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IP Number for SCHC
draft-moskowitz-lpwan-ipnumber-00

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This is an older version of an Internet-Draft whose latest revision state is "Replaced".
Author Robert Moskowitz
Last updated 2022-06-03
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draft-moskowitz-lpwan-ipnumber-00
LPWAN                                                       R. Moskowitz
Internet-Draft                                            HTT Consulting
Intended status: Standards Track                             3 June 2022
Expires: 5 December 2022

                           IP Number for SCHC
                   draft-moskowitz-lpwan-ipnumber-00

Abstract

   This document requests an Internet Protocol Number assignment for
   SCHC so that SCHC can be used for IP independent SCHC of other
   transports such as UDP and ESP.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 5 December 2022.

Copyright Notice

   Copyright (c) 2022 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 (https://trustee.ietf.org/
   license-info) 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.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Use case for SCHC as an IP Number . . . . . . . . . . . .   3
   2.  Terms and Definitions . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirements Terminology  . . . . . . . . . . . . . . . .   3
   3.  Internet Protocol Number for SCHC . . . . . . . . . . . . . .   3
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  IANA IP Number Registry Update  . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   5
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   5
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .   6
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   LPWAN Static Context Header Compression (SCHC) Architecture
   [lpwan-architecture] originally envisioned SCHC used at the Network
   layer, encompassing IP and Transport, by the network provider.  Then
   SCHC would be used by the application; this would include any
   security envelope.

   This approach brakes down when dealing with Diet ESP [diet-esp].
   When Next Header is ESP, it is challenging for the ESP process to
   determine if an incoming ESP payload is regular ESP [RFC4303] or a
   diet ESP payload.  Careful allocation of the incoming SPI
   [ikev2-diet-esp] can mitigate this and have an implicit SCHC header,
   but it is not sound protocol design.  If the Next Header in the IP
   header were SCHC, not ESP, a clear segregation of incoming traffic is
   directly supportable.

   DTLS 1.3 [RFC9147] further complicates this.  DTLS 1.3 headers
   themselves are typically already very compressed and SCHC would not
   provide much value.  But the UDP header in front of DTLS would
   benefit of a separate compression from the IP Header compression.
   Where it is possible with ESP's SPI to mitigate inbound packet
   processing challenges implicit SCHC would generate, DTLS header does
   not safely even provide this and a SCHC IP number is necessary to
   separate traffic.

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1.1.  Use case for SCHC as an IP Number

   A mobile node, or network, may use different links over a period of
   time.  In some cases the node has the multiple interfaces and, in
   theory, could tune the compression to each interface.  In other
   cases, it is the whole network that is mobile and individual nodes
   have no "knowledge" of which link with what characteristics is
   actively handling the traffic.  In either case, the node
   administrator is aware that some links are constrained and use of
   SCHC compression is highly recommended.

   One example is an Unmanned Aircraft (UA) that uses different links
   over the duration of an operation (i.e. flight).

   *  Operation starts using Veriport's WiFi service.

   *  On gaining altitude, UA transitions to a Cellular service.

   *  On gaining more altitude, UA transitions to a constrained 700MHz
      UHF service.

   *  On approach to destination vertiport, link transition is reversed.

   The UA could use SCHC compression only on the UHF link, but this may
   complicate the implementation.

   A more complex example is an Unmanned Cargo Aircraft that has
   multiple avionics systems, all Ethernet connected to an onboard
   router that has the multiple interfaces.  Here the nodes each manage
   their own secure path to their ground-based server, but have no
   knowledge of which link is in use to intelligently use compression.

2.  Terms and Definitions

2.1.  Requirements 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.

3.  Internet Protocol Number for SCHC

   SCHC as the IP payload SHOULD be indicated in the IPv4 "Protocol"
   field or the IPv6 "Next Header" field with a value of TBD1
   (recommended: 144) as shown below:

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    +=========+=========+================+================+===========+
    | Decimal | Keyword | Protocol       | IPv6 Extension | Reference |
    |         |         |                | Header         |           |
    +=========+=========+================+================+===========+
    |    TBD1 | SCHC    | Static Context |                | This RFC  |
    |   (144) |         | Header         |                |           |
    |         |         | Compression    |                |           |
    +---------+---------+----------------+----------------+-----------+

                     Table 1: Internet Protocol Numbers

   The SCHC compressed header with payload is shown below.  The size of
   the SCHC RuleID is variable as described in [RFC8724].  An
   implementation should have a table of source IP address and RuleID
   size.  The addresses should be represented in prefix format to allow
   for groups of addresses having the same RuleID size.

       |------- Compressed Header -------|
       +---------------------------------+--------------------+
       |  RuleID  |  Compression Residue |      Payload       |
       +---------------------------------+--------------------+

                           Figure 1: SCHC Packet

   The RuleID may be statically configured per [RFC8724], or may be
   negotiated within a protocol as in IKE [ikev2-diet-esp].

4.  IANA Considerations

4.1.  IANA IP Number Registry Update

   This document requests IANA to make the following change to the
   "Assigned Internet Protocol Numbers" [IANA-IPN] registry:

   IP Number:
      This document defines the new IP Number value TBD1 (suggested:
      144) (Section 3) in the "Assigned Internet Protocol Numbers"
      registry.

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    +=========+=========+================+================+===========+
    | Decimal | Keyword | Protocol       | IPv6 Extension | Reference |
    |         |         |                | Header         |           |
    +=========+=========+================+================+===========+
    |    TBD1 | SCHC    | Static Context |                | This RFC  |
    |   (144) |         | Header         |                |           |
    |         |         | Compression    |                |           |
    +---------+---------+----------------+----------------+-----------+

                                  Table 2

5.  Security Considerations

   TBD

6.  References

6.1.  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,
              <https://www.rfc-editor.org/info/rfc2119>.

   [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>.

6.2.  Informative References

   [diet-esp] Migault, D., Guggemos, T., Bormann, C., and D. Schinazi,
              "ESP Header Compression and Diet-ESP", Work in Progress,
              Internet-Draft, draft-mglt-ipsecme-diet-esp-08, 13 May
              2022, <https://datatracker.ietf.org/doc/html/draft-mglt-
              ipsecme-diet-esp-08>.

   [IANA-IPN] IANA, "Assigned Internet Protocol Numbers",
              <https://www.iana.org/assignments/protocol-numbers/
              protocol-numbers.xhtml>.

   [ikev2-diet-esp]
              Migault, D., Guggemos, T., and D. Schinazi, "Internet Key
              Exchange version 2 (IKEv2) extension for the ESP Header
              Compression (EHC) Strategy", Work in Progress, Internet-
              Draft, draft-mglt-ipsecme-ikev2-diet-esp-extension-02, 13
              May 2022, <https://datatracker.ietf.org/doc/html/draft-
              mglt-ipsecme-ikev2-diet-esp-extension-02>.

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   [lpwan-architecture]
              Pelov, A., Thubert, P., and A. Minaburo, "LPWAN Static
              Context Header Compression (SCHC) Architecture", Work in
              Progress, Internet-Draft, draft-ietf-lpwan-architecture-
              01, 26 November 2021,
              <https://datatracker.ietf.org/doc/html/draft-ietf-lpwan-
              architecture-01>.

   [RFC4303]  Kent, S., "IP Encapsulating Security Payload (ESP)",
              RFC 4303, DOI 10.17487/RFC4303, December 2005,
              <https://www.rfc-editor.org/info/rfc4303>.

   [RFC8724]  Minaburo, A., Toutain, L., Gomez, C., Barthel, D., and JC.
              Zuniga, "SCHC: Generic Framework for Static Context Header
              Compression and Fragmentation", RFC 8724,
              DOI 10.17487/RFC8724, April 2020,
              <https://www.rfc-editor.org/info/rfc8724>.

   [RFC9147]  Rescorla, E., Tschofenig, H., and N. Modadugu, "The
              Datagram Transport Layer Security (DTLS) Protocol Version
              1.3", RFC 9147, DOI 10.17487/RFC9147, April 2022,
              <https://www.rfc-editor.org/info/rfc9147>.

Acknowledgments

   TBD

Author's Address

   Robert Moskowitz
   HTT Consulting
   Oak Park, MI 48237
   United States of America
   Email: rgm@labs.htt-consult.com

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