The next generation of protocols for the Internet is known as Internet protocol version 6 (IPv6). It represents a huge 96-bit increase over today’s IPv4 32-bit address space. This update is necessary to accommodate as many unique entities as there are grains of sand, and still operate in the traditional end-to-end manner. The migration to IPv6 is so far a rare, slow, and yet noteworthy event, something that occurs maybe once in the career of a professional involved in computer communications. This paper recounts the experiences of World IPv6 Day. Protocol-wise, perhaps the one comparable event in the past was the transition from the early network control program (NCP) to the transmission control protocol (TCP) in the early ‘80s.

Compared to that simple “flag day” transition, migration to IPv6 has required grappling with the sheer size of today’s Internet and the numerous deployed TCP/IP applications, which must continue working as before. A long coexistence period with both IPv4 and IPv6 protocols running simultaneously is expected, but the birth needs to be triggered. The first World IPv6 Day, on June 8, 2011, allowed major providers to experiment briefly and on a large scale with IPv6, learn lessons, and turn IPv6 back off. One year later, a similar event called World IPv6 Launch Day (not reported in this paper) turned IPv6 on permanently.

The authors put a significant amount of work into analyzing traffic at two different sampling points at the core and toward the edge of the Internet: specifically, a European Union (EU) Internet exchange point and the campus of the University of California, Berkeley, respectively.

The main findings show that (1) large and well-known IPv4 content providers were the main source of IPv6 traffic during the day to both sampling points, and (2) the Internet experienced a sustained increase in IPv6 traffic during the day, compared to the day before.

The interpreted encapsulation methods include 6in4 (a combination of manual methods such as protocol 41 and automatic methods such as the better-known 6to4), Teredo, and AYIYA (a well-known automatic tunneling protocol at SixXS).

The application-level protocols are sampled by their port numbers (via the file transfer protocol (FTP), secure shell (SSH), and so on) and, surprisingly enough, the analysis concludes it is not the hypertext transfer protocol (HTTP) that dominates, but the network news transfer protocol (NNTP), a once famous protocol for distributing “news.” Its appearance here is attributed to recent reuse of the protocol as a file-sharing tool in high-bandwidth networks.

The authors take great care--maybe unnecessarily--to avoid citing trademarks and brand names, keeping the list to a bare minimum.

This paper offers a detailed, systematic analysis, and is the first of its kind on this particular event. Additionally, a good number of relevant publications about this same event are referred to. It is a must-read for IPv6 enthusiasts.