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Internet Engineering Task Force (IETF)                        T. KivinenRequest for Comments: 8137                                 INSIDE SecureCategory: Informational                                        P. KinneyISSN: 2070-1721                                    Kinney Consulting LLC                                                                May 2017IEEE 802.15.4 Information Element for the IETFAbstract   IEEE Std 802.15.4 defines Information Elements (IEs) that can be used   to extend 802.15.4 in an interoperable manner.  The IEEE 802.15   Assigned Numbers Authority (ANA) manages the registry of the   Information Elements.  This document formulates a request for ANA to   allocate a number from that registry for the IETF and describes how   the IE is formatted to provide subtypes.Status of This Memo   This document is not an Internet Standards Track specification; it is   published for informational purposes.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Not all documents   approved by the IESG are a candidate for any level of Internet   Standard; seeSection 2 of RFC 7841.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc8137.Copyright Notice   Copyright (c) 2017 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 78 and the IETF Trust's Legal   Provisions Relating to IETF Documents   (http://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.Kivinen & Kinney              Informational                     [Page 1]

RFC 8137       IEEE 802.15.4 Information Element for IETF       May 2017Table of Contents1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .22.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .33.  Working Groups Benefiting from the IETF 802.15.4 IE . . . . .34.  IETF IE Subtype Format  . . . . . . . . . . . . . . . . . . .35.  Request to Allocate an IETF IE  . . . . . . . . . . . . . . .46.  Security Considerations . . . . . . . . . . . . . . . . . . .47.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .58.  References  . . . . . . . . . . . . . . . . . . . . . . . . .68.1.  Normative References  . . . . . . . . . . . . . . . . . .68.2.  Informative References  . . . . . . . . . . . . . . . . .6Appendix A.  Vendor Specific IE in IEEE 802.15.4  . . . . . . . .7   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .71.  Introduction   IEEE Std 802.15.4 [IEEE802.15.4] is a standard, referred to byRFC4944 [RFC4944] and other documents, that enables very low-cost and   low-power communications.  The standard defines numerous optional   Physical Layers (PHYs) operating in many different frequency bands   with a simple and effective Medium Access Control (MAC).   IEEE Std 802.15.4 defines Information Elements (IEs) that can be used   to extend 802.15.4 in an interoperable manner.  An IE provides a   flexible, extensible, and easily implementable method of   encapsulating information.  The general format of an IE as defined inSection 7.4 of IEEE Std 802.15.4-2015 [IEEE802.15.4] consists of an   identification (ID) field, a length field, and a content field.   Multiple IEs may be concatenated, and elements with unknown ID values   in a list of IEs can be skipped since their length is known.  IEs   provide a flexible container for information that allows the addition   of new IE definitions in future versions of the standard in a   backwards-compatible manner.   There are two different IE types, Header IE and Payload IE.  A Header   IE is part of the MAC header; it is never encrypted, but it may be   authenticated.  Most of the Header IE processing is done by the MAC,   and IETF protocols should not have any direct effect on that   processing.  A Payload IE is part of the MAC payload and may be   encrypted and authenticated.   IETF protocols will need to insert information in the 802.15.4   frames; the 802.15.4 standard enables that by including one or more   payload IEs in the frame that will contain the information.  For this   purpose, the IETF requests a dedicated Payload IE from the IEEE   802.15 Assigned Numbers Authority (ANA) [IEEE802.15-ANA].  The   current 802.15 ANA database can be found at [IEEE802.15-ANA-DB].Kivinen & Kinney              Informational                     [Page 2]

RFC 8137       IEEE 802.15.4 Information Element for IETF       May 2017   The 802.15.4 operations manual [IEEE802.15-OPS] describes how a   Standards Development Organization (SDO) may request an allocation of   one IE.  To make this request the SDO has to provide (i) the reason   for the request, (ii) a description of the protocol format that shows   an appropriate subtype capability, and (iii) an agreement that only   one IE number will be allocated for use by the SDO.   This document provides the information needed for the request.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 inBCP 14 [RFC2119] [RFC8174] when, and only when, they    appear in all capitals, as shown here.3.  Working Groups Benefiting from the IETF 802.15.4 IE   There are several IETF working groups such as 6TiSCH, 6lo, and CoRE   that could benefit from the IETF IE.  The 6TiSCH Working Group has   already expressed the need for the IE; this allocation is expected to   satisfy that need.4.  IETF IE Subtype Format   The maximum length of the Payload IE content is 2047 octets, and the   802.15.4 frame contains a list of payload IEs.  A single frame can   have multiple payload IEs, terminated with the payload IE terminator,   which may then be followed by the payload.   Since the 802.15.4 standard defines a list of payload IEs along with   their structures, there is no need for this document to specify the   internal nesting structure of the IETF IE.  The Payload IE format of   802.15.4 standard contains the Length field.  The length of the   subtype content can be calculated from the 802.15.4 Payload IE Length   field of the IETF IE.Kivinen & Kinney              Informational                     [Page 3]

RFC 8137       IEEE 802.15.4 Information Element for IETF       May 2017   The format of the IETF IE is as follows:                        1                   2                   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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   | Subtype ID    |                                               |   +-+-+-+-+-+-+-+-+                                               |   ~                       subtype content                         ~   |                                                               |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                     Figure 1: IETF IE Subtype Format   o  Subtype ID is the IANA-allocated number specifying the subtype of      the IETF IE.  Value 0 is reserved for future extensibility, i.e.,      in case a longer subtype ID field is needed.   o  Subtype content is the actual content of the Information Element,      and its length can be calculated from the Length field of the IETF      IE.   One IEEE 802.15.4 frame MAY contain multiple IETF IEs with the same   or different subtypes.5.  Request to Allocate an IETF IE   Per the IETF's request, the IEEE 802.15 Working Group has allocated   an ID (5) for a Payload IE for IETF use.  The IETF understands that   this is the only ID it will be issued.6.  Security Considerations   This document creates an IANA registry for IETF IE subtype IDs (seeSection 7).  The security of the protocols using the IEs MUST be   described in the documents requesting allocations from this registry.   The IEEE Std 802.15.4 [IEEE802.15.4] contains methods in which   security of the IE can be enforced when a frame is received, but this   is only per IE type.  Therefore, all IETF IEs will have the same   security-level requirements regardless of the subtype ID used.  This   can cause issues if different security processing would be needed and   any of those IEs would need to be processed in the MAC level.  Since   all IETF protocols should operate at a higher level than the MAC   level, the higher-layer processing for these IEs SHOULD perform   separate security policy checking based on the IETF IE subtype ID in   addition to the checks done by the MAC.Kivinen & Kinney              Informational                     [Page 4]

RFC 8137       IEEE 802.15.4 Information Element for IETF       May 20177.  IANA Considerations   The "IEEE Std 802.15.4 IETF IE Subtype IDs" registry has been created   as follows:   Value     Subtype ID   0         Reserved   1-200     Unassigned   201-255   Experimental Use   Any change or addition to this registry requires Expert Review   [RFC5226].   Note that there are vendor-specific IEs already defined in IEEE   802.15.4 (seeAppendix A); because of this, there is no need to   reserve any subtype IDs for the vendor-specific uses.Kivinen & Kinney              Informational                     [Page 5]

RFC 8137       IEEE 802.15.4 Information Element for IETF       May 20178.  References8.1.  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,              <http://www.rfc-editor.org/info/rfc2119>.   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase inRFC2119 Key Words",BCP 14,RFC 8174, DOI 10.17487/RFC8174,              May 2017, <http://www.rfc-editor.org/info/rfc8174>.8.2.  Informative References   [IEEE802.15.4]              IEEE, "IEEE Standard for Low-Rate Wireless Networks",              IEEE Standard 802.15.4,              <https://standards.ieee.org/about/get/802/802.15.html>.   [IEEE802.15-ANA]              IEEE 802.15, "IEEE 802.15 Assigned Numbers Authority",              <http://www.ieee802.org/15/ANA.html>.   [IEEE802.15-ANA-DB]              IEEE, "IEEE 802.15 ANA database",              <https://mentor.ieee.org/802.15/documents?is_dcn=257&is_group=0000>.   [IEEE802.15-OPS]              IEEE, "IEEE 802.15 Operations Manual",              <https://mentor.ieee.org/802.15/documents?is_dcn=235&is_group=0000>.   [RFC4944]  Montenegro, G., Kushalnagar, N., Hui, J., and D. Culler,              "Transmission of IPv6 Packets over IEEE 802.15.4              Networks",RFC 4944, DOI 10.17487/RFC4944, September 2007,              <http://www.rfc-editor.org/info/rfc4944>.   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an              IANA Considerations Section in RFCs",BCP 26,RFC 5226,              DOI 10.17487/RFC5226, May 2008,              <http://www.rfc-editor.org/info/rfc5226>.Kivinen & Kinney              Informational                     [Page 6]

RFC 8137       IEEE 802.15.4 Information Element for IETF       May 2017Appendix A.  Vendor Specific IE in IEEE 802.15.4   IEEE 802.15.4 already has several numbers for different Vendor   Specific IE types.  There is one for the Vendor Specific Header IE   for Header IEs.  There is one incorrectly named Vendor Specific   Nested IE for Payload IEs, and there is another one with exactly the   same name, but under the MLME Nested IE long format.  All of the   Vendor Specific IEs start with a 3-octet vendor OUI to identify the   organization.Authors' Addresses   Tero Kivinen   INSIDE Secure   Lonnrotinkatu 11   Helsinki  FI-00120   Finland   Email: kivinen@iki.fi   Pat Kinney   Kinney Consulting LLC   Email: pat.kinney@kinneyconsultingllc.comKivinen & Kinney              Informational                     [Page 7]