Technical Summary
This document draws on several years of operational experience to
update RFC 6724, defining the concept of "known-local" ULA prefixes
that enable ULA-to-ULA communications within fd00::/8 to become
preferred over both IPv4-IPv4 and GUA-to-GUA for local use. The
document defines the means by which nodes can both identify and
insert such prefixes into their address selection policy table. It
also clarifies the mandatory, unconditional requirement for support
for Rule 5.5 and demotes the preference for 6to4 addresses. These
changes to default behavior improve supportability of common use
cases, including automatic / unmanaged scenarios, and makes
preference for IPv6 over IPv4 consistent in local site networks for
both ULA and GUA prefixes. It is recognized that some less common
deployment scenarios may require explicit configuration or custom
changes to achieve desired operational parameters.
Working Group Summary
The document has been actively discussed in the WG mailing list and
during 6MAN sessions, with many participants expressing their opinions,
comments and suggestions.
Document Quality
There are two implementations of the proposed changes to RFC6724:
- Android implements the proposed changes to insert "known-local" ULAs
into the policy table: https://r.android.com/3046000
- The authors created a proof-of-concept implementation, available at
https://github.com/jeremy-duncan/raio_ula
Those details are also reported in The "Implementation Status" section of the
document.
Personnel
The Document Shepherd for this document is Jen Linkova. The Responsible
Area Director is Erik Kline.