Providers have started deploying and transitioning to IPv6. Several IPv4 service continuity mechanisms based on Address plus Port (A+P) [RFC 6346
] have been proposed for providing unicast IPv4-over-IPv6-only infrastructure, such as Mapping of Address and Port with Encapsulation (MAP-E) [RFC 7597
], Mapping of Address and Port using Translation (MAP-T) [RFC 7599
], and Lightweight 4over6 [RFC 7596
]. Also, [RFC 8114
] specifies a generic solution for the delivery of IPv4 multicast services to IPv4 clients over an IPv6 multicast network. For each of these mechanisms, DHCPv6 options have been specified for client configuration.
In many networks, user configuration information is stored in an Authentication, Authorization, and Accounting (AAA) server. AAA servers generally communicate using the Remote Authentication Dial In User Service (RADIUS) [RFC 2865
] protocol. In a fixed broadband network, a Broadband Network Gateway (BNG) acts as the access gateway for users. That is, the BNG acts as both a AAA client to the AAA server and a DHCPv6 server for DHCPv6 messages sent by clients. Throughout this document, the term "BNG" describes a device implementing both the AAA client and DHCPv6 server functions.
Since IPv4-in-IPv6 softwire configuration information is stored in a AAA server and user configuration information is mainly transmitted through DHCPv6 between the BNGs and Customer Premises Equipment (CEs, a.k.a., CPE), new RADIUS attributes are needed to propagate the information from the AAA servers to BNGs so that they can be provided to CEs using the existing DHCPv6 options.
The RADIUS attributes defined in this document provide the configuration to populate the corresponding DHCPv6 options for unicast and multicast softwire configurations, specifically:
"Mapping of Address and Port with Encapsulation (MAP-E)" [RFC 7597] (DHCPv6 options defined in [RFC 7598]).
"Mapping of Address and Port using Translation (MAP-T)" [RFC 7599] (DHCPv6 options defined in [RFC 7598]).
"Lightweight 4over6: An Extension to the Dual-Stack Lite Architecture" [RFC 7596] (DHCPv6 options defined in [RFC 7598]).
"Unified IPv4-in-IPv6 Softwire Customer Premises Equipment (CPE): A DHCPv6-Based Prioritization Mechanism" [RFC 8026].
"Delivery of IPv4 Multicast Services to IPv4 Clients over an IPv6 Multicast Network" [RFC 8114] (DHCPv6 options defined in [RFC 8115]).
The contents of the attributes defined in this document have a 1:1 mapping into the fields of the various DHCPv6 options in [RFC 7598
], [RFC 8026
], and [RFC 8115
]. Table 1
shows how the DHCPv6 options map to the corresponding RADIUS attribute. For detailed mappings between each DHCPv6 option field and the corresponding RADIUS attribute or field, see Appendix A
Table 1: Mapping between DHCPv6 Options and RADIUS Attributes
A RADIUS attribute for Dual-Stack Lite [RFC 6333
] is defined in [RFC 6519
This document targets deployments where a trusted relationship is in place between the RADIUS client and server.