Transition Mechanisms for IPv6 Hosts and Routers
RFC 1933
Document | Type |
RFC - Proposed Standard
(April 1996; No errata)
Obsoleted by RFC 2893
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---|---|---|---|
Authors | Erik Nordmark , Robert Gilligan | ||
Last updated | 2013-03-02 | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 1933 (Proposed Standard) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group R. Gilligan Request for Comments: 1933 E. Nordmark Category: Standards Track Sun Microsystems, Inc. April 1996 Transition Mechanisms for IPv6 Hosts and Routers Status of this Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Abstract This document specifies IPv4 compatibility mechanisms that can be implemented by IPv6 hosts and routers. These mechanisms include providing complete implementations of both versions of the Internet Protocol (IPv4 and IPv6), and tunneling IPv6 packets over IPv4 routing infrastructures. They are designed to allow IPv6 nodes to maintain complete compatibility with IPv4, which should greatly simplify the deployment of IPv6 in the Internet, and facilitate the eventual transition of the entire Internet to IPv6. 1. Introduction The key to a successful IPv6 transition is compatibility with the large installed base of IPv4 hosts and routers. Maintaining compatibility with IPv4 while deploying IPv6 will streamline the task of transitioning the Internet to IPv6. This specification defines a set of mechanisms that IPv6 hosts and routers may implement in order to be compatible with IPv4 hosts and routers. The mechanisms in this document are designed to be employed by IPv6 hosts and routers that need to interoperate with IPv4 hosts and utilize IPv4 routing infrastructures. We expect that most nodes in the Internet will need such compatibility for a long time to come, and perhaps even indefinitely. However, IPv6 may be used in some environments where interoperability with IPv4 is not required. IPv6 nodes that are designed to be used in such environments need not use or even implement these mechanisms. The mechanisms specified here include: Gilligan & Nordmark Standards Track [Page 1] RFC 1933 IPv6 Transition Mechanisms April 1996 - Dual IP layer. Providing complete support for both IPv4 and IPv6 in hosts and routers. - IPv6 over IPv4 tunneling. Encapsulating IPv6 packets within IPv4 headers to carry them over IPv4 routing infrastructures. Two types of tunneling are employed: configured and automatic. Additional transition and compatibility mechanisms may be developed in the future. These will be specified in other documents. 1.2. Terminology The following terms are used in this document: Types of Nodes IPv4-only node: A host or router that implements only IPv4. An IPv4-only node does not understand IPv6. The installed base of IPv4 hosts and routers existing before the transition begins are IPv4-only nodes. IPv6/IPv4 node: A host or router that implements both IPv4 and IPv6. IPv6-only node: A host or router that implements IPv6, and does not implement IPv4. The operation of IPv6-only nodes is not addressed here. IPv6 node: Any host or router that implements IPv6. IPv6/IPv4 and IPv6-only nodes are both IPv6 nodes. IPv4 node: Any host or router that implements IPv4. IPv6/IPv4 and IPv4-only nodes are both IPv4 nodes. Gilligan & Nordmark Standards Track [Page 2] RFC 1933 IPv6 Transition Mechanisms April 1996 Types of IPv6 Addresses IPv4-compatible IPv6 address: An IPv6 address, assigned to an IPv6/IPv4 node, which bears the high-order 96-bit prefix 0:0:0:0:0:0, and an IPv4 address in the low-order 32-bits. IPv4-compatible addresses are used by the automatic tunneling mechanism. IPv6-only address: The remainder of the IPv6 address space. An IPv6 address that bears a prefix other than 0:0:0:0:0:0. Techniques Used in the Transition IPv6-over-IPv4 tunneling: The technique of encapsulating IPv6 packets within IPv4 so that they can be carried across IPv4 routing infrastructures. IPv6-in-IPv4 encapsulation: IPv6-over-IPv4 tunneling. Configured tunneling: IPv6-over-IPv4 tunneling where the IPv4 tunnel endpoint address is determined by configuration information onShow full document text