IPv6 Tunnel Discovery
Methods for discovering, and collecting information about, IPv6-in-IPv4 tunnels in the Internet.
Our work aims to develop non-invasive methods for discovering, and collecting information about, IPv6-in-IPv4 tunnels in the Internet at large. This can be useful for diagnostic and troubleshooting purposes, and also provides insight on the evolution and the present structure of the IPv6 Internet.
Tunnel discovery differs from other types of network discovery in that a tunneled network is made up of two distinct network layer topologies that interact, and the resulting network is thus a complex "overlay" of two forwarding planes, whose topology cannot be deduced simply by applying known methods to explore each plane separately. The problem is further complicated by the fact that tunnels are transparent to the IPv6 network layer.