Skip to main content

IPv4 Residual Deployment via IPv6 - A Stateless Solution (4rd)
RFC 7600

Approval announcement
Draft of message to be sent after approval:


From: The IESG <>
To: IETF-Announce <>
Cc: RFC Editor <>,
    softwire mailing list <>,
    softwire chair <>
Subject: Document Action: 'IPv4 Residual Deployment via IPv6 - a Stateless Solution (4rd)' to Experimental RFC (draft-ietf-softwire-4rd-10.txt)

The IESG has approved the following document:
- 'IPv4 Residual Deployment via IPv6 - a Stateless Solution (4rd)'
  (draft-ietf-softwire-4rd-10.txt) as Experimental RFC

This document is the product of the Softwires Working Group.

The IESG contact persons are Brian Haberman and Ted Lemon.

A URL of this Internet Draft is:

Ballot Text

Technical Summary:

This document specifies a stateless softwire IPv4 over IPv6 Migration
Solution called 4rd. Using the 4rd solution IPv4 packets are
transparently carried across IPv6 networks (reverse of 6rd [RFC5969]
in which IPv6 packets are statelessly tunneled across IPv4 networks).
While IPv6 headers are too long to be mapped into IPv4 headers, so
that 6rd requires encapsulation of full IPv6 packets in IPv4 packets,
IPv4 headers can be reversibly translated into IPv6 headers in such a
way that, during IPv6 domain traversal, UDP packets having checksums
and TCP packets are valid IPv6 packets. IPv6-only middle boxes that
perform deep-packet- inspection can operate on them, in particular for
port inspection and web caches.

Working Group Summary:

The working group had active discussion on the draft and the current
text of the draft is representative of the consensus of the working

Document Quality:

The document has received adequate review. The Document Shepherd has
no concerns about the depth or breadth of these reviews. Certain
aspects of the scheme have also been reviewed by the 6man working
group due to the concerns with the address format. These concerns were
successfully resolved.


Suresh Krishnan is the document shepherd. Ted Lemon is the responsible

RFC Editor Note:

This document is one of a set of five softwire documents that should be published with sequential RFC numbers.  The numbering should be in the following order:


RFC Editor Note