draft-ietf-core-too-many-reqs-02.txt   draft-ietf-core-too-many-reqs-03.txt 
Network Working Group A. Keranen Network Working Group A. Keranen
Internet-Draft Ericsson Internet-Draft Ericsson
Intended status: Standards Track July 2, 2018 Intended status: Standards Track July 22, 2018
Expires: January 3, 2019 Expires: January 23, 2019
Too Many Requests Response Code for the Constrained Application Protocol Too Many Requests Response Code for the Constrained Application Protocol
draft-ietf-core-too-many-reqs-02 draft-ietf-core-too-many-reqs-03
Abstract Abstract
A Constrained Application Protocol (CoAP) server can experience A Constrained Application Protocol (CoAP) server can experience
temporary overload because one or more clients are sending requests temporary overload because one or more clients are sending requests
to the server at a higher rate than the server is capable or willing to the server at a higher rate than the server is capable or willing
to handle. This document defines a new CoAP Response Code for a to handle. This document defines a new CoAP Response Code for a
server to indicate that a client should reduce the rate of requests. server to indicate that a client should reduce the rate of requests.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 3, 2019. This Internet-Draft will expire on January 23, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. CoAP Server Behavior . . . . . . . . . . . . . . . . . . . . 3 3. CoAP Server Behavior . . . . . . . . . . . . . . . . . . . . 3
4. CoAP Client Behavior . . . . . . . . . . . . . . . . . . . . 3 4. CoAP Client Behavior . . . . . . . . . . . . . . . . . . . . 3
5. Security Considerations . . . . . . . . . . . . . . . . . . . 3 5. Security Considerations . . . . . . . . . . . . . . . . . . . 3
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4
8.1. Normative References . . . . . . . . . . . . . . . . . . 4 8.1. Normative References . . . . . . . . . . . . . . . . . . 4
8.2. Informative References . . . . . . . . . . . . . . . . . 4 8.2. Informative References . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction 1. Introduction
The Constrained Application Protocol (CoAP) [RFC7252] Response Codes The Constrained Application Protocol (CoAP) [RFC7252] Response Codes
are used by a CoAP server to indicate the result of the attempt to are used by a CoAP server to indicate the result of the attempt to
understand and satisfy a request sent by a client. understand and satisfy a request sent by a client.
CoAP Response Codes are similar to the HTTP [RFC7230] Status Codes CoAP Response Codes are similar to the HTTP [RFC7230] Status Codes
and many codes are shared with similar semantics by both CoAP and and many codes are shared with similar semantics by both CoAP and
HTTP. HTTP has the code "429" registered for "Too Many Requests" HTTP. HTTP has the code "429" registered for "Too Many Requests"
[RFC6585]. This document registers a CoAP Response Code "4.29" for [RFC6585]. This document registers a CoAP Response Code "4.29" for
similar purpose and also defines use of the Max-Age option to similar purpose and also defines use of the Max-Age option to
indicate a back-off period after which a client can try the request indicate a back-off period after which a client can try the request
again. again.
While a server may not be able to response to a one kind of request, While a server may not be able to respond to one kind of request, it
it may be able to respond to a different request, even from the same may be able to respond to a request of different kind, even from the
client. Therefore the back-off period applies only to similar same client. Therefore the back-off period applies only to similar
requests. For the purpose of this response code, a request is requests. For the purpose of this response code, a request is
similar if it has the same method, Request-URI, and payload. Also if similar if it has the same method and Request-URI. Also if a client
a client is sending a sequence of requests that are part of the same is sending a sequence of requests that are part of the same series
series (e.g., a set of measurements to be processed by the server) (e.g., a set of measurements to be processed by the server) they can
they can be considered similar even if request payloads or URIs may be considered similar even if request URIs may be different. Because
be different. Because request similarity is context-dependent, it is request similarity is context-dependent, it is up to the application
up to the application logic to decide how similar requests should be logic to decide how the similarity of the requests should be
suppressed. evaluated.
The 4.29 code is similar to the 5.03 "Service Unavailable" [RFC7252] The 4.29 code is similar to the 5.03 "Service Unavailable" [RFC7252]
code in a way that the 5.03 code can also be used by a server to code in a way that the 5.03 code can also be used by a server to
signal an overload situation. However the 4.29 code indicates that signal an overload situation. However the 4.29 code indicates that
the too frequent requests from the requesting client are the reason the too frequent requests from the requesting client are the reason
for the overload. for the overload.
2. Terminology 2. Terminology
The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL', 'SHALL NOT', The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
'SHOULD', 'SHOULD NOT', 'RECOMMENDED', 'MAY', and 'OPTIONAL' in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
specification are to be interpreted as described in [RFC2119]. "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 Readers should also be familiar with the terms and concepts discussed
in [RFC7252]. in [RFC7252].
3. CoAP Server Behavior 3. CoAP Server Behavior
If a CoAP server is unable to serve a client that is sending CoAP If a CoAP server is unable to serve a client that is sending CoAP
request messages more often than the server is capable or willing to request messages more often than the server is capable or willing to
handle, the server SHOULD respond to the request(s) with the Response handle, the server SHOULD respond to the request(s) with the Response
Code 4.29, "Too Many Requests". The Max-Age option is used to Code 4.29, "Too Many Requests". The Max-Age option is used to
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/ Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997, <https://www.rfc-editor.org/info/ RFC2119, March 1997, <https://www.rfc-editor.org/info/
rfc2119>. rfc2119>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252, DOI 10.17487/ Application Protocol (CoAP)", RFC 7252, DOI 10.17487/
RFC7252, June 2014, <https://www.rfc-editor.org/info/ RFC7252, June 2014, <https://www.rfc-editor.org/info/
rfc7252>. rfc7252>.
[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>.
8.2. Informative References 8.2. Informative References
[I-D.ietf-core-coap-pubsub] [I-D.ietf-core-coap-pubsub]
Koster, M., Keranen, A., and J. Jimenez, "Publish- Koster, M., Keranen, A., and J. Jimenez, "Publish-
Subscribe Broker for the Constrained Application Protocol Subscribe Broker for the Constrained Application Protocol
(CoAP)", draft-ietf-core-coap-pubsub-04 (work in (CoAP)", draft-ietf-core-coap-pubsub-05 (work in
progress), March 2018. progress), July 2018.
[RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status [RFC6585] Nottingham, M. and R. Fielding, "Additional HTTP Status
Codes", RFC 6585, DOI 10.17487/RFC6585, April 2012, Codes", RFC 6585, DOI 10.17487/RFC6585, April 2012,
<https://www.rfc-editor.org/info/rfc6585>. <https://www.rfc-editor.org/info/rfc6585>.
[RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Message Syntax and Routing", RFC Protocol (HTTP/1.1): Message Syntax and Routing", RFC
7230, DOI 10.17487/RFC7230, June 2014, <https://www.rfc- 7230, DOI 10.17487/RFC7230, June 2014, <https://www.rfc-
editor.org/info/rfc7230>. editor.org/info/rfc7230>.
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