IETF RFC 6519 PDF

Dual-Stack Lite is a solution to offer both IPv4 and IPv6 connectivity to customers that are addressed only with an IPv6 prefix. Dual-Stack Lite requires pre-configuration of the Dual-Stack Lite Address Family Transition Router (AFTR) tunnel information on the Basic Bridging BroadBand (B4) element. In many networks, the customer profile information may be stored in Authentication, Authorization, and Accounting (AAA) servers, while client configurations are mainly provided through the Dynamic Host Configuration Protocol (DHCP). This document specifies a new Remote Authentication Dial-In User Service (RADIUS) attribute to carry the Dual-Stack Lite AFTR tunnel name; the RADIUS attribute is defined based on the equivalent DHCPv6 OPTION_AFTR_NAME option. This RADIUS attribute is meant to be used between the RADIUS server and the Network Access Server (NAS); it is not intended to be used directly between the B4 element and the RADIUS server.