6rd

This document specifies requirements for an IPv6 Customer Edge (CE) router. Specifically, the current version of this document focuses on the basic provisioning of an IPv6 CE router and the provisioning of IPv6 hosts attached to it. The document also covers IP transition technologies. Two transition technologies in RFC 5969's IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) and RFC 6333's Dual-Stack Lite (DS-Lite) are covered in the document. The document obsoletes RFC 6204.

The IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) provides both IPv4 and IPv6 connectivity services simultaneously during the IPv4/IPv6 coexistence period. The Dynamic Host Configuration Protocol (DHCP) 6rd option has been defined to configure the 6rd Customer Edge (CE). However, in many networks, the configuration information may be stored in the Authentication Authorization and Accounting (AAA) servers, while user configuration is mainly acquired from a Broadband Network Gateway (BNG) through the DHCP protocol. This document defines a Remote Authentication Dial-In User Service (RADIUS) attribute that carries 6rd configuration information from the AAA server to BNGs.

This document proposes an alternative IPv6 Rapid Deployment on IPv4 Infrastructures (6rd) deployment model to that of RFC 5969. The basic 6rd model allows IPv6 hosts to gain access to IPv6 networks across an IPv4 access network using 6-in-4 tunnels. 6rd requires support by a device (the 6rd customer edge, or 6rd-CE) on the customer site, which must also be assigned an IPv4 address. The alternative model described in this document initiates the 6-in-4 tunnels from an operator-owned Gateway collocated with the operator's IPv4 network edge rather than from customer equipment, and hence is termed "Gateway-initiated 6rd" (GI 6rd). The advantages of this approach are that it requires no modification to customer equipment and avoids assignment of IPv4 addresses to customer equipment. The latter point means less pressure on IPv4 addresses in a high-growth environment. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document is concerned with security vulnerabilities in IPv6-in- IPv4 automatic tunnels. These vulnerabilities allow an attacker to take advantage of inconsistencies between the IPv4 routing state and the IPv6 routing state. The attack forms a routing loop that can be abused as a vehicle for traffic amplification to facilitate denial- of-service (DoS) attacks. The first aim of this document is to inform on this attack and its root causes. The second aim is to present some possible mitigation measures. It should be noted that at the time of this writing there are no known reports of malicious attacks exploiting these vulnerabilities. Nonetheless, these vulnerabilities can be activated by accidental misconfiguration. This document is not an Internet Standards Track specification; it is published for informational purposes.

This document specifies an automatic tunneling mechanism tailored to advance deployment of IPv6 to end users via a service provider's IPv4 network infrastructure. Key aspects include automatic IPv6 prefix delegation to sites, stateless operation, simple provisioning, and service, which is equivalent to native IPv6 at the sites that are served by the mechanism. [STANDARDS-TRACK]

IPv6 rapid deployment on IPv4 infrastructures (6rd) builds upon mechanisms of 6to4 to enable a service provider to rapidly deploy IPv6 unicast service to IPv4 sites to which it provides customer premise equipment. Like 6to4, it utilizes stateless IPv6 in IPv4 encapsulation in order to transit IPv4-only network infrastructure. Unlike 6to4, a 6rd service provider uses an IPv6 prefix of its own in place of the fixed 6to4 prefix. A service provider has used this mechanism for its own IPv6 "rapid deployment": five weeks from first exposure to 6rd principles to more than 1,500,000 residential sites being provided native IPv6, under the only condition that they activate it. This document is not an Internet Standards Track specification; it is published for informational purposes.