103 lines
3.7 KiB
Plaintext
103 lines
3.7 KiB
Plaintext
Internet Engineering Task Force (IETF) Z. Shelby
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Request for Comments: 7252 ARM
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Category: Standards Track K. Hartke
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ISSN: 2070-1721 C. Bormann
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Universitaet Bremen TZI
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June 2014
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The Constrained Application Protocol (CoAP)
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Abstract
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The Constrained Application Protocol (CoAP) is a specialized web
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transfer protocol for use with constrained nodes and constrained
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(e.g., low-power, lossy) networks. The nodes often have 8-bit
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microcontrollers with small amounts of ROM and RAM, while constrained
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networks such as IPv6 over Low-Power Wireless Personal Area Networks
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(6LoWPANs) often have high packet error rates and a typical
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throughput of 10s of kbit/s. The protocol is designed for machine-
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to-machine (M2M) applications such as smart energy and building
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automation.
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CoAP provides a request/response interaction model between
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application endpoints, supports built-in discovery of services and
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resources, and includes key concepts of the Web such as URIs and
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Internet media types. CoAP is designed to easily interface with HTTP
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for integration with the Web while meeting specialized requirements
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such as multicast support, very low overhead, and simplicity for
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constrained environments.
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Status of This Memo
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This is an Internet Standards Track document.
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Information about the current status of this document, any errata,
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and how to provide feedback on it may be obtained at
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http://www.rfc-editor.org/info/rfc7252.
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Table of Contents
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1. Introduction
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1.1. Features
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1.2. Terminology
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2. Constrained Application Protocol
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2.1. Messaging Model
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2.2. Request/Response Model
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2.3. Intermediaries and Caching
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2.4. Resource Discovery
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3. Message Format
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3.1. Option Format
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3.2. Option Value Formats
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4. Message Transmission
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4.1. Messages and Endpoints
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4.2. Messages Transmitted Reliably
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4.3. Messages Transmitted without Reliability
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4.4. Message Correlation
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4.5. Message Deduplication
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4.6. Message Size
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4.7. Congestion Control
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4.8. Transmission Parameters
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5. Request/Response Semantics
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5.1. Requests
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5.2. Responses
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5.3. Request/Response Matching
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5.4. Options
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5.5. Payloads and Representations
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5.6. Caching
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5.7. Proxying
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5.8. Method Definitions
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5.9. Response Code Definitions
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5.10. Option Definitions
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6. CoAP URIs
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6.1. coap URI Scheme
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6.2. coaps URI Scheme
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6.3. Normalization and Comparison Rules
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6.4. Decomposing URIs into Options
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6.5. Composing URIs from Options
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7. Discovery
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7.1. Service Discovery
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7.2. Resource Discovery
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8. Multicast CoAP
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8.1. Messaging Layer
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8.2. Request/Response Layer
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9. Securing CoAP
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9.1. DTLS-Secured CoAP
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10. Cross-Protocol Proxying between CoAP and HTTP
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10.1. CoAP-HTTP Proxying
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10.2. HTTP-CoAP Proxying
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11. Security Considerations
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12. IANA Considerations
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13. References
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13.1. Normative References
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13.2. Informative References
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[NOTE: This file contains the header, abstract, and table of contents
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of RFC 7252. The full specification text is available at:
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https://www.rfc-editor.org/rfc/rfc7252
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https://www.rfc-editor.org/rfc/rfc7252.txt (text)
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https://www.rfc-editor.org/rfc/rfc7252.pdf (PDF)
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Full document: 112 pages, June 2014
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Authors: Zach Shelby (ARM), Klaus Hartke, Carsten Bormann (Universitaet Bremen TZI)
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DOI: 10.17487/RFC7252]
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