[Docs] [txt|pdf] [Tracker] [Email] [Nits] [IPR]

Versions: 00

Network Working Group                                         A. Keranen
Internet-Draft                                                  Ericsson
Intended status: Standards Track                              C. Amsuess
Expires: January 23, 2020                                  July 22, 2019


                   SenML Base Name Prefix Indication
                draft-keranen-core-senml-base-prefix-00

Abstract

   The Sensor Measurement Lists (SenML) media type uses globally unique
   names to facilitate information exchange across systems.  This
   requirement often leads to long names and hence large amount of data
   to be transmitted with each SenML Pack.  This document defines an
   efficient mechanism to indicate a globally unique prefix for names.

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 January 23, 2020.

Copyright Notice

   Copyright (c) 2019 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 Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.



Keranen & Amsuess       Expires January 23, 2020                [Page 1]


Internet-Draft      SenML Base Name Prefix Indication          July 2019


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Indicating base name prefix . . . . . . . . . . . . . . . . .   3
     3.1.  IP address  . . . . . . . . . . . . . . . . . . . . . . .   4
     3.2.  Request Base URI  . . . . . . . . . . . . . . . . . . . .   4
     3.3.  Public key fingerprint  . . . . . . . . . . . . . . . . .   4
     3.4.  TLS PSK Identity  . . . . . . . . . . . . . . . . . . . .   5
     3.5.  CoRE Resource Directory endpoint ID . . . . . . . . . . .   5
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The Sensor Measurement Lists (SenML) media type [RFC8428] indicates
   sources of information with globally unique names.  A SenML Pack can
   indicate "base names" ("bn" field) that are prefixed to all names
   ("n" fields) in the SenML Records where the "bn" appears and all
   subsequent records until a new base name is indicated.  Example of a
   SenML Pack with two sources of measurement data that share a base
   name is shown in Figure 1.

      [
        {"bn":"2001:db8:1234:5678::1/",
         "n":"temperature", "u":"Cel", "v":25.2},
        {"n":"humidity", "u":"%RH", "v":30}
      ]

           Figure 1: SenML Pack with two sources of measurements

   The base name construct enables indicating the globally unique part
   of the name only once for a set of Records.  However, the globally
   unique part still needs to be indicated in each Pack.  Since base
   name is often relatively long, in some scenarios it would be useful
   to be able to further compress or omit this information.

   Since the sender and receiver of a SenML Pack often share context
   information beyond what is in the SenML Pack, e.g., request URI when
   a RESTful protocol is used, sender IP address, or security
   association information.  This information can be used to assist
   constructing the globally unique part of a name.  However, the sender
   of the Pack needs to be able to indicate unambiguously what




Keranen & Amsuess       Expires January 23, 2020                [Page 2]


Internet-Draft      SenML Base Name Prefix Indication          July 2019


   information is used and how the name is generated from that
   information.

   This document registers a new SenML field to indicate what
   information outside of the SenML Pack should be used as a prefix to
   the base name(s).  Also rules for consistently creating SenML names
   from this information is specified for each information source.

   Since SenML has only a small set of characters that are allowed in
   names (see Section 4.5.1 in [RFC8428]) replacing rules for characters
   outside of this set (e.g., brackets and semicolons) are also defined.

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.

   Readers should also be familiar with the terms and concepts discussed
   in [RFC8428].

3.  Indicating base name prefix

   SenML field "bpi" contains an integer value that indicates what
   information should be used by the receiver to construct a prefix to
   the base names.  This document defines following modes:

   1: IPv4 or IPv6 address of the sender

   2: IPv4 or IPv6 address and port of the sender

   3: Base URI of the request URI

   5: Fingerprint of the public key of the sender

   6: TLS PSK Identity

   10: CoRE Resource Directory endpoint ID

   The following sub-sections define rules for generating SenML basename
   prefix for each mode.  Some rules require replacing characters from
   the input identifiers with characters that are safe for SenML names.
   Applying these rules may result in multiple different input
   identifiers being mapped to the same output identifer.  The sender of
   the SenML Pack MUST ensure that such mapping does not result in
   conflicting names from that sender.



Keranen & Amsuess       Expires January 23, 2020                [Page 3]


Internet-Draft      SenML Base Name Prefix Indication          July 2019


3.1.  IP address

   The SenML Pack sender IP address can be used without (mode 1) or with
   (mode 2) port number to generate the base name prefix.

   For IPv6 addresses the format defined in [RFC5952] without brackets
   ("[" and "]") MUST be used.

   Example: "2001:db8::1"

   For IPv6 address and port underscore ("_") for port separator MUST be
   used.

   Example: "2001:db8::1_5683"

   For IPv4 addresses the "dot decimal" notation MUST be used.

   Example: "192.0.2.1"

   For IPv4 addresses colon (":") MUST be used for port separator.

   Example: "192.0.2.1:5684"

3.2.  Request Base URI

   When a RESTful protocol (e.g., CoAP [RFC7252] or HTTP [RFC7230]) is
   used to request a SenML Pack, the base of the target request URI can
   be used as the base name prefix.  If IP address is used in the
   authority part of the URI, rules in Section 3.1 MUST be followed for
   it.

   Characters in the URI that are not in the character set allowed for
   SenML names MUST be replaced with the underscore ("_") character.

   Example: "coap://example.com/room1/"

3.3.  Public key fingerprint

   When X.509 certificate or raw public key is used to setup the
   security association (e.g., a TLS connection) to retrieve a SenML
   Pack, a fingerprint of the public key of the sender of the SenML Pack
   can be used as the base name prefix.  For a public key fingerprint
   the "URL Segment Format" of [RFC6920] with ";" characters replaced
   with "_" MUST be used.

   Example: "sha-256_UyaQV-Ev4rdLoHyJJWCi11OHfrYv9E1aGQAlMO2X_-Q"





Keranen & Amsuess       Expires January 23, 2020                [Page 4]


Internet-Draft      SenML Base Name Prefix Indication          July 2019


3.4.  TLS PSK Identity

   When a pre-shared key (PSK) ciphersuites (e.g., [RFC4279])) are used
   to establish a TLS connection, the PSK identity can be used as the
   base name prefix.  In this mode the PSK identity from the TLS
   handshake with characters not allowed for SenML names replaced with
   "_" MUST be used.

   Example: "foo.example.com"

3.5.  CoRE Resource Directory endpoint ID

   When the sender has registered with the receiving system using the
   CoRE Resource Directory [I-D.ietf-core-resource-directory] interface,
   and has defined an "endpoint name" during the registration, the
   endpoint name can be used as the base name prefix.  Characters not
   allowed for SenML names MUST be replaced with "_".

   Example: "urn:dev:ow:10e2073a01080063"

4.  IANA Considerations

   IANA is requested to assign a new label in the "SenML Labels"
   subregistry of the SenML registry [IANA.senml] (as defined in
   [RFC8428]) for the "Base Name Prefix Indicator" as follows:

   +-----------------------+-------+----------+---------+--------------+
   | Name                  | Label | JSON     | XML     | Reference    |
   |                       |       | Type     | Type    |              |
   +-----------------------+-------+----------+---------+--------------+
   | Base Name Prefix      | bpi   | Number   | int     | this         |
   | Indicator             |       |          |         | document     |
   +-----------------------+-------+----------+---------+--------------+

   IANA is requested to create a new "SenML Base Name Prefix Indicator
   modes" subregistry to the SenML registry.  Initial contents of the
   subregistry is shown below:














Keranen & Amsuess       Expires January 23, 2020                [Page 5]


Internet-Draft      SenML Base Name Prefix Indication          July 2019


               +-------------------+-------+---------------+
               | Name              | Value | Reference     |
               +-------------------+-------+---------------+
               | IP address        | 1     | this document |
               |                   |       |               |
               | IP address & port | 2     | this document |
               |                   |       |               |
               | Base URI          | 3     | this document |
               |                   |       |               |
               | Public key        | 5     | this document |
               |                   |       |               |
               | TLS PSK ID        | 6     | this document |
               |                   |       |               |
               | CoRE RD endpoint  | 10    | this document |
               +-------------------+-------+---------------+

Acknowledgements

   TBD

6.  References

6.1.  Normative References

   [I-D.ietf-core-resource-directory]
              Shelby, Z., Koster, M., Bormann, C., Stok, P., and C.
              Amsuess, "CoRE Resource Directory", draft-ietf-core-
              resource-directory-23 (work in progress), July 2019.

   [IANA.senml]
              IANA, "Sensor Measurement Lists (SenML)",
              <http://www.iana.org/assignments/senml>.

   [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>.

   [RFC4279]  Eronen, P., Ed. and H. Tschofenig, Ed., "Pre-Shared Key
              Ciphersuites for Transport Layer Security (TLS)",
              RFC 4279, DOI 10.17487/RFC4279, December 2005,
              <https://www.rfc-editor.org/info/rfc4279>.

   [RFC5952]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
              Address Text Representation", RFC 5952,
              DOI 10.17487/RFC5952, August 2010,
              <https://www.rfc-editor.org/info/rfc5952>.




Keranen & Amsuess       Expires January 23, 2020                [Page 6]


Internet-Draft      SenML Base Name Prefix Indication          July 2019


   [RFC6920]  Farrell, S., Kutscher, D., Dannewitz, C., Ohlman, B.,
              Keranen, A., and P. Hallam-Baker, "Naming Things with
              Hashes", RFC 6920, DOI 10.17487/RFC6920, April 2013,
              <https://www.rfc-editor.org/info/rfc6920>.

   [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>.

   [RFC8428]  Jennings, C., Shelby, Z., Arkko, J., Keranen, A., and C.
              Bormann, "Sensor Measurement Lists (SenML)", RFC 8428,
              DOI 10.17487/RFC8428, August 2018,
              <https://www.rfc-editor.org/info/rfc8428>.

6.2.  Informative References

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,
              <https://www.rfc-editor.org/info/rfc7230>.

   [RFC7252]  Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
              Application Protocol (CoAP)", RFC 7252,
              DOI 10.17487/RFC7252, June 2014,
              <https://www.rfc-editor.org/info/rfc7252>.

Authors' Addresses

   Ari Keranen
   Ericsson
   Jorvas  02420
   Finland

   Email: ari.keranen@ericsson.com


   Christian Amsuess
   Hollandstr. 12/4
   1020
   Austria

   Phone: +43-664-9790639
   Email: christian@amsuess.com








Keranen & Amsuess       Expires January 23, 2020                [Page 7]


Html markup produced by rfcmarkup 1.129d, available from https://tools.ietf.org/tools/rfcmarkup/