1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T Y.4500.8 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2018) SERIES Y: GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS, NEXT-GENERATION NETWORKS, INTERNET OF THINGS AND SMART CITIES Internet of things and
2、 smart cities and communities Frameworks, architectures and protocols oneM2M CoAP protocol binding Recommendation ITU-T Y.4500.8 ITU-T Y-SERIES RECOMMENDATIONS GLOBAL INFORMATION INFRASTRUCTURE, INTERNET PROTOCOL ASPECTS, NEXT-GENERATION NETWORKS, INTERNET OF THINGS AND SMART CITIES GLOBAL INFORMATI
3、ON INFRASTRUCTURE General Y.100Y.199 Services, applications and middleware Y.200Y.299 Network aspects Y.300Y.399 Interfaces and protocols Y.400Y.499 Numbering, addressing and naming Y.500Y.599 Operation, administration and maintenance Y.600Y.699 Security Y.700Y.799 Performances Y.800Y.899 INTERNET P
4、ROTOCOL ASPECTS General Y.1000Y.1099 Services and applications Y.1100Y.1199 Architecture, access, network capabilities and resource management Y.1200Y.1299 Transport Y.1300Y.1399 Interworking Y.1400Y.1499 Quality of service and network performance Y.1500Y.1599 Signalling Y.1600Y.1699 Operation, admi
5、nistration and maintenance Y.1700Y.1799 Charging Y.1800Y.1899 IPTV over NGN Y.1900Y.1999 NEXT GENERATION NETWORKS Frameworks and functional architecture models Y.2000Y.2099 Quality of Service and performance Y.2100Y.2199 Service aspects: Service capabilities and service architecture Y.2200Y.2249 Ser
6、vice aspects: Interoperability of services and networks in NGN Y.2250Y.2299 Enhancements to NGN Y.2300Y.2399 Network management Y.2400Y.2499 Network control architectures and protocols Y.2500Y.2599 Packet-based Networks Y.2600Y.2699 Security Y.2700Y.2799 Generalized mobility Y.2800Y.2899 Carrier gra
7、de open environment Y.2900Y.2999 FUTURE NETWORKS Y.3000Y.3499 CLOUD COMPUTING Y.3500Y.3999 INTERNET OF THINGS AND SMART CITIES AND COMMUNITIES General Y.4000Y.4049 Definitions and terminologies Y.4050Y.4099 Requirements and use cases Y.4100Y.4249 Infrastructure, connectivity and networks Y.4250Y.439
8、9 Frameworks, architectures and protocols Y.4400Y.4549 Services, applications, computation and data processing Y.4550Y.4699 Management, control and performance Y.4700Y.4799 Identification and security Y.4800Y.4899 Evaluation and assessment Y.4900Y.4999 For further details, please refer to the list o
9、f ITU-T Recommendations. Rec. ITU-T Y.4500.8 (03/2018) i Recommendation ITU-T Y.4500.8 oneM2M CoAP protocol binding Summary Recommendation ITU-T Y.4500.8 covers the protocol specific part of communication protocol used by oneM2M compliant systems as constrained application protocol (CoAP) bindings.
10、History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T Y.4500.8 2018-03-01 20 11.1002/1000/13503 Keywords CoAP binding, oneM2M * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For
11、 example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T Y.4500.8 (03/2018) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication St
12、andardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA),
13、 which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall with
14、in ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommen
15、dation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such a
16、s “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendati
17、on may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval o
18、f this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent
19、 database at http:/www.itu.int/ITU-T/ipr/. NOTE This Recommendation departs slightly from the usual editorial style of ITU-T Recommendations to preserve existing cross-referencing from external documents. ITU 2018 All rights reserved. No part of this publication may be reproduced, by any means whats
20、oever, without the prior written permission of ITU. Rec. ITU-T Y.4500.8 (03/2018) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Overview . 3 6.0 Intro
21、duction 3 6.1 Required features 3 6.2 Introduction of CoAP . 3 7 CoAP message mapping . 4 7.1 Introduction 4 7.2 Primitive mapping to CoAP message . 5 7.3 Accessing resources in CSEs 11 7.4 Mapping rules of caching . 13 7.5 Usage of blockwise transfers 13 8 Security consideration 13 Annex A oneM2M s
22、pecification update and maintenance control procedure 15 Appendix I Example procedures . 16 I.1 Blocking case of AE registration 16 I.2 Non-blocking synchronous case of AE registration . 17 Bibliography. 18 Rec. ITU-T Y.4500.8 (03/2018) 1 Recommendation ITU-T Y.4500.1 oneM2M CoAP protocol binding 1
23、Scope This Recommendation covers the protocol specific part of communication protocol used by oneM2M compliant systems as representational state transfer (REST) constrained application protocol (CoAP) RESTful CoAP bindings. The scope of this Recommendation is (but not limited to as shown below): Bin
24、ding oneM2M primitives to CoAP messages. Binding oneM2M response status codes to CoAP response codes. Defining behaviour of a CoAP client and server depending on oneM2M parameters. The Recommendation contains oneM2M Release 2 specification oneM2M CoAP Protocol Binding V1.0.1 and is equivalent to sta
25、ndards of oneM2M partners including Association of Radio Industries and Businesses (ARIB), Alliance for Telecommunications Industry Solutions (ATIS) b-ATIS.oneM2M, China Communications Standards Association (CCSA), European Telecommunications Standards Institute (ETSI) b-ETSI TS 118 108, Telecommuni
26、cations Industry Association (TIA) b-TIA-5022.008, Telecommunications Standards Development Society India (TSDSI), Telecommunications Technology Association (TTA) b-TTAT.MM-TS.0008 and Telecommunication Technology Committee (TTC) b-TTC TS-M2M-0008. 2 References The following ITU-T Recommendations an
27、d other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encou
28、raged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone doc
29、ument, the status of a Recommendation. ITU-T Y.4500.1 Recommendation ITU-T Y.4500.1 (2018), oneM2M Functional architecture. ITU-T Y.4500.4 Recommendation ITU-T Y. 4500.4 (2018), Service layer core protocol. ETSI TS 118 103 ETSI TS 118 103 V2.4.1 (2016), oneM2M; Security solutions. IETF RFC 6347 IETF
30、 RFC 6347 (2012), Datagram Transport Layer Security Version 1.2. IETF RFC 7252 IETF RFC 7252 (2014), The Constrained Application Protocol (CoAP). IETF RFC 7959 IETF RFC 7959 (2016), Block-Wise Transfers in the Constrained Application Protocol (CoAP). 3 Definitions 3.1 Terms defined elsewhere This Re
31、commendation uses the following terms defined elsewhere: 3.1.1 application entity (AE) b-ITU-T Y.4500.11: represents an instantiation of Application logic for end-to-end M2M solutions. 2 Rec. ITU-T Y.4500.8 (03/2018) 3.1.2 common services entity (CSE) b-ITU-T Y.4500.11: represents an instantiation o
32、f a set of Common Service Functions of the M2M environments. Such service functions are exposed to other entities through reference points. 3.2 Terms defined in this Recommendation None. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ACK Acknowledgeme
33、nt AE Application Entity CON Confirmable CSE Common Services Entity DTLS Datagram Transport Layer Security HTTP Hypertext Transfer Protocol IANA Internet Assigned Numbers Authority IP Internet Protocol REST Representational state transfer RST CoAP Reset message TCP Transport Control Protocol TLS Tra
34、nsport Layer Security TLV Tag - Length - Value (data structure) UDP User Datagram Protocol URI Uniform Resource Identifier XML extensible Markup Language 5 Conventions The keywords “Shall“, “Shall not“, “May“, “Need not“, “Should“, “Should not“ in the present document are to be interpreted as descri
35、bed. Shall/Shall not: Requirements 1) effect this Recommendation: This Recommendation needs to describe the required feature (i.e., specify a technical solution for the Requirement); 2) effect on products: every implementation (M2M Solution that complies to this Standard) must support it; 3) effect
36、on deployments: every deployment (M2M Service based on this Standard) must use the Standardized feature where applicable otherwise e.g., interoperability problems with other services could arise. Should/Should not: Rec. ITU-T Y.4500.8 (03/2018) 3 Recommendation 1) effect on this Recommendation: This
37、 Recommendation needs to describe a solution that allows the presence and the absence of the feature; 2) effect on products: an implementation may or may not support it, however support is recommended; 3) effect on deployments: a deployment may or may not use it, however usage is recommended. May/Ne
38、ed not: Permission/option 1) effect on this Recommendation: This Recommendation needs to describe a solution that allows the presence and the absence of the required feature; 2) effect on products: an implementation may or may not support it; 3) effect on deployments: A deployment may or may not use
39、 it. 6 Overview 6.0 Introduction The clause describes which features need to be supported in CoAP layer and introduces a message format and several features of CoAP used in this protocol binding specification. 6.1 Required features This clause explicitly specifies the required features of the CoAP l
40、ayer for oneM2M to properly bind oneM2M primitives into CoAP messages: The 4-byte binary CoAP message header is defined in section 3 of IETF RFC 7252. Confirmable (CON), acknowledgement (ACK) and reset (RST) messages shall be supported. The reset message is used to send an error message in response
41、to a malformed confirmable message in CoAP layer. GET, PUT, POST and DELETE methods shall be supported. oneM2M primitives map to these methods. A subset of response codes specified in clause 7.2.4 shall be supported for oneM2M Response Status Code parameter mapping. The Uri-Host, Uri-Port, Uri-Path,
42、 and Uri-Query shall be supported. The content-type option shall be used to indicate the media types of the payload. The token option may be used. Block-wise transfers feature may be supported to carry large payloads. Caching feature may be supported. 6.2 Introduction of CoAP 6.2.0 Introduction This
43、 clause describes a message format, and caching and block-wise transfers features which may be used to map oneM2M primitives to CoAP messages. 6.2.1 Message format This clause specifies details about the CoAP IETF RFC 7252 message format: CoAP message occupies the data section of one user datagram p
44、rotocol (UDP) datagram; CoAP message format supports a 4-byte fixed-size header; 4 Rec. ITU-T Y.4500.8 (03/2018) fixed-size header is followed by a Token value of length 0 to 8 bytes; the token value is followed by a sequence of zero or more CoAP options in type length value (TLV) format; CoAP optio
45、ns are followed by the payload part. For more details on the CoAP message format and the supported header fields, refer IETF RFC 7252. 6.2.2 Caching 6.2.2.0 Introduction CoAP IETF RFC 7252 supports caching of responses to fulfil future equivalent requests to the same resource. Caching is supported u
46、sing freshness and validity information carried with CoAP IETF RFC 7252 responses. 6.2.2.1 Freshness CoAP server shall use Max-Age CoAP option to specify the explicit expiration time for the CoAP responses resource representation. This indicates that the response is not fresh after its age is greate
47、r than the specified number of seconds; Max-Age option defaults to a value of 60 (seconds). In case, Max-Age option is not present in the cacheable response, the response shall not be considered fresh after its age is greater than 60 seconds; The CoAP server shall set the Max-Age option value to 0 (
48、zero) to prevent or disable caching; The CoAP client, having a fresh stored response, can make new request matching the request for that stored response. In this case, the new response shall invalidate the old response. 6.2.2.2 Validity A CoAP endpoint with stored responses but not able to satisfy s
49、ubsequent requests (for example, the response is not fresh), shall use the ETag option to perform a conditional request to the CoAP server where the resource is hosted; If the cached response with the CoAP client is still valid, the server shall include the Max-Age option in the response along with a code of 2.03 - Valid. This shall update the freshness of the cached response at the CoAP client; If the cached response with the Co
