I’m fortunate enough to have an ISP that provides IPv6, and a cable modem that supports it. While there’s a router built into the modem, I have an Apple Airport Extreme that I’d rather use because it–and many of my devices–support 802.11ac, while the cable modem’s wifi does not. Despite that, I’m forced to use the cable modem’s routing, and put the Airport into bridge mode, otherwise nothing connected to the Airport receives an IPv6 address.
The issue is utterly perplexing, because in bridge mode, the Airport does distribute both IPv4 and IPv6 addresses. If the Airport is handling routing–failing to distribute IPv6 addresses–I can connect another device directly to the cable modem and receive an IPv6 address without fail. So, the network exists in this annoying split state, where the cable modem handles routing and the router only handles wifi.
If anyone’s wondering why I care so much about IPv6, the answer is simple: most of my neighbors seem not to be using that side of the network. In the evenings and on weekends, the IPv4 half of our connection can slow considerably compared to its IPv6 counterpart. Fortunately, Netflix is fully available over both (goodbye buffering) as are an ever-increasing number of sites and services.