Internet Engineering Task Force                              D. Eastlake
Internet-Draft                                                   H. Song
Intended status: Standards Track                  Futurewei Technologies
Expires: 7 September 2022                                   6 March 2022


An IPv6 Segment Routing (SRv6) Domain Name System (DNS) Resource Record
                  draft-eastlake-dnsop-rrtype-srv6-00

Abstract

   A Domain Name System (DNS) Resource Record (RR) Type is specified for
   storing IPv6 Segment Routing (SRv6) Information in the DNS.

Status of This Memo

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  IPv6 Segment Routing  . . . . . . . . . . . . . . . . . .   2
     1.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  SRV6 RR Type RDATA  . . . . . . . . . . . . . . . . . . . . .   3
   3.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   4
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   4
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Appendix A.  SRV6 RR Type Template  . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   The Domain Name System (DNS) is a hierarchical, distributed, highly
   available database with a variety of security features used for bi-
   directional mapping between domain names and addresses, for email
   routing, and for other information [RFC1034] [RFC1035].  This data is
   formatted into resource records (RRs) whose content type and
   structure are indicated by the RR Type field.  General familiarity
   with the DNS and its terminology [RFC8499] is assumed in this
   document.

1.1.  IPv6 Segment Routing

   Internet Protocol versions 4 (IPv4,[RFC0791]) and 6 (IPv5, [RFC8200])
   have long provided header options to include an ordered sequence of
   addresses in a packet header so the packet travels in order through
   the nodes specified by that sequence of addresses.  This is sometimes
   referred to as "source routing" because the route or path the packet
   follows is set at least in part when a sequence of addresses is added
   to the packet, usually at the packet's source, rather than being
   dynamically determined as the packet proceeds through the network.

   IPv6 Segment Routing (SRv6, [RFC8402]) extends "source routing" by
   generalizing the IPv6 sized "address" quantities in a sequence to be
   "instructions".  [RFC8754] specifies a particular Segment Routing
   Header (SRH) that may be use used as part of the headers of an IPv6
   packet to indicate an IPv6 Segment Routing sequence of addresses/
   instructions.  And [RFC8986] further specifies the structuring of an
   IPv6 address size quantity such that it is composed of addressing
   information followed by a function designation which is optionally
   further followed by arguments to that function.  Thus, segment
   routing might encode a series of operations to be performed on a
   packet.



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   Furthermore, because a sequence of SRv6 instructions may start with
   the same constant addressing prefix, methods of compression have been
   suggested to represent this addressing prefix less often and pack an
   increased number of quantities into a Segment Routing Header where
   each quantity may consist optionally of additional address
   information and/or function designation and/or function arguments.

   In many ways, the data returned for an SRV6 DNS RR is like an
   address.  For example, it would be reasonable for an application
   using SRv6 to do a type SRV DNS query [RFC2782] followed by an SRV6
   query at the resulting domain name.  Furthermore, as a fall back, if
   no SRV6 RR is present in the DNS at a domain name, an application
   could try querying for the AAAA IPv6 address RR type.

1.2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "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.

   The following acronyms are used in this document:

      DNS - Domain Name System

      IANA - Internet Assigned Number Authority

      RR - DNS Resource Record

      SRv6 - IPv6 Segment Routing

      SRV6 - Mnemonic for the SRv6 RR Type

2.  SRV6 RR Type RDATA

   The SRV6 RR type enables the storage and retrieval of an ordered
   sequence of SRv6 quantities each of which is the size of IPv6
   [RFC8200] addresses.  The RDATA for this type of RR is simple a
   sequence of such quantities preceded by 16 bits that are available
   for future definition as flags (see Figure 1) and will be 2+(N*16)
   bytes long where N is the number of such quantities present.

   The RR Type Code for the SRV6 RR is TBD1.

   The Flags field is for future flexibility and MUST be sent as zero
   and ignored on receipt.




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      0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |              Flags            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     |                 128-bit SRv6 Address/Instruction              |
     |                                                               |
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     .                                                               .
     .         Additional 128-bit SRv6 Addresses/Instructions        .
     .                                                               .
     .................................................................

                         Figure 1: SRV6 RRTYPE Data

3.  Acknowledgements

   The suggestions and comments of the following persons are gratefully
   acknowledged:

   tbd

4.  IANA Considerations

   IANA is request to assign an SRV6 RR Type (TBD1) as in the template
   in Appendix A.

5.  Security Considerations

   tbd

6.  References

6.1.  Normative References

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,
              <https://www.rfc-editor.org/info/rfc1034>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.






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   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.

   [RFC8402]  Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
              Decraene, B., Litkowski, S., and R. Shakir, "Segment
              Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
              July 2018, <https://www.rfc-editor.org/info/rfc8402>.

   [RFC8986]  Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer,
              D., Matsushima, S., and Z. Li, "Segment Routing over IPv6
              (SRv6) Network Programming", RFC 8986,
              DOI 10.17487/RFC8986, February 2021,
              <https://www.rfc-editor.org/info/rfc8986>.

6.2.  Informative References

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              DOI 10.17487/RFC0791, September 1981,
              <https://www.rfc-editor.org/info/rfc791>.

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <https://www.rfc-editor.org/info/rfc1035>.

   [RFC2782]  Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
              specifying the location of services (DNS SRV)", RFC 2782,
              DOI 10.17487/RFC2782, February 2000,
              <https://www.rfc-editor.org/info/rfc2782>.

   [RFC3597]  Gustafsson, A., "Handling of Unknown DNS Resource Record
              (RR) Types", RFC 3597, DOI 10.17487/RFC3597, September
              2003, <https://www.rfc-editor.org/info/rfc3597>.

   [RFC8499]  Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
              Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
              January 2019, <https://www.rfc-editor.org/info/rfc8499>.

   [RFC8754]  Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
              Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
              (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
              <https://www.rfc-editor.org/info/rfc8754>.




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Appendix A.  SRV6 RR Type Template

   A. Submission Date: tbd

   B.1 Submission Type:  [X] New RRTYPE  [ ] Modification to RRTYPE
   B.2 Kind of RR:  [X] Data RR  [ ] Meta-RR

   C. Contact Information for submitter (will be publicly posted):
      Name: Donald Eastlake       Email Address: d3e3e3@gmail.com
      International telephone number: +1-508-333-2270
      Other contact handles:

   D. Motivation for the new RRTYPE application.

      Need to store IPv6 Segment Routing sequences in the DNS.

   E. Description of the proposed RR type.
      See draft-eastlake-dnsop-rrtype-srv6

   F. What existing RRTYPE or RRTYPEs come closest to filling that need
      and why are they unsatisfactory?

      Perhaps AAAA but that only returns a single IPv6 address, not an
      ordered sequence of IPv6 sized SRv6 instructions.

   G. What mnemonic is requested for the new RRTYPE (optional)?

      SRV6

   H. Does the requested RRTYPE make use of any existing IANA registry
      or require the creation of a new IANA subregistry in DNS
      Parameters?  If so, please indicate which registry is to be used
      or created.  If a new subregistry is needed, specify the
      allocation policy for it and its initial contents.

      Does not use any existing registry (other than, of course, the RR
      Type registry) and does not create a new registry.

   I. Does the proposal require/expect any changes in DNS
      servers/resolvers that prevent the new type from being processed
      as an unknown RRTYPE (see [RFC3597])?

      No.

   J. Comments:  None.

Authors' Addresses




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   Donald Eastlake
   Futurewei Technologies
   2386 Panoramic Circle
   Apopka, FL 32703
   United States of America
   Phone: +1 508 333 2270
   Email: d3e3e3@gmail.com


   Haoyu Song
   Futurewei Technologies
   2220 Central Expressway
   Santa Clara, CA 95050
   United States of America
   Email: haoyu.song@futurewei.com




































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