Is it possible to extend IPv6?

The IPv6 Hop-by-Hop Options and Destination Options Extension Headers have historically faced challenges in deployment due to a lack of router support coupled with concerns around potential for denial-of-service attacks. However, there has been a renewed interest within the standards community both in simplifying their processing, and in using these extension headers for new applications. Through a wide-scale measurement campaign, we show that many autonomous systems in both access networks and the core of the Internet do permit the traversal of packets that include options, and that the path traversal currently depends on the type of network, size of the option and the transport protocol used, but does not usually depend on the type of included option. This is an encouraging result when considering the extensibility of IPv6. We show that packets that include an extension header can also impact the function of load balancing network devices, and present evidence of equipment mis-configuration, noting that a different path to the same destination can result in a different traversal result. Finally, we outline the current deployment challenges and provide recommendations for how extension headers can utilise options to extend IPv6.