Technical Summary
This document describes Path MTU Discovery for IP version 6. It is
largely derived from RFC 1191, which describes Path MTU Discovery for
IP version 4. It obsoletes RFC1981.
Working Group Summary
The 6MAN working started working on advancing the IPv6 core
specifications to Internet Standard at IETF93 July 2015. See:
https://www.ietf.org/proceedings/93/slides/slides-93-6man-3.pdf The
working group identified three RFCs to update (RFC2460, RFC4291, and
RFC1981) by incorporating updates from other RFCs and Errata, and
three to advance in place RFC4443, RFC3596, and RFC4941. After
further analysis, the w.g. decided to not reclassify RFC4941 at this
time.
The working followed the requirements in RFC6410 for advancing a Draft
Standard to Internet Standard. While RFC6410 describes how to handle
Errata, it doesn't say anything about Updated-By RFCs. The working
group, with the advice of our AD, incorporated the changes from the
the Updated-By RFC and verified there was interoperability of the
updates.
All of the Updated-By and errata were brought into the new draft in
small steps to allow thorough review of all of the changes. A summary
and link to diff from the previous version was sent to the mailing
list. All of the changes to each draft were also discussed in detail
at IETF94, IETF95, IETF96, and IETF97. All of the changes from
RFC1981 are summarized in Appendix B and are ordered by the Internet
Draft that brought the change in.
This document is an update to RFC1981 that was published prior to
RFC2119 being published. Consequently while it does use "should/must"
style language in upper and lower case, the document does not cite the
RFC2119 definitions. Since the changes in this update were very
limited, the w.g. concluded to not change any of this language.
A working group last call for moving this and the other two documents
to Internet Standard was started on 30 May 2016. Reviews were also
requested. Issues found during the last call and reviews were entered
into the 6MAN ticket system. These are now closed.
Document Quality
IPv6 is implemented on most platforms (hosts, routers, servers, etc.),
including proprietary and open source. A list of products that have
received the IPV6 Ready logo can be found at:
https://www.ipv6ready.org/db/index.php/public/?o=4
Most major ISP now support IPv6, as well as many mobile
operators.
Google’s IPv6 stats at
https://www.google.com/intl/en/ipv6/statistics.html show they are
seeing now about 15% of their overall user traffic is IPv6. Country
adoption is 29% in the US, Germany 27%, Finland 12%, Japan 14%, Brazil
11%. IPv6 users per AS can be found at
http://stats.labs.apnic.net/aspop
The University of New Hampshire InterOperability Laboratory (UNH)
analyzed the incorporated updates to insure they were implemented and
interoperable. No problems were found. Their report can be found at:
https://www.ietf.org/proceedings/95/slides/slides-95-6man-2.pdf
No MIB, Media, or other expert reviews are required.
Personnel
Document Shepherd: Ole Trøan
Responsible AD: Suresh Krishnan
IETF Last Call Summary
The document received lots of comments during IETF last call. The two main classes of issues that were brought up were transport layer related issues and security related issues. These issues have been fixed in the latest version of the document. There was also some concern raised about the effects of ICMPv6 filtering on the Internet on the PMTUD protocol. To address this, text was added to the introduction to describe the effects of ICMPv6 filtering.
RFC Editor Note
RFC Editor Note
OLD:
Alternatively, the retransmission could be done in immediate response
to a notification that the Path MTU was decreased, but only for the
specific connection specified by the Packet Too Big message, but only
based on the message and connection.
NEW:
Alternatively, the retransmission could be done in immediate response
to a notification that the Path MTU was decreased, but only for the
specific connection specified by the Packet Too Big message.