresses represent more than 1 billion web users, as multiple individuals may be represented by a single IPv4 address when accessing through a firewall or proxy server. On the other hand, a single user may be associated with multiple IPv4 addresses, due to multiple connected devices.
Unique IPv4 Addresses
The number of unique IPv4 addresses seen by Akamai grew about 12 million from the third quarter. Going forward, Akamai anticipates this growth will slow or decline as it did in the previous two quarters. The decline will likely be driven by the implementation of carrier-grade network address translation (CGN) solutions that aim to conserve limited IPv4 address space and by increasing support for native IPv6 connectivity.
When looking over the entire year, Brazil was the only country among the top 10 countries to see a double-digit percentage increase. Seven other countries in the top 10 saw increases, with South Korea's 8.4 percent gain leading the pack. Of the two countries to see year-over-year declines, the U.S. decreased 8.2 percent while Italy decreased 5.2 percent. These declines are indicative of possible changes to IP address management practices, increases in IPv6 adoption or updates to the underlying database used by Akamai for IP address geolocation.
In total, 70 percent of countries/regions around the globe had higher unique IPv4 address counts than the previous year. In all, 27 countries saw strong annual growth rates of more than 50 percent.
As Regional Internet Registries (RIRs) allocated pools of IPv4 address space to organizations within their respective territories, available IPv4 address space was depleted. The size of available IPv4 address pools at each RIR showed a range of depletion rates. The most severe was ARIN's 49 percent rate of depletion, accounting for 7.2 million IPv4 addresses. LACNIC, APNIC and AFRINIC had more moderate declines, all of which delegated roughly 7 percent of their available IPv4 address pools. AFRINIC is the only remaining RIR with a substantial pool of available IPv4 addresses remaining.
As IPv4 address space becomes increasingly scarce, it's fascinating to examine the cost per IPv4 address in the private transfer market. According to a data set shared by a single address broker, IPv4 transfers in the fourth quarter ranged between $8.00 USD and $13.57 USD per address -- a slight decline from the third quarter.
Starting with the Third Quarter, 2013 State of the Internet Report, Akamai included IPv6 adoption insights into the report. To calculate the percentage of requests made to Akamai over IPv6, the number of content requests made over IPv6 was divided by the total number of requests to Akamai, only for customer Web properties that have enabled Akamai edge delivery via IPv6. In compiling these figures, a minimum of 90 million total requests during the fourth quarter of 2014 was required to qualify.
Europe continued its IPv6 domination in the fourth quarter. Of those top 10 countries with the highest levels of IPv6 adoption, 8 were European. Belgium maintained its lead in the fourth quarter, with 32 percent of content requests made over IPv6. The next closest country was Germany, which had fewer than half the percentage of Belgium. Only two non-European countries cracked the top 10. These countries were the U.S. and Peru -- both of which had strong quarterly gains of 12 percent and 11 percent, respectively. Of those countries in the top 10, Romania was the only one to have a quarterly decline after dropping 5.5 percent.
IPv6 adoption was led by cable and wireless providers like Verizon Wireless and Brutele, both of which saw more than half of their content requests to Akamai over IPv6. Other leading IPv6 providers included Telenet, which had 49 percent of its request over IPv6; German carriers such as Kabel Deutschland, Kabel BW and Unitymedia; U.S. providers such as T-Mobile and Comcast; and Greek provider Hellas On Line.
For more insight into IPv6 adoption, see the IPv6 Adoption Trends by Country and Network data visualization and download the full Fourth Quarter, 2014 State of the Internet Report .