Transition Mechanisms for IPv6 Hosts and Routers (RFC1933)
Original Publication Date: 1996-Apr-01
Included in the Prior Art Database: 2019-Feb-12
Internet Society Requests For Comment (RFCs)
R. Gilligan: AUTHOR [+1]
This document specifies IPv4 compatibility mechanisms that can be implemented by IPv6 hosts and routers. [STANDARDS-TRACK]
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.
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.
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.
The following terms are used in this document:
Types of Nodes
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.
A host or router that implements both IPv4 and IPv6.
A host or router that implements IPv6, and does not implement IPv4. The operation of IPv6-only nodes is not addressed here.