Request for Comments: 3162 - RADIUS and IPv6 Request for Comments: 4779 - ISP IPv6 Deployment Scenarios in Broadband Access Networks Request for Comments: 5072 - IP Version 6 over PPP Request for Comments: 5172 - Negotiation for IPv6 Datagram Compression Using IPv6 Control Protocol
If you're using a broadband connection and you're having problems retreiving your mail or viewing graphics online then try lowering your mtu.