draft-ietf-core-hop-limit-07.txt   rfc8768.txt 
CORE M. Boucadair Internet Engineering Task Force (IETF) M. Boucadair
Internet-Draft Orange Request for Comments: 8768 Orange
Intended status: Standards Track T. Reddy Category: Standards Track T. Reddy.K
Expires: April 19, 2020 McAfee ISSN: 2070-1721 McAfee
J. Shallow J. Shallow
October 17, 2019 March 2020
Constrained Application Protocol (CoAP) Hop-Limit Option Constrained Application Protocol (CoAP) Hop-Limit Option
draft-ietf-core-hop-limit-07
Abstract Abstract
The presence of Constrained Application Protocol (CoAP) proxies may The presence of Constrained Application Protocol (CoAP) proxies may
lead to infinite forwarding loops, which is undesirable. To prevent lead to infinite forwarding loops, which is undesirable. To prevent
and detect such loops, this document specifies the Hop-Limit CoAP and detect such loops, this document specifies the Hop-Limit CoAP
option. option.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
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time. It is inappropriate to use Internet-Drafts as reference received public review and has been approved for publication by the
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Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on April 19, 2020. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8768.
Copyright Notice Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction
1.1. Intended Usage . . . . . . . . . . . . . . . . . . . . . 2 1.1. Intended Usage
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology
3. Hop-Limit Option . . . . . . . . . . . . . . . . . . . . . . 3 3. Hop-Limit Option
4. Debugging & Troubleshooting . . . . . . . . . . . . . . . . . 5 4. Debugging and Troubleshooting
5. HTTP-Mapping Considerations . . . . . . . . . . . . . . . . . 5 5. HTTP Mapping Considerations
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations
6.1. CoAP Response Code . . . . . . . . . . . . . . . . . . . 6 6.1. CoAP Response Code
6.2. CoAP Option Number . . . . . . . . . . . . . . . . . . . 6 6.2. CoAP Option Number
7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 7. Security Considerations
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 7 8. References
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 7 8.1. Normative References
9.1. Normative References . . . . . . . . . . . . . . . . . . 8 8.2. Informative References
9.2. Informative References . . . . . . . . . . . . . . . . . 8 Acknowledgements
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses
1. Introduction 1. Introduction
More and more applications are using the Constrained Application More and more applications are using the Constrained Application
Protocol (CoAP) [RFC7252] as a communication protocol between Protocol (CoAP) [RFC7252] as a communication protocol between
application agents. For example, [I-D.ietf-dots-signal-channel] application agents. For example, [DOTS-SIG-CHANNEL] specifies how
specifies how CoAP is used as a signaling protocol between domains CoAP is used as a signaling protocol between domains under
under distributed denial-of-service (DDoS) attacks and DDoS distributed denial-of-service (DDoS) attacks and DDoS mitigation
mitigation providers. In such contexts, a CoAP client can providers. In such contexts, a CoAP client can communicate directly
communicate directly with a server or indirectly via proxies. with a server or indirectly via proxies.
When multiple proxies are involved, infinite forwarding loops may be When multiple proxies are involved, infinite forwarding loops may be
experienced (e.g., routing misconfiguration, policy conflicts). To experienced (e.g., routing misconfiguration, policy conflicts). To
prevent such loops, this document defines a new CoAP option, called prevent such loops, this document defines a new CoAP option, called
Hop-Limit (Section 3). Also, the document defines a new CoAP Hop-Limit (Section 3). Also, the document defines a new CoAP
Response Code (Section 6.1) to report loops together with relevant Response Code (Section 6.1) to report loops together with relevant
diagnostic information to ease troubleshooting (Section 4). diagnostic information to ease troubleshooting (Section 4).
1.1. Intended Usage 1.1. Intended Usage
The Hop-Limit option was originally designed for a specific use case The Hop-Limit option was originally designed for a specific use case
[I-D.ietf-dots-signal-channel]. However, its intended usage is [DOTS-SIG-CHANNEL]. However, its intended usage is general:
general:
New CoAP proxies MUST implement this option and have it enabled by New CoAP proxies MUST implement this option and have it enabled by
default. default.
Note that this means that a server that receives requests both via Note that this means that a server that receives requests both via
proxies and directly from clients may see otherwise identical proxies and directly from clients may see otherwise identical
requests with and without the Hop-Limit option included; servers with requests with and without the Hop-Limit option included; servers with
internal caching will therefore also want to implement this option, internal caching will therefore also want to implement this option,
since understanding the Hop-Limit option will improve caching since understanding the Hop-Limit option will improve caching
efficiency. efficiency.
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", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119][RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
Readers should be familiar with the terms and concepts defined in Readers should be familiar with the terms and concepts defined in
[RFC7252]. [RFC7252].
3. Hop-Limit Option 3. Hop-Limit Option
The properties of the Hop-Limit option are shown in Table 1. The The properties of the Hop-Limit option are shown in Table 1. The
formatting of this table follows the one used in Table 4 of [RFC7252] formatting of this table follows the one used in Table 4 of [RFC7252]
(Section 5.10). The C, U, N, and R columns indicate the properties (Section 5.10). The C, U, N, and R columns indicate the properties
Critical, Unsafe, NoCacheKey, and Repeatable defined in Section 5.4 Critical, Unsafe, NoCacheKey, and Repeatable defined in Section 5.4
of [RFC7252]. None of these properties is marked for the Hop-Limit of [RFC7252]. None of these properties is marked for the Hop-Limit
option. option.
+--------+---+---+---+---+-----------+--------+--------+---------+ +--------+---+---+---+---+-----------+--------+--------+---------+
| Number | C | U | N | R | Name | Format | Length | Default | | Number | C | U | N | R | Name | Format | Length | Default |
+--------+---+---+---+---+-----------+--------+--------+---------+ +========+===+===+===+===+===========+========+========+=========+
| TBA2 | | | | | Hop-Limit | uint | 1 | 16 | | 16 | | | | | Hop-Limit | uint | 1 | 16 |
+--------+---+---+---+---+-----------+--------+--------+---------+ +--------+---+---+---+---+-----------+--------+--------+---------+
Table 1: CoAP Hop-Limit Option Properties Table 1: CoAP Hop-Limit Option Properties
The Hop-Limit option (Section 6.2) is an elective option used to The Hop-Limit option (Section 6.2) is an elective option used to
detect and prevent infinite loops of CoAP requests when proxies are detect and prevent infinite loops of CoAP requests when proxies are
involved. The option is not repeatable. Therefore, any request involved. The option is not repeatable. Therefore, any request
carrying multiple Hop-Limit options MUST be handled following the carrying multiple Hop-Limit options MUST be handled following the
procedure specified in Section 5.4.5 of [RFC7252]. procedure specified in Section 5.4.5 of [RFC7252].
The value of the Hop-Limit option is encoded as an unsigned integer The value of the Hop-Limit option is encoded as an unsigned integer
(see Section 3.2 of [RFC7252]). This value MUST be between 1 and 255 (see Section 3.2 of [RFC7252]). This value MUST be between 1 and 255
inclusive. CoAP requests received with a Hop-Limit option set to '0' inclusive. CoAP requests received with a Hop-Limit option set to '0'
skipping to change at page 4, line 23 skipping to change at line 155
option is involved in the loop. option is involved in the loop.
A CoAP proxy that understands the Hop-Limit option SHOULD be A CoAP proxy that understands the Hop-Limit option SHOULD be
instructed, using a configuration parameter, to insert a Hop-Limit instructed, using a configuration parameter, to insert a Hop-Limit
option when relaying a request that does not include the Hop-Limit option when relaying a request that does not include the Hop-Limit
option. option.
The initial Hop-Limit value should be configurable. If no initial The initial Hop-Limit value should be configurable. If no initial
value is explicitly provided, the default initial Hop-Limit value of value is explicitly provided, the default initial Hop-Limit value of
16 MUST be used. This value is chosen so that in the majority of 16 MUST be used. This value is chosen so that in the majority of
cases it is sufficiently large to guarantee that a CoAP request would cases, it is sufficiently large to guarantee that a CoAP request
not be dropped in networks when there were no loops, but not so large would not be dropped in networks when there were no loops, but not so
as to consume CoAP proxy resources when a loop does occur. The value large as to consume CoAP proxy resources when a loop does occur. The
is still configurable to accommodate unusual topologies. Lower value is still configurable to accommodate unusual topologies. Lower
values should be used with caution and only in networks where values should be used with caution and only in networks where
topologies are known by the CoAP client (or proxy) inserting the Hop- topologies are known by the CoAP client (or proxy) inserting the Hop-
Limit option. Limit option.
Because forwarding errors may occur if inadequate Hop-Limit values Because forwarding errors may occur if inadequate Hop-Limit values
are used, proxies at the boundaries of an administrative domain MAY are used, proxies at the boundaries of an administrative domain MAY
be instructed to remove or rewrite the value of Hop-Limit carried in be instructed to remove or rewrite the value of Hop-Limit carried in
received requests (i.e., ignore the value of Hop-Limit received in a received requests (i.e., ignore the value of Hop-Limit received in a
request). This modification should be done with caution in case request). This modification should be done with caution in case
proxy-forwarded traffic repeatedly crosses the administrative domain proxy-forwarded traffic repeatedly crosses the administrative domain
boundary in a loop rendering ineffective the efficacy of loop boundary in a loop, rendering ineffective the efficacy of loop
detection through the Hop-Limit option. detection through the Hop-Limit option.
Otherwise, a CoAP proxy that understands the Hop-Limit option MUST Otherwise, a CoAP proxy that understands the Hop-Limit option MUST
decrement the value of the option by 1 prior to forwarding it. A decrement the value of the option by 1 prior to forwarding it. A
CoAP proxy that understands the Hop-Limit option MUST NOT use a CoAP proxy that understands the Hop-Limit option MUST NOT use a
stored TBA1 (Hop Limit Reached) error response unless the value of stored 5.08 (Hop Limit Reached) error response unless the value of
the Hop-Limit option in the presented request is smaller than or the Hop-Limit option in the presented request is smaller than or
equal to the value of the Hop-Limit option in the request used to equal to the value of the Hop-Limit option in the request used to
obtain the stored response. Otherwise, the CoAP proxy follows the obtain the stored response. Otherwise, the CoAP proxy follows the
behavior in Section 5.6 of [RFC7252]. behavior in Section 5.6 of [RFC7252].
Note: If a request with a given value of Hop-Limit failed to reach Note: If a request with a given value of Hop-Limit failed to reach
a server because the hop limit is exhausted, then the same failure a server because the hop limit is exhausted, then the same failure
will be observed if a smaller value of the Hop-Limit option is will be observed if a smaller value of the Hop-Limit option is
used instead. used instead.
CoAP requests MUST NOT be forwarded if the Hop-Limit option is set to CoAP requests MUST NOT be forwarded if the Hop-Limit option is set to
'0' after decrement. Requests that cannot be forwarded because of '0' after decrement. Requests that cannot be forwarded because of
exhausted Hop-Limit SHOULD be logged with a TBA1 (Hop Limit Reached) exhausted Hop-Limit SHOULD be logged with a 5.08 (Hop Limit Reached)
error response sent back to the CoAP peer. It is RECOMMENDED that error response sent back to the CoAP peer. It is RECOMMENDED that
CoAP implementations support means to alert administrators about loop CoAP implementations support means to alert administrators about loop
errors so that appropriate actions are undertaken. errors so that appropriate actions are undertaken.
4. Debugging & Troubleshooting 4. Debugging and Troubleshooting
To ease debugging and troubleshooting, the CoAP proxy that detects a To ease debugging and troubleshooting, the CoAP proxy that detects a
loop includes an identifier for itself in the diagnostic payload loop includes an identifier for itself in the diagnostic payload
under the conditions detailed in Section 5.5.2 of [RFC7252]. That under the conditions detailed in Section 5.5.2 of [RFC7252]. That
identifier MUST NOT include any space character (ASCII value 32). identifier MUST NOT include any space character (ASCII value 32).
The identifier inserted by a CoAP proxy can be, for example, a proxy The identifier inserted by a CoAP proxy can be, for example, a proxy
name (e.g., p11.example.net), proxy alias (e.g., myproxyalias), or IP name (e.g., p11.example.net), proxy alias (e.g., myproxyalias), or IP
address (e.g., 2001:db8::1). address (e.g., 2001:db8::1).
Each intermediate proxy involved in relaying a TBA1 (Hop Limit Each intermediate proxy involved in relaying a 5.08 (Hop Limit
Reached) error message prepends its own identifier in the diagnostic Reached) error message prepends its own identifier in the diagnostic
payload with a space character used as separator. Only one payload with a space character used as separator. Only one
identifier per proxy should appear in the diagnostic payload. This identifier per proxy should appear in the diagnostic payload. This
approach allows to limit the size of the TBA1 (Hop Limit Reached) approach allows the limiting of the size of the 5.08 (Hop Limit
error message, ease correlation with hops count, and detect whether a Reached) error message, eases the correlation with hops count, and
proxy was involved in the forwarding of the TBA1 (Hop Limit Reached) detects whether a proxy was involved in the forwarding of the 5.08
error message. Note that an intermediate proxy prepends its (Hop Limit Reached) error message. Note that an intermediate proxy
identifier only if there is enough space as determined by the Path prepends its identifier only if there is enough space as determined
MTU (Section 4.6 of [RFC7252]). If not, an intermediate proxy by the Path MTU (Section 4.6 of [RFC7252]). If not, an intermediate
forwards the TBA1 (Hop Limit Reached) error message to the next hop proxy forwards the 5.08 (Hop Limit Reached) error message to the next
without updating the diagnostic payload. hop without updating the diagnostic payload.
An intermediate proxy MUST NOT forward a TBA1 (Hop Limit Reached) An intermediate proxy MUST NOT forward a 5.08 (Hop Limit Reached)
error message if it detects that its identifier is included in the error message if it detects that its identifier is included in the
diagnostic payload. Such messages SHOULD be logged and appropriate diagnostic payload. Such messages SHOULD be logged and appropriate
alerts sent to the administrators. alerts sent to the administrators.
5. HTTP-Mapping Considerations 5. HTTP Mapping Considerations
This section focuses on the HTTP mappings specific to the CoAP This section focuses on the HTTP mappings specific to the CoAP
extension specified in this document. As a reminder, the basic extension specified in this document. As a reminder, the basic
normative requirements on HTTP/CoAP mappings are defined in normative requirements on HTTP/CoAP mappings are defined in
Section 10 of [RFC7252]. The implementation guidelines for HTTP/CoAP Section 10 of [RFC7252]. The implementation guidelines for HTTP/CoAP
mappings are elaborated in [RFC8075]. mappings are elaborated in [RFC8075].
By default, the HTTP-to-CoAP Proxy inserts a Hop-Limit option By default, the HTTP-to-CoAP Proxy inserts a Hop-Limit option
following the guidelines in Section 3. The HTTP-to-CoAP Proxy may be following the guidelines in Section 3. The HTTP-to-CoAP Proxy may be
instructed by policy to insert a Hop-Limit option only if a Via instructed by policy to insert a Hop-Limit option only if a Via
(Section 5.7.1 of [RFC7230]) or CDN-Loop header field [RFC8586] is (Section 5.7.1 of [RFC7230]) or CDN-Loop header field [RFC8586] is
present in the HTTP request. present in the HTTP request.
The HTTP-to-CoAP Proxy uses 508 (Loop Detected) as the HTTP response The HTTP-to-CoAP Proxy uses 508 (Loop Detected) as the HTTP response
status code to map TBA1 (Hop Limit Reached). Furthermore, it maps status code to map 5.08 (Hop Limit Reached). Furthermore, it maps
the diagnostic payload of TBA1 (Hop Limit Reached) as per Section 6.6 the diagnostic payload of 5.08 (Hop Limit Reached) as per Section 6.6
of [RFC8075]. of [RFC8075].
By default, the CoAP-to-HTTP Proxy inserts a Via header field in the By default, the CoAP-to-HTTP Proxy inserts a Via header field in the
HTTP request if the CoAP request includes a Hop-Limit option. The HTTP request if the CoAP request includes a Hop-Limit option. The
CoAP-to-HTTP Proxy may be instructed by policy to insert a CDN-Loop CoAP-to-HTTP Proxy may be instructed by policy to insert a CDN-Loop
header field instead of the Via header field. header field instead of the Via header field.
The CoAP-to-HTTP Proxy maps the 508 (Loop Detected) HTTP response The CoAP-to-HTTP Proxy maps the 508 (Loop Detected) HTTP response
status code to TBA1 (Hop Limit Reached). Moreover, the CoAP-to-HTTP status code to 5.08 (Hop Limit Reached). Moreover, the CoAP-to-HTTP
Proxy inserts its information following the guidelines in Section 4. Proxy inserts its information following the guidelines in Section 4.
When both HTTP-to-CoAP and CoAP-to-HTTP proxies are involved, the When both HTTP-to-CoAP and CoAP-to-HTTP proxies are involved, the
loop detection may get broken if the proxy-forwarded traffic loop detection may break if the proxy-forwarded traffic repeatedly
repeatedly crosses the HTTP-to-CoAP and CoAP-to-HTTP proxies. crosses the HTTP-to-CoAP and CoAP-to-HTTP proxies. Nevertheless, if
Nevertheless, if the loop is within the CoAP or HTTP legs, the loop the loop is within the CoAP or HTTP legs, the loop detection is still
detection is still functional. functional.
6. IANA Considerations 6. IANA Considerations
Editorial Note: Please update TBA1/TBA2 statements within the
document with the assigned codes.
6.1. CoAP Response Code 6.1. CoAP Response Code
IANA is requested to add the following entry to the "CoAP Response IANA has registered the following entry in the "CoAP Response Codes"
Codes" sub-registry available at https://www.iana.org/assignments/ subregistry available at <https://www.iana.org/assignments/core-
core-parameters/core-parameters.xhtml#response-codes: parameters>:
+------+------------------+-----------+
| Code | Description | Reference |
+------+------------------+-----------+
| TBA1 | Hop Limit Reached| [RFCXXXX] |
+------+------------------+-----------+
Table 2: CoAP Response Codes +------+-------------------+-----------+
| Code | Description | Reference |
+======+===================+===========+
| 5.08 | Hop Limit Reached | RFC 8768 |
+------+-------------------+-----------+
This document suggests 5.08 as a code to be assigned for the new Table 2: CoAP Response Codes
response code.
6.2. CoAP Option Number 6.2. CoAP Option Number
IANA is requested to add the following entry to the "CoAP Option IANA has registered the following entry in the "CoAP Option Numbers"
Numbers" sub-registry available at https://www.iana.org/assignments/ subregistry available at <https://www.iana.org/assignments/core-
core-parameters/core-parameters.xhtml#option-numbers: parameters>:
+--------+------------------+-----------+
| Number | Name | Reference |
+--------+------------------+-----------+
| TBA2 | Hop-Limit | [RFCXXXX] |
+--------+------------------+-----------+
Table 3: CoAP Option Number +--------+-----------+-----------+
| Number | Name | Reference |
+========+===========+===========+
| 16 | Hop-Limit | RFC 8768 |
+--------+-----------+-----------+
This document suggests 16 as a value to be assigned for the new Table 3: CoAP Option Number
option number.
7. Security Considerations 7. Security Considerations
Security considerations related to CoAP proxying are discussed in Security considerations related to CoAP proxying are discussed in
Section 11.2 of [RFC7252]. Section 11.2 of [RFC7252].
A CoAP endpoint can probe the topology of a network into which it is A CoAP endpoint can probe the topology of a network into which it is
making requests by tweaking the value of the Hop-Limit option. Such making requests by tweaking the value of the Hop-Limit option. Such
probing is likely to fail if proxies at the boundaries of that probing is likely to fail if proxies at the boundaries of that
network rewrite the value of Hop-Limit carried in received requests network rewrite the value of Hop-Limit carried in received requests
(see Section 3). (see Section 3).
The diagnostic payload of a TBA1 (Hop Limit Reached) error message The diagnostic payload of a 5.08 (Hop Limit Reached) error message
may leak sensitive information revealing the topology of an may leak sensitive information revealing the topology of an
administrative domain. To prevent that, a CoAP proxy that is located administrative domain. To prevent that, a CoAP proxy that is located
at the boundary of an administrative domain MAY be instructed to at the boundary of an administrative domain MAY be instructed to
strip the diagnostic payload or part of it before forwarding on the strip the diagnostic payload or part of it before forwarding on the
TBA1 (Hop Limit Reached) response. 5.08 (Hop Limit Reached) response.
8. Acknowledgements
This specification was part of [I-D.ietf-dots-signal-channel]. Many
thanks to those who reviewed DOTS specifications.
Thanks to Klaus Hartke, Carsten Bormann, Peter van der Stok, Jim
Schaad, Jaime Jimenez, Roni Even, Scott Bradner, Thomas Fossati,
Radia Perlman, Eric Vyncke, Suresh Krishnan, Roman Danyliw, Barry
Leiba, Christer Holmberg, Benjamin Kaduk, and Adam Roach for their
review and comments.
Carsten Bormann provided the "Intended Usage" text. 8. References
9. References 8.1. Normative References
9.1. Normative References
[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, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[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", Protocol (HTTP/1.1): Message Syntax and Routing",
RFC 7230, DOI 10.17487/RFC7230, June 2014, RFC 7230, DOI 10.17487/RFC7230, June 2014,
<https://www.rfc-editor.org/info/rfc7230>. <https://www.rfc-editor.org/info/rfc7230>.
skipping to change at page 8, line 31 skipping to change at line 332
[RFC8075] Castellani, A., Loreto, S., Rahman, A., Fossati, T., and [RFC8075] Castellani, A., Loreto, S., Rahman, A., Fossati, T., and
E. Dijk, "Guidelines for Mapping Implementations: HTTP to E. Dijk, "Guidelines for Mapping Implementations: HTTP to
the Constrained Application Protocol (CoAP)", RFC 8075, the Constrained Application Protocol (CoAP)", RFC 8075,
DOI 10.17487/RFC8075, February 2017, DOI 10.17487/RFC8075, February 2017,
<https://www.rfc-editor.org/info/rfc8075>. <https://www.rfc-editor.org/info/rfc8075>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
9.2. Informative References 8.2. Informative References
[I-D.ietf-dots-signal-channel] [DOTS-SIG-CHANNEL]
K, R., Boucadair, M., Patil, P., Mortensen, A., and N. Reddy, T., Boucadair, M., Patil, P., Mortensen, A., and N.
Teague, "Distributed Denial-of-Service Open Threat Teague, "Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification", draft- Signaling (DOTS) Signal Channel Specification", Work in
ietf-dots-signal-channel-37 (work in progress), July 2019. Progress, Internet-Draft, draft-ietf-dots-signal-channel-
41, 6 January 2020, <https://tools.ietf.org/html/draft-
ietf-dots-signal-channel-41>.
[RFC8586] Ludin, S., Nottingham, M., and N. Sullivan, "Loop [RFC8586] Ludin, S., Nottingham, M., and N. Sullivan, "Loop
Detection in Content Delivery Networks (CDNs)", RFC 8586, Detection in Content Delivery Networks (CDNs)", RFC 8586,
DOI 10.17487/RFC8586, April 2019, DOI 10.17487/RFC8586, April 2019,
<https://www.rfc-editor.org/info/rfc8586>. <https://www.rfc-editor.org/info/rfc8586>.
Acknowledgements
This specification was part of [DOTS-SIG-CHANNEL]. Many thanks to
those who reviewed DOTS specifications.
Thanks to Klaus Hartke, Carsten Bormann, Peter van der Stok, Jim
Schaad, Jaime Jiménez, Roni Even, Scott Bradner, Thomas Fossati,
Radia Perlman, Éric Vyncke, Suresh Krishnan, Roman Danyliw, Barry
Leiba, Christer Holmberg, Benjamin Kaduk, and Adam Roach for their
review and comments.
Carsten Bormann provided the "Intended Usage" text.
Authors' Addresses Authors' Addresses
Mohamed Boucadair Mohamed Boucadair
Orange Orange
Rennes 35000 35000 Rennes
France France
Email: mohamed.boucadair@orange.com Email: mohamed.boucadair@orange.com
Tirumaleswar Reddy
Tirumaleswar Reddy.K
McAfee, Inc. McAfee, Inc.
Embassy Golf Link Business Park Embassy Golf Link Business Park
Bangalore, Karnataka 560071 Bangalore 560071
Karnataka
India India
Email: kondtir@gmail.com Email: kondtir@gmail.com
Jon Shallow Jon Shallow
United Kingdom United Kingdom
Email: supjps-ietf@jpshallow.com Email: supjps-ietf@jpshallow.com
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