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Internationalizing IPv6 Using 128-Bit Unicode
RFC 8369

Document Type RFC - Informational (April 2018) Errata
Last updated 2018-04-30
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RFC 8369
Independent Submission                                         H. Kaplan
Request for Comments: 8369                                128 Technology
Category: Informational                                     1 April 2018
ISSN: 2070-1721

             Internationalizing IPv6 Using 128-Bit Unicode


   It is clear that Unicode will eventually exhaust its supply of code
   points, and more will be needed.  Assuming ISO and the Unicode
   Consortium follow the practices of the IETF, the next Unicode code
   point size will be 128 bits.  This document describes how this future
   128-bit Unicode can be leveraged to improve IPv6 adoption and finally
   bring internationalization support to IPv6.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   This is a contribution to the RFC Series, independently of any other
   RFC stream.  The RFC Editor has chosen to publish this document at
   its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not candidates for any level of Internet Standard;
   see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2018 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   ( in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     1.2.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   4
   2.  The Need for 128-Bit Code Points  . . . . . . . . . . . . . .   4
   3.  Unicode IPv6 Addresses  . . . . . . . . . . . . . . . . . . .   6
     3.1.  Reserved Addresses  . . . . . . . . . . . . . . . . . . .   6
     3.2.  Multicast . . . . . . . . . . . . . . . . . . . . . . . .   7
     3.3.  IPv6 Routing  . . . . . . . . . . . . . . . . . . . . . .   7
   4.  Using Unicode IPv6 Addresses  . . . . . . . . . . . . . . . .   8
     4.1.  Uniform Resource Identifiers  . . . . . . . . . . . . . .   8
     4.2.  Address Allocation and Resolution . . . . . . . . . . . .   8
   5.  Summary . . . . . . . . . . . . . . . . . . . . . . . . . . .   9
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  11
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  11

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1.  Introduction

   Unicode [Unicode] is currently limited to 1,114,112 code points,
   encoded in various encoding formats (e.g., UTF-8, UTF-16, UTF-32).
   At the time of this document's publication, 136,755 code points have
   been allocated, with more already in the approval process.  Every
   year, more writing scripts, symbols, and emojis are added, while none
   are removed.  After consulting expert mathematicians, we have
   determined that the world will run out of code points someday in the

   While it might appear that the current rate of code point allocation
   gives us plenty of time to deal with the exhaustion problem, the
   Internet's history has shown that popular number spaces do not fill
   up linearly, but rather exponentially.  And once the size of a
   particular number space becomes entrenched, it takes decades to
   migrate to a larger one.  Therefore, the code point number space must
   be increased as soon as possible.

   The details for expanding the Unicode code point space are not
   covered in this document.  Such details need to be worked out between
   the IETF, ISO, the Unicode Consortium, and various gods.  We assume,
   however, that the code point space will need to grow dramatically,
   and there will continue to be a need for a fixed-length encoding
   scheme similar to UTF-32.  Naturally, the next size increment should
   go from UTF-32 to UTF-128, and thus the rest of this document follows
   this assumption.

   This new 128-bit Unicode code point space can be leveraged by the
   IETF to address one of the lingering issues with IPv6: there's not
   much left to standardize.  With the changes described in this
   document, the IETF will be kept busy for decades to come.  It also
   enables new features and market opportunities, to help the global
   economy.  This in turn will increase tax revenues for governments,
   which eventually may lead to increased funds for combating global
   warming.  Therefore, the ultimate goal of this document is to reduce
   global warming.

1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.  All other words SHOULD be interpreted as
   described by the Oxford English Dictionary OED [OED], which MAY be
   considered almost as authoritative for word definitions as the IETF.

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1.2.  Definitions

   UTF-128:  A fixed-length encoding for 128-bit Unicode.  It is
         implemented as an array of bytes in the same manner as legacy
         IPv6 addresses to avoid endianness issues.

   Short-Name Tag:  A short descriptive name for a Unicode character
         code point, surrounded by colons (:).  For example ":garfield:"
         represents the Unicode code point for the Garfield cat imoji.

   Emoji:  Pictographic symbol encoded in Unicode, used to express a
         general item, concept, or emotion.

   Imoji:  Pictographic symbol encoded in Unicode, used to represent an
         individual, specific thing: a specific human, a favorite pet, a
         famous animal, etc.

   Amoji:  Pictographic symbol encoded in Unicode, used to represent an
         individual of an alien species.

   Umoji:  Pictographic symbol encoded in Unicode, used to represent
         unknown things not covered by the other mojis.

   Omoji:  Pictographic symbol encoded in Unicode, used to represent
         obfuscated identities, used as addresses for the purpose of

2.  The Need for 128-Bit Code Points

   The exponentially increasing demand for Unicode character code points
   might not be obvious at first glance.  While it is true that the
   number of languages and their writing scripts do not grow quickly
   over time, one type of "character" will: emojis.  Unicode has barely
   begun providing code points for all of the various emojis currently
   in use, and it is likely that more emojis will be created in the
   future.  For example, there are still missing emoji symbols for most
   types of food and drink, the flags of each town and city on Earth,
   all human sporting and leisure activities including all local and
   national sports teams and players, and every plant and animal species
   and gender.

   Furthermore, it has become common for some applications to allow
   their users to create custom emojis, whereby the user can provide the
   graphic to display for a new "character".  For example, a user might
   set their chat application to display a graphic of Carlos Ramirez's
   popular "Trollface" meme [TROLL], using the short-name tag
   ':trollface:' in their chat application.  All other users of the same
   chat app will be able to see and use the same custom trollface emoji.

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   However, since there is no Unicode code point for :trollface:, the
   chat app cannot export the trollface emoji to other chat apps or
   protocols, such as Internet Relay Chat (IRC) or the Extensible
   Messaging and Presence Protocol (XMPP).  This represents a clear
   interoperability issue.

   In the future, it might also become desirable to assign each human a
   Unicode code point to represent them, similar to names, with the
   glyph being a picture of their face or a custom graphic.  These
   personal code points are not truly "emojis" in the classical sense of
   being generic concepts, so we've decided to give them a new name to
   avoid confusion: imoji.  Unlike human names, code points for imojis
   will be unique per human, for all space and time.  Favorite pets and
   famous animals can also be assigned imojis.

   Lastly, if we ever encounter sentient species from other planets,
   they too will need Unicode code points for their writing scripts and
   emojis; and they will each need unique amojis (imojis for aliens),
   for whatever form their individual identity might take.  Section 4 of
   RFC 8136 [RFC8136] clearly supports such a scenario, with the new UFO
   IPv6 option.

   Based on the above obvious use cases, it is clear that the current ~1
   million code points are nowhere near enough.  Increasing to 64 bits
   might be sufficient for now, but since this will be a painful
   transition process no matter the size, we believe jumping to 128 bits
   is the appropriate choice.

   Note: The current limit of ~1 million code points is a formal limit
   due to what UTF-16 can encode today.  Increasing the limit will
   either require deprecating UTF-16 or paying a hefty overhead penalty
   to encode 128 bits across many pairs of surrogate code points.  Since
   the ultimate goal of this document is to reduce global warming, the
   challenge of choosing between deprecating UTF-16 or paying the
   overhead price is a trivial dilemma to solve by comparison.

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3.  Unicode IPv6 Addresses

   Assuming the new Unicode code point space is 128 bits -- excluding
   some reserved bits for backwards compatibility and future expansion
   -- it seems only natural to use Unicode code points for IPv6
   addresses, and vice versa.  This leads to some exciting changes, such

   o  IPv6 addresses no longer need to be typed as hex values --
      instead, the glyph for the script character, symbol, emoji, or
      imoji representing that address can be input by the user, and it
      will be displayed by the application as the graphic itself.  From
      the user's perspective, this will also be more compact than the
      representation described in RFC 1924 [RFC1924].

   o  Network monitoring and troubleshooting tools can now display
      pretty glyphs in place of ugly IPv6 addresses, leading to less
      stress on the eyes of network administrators.

   o  For cases where graphical glyphs cannot be used, such as IETF
      documents, we can deprecate the legacy textual notation of IPv6
      addresses of the style '2001:db8:85a3::8a2e:370:7334' to the
      simpler Unicode textual notation
      'U+20010DB885A3000000008A2E03707334'.  Using the short-name tag is
      also possible, such as ':v6address-1:'.

   Due to the nature of having IPv6 addresses be Unicode code points,
   RFC 8135 [RFC8135] is made obsolete by this document.  It was found
   to be too complex to implement anyway.

3.1.  Reserved Addresses

   Some address code points will be inappropriate for IPv6 addressing,
   such as formatting characters and control codes.  Such code points
   MUST NOT be used for IPv6 addresses.

   We do, however, still need to reserve some code points for private
   network use.  Since no sentient life has been found on Mars, the code
   points that would have been allocated for Martian imojis are hereby
   allocated for this private use.  These addresses are thus called
   "Martians", also known as "Bogons" due to them being bogus.

   Note: Should life be found on Mars in the future, new code points
   will be allocated for them.  To avoid confusion, they will be called
   "Barsoom Indigenous Glyph Off-world Network" addresses, or "Bigons"
   (pronounced "bye-gons").  We're certain the Martians will let Bogons
   be bygones, and Bigons be Bigons.

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3.2.  Multicast

   In both IPv4 and IPv6, multicast addresses have been relegated to
   predefined IP address ranges, limiting how many multicast groups
   could be used simultaneously.  Given the rise of broadcasting-style
   social media platforms, and the market demand for individuals to be
   watched/followed by numerous random strangers constantly, it seems
   clear that we need to be able to multicast everything, all the time.

   To address this need, the high-order bit of the 128-bit code point
   space SHALL be reserved to indicate multicast.  All valid code points
   (i.e., IPv6 addresses) will thus have multicast counterparts.  For
   example, the code point allocated for :cat: is U+1F408.  The
   multicast group U+8000000000000000000000000001F408 is thus for
   content about cats.  Note that this is for general cat content --
   other code points are allocated for specific cat content, such as joy
   cat, grinning cat, pouty cat, etc.  For an individual cat like
   Garfield, setting the high-order bit to the code point allocated for
   :garfield: will indicate that it is multicast content about Garfield.

   Source-specific multicast also plays a role; for example, joining the
   :garfield: multicast group and restricting it to a source of
   :garfield: results in only receiving content about Garfield, from

3.3.  IPv6 Routing

   There should be little impact on routing using code-point-based IPv6
   addresses.  There might be some exponential growth in routing and
   forwarding tables due to difficulties in aggregating code points;
   hopefully, this will be offset by increases in processor and memory
   capacity.  Of course this will also drive the need to frequently
   upgrade networking hardware, resulting in a boost to the global
   economy, and thus a reduction in global warming.

   One improvement to routing that MAY be considered is for scenic
   routing as defined by RFC 7511 [RFC7511].  With emojis and imojis
   being available for addressing, we can now specify which exact type
   of scenery to visit along the way, or even which exact avian carrier
   [RFC6214] to ride with.  Note that avian carriers as described in RFC
   1149 [RFC1149] are not supported, since they only support IPv4.

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4.  Using Unicode IPv6 Addresses

4.1.  Uniform Resource Identifiers

   Uniform Resource Identifiers (URIs) and Uniform Resource Locators
   (URLs) already support Unicode through Internationalized Resource
   Identifiers (IRIs), but these are merely a means to use multiple
   Unicode characters to indicate a resource.  With 128-bit Unicode, the
   number space is large enough to identify each resource with a single
   Unicode character.  Why waste space and time typing out multiple
   characters, when you can just use one?

   For URLs, this new model might only mean using a single Unicode
   character for the hostname portion -- for example, a corporate logo
   in place of the legacy corporate domain name.  Another alternative is
   to allocate a code point for the entire host and path, possibly even
   including the scheme.  These types of decisions can be made in future
   IETF Working Groups.

   The interesting aspect of this change for URIs/URLs is that no
   address lookup needs to be performed.  The single 128-bit Unicode for
   the URL *is* the IPv6 address.  An additional step is only needed if
   the user inputs a private Unicode character or short-name tag that
   needs to be converted to a publicly allocated one.  This would
   require Network Address Translation (NAT) from the private code point
   or short-name tag to a public Unicode code point.  This can be done
   locally, thus finally bringing NATs into the last part of the
   Internet in which they are not currently deployed: the user's

4.2.  Address Allocation and Resolution

   It is obvious that once a single 128-bit Unicode character is used
   for addresses and URIs, using domain names will quickly become
   obsolete.  The subsequent collapse of the domain name industry
   presents a threat to the world economy, which MUST be addressed.

   One solution to this danger is to establish a Unicode registry model
   and an accompanying Code Point Unicode Resolution System (CPURS,
   pronounced "keepers").  CPURS would replace DNS and provide an
   architecture and resolution mechanism to resolve Unicode code points
   to their registered glyphs and short-name tags, and vice versa.  The
   new Unicode registries and registrars would thus replace the legacy
   domain name counterparts.  This would lead to a new gold rush for
   registering Unicode code points for corporate logos and product
   icons, and thus usher in an era of economic prosperity, which would
   eventually reduce global warming.

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   Once Unicode registries and CPURS are in place, IPv6 addresses would
   be allocated by registering code points through that system; they
   would no longer be registered by IANA and RIRs.  This is not a major
   concern, however, because any tax revenue loss will be more than
   offset by Unicode registries allocating code points.  Furthermore, in
   order to make CPURS possible, the actual graphic files for the glyphs
   need to be standardized and created in numerous formats and sizes,
   with various intellectual property rules.  This will provide more
   work for graphic artists and lawyers, further increasing tax revenue.

   The astute reader might ask why we need CPURS if Unicode translation
   is performed locally on hosts today.  The answer is volume: it is
   unlikely that host applications can keep up with the rate of new
   Unicode code points being allocated for emojis, imojis, and umojis.
   While application and operating system updates have been occurring at
   an ever-increasing rate, and will soon reach the same rate as human
   births, it is doubtful that it will ever reach the rate of sentient
   extraterrestrial births.  Therefore, we need a system that can scale
   to reach such volume before we make first contact; otherwise, the
   diplomatic failure to quickly provide the aliens with amojis of their
   own may lead to armed conflict.  An armed conflict with other
   sentient beings capable of reaching Earth might increase global
   warming, defeating this document's ultimate purpose.

5.  Summary

   There is still much to be decided on, most of which is frankly rather
   boring.  It is clear, however, that 128-bit Unicode code points will
   be needed eventually, and IPv6 addressing MUST be migrated to it.
   Thus, the time to act is now!

6.  IANA Considerations

   This document has no IANA actions.

7.  Security Considerations

   The main security concern with using 128-bit Unicode for IPv6
   addressing is the need for privacy, in terms of anonymity.  If an
   IPv6 packet is sent with an imoji or amoji address, then man-in-the-
   middle devices in the network will know the specific human or alien
   that sent or received the packet.  Using such information might lead
   to heated discussions, thereby increasing global warming.

   To address this concern, an IPv6 address MAY be obfuscated by using
   an omoji.  An omoji is simply the original Unicode code point but
   with the least-significant bit set; all other types of 128-bit
   Unicode code points MUST have the least-significant bit cleared.  The

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   graphical representation of an omoji is the same as its unobfsucated
   moji counterpart, except that it is covered over by a solid black

   By setting the least-significant bit of the source or destination and
   thus turning it into an omoji, the IPv6 address is obfuscated and the
   true identity cannot be determined, while IPv6 routers can still
   route the packet appropriately.  Note that this only provides a bit
   of privacy, but every bit helps.

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <>.

8.2.  Informative References

   [OED]      Oxford University Press, "Oxford English Dictionary",

   [RFC1149]  Waitzman, D., "Standard for the transmission of IP
              datagrams on avian carriers", RFC 1149,
              DOI 10.17487/RFC1149, April 1990,

   [RFC1924]  Elz, R., "A Compact Representation of IPv6 Addresses",
              RFC 1924, DOI 10.17487/RFC1924, April 1996,

   [RFC6214]  Carpenter, B. and R. Hinden, "Adaptation of RFC 1149 for
              IPv6", RFC 6214, DOI 10.17487/RFC6214, April 2011,

   [RFC7511]  Wilhelm, M., "Scenic Routing for IPv6", RFC 7511,
              DOI 10.17487/RFC7511, April 2015,

   [RFC8135]  Danielson, M. and M. Nilsson, "Complex Addressing in
              IPv6", RFC 8135, DOI 10.17487/RFC8135, April 2017,

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   [RFC8136]  Carpenter, B. and R. Hinden, "Additional Transition
              Functionality for IPv6", RFC 8136, DOI 10.17487/RFC8136,
              April 2017, <>.

   [TROLL]    The Meme Wikia, "Trollface",

   [Unicode]  The Unicode Consortium, "Unicode", <>.


   The authors wish to thank the following people for providing the
   inspiration for this work: Cal Henderson, Carlos Ramirez, Graham
   Linehan, Agnetha Faltskog, Bjorn Ulvaeus, Benny Andersson, and
   Anni-Frid Lyngstad.

Author's Address

   Hadriel Kaplan
   128 Technology
   Burlington, MA
   United States of America


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