In this chapter we present case studies of IPv6 in the backbone. First we look at the core 6NET backbone and the NRENs that were connected to it before the core network was decommissioned in January 2005.

Next, we detail case studies of IPv6 deployment by the NRENs themselves inside their own country backbone networks. The most common method to introduce IPv6 services into IPv4 networks will be through dual-stack networking. This complements the backbone transition and pushes the issue of deployment to the edge, e.g. to the universities.

In the timeframe of 6NET, many NRENs migrated to dual stack; the specific experiences of SURFnet, Funet and Renater are reported here.