< draft-ietf-dots-signal-channel-05.txt		draft-ietf-dots-signal-channel-06.txt >
	DOTS T. Reddy		DOTS T. Reddy
	Internet-Draft McAfee		Internet-Draft McAfee
	Intended status: Standards Track M. Boucadair		Intended status: Standards Track M. Boucadair
	Expires: April 15, 2018 Orange		Expires: April 30, 2018 Orange
	P. Patil		P. Patil
	Cisco		Cisco
	A. Mortensen		A. Mortensen
	Arbor Networks, Inc.		Arbor Networks, Inc.
	N. Teague		N. Teague
	Verisign, Inc.		Verisign, Inc.
	October 12, 2017		October 27, 2017
	Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal		Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal
	Channel		Channel
	draft-ietf-dots-signal-channel-05		draft-ietf-dots-signal-channel-06
	Abstract		Abstract
	This document specifies the DOTS signal channel, a protocol for		This document specifies the DOTS signal channel, a protocol for
	signaling the need for protection against Distributed Denial-of-		signaling the need for protection against Distributed Denial-of-
	Service (DDoS) attacks to a server capable of enabling network		Service (DDoS) attacks to a server capable of enabling network
	traffic mitigation on behalf of the requesting client. A companion		traffic mitigation on behalf of the requesting client. A companion
	document defines the DOTS data channel, a separate reliable		document defines the DOTS data channel, a separate reliable
	communication layer for DOTS management and configuration.		communication layer for DOTS management and configuration.
	skipping to change at page 1, line 43 ¶		skipping to change at page 1, line 43 ¶
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at https://datatracker.ietf.org/drafts/current/.		Drafts is at https://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	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 April 15, 2018.		This Internet-Draft will expire on April 30, 2018.
	Copyright Notice		Copyright Notice
	Copyright (c) 2017 IETF Trust and the persons identified as the		Copyright (c) 2017 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
	(https://trustee.ietf.org/license-info) in effect on the date of		(https://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
	skipping to change at page 2, line 21 ¶		skipping to change at page 2, line 21 ¶
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	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 . . . . . . . . . . . . . . . . . . . . . . . . 3		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
	2. Notational Conventions and Terminology . . . . . . . . . . . 3		2. Notational Conventions and Terminology . . . . . . . . . . . 3
	3. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 4		3. Solution Overview . . . . . . . . . . . . . . . . . . . . . . 4
	4. Happy Eyeballs for DOTS Signal Channel . . . . . . . . . . . 5		4. Happy Eyeballs for DOTS Signal Channel . . . . . . . . . . . 5
	5. DOTS Signal Channel . . . . . . . . . . . . . . . . . . . . . 7		5. DOTS Signal Channel . . . . . . . . . . . . . . . . . . . . . 6
	5.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 7		5.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 7
	5.2. DOTS Signal YANG Module . . . . . . . . . . . . . . . . . 8		5.2. DOTS Signal YANG Module . . . . . . . . . . . . . . . . . 8
	5.2.1. Mitigation Request YANG Module Tree Structure . . . . 8		5.2.1. Mitigation Request YANG Module Tree Structure . . . . 8
	5.2.2. Mitigation Request YANG Module . . . . . . . . . . . 8		5.2.2. Mitigation Request YANG Module . . . . . . . . . . . 8
	5.2.3. Session Configuration YANG Module Tree Structure . . 11		5.2.3. Session Configuration YANG Module Tree Structure . . 11
	5.2.4. Session Configuration YANG Module . . . . . . . . . . 12		5.2.4. Session Configuration YANG Module . . . . . . . . . . 12
	5.3. Mitigation Request . . . . . . . . . . . . . . . . . . . 14		5.3. Mitigation Request . . . . . . . . . . . . . . . . . . . 14
	5.3.1. Requesting mitigation . . . . . . . . . . . . . . . . 15		5.3.1. Requesting mitigation . . . . . . . . . . . . . . . . 15
	5.3.2. Withdraw a DOTS Signal . . . . . . . . . . . . . . . 22		5.3.2. Withdraw a DOTS Signal . . . . . . . . . . . . . . . 23
	5.3.3. Retrieving a DOTS Signal . . . . . . . . . . . . . . 23		5.3.3. Retrieving a DOTS Signal . . . . . . . . . . . . . . 24
	5.3.4. Efficacy Update from DOTS Client . . . . . . . . . . 28		5.3.4. Efficacy Update from DOTS Client . . . . . . . . . . 29
	5.4. DOTS Signal Channel Session Configuration . . . . . . . . 30		5.4. DOTS Signal Channel Session Configuration . . . . . . . . 31
	5.4.1. Discover Configuration Parameters . . . . . . . . . . 31		5.4.1. Discover Configuration Parameters . . . . . . . . . . 32
	5.4.2. Convey DOTS Signal Channel Session Configuration . . 33		5.4.2. Convey DOTS Signal Channel Session Configuration . . 34
	5.4.3. Delete DOTS Signal Channel Session Configuration . . 37		5.4.3. Delete DOTS Signal Channel Session Configuration . . 38
	5.4.4. Retrieving DOTS Signal Channel Session Configuration 38
	5.5. Redirected Signaling . . . . . . . . . . . . . . . . . . 38		5.5. Redirected Signaling . . . . . . . . . . . . . . . . . . 38
	5.6. Heartbeat Mechanism . . . . . . . . . . . . . . . . . . . 39		5.6. Heartbeat Mechanism . . . . . . . . . . . . . . . . . . . 40
	6. Mapping parameters to CBOR . . . . . . . . . . . . . . . . . 40		6. Mapping parameters to CBOR . . . . . . . . . . . . . . . . . 40
	7. (D)TLS Protocol Profile and Performance considerations . . . 41		7. (D)TLS Protocol Profile and Performance considerations . . . 41
	7.1. MTU and Fragmentation Issues . . . . . . . . . . . . . . 42		7.1. MTU and Fragmentation Issues . . . . . . . . . . . . . . 42
	8. (D)TLS 1.3 considerations . . . . . . . . . . . . . . . . . . 43		8. (D)TLS 1.3 considerations . . . . . . . . . . . . . . . . . . 43
	9. Mutual Authentication of DOTS Agents & Authorization of DOTS		9. Mutual Authentication of DOTS Agents & Authorization of DOTS
	Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 44		Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
	10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46		10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46
	10.1. CoAP Response Code . . . . . . . . . . . . . . . . . . . 46		10.1. CoAP Response Code . . . . . . . . . . . . . . . . . . . 46
	10.2. DOTS signal channel CBOR Mappings Registry . . . . . . . 46		10.2. DOTS signal channel CBOR Mappings Registry . . . . . . . 46
	10.2.1. Registration Template . . . . . . . . . . . . . . . 46		10.2.1. Registration Template . . . . . . . . . . . . . . . 46
	skipping to change at page 3, line 4 ¶		skipping to change at page 2, line 52 ¶
	8. (D)TLS 1.3 considerations . . . . . . . . . . . . . . . . . . 43		8. (D)TLS 1.3 considerations . . . . . . . . . . . . . . . . . . 43
	9. Mutual Authentication of DOTS Agents & Authorization of DOTS		9. Mutual Authentication of DOTS Agents & Authorization of DOTS
	Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 44		Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
	10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46		10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46
	10.1. CoAP Response Code . . . . . . . . . . . . . . . . . . . 46		10.1. CoAP Response Code . . . . . . . . . . . . . . . . . . . 46
	10.2. DOTS signal channel CBOR Mappings Registry . . . . . . . 46		10.2. DOTS signal channel CBOR Mappings Registry . . . . . . . 46
	10.2.1. Registration Template . . . . . . . . . . . . . . . 46		10.2.1. Registration Template . . . . . . . . . . . . . . . 46
	10.2.2. Initial Registry Contents . . . . . . . . . . . . . 47		10.2.2. Initial Registry Contents . . . . . . . . . . . . . 47
	11. Implementation Status . . . . . . . . . . . . . . . . . . . . 51		11. Implementation Status . . . . . . . . . . . . . . . . . . . . 51
	11.1. nttdots . . . . . . . . . . . . . . . . . . . . . . . . 51		11.1. nttdots . . . . . . . . . . . . . . . . . . . . . . . . 51
	12. Security Considerations . . . . . . . . . . . . . . . . . . . 52		12. Security Considerations . . . . . . . . . . . . . . . . . . . 52
	13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 53		13. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 53
	14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 53		14. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 53
	15. References . . . . . . . . . . . . . . . . . . . . . . . . . 53		15. References . . . . . . . . . . . . . . . . . . . . . . . . . 53
	15.1. Normative References . . . . . . . . . . . . . . . . . . 53		15.1. Normative References . . . . . . . . . . . . . . . . . . 53
	15.2. Informative References . . . . . . . . . . . . . . . . . 54		15.2. Informative References . . . . . . . . . . . . . . . . . 54
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 57		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 57
	1. Introduction		1. Introduction
	A distributed denial-of-service (DDoS) attack is an attempt to make		A distributed denial-of-service (DDoS) attack is an attempt to make
	machines or network resources unavailable to their intended users.		machines or network resources unavailable to their intended users.
	In most cases, sufficient scale can be achieved by compromising		In most cases, sufficient scale can be achieved by compromising
	enough end-hosts and using those infected hosts to perpetrate and		enough end-hosts and using those infected hosts to perpetrate and
	amplify the attack. The victim in this attack can be an application		amplify the attack. The victim in this attack can be an application
	server, a host, a router, a firewall, or an entire network.		server, a host, a router, a firewall, or an entire network.
	In many cases, it may not be possible for an network administrators		In many cases, it may not be possible for network administrators to
	to determine the causes of an attack, but instead just realize that		determine the causes of an attack, but instead just realize that
	certain resources seem to be under attack. This document defines a		certain resources seem to be under attack. This document defines a
	lightweight protocol permitting a DOTS client to request mitigation		lightweight protocol permitting a DOTS client to request mitigation
	from one or more DOTS servers for protection against detected,		from one or more DOTS servers for protection against detected,
	suspected, or anticipated attacks . This protocol enables cooperation		suspected, or anticipated attacks . This protocol enables cooperation
	between DOTS agents to permit a highly-automated network defense that		between DOTS agents to permit a highly-automated network defense that
	is robust, reliable and secure.		is robust, reliable and secure.
	The requirements for DOTS signal channel protocol are obtained from		The document adheres to the DOTS architecture
	[I-D.ietf-dots-requirements].		[I-D.ietf-dots-architecture]. The requirements for DOTS signal
			channel protocol are obtained from [I-D.ietf-dots-requirements].
	This document satisfies all the use cases discussed in		This document satisfies all the use cases discussed in
	[I-D.ietf-dots-use-cases] except the Third-party DOTS notifications		[I-D.ietf-dots-use-cases].
	use case in Section 3.2.3 of [I-D.ietf-dots-use-cases] which is an
	optional feature and not a core use case. Third-party DOTS
	notifications are not part of the DOTS requirements document.
	Moreover, the DOTS architecture does not assess whether that use case
	may have an impact on the architecture itself and/or the DOTS trust
	model.
	This is a companion document to the DOTS data channel specification		This is a companion document to the DOTS data channel specification
	[I-D.ietf-dots-data-channel] that defines a configuration and bulk		[I-D.ietf-dots-data-channel] that defines a configuration and bulk
	data exchange mechanism supporting the DOTS signal channel.		data exchange mechanism supporting the DOTS signal channel.
	2. Notational Conventions and Terminology		2. Notational Conventions and 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		"OPTIONAL" in this document are to be interpreted as described in
	skipping to change at page 6, line 41 ¶		skipping to change at page 6, line 38 ¶
	|--TCP ACK----------------------------------------------->|		|--TCP ACK----------------------------------------------->|
	|<------------Establish TLS Session---------------------->|		|<------------Establish TLS Session---------------------->|
	|----------------DOTS signal----------------------------->|		|----------------DOTS signal----------------------------->|
	| |		| |
	Figure 3: Happy Eyeballs		Figure 3: Happy Eyeballs
	In reference to Figure 3, the DOTS client sends two TCP SYNs and two		In reference to Figure 3, the DOTS client sends two TCP SYNs and two
	DTLS ClientHello messages at the same time over IPv6 and IPv4. In		DTLS ClientHello messages at the same time over IPv6 and IPv4. In
	this example, it is assumed that the IPv6 path is broken and UDP is		this example, it is assumed that the IPv6 path is broken and UDP is
	dropped by a middle box but has little impact to the DOTS client		dropped by a middlebox but has little impact to the DOTS client
	because there is no long delay before using IPv4 and TCP. The DOTS		because there is no long delay before using IPv4 and TCP. The DOTS
	client repeats the mechanism to discover if DOTS signaling with DTLS		client repeats the mechanism to discover if DOTS signaling with DTLS
	over UDP becomes available from the DOTS server, so the DOTS client		over UDP becomes available from the DOTS server, so the DOTS client
	can migrate the DOTS signal channel from TCP to UDP, but such probing		can migrate the DOTS signal channel from TCP to UDP, but such probing
	SHOULD NOT be done more frequently than every 24 hours and MUST NOT		SHOULD NOT be done more frequently than every 24 hours and MUST NOT
	be done more frequently than every 5 minutes.		be done more frequently than every 5 minutes.
	5. DOTS Signal Channel		5. DOTS Signal Channel
	5.1. Overview		5.1. Overview
	The DOTS signal channel is built on top of the Constrained		The DOTS signal channel is built on top of the Constrained
	Application Protocol (CoAP) [RFC7252], a lightweight protocol		Application Protocol (CoAP) [RFC7252], a lightweight protocol
	originally designed for constrained devices and networks. CoAP's		originally designed for constrained devices and networks. CoAP's
	expectation of packet loss, support for asynchronous non-confirmable		expectation of packet loss, support for asynchronous non-confirmable
	messaging, congestion control, small message overhead limiting the		messaging, congestion control, small message overhead limiting the
	need for fragmentation, use of minimal resources, and support for		need for fragmentation, use of minimal resources, and support for
	(D)TLS make it a good foundation on which to build the DOTS signaling		(D)TLS make it a good foundation on which to build the DOTS signaling
	mechanism.		mechanism.
	skipping to change at page 7, line 43 ¶		skipping to change at page 7, line 40 ¶
	| IP |		| IP |
	+--------------+		+--------------+
	Figure 4: Abstract Layering of DOTS signal channel over CoAP over		Figure 4: Abstract Layering of DOTS signal channel over CoAP over
	(D)TLS		(D)TLS
	The signal channel is initiated by the DOTS client. Once the signal		The signal channel is initiated by the DOTS client. Once the signal
	channel is established, the DOTS agents periodically send heartbeats		channel is established, the DOTS agents periodically send heartbeats
	to keep the channel active. At any time, the DOTS client may send a		to keep the channel active. At any time, the DOTS client may send a
	mitigation request message to the DOTS server over the active		mitigation request message to the DOTS server over the active
	channel. While mitigation is active, the DOTS server periodically		channel. While mitigation is active, due to the higher likelihood of
	sends status messages to the client, including basic mitigation		packet loss during a DDoS attack, the DOTS server periodically sends
	feedback details. Mitigation remains active until the DOTS client		status messages to the client, including basic mitigation feedback
	explicitly terminates mitigation, or the mitigation lifetime expires.		details. Mitigation remains active until the DOTS client explicitly
			terminates mitigation, or the mitigation lifetime expires.
	Messages exchanged between DOTS client and server are serialized		Messages exchanged between DOTS client and server are serialized
	using Concise Binary Object Representation (CBOR) [RFC7049], CBOR is		using Concise Binary Object Representation (CBOR) [RFC7049], CBOR is
	a binary encoding designed for small code and message size. CBOR		a binary encoding designed for small code and message size. CBOR
	encoded payloads are used to convey signal channel specific payload		encoded payloads are used to convey signal channel specific payload
	messages that convey request parameters and response information such		messages that convey request parameters and response information such
	as errors. This specification uses the encoding rules defined in		as errors. This specification uses the encoding rules defined in
	[I-D.ietf-core-yang-cbor] for representing mitigation scope and DOTS		[I-D.ietf-core-yang-cbor] for representing mitigation scope and DOTS
	signal channel session configuration data defined using YANG		signal channel session configuration data defined using YANG
	(Section 5.2) as CBOR data.		(Section 5.2) as CBOR data.
	DOTS agents MUST support GET, PUT, and DELETE CoAP methods. The		DOTS agents MUST support GET, PUT, and DELETE CoAP methods. The
	payload included in CoAP responses with 2.xx and 3.xx Response Codes		payload included in CoAP responses with 2.xx and 3.xx Response Codes
	MUST be of content type "application/cbor" (Section 5.5.1 of		MUST be of content type "application/cbor" (Section 5.5.1 of
	[RFC7252]). CoAP responses with 4.xx and 5.xx error Response Codes		[RFC7252]). CoAP responses with 4.xx and 5.xx error Response Codes
	MUST include a diagnostic payload (Section 5.5.2 of [RFC7252]). The		MUST include a diagnostic payload (Section 5.5.2 of [RFC7252]). The
	Diagnostic Payload may contain additional information to aid		Diagnostic Payload may contain additional information to aid
	skipping to change at page 16, line 13 ¶		skipping to change at page 16, line 13 ¶
	selected mitigator feedback to the requesting DOTS client.		selected mitigator feedback to the requesting DOTS client.
	Header: PUT (Code=0.03)		Header: PUT (Code=0.03)
	Uri-Host: "host"		Uri-Host: "host"
	Uri-Path: "version"		Uri-Path: "version"
	Uri-Path: "dots-signal"		Uri-Path: "dots-signal"
	Uri-Path: "signal"		Uri-Path: "signal"
	Content-Type: "application/cbor"		Content-Type: "application/cbor"
	{		{
	"mitigation-scope": {		"mitigation-scope": {
	"client-identifer": "string",		"client-identifier": [
			"string"
			],
	"scope": [		"scope": [
	{		{
	"mitigation-id": integer,		"mitigation-id": integer,
	"target-ip": [		"target-ip": [
	"string"		"string"
	],		],
	"target-prefix": [		"target-prefix": [
	"string"		"string"
	],		],
	"target-port-range": [		"target-port-range": [
	skipping to change at page 16, line 51 ¶		skipping to change at page 17, line 5 ¶
	"lifetime": integer		"lifetime": integer
	}		}
	]		]
	}		}
	}		}
	Figure 5: PUT to convey DOTS signals		Figure 5: PUT to convey DOTS signals
	The parameters are described below.		The parameters are described below.
	client-identifer: The client identifer MAY be conveyed by the DOTS		client-identifier: The client identifier MAY be conveyed by the DOTS
	gateway to propagate the DOTS client identity to the DOTS server.		gateway to propagate the DOTS client identity from the gateway's
			client-side to the gateway's server-side, and from the gateway's
			server-side to the DOTS server. This allows the final DOTS server
			to accept mitigation requests with scopes which the DOTS client is
			authorized to manage.
	The'client-identifier' value MUST be assigned by the DOTS gateway		The 'client-identifier' value MUST be assigned by the DOTS gateway
	in a manner that ensures that there is no probability that the		in a manner that ensures that there is no probability that the
	same value will be accidentally assigned to a different DOTS		same value will be assigned to a different DOTS client. The DOTS
	client. The client-identifier attribute SHOULD NOT to be		gateway MUST obscure potentially sensitive DOTS client identity
	advertised by the DOTS client.		information. The client-identifier attribute SHOULD NOT to be
			generated and included by the DOTS client.
			This is an optional attribute.
	mitigation-id: Identifier for the mitigation request represented		mitigation-id: Identifier for the mitigation request represented
	using an integer. This identifier MUST be unique for each		using an integer. This identifier MUST be unique for each
	mitigation request bound to the DOTS client, i.e., the mitigation-		mitigation request bound to the DOTS client, i.e., the mitigation-
	id parameter value in the mitigation request needs to be unique		id parameter value in the mitigation request needs to be unique
	relative to the mitigation-id parameter values of active		relative to the mitigation-id parameter values of active
	mitigation requests conveyed from the DOTS client to the DOTS		mitigation requests conveyed from the DOTS client to the DOTS
	server. This identifier MUST be generated by the DOTS client.		server. This identifier MUST be generated by the DOTS client.
	This document does not make any assumption about how this		This document does not make any assumption about how this
	identifier is generated. This is a mandatory attribute.		identifier is generated. This is a mandatory attribute.
	skipping to change at page 17, line 31 ¶		skipping to change at page 17, line 41 ¶
	target-ip: A list of IP addresses under attack. This is an optional		target-ip: A list of IP addresses under attack. This is an optional
	attribute.		attribute.
	target-prefix: A list of prefixes under attack. Prefixes are		target-prefix: A list of prefixes under attack. Prefixes are
	represented using CIDR notation [RFC4632]. This is an optional		represented using CIDR notation [RFC4632]. This is an optional
	attribute.		attribute.
	target-port-range: A list of ports under attack. The port range,		target-port-range: A list of ports under attack. The port range,
	lower-port for lower port number and upper-port for upper port		lower-port for lower port number and upper-port for upper port
	number. When only lower-port is present, it represents a single		number. When only lower-port is present, it represents a single
	port. For TCP, UDP, SCTP, or DCCP: the range of ports (e.g.,		port. For TCP, UDP, Stream Control Transmission Protocol (SCTP)
	1024-65535). This is an optional attribute.		[RFC4960], or Datagram Congestion Control Protocol (DCCP)
			[RFC4340]: the range of ports (e.g., 1024-65535). This is an
			optional attribute.
	target-protocol: A list of protocols under attack. Values are taken		target-protocol: A list of protocols under attack. Values are taken
	from the IANA protocol registry [proto_numbers]. The value 0 has		from the IANA protocol registry [proto_numbers]. The value 0 has
	a special meaning for 'all protocols'. This is an optional		a special meaning for 'all protocols'. This is an optional
	attribute.		attribute.
	fqdn: A list of Fully Qualified Domain Names. Fully Qualified		fqdn: A list of Fully Qualified Domain Names. Fully Qualified
	Domain Name (FQDN) is the full name of a system, rather than just		Domain Name (FQDN) is the full name of a system, rather than just
	its hostname. For example, "venera" is a hostname, and		its hostname. For example, "venera" is a hostname, and
	"venera.isi.edu" is an FQDN. This is an optional attribute.		"venera.isi.edu" is an FQDN. This is an optional attribute.
	uri: A list of Uniform Resource Identifiers (URI). This is an		uri: A list of Uniform Resource Identifiers (URI). This is an
	optional attribute.		optional attribute.
	alias-name: A list of aliases. Aliases can be created using the		alias-name: A list of aliases. Aliases can be created using the
	DOTS data channel (Section 3.1.1 of [I-D.ietf-dots-data-channel])		DOTS data channel (Section 3.1.1 of [I-D.ietf-dots-data-channel])
	or direct configuration, or other means and then used in		or direct configuration, or other means and then used in
	subsequent signal channel exchanges to refer more efficiently to		subsequent signal channel exchanges to refer more efficiently to
	the resources under attack. This is an optional attribute.		the resources under attack. This is an optional attribute.
	lifetime: Lifetime of the mitigation request in seconds. Upon the		lifetime: Lifetime of the mitigation request in seconds. The
			default lifetime of a mitigation request is 3600 seconds (60
			minutes) -- this value was chosen to be long enough so that
			refreshing is not typically a burden on the DOTS client, while
			expiring the request where the client has unexpectedly quit in a
			timely manner.
			A lifetime of negative one (-1) indicates indefinite lifetime for
			the mitigation request.
			DOTS clients SHOULD include this parameter in their mitigation
			requests. If no lifetime is supplied by a DOTS client, the DOTS
			server uses the default lifetime value (3600 seconds). Upon the
	expiry of this lifetime, and if the request is not refreshed, the		expiry of this lifetime, and if the request is not refreshed, the
	mitigation request is removed. The request can be refreshed by		mitigation request is removed. The request can be refreshed by
	sending the same request again. The default lifetime of the		sending the same request again. The server MAY refuse indefinite
	mitigation request is 3600 seconds (60 minutes) -- this value was		lifetime; the granted lifetime value is returned in the response.
	chosen to be long enough so that refreshing is not typically a		The server MUST always indicate the actual lifetime in the
	burden on the DOTS client, while expiring the request where the		response and the remaining lifetime in status messages sent to the
	client has unexpectedly quit in a timely manner. A lifetime of		client. This is a mandatory parameter for responses.
	negative one (-1) indicates indefinite lifetime for the mitigation
	request. The server MUST always indicate the actual lifetime in
	the response and the remaining lifetime in status messages sent to
	the client. This is an optional attribute in the request.
	The CBOR key values for the parameters are defined in Section 6.		The CBOR key values for the parameters are defined in Section 6.
	Section 10 defines how the CBOR key values can be allocated to		Section 10 defines how the CBOR key values can be allocated to
	standards bodies and vendors.		standards bodies and vendors.
	FQDN and URI mitigation scopes may be thought of as a form of scope		FQDN and URI mitigation scopes may be thought of as a form of scope
	alias, in which the addresses to which the domain name or URI resolve		alias, in which the addresses to which the domain name or URI resolve
	represent the full scope of the mitigation.		represent the full scope of the mitigation.
	In the PUT request at least one of the attributes target-ip or		In the PUT request at least one of the attributes 'target-ip' or
	target-prefix or fqdn or uri or alias-name MUST be present. DOTS		'target-prefix' or 'fqdn' or 'uri 'or 'alias-name' MUST be present.
	agents can safely ignore Vendor-Specific parameters they don't		DOTS agents can safely ignore Vendor-Specific parameters they don't
	understand.		understand.
	The relative order of two mitigation requests from a DOTS client is		The relative order of two mitigation requests from a DOTS client is
	determined by comparing their respective 'mitigation-id' values. If		determined by comparing their respective 'mitigation-id' values. If
	two mitigation requests have overlapping mitigation scopes, the		two mitigation requests have overlapping mitigation scopes, the
	mitigation request with higher numeric 'mitigation-id' value will		mitigation request with higher numeric 'mitigation-id' value will
	override the mitigation request with a lower numeric 'mitigation-id'		override the mitigation request with a lower numeric 'mitigation-id'
	value. Two mitigation-ids are overlapping if there is a common IP		value. Two mitigation-ids are overlapping if there is a common IP
	address, IP prefix, FQDN, URI, or alias-name. The overlapped lower		address, IP prefix, FQDN, URI, or alias-name. The overlapped lower
	numeric 'mitigation-id' MUST be automatically deleted and no longer		numeric 'mitigation-id' MUST be automatically deleted and no longer
	available at the DOTS server.		available at the DOTS server.
	The Uri-Path option carries a major and minor version nomenclature to		The Uri-Path option carries a major and minor version nomenclature to
	manage versioning and DOTS signal channel in this specification uses		manage versioning and DOTS signal channel in this specification uses
	v1 major version.		v1 major version.
	If the DOTS client is using the certificate provisioned by the EST		If the DOTS client is using the certificate provisioned by the
	server in the DOTS gateway-domain to authenticate itself to the DOTS		Enrollment over Secure Transport (EST) server [RFC6234] in the DOTS
	gateway, then the 'client-identifier' value will be the output of a		gateway-domain to authenticate itself to the DOTS gateway, then the
	cryptographic hash algorithm whose input is the DER-encoded ASN.1		'client-identifier' value will be the output of a cryptographic hash
	representation of the Subject Public Key Info (SPKI) of an X.509		algorithm whose input is the DER-encoded ASN.1 representation of the
	certificate. The output of the cryptographic hash algorithm is		Subject Public Key Info (SPKI) of an X.509 certificate. The output
	base64url encoded. In this version of the specification, the		of the cryptographic hash algorithm is base64url encoded. In this
	cryptographic hash algorithm used is SHA-256 [RFC6234]. If the		version of the specification, the cryptographic hash algorithm used
	'client-identifier' value is already present in the mitigation		is SHA-256 [RFC6234]. If the 'client-identifier' value is already
	request received from the DOTS client, the DOTS gateway computes the		present in the mitigation request received from the DOTS client, the
	'client-identifier' value, as discussed above, and adds the computed		DOTS gateway computes the 'client-identifier' value, as discussed
	'client-identifier' value to the end of the 'client-identifier' list.		above, and adds the computed 'client-identifier' value to the end of
			the 'client-identifier' list. The DOTS server MUST NOT use the
			'client-identifier' for the DOTS client authentication process.
	In both DOTS signal and data channel sessions, the DOTS client MUST		In both DOTS signal and data channel sessions, the DOTS client MUST
	authenticate itself to the DOTS server (Section 9). If the 'client-		authenticate itself to the DOTS server (Section 9). The DOTS server
	identifier' value is not present in the mitigation request, the DOTS		may use the algorithm in Section 7 of [RFC7589] to derive the DOTS
	server may use the algorithm in Section 7 of [RFC7589] to derive the		client identity or username from the client certificate. The DOTS
	DOTS client identity or username from the client certificate. The		client identity allows the DOTS server to accept mitigation requests
	DOTS server couples the DOTS signal and data channel sessions using		with scopes which the DOTS client is authorized to manage. The DOTS
	the DOTS client identity, so the DOTS server can validate whether the		server couples the DOTS signal and data channel sessions using the
	aliases conveyed in the mitigation request were indeed created by the		DOTS client identity and the 'client-identifier' parameter value, so
	same DOTS client using the DOTS data channel session. If the aliases		the DOTS server can validate whether the aliases conveyed in the
	were not created by the DOTS client, the DOTS server returns 4.00		mitigation request were indeed created by the same DOTS client using
	(Bad Request) in the response.		the DOTS data channel session. If the aliases were not created by
			the DOTS client, the DOTS server returns 4.00 (Bad Request) in the
			response.
	The DOTS server couples the DOTS signal channel sessions using the		The DOTS server couples the DOTS signal channel sessions using the
	DOTS client identity, and the DOTS server uses 'mitigation-id'		DOTS client identity and the 'client-identifier' parameter value, and
	parameter value to detect duplicate mitigation requests. If the		the DOTS server uses 'mitigation-id' parameter value to detect
	mitigation request contains both alias-name and other parameters		duplicate mitigation requests. If the mitigation request contains
	identifying the target resources (such as, target-ip, target-prefix,		both alias-name and other parameters identifying the target resources
	target-port-range, fqdn, or uri), then the DOTS server appends the		(such as, 'target-ip', 'target-prefix', 'target-port-range', 'fqdn',
	parameter values in alias-name with the corresponding parameter		or 'uri'), then the DOTS server appends the parameter values in
	values in target-ip, target-prefix, target-port-range, fqdn, or uri.		'alias-name' with the corresponding parameter values in 'target-ip',
			'target-prefix', 'target-port-range', 'fqdn', or 'uri'.
	Figure 6 shows a PUT request example to signal that ports 80, 8080,		Figure 6 shows a PUT request example to signal that ports 80, 8080,
	and 443 on the servers 2001:db8:6401::1 and 2001:db8:6401::2 are		and 443 on the servers 2001:db8:6401::1 and 2001:db8:6401::2 are
	being attacked (illustrated in JSON diagnostic notation).		being attacked (illustrated in JSON diagnostic notation).
	Header: PUT (Code=0.03)		Header: PUT (Code=0.03)
	Uri-Host: "www.example.com"		Uri-Host: "www.example.com"
	Uri-Path: "v1"		Uri-Path: "v1"
	Uri-Path: "dots-signal"		Uri-Path: "dots-signal"
	Uri-Path: "signal"		Uri-Path: "signal"
	Content-Format: "application/cbor"		Content-Format: "application/cbor"
	{		{
	"mitigation-scope": {		"mitigation-scope": {
	"client-identifier": "E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g=",		"client-identifier": [
			"E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g="
			],
	"scope": [		"scope": [
	{		{
	"mitigation-id": 12332,		"mitigation-id": 12332,
	"target-ip": [		"target-ip": [
	"2001:db8:6401::1",		"2001:db8:6401::1",
	"2001:db8:6401::2"		"2001:db8:6401::2"
	],		],
	"target-port-range": [		"target-port-range": [
	{		{
	"lower-port": 80		"lower-port": 80
	skipping to change at page 20, line 27 ¶		skipping to change at page 21, line 6 ¶
	]		]
	}		}
	}		}
	The CBOR encoding format is shown below:		The CBOR encoding format is shown below:
	A1 # map(1)		A1 # map(1)
	01 # unsigned(1)		01 # unsigned(1)
	A2 # map(2)		A2 # map(2)
	18 20 # unsigned(32)		18 20 # unsigned(32)
	78 2C # text(44)		81 # array(1)
	4539435A39494E4462642B326552516F7A59717162513279584C564B42392B786370724D462B34345531673D		78 2C # text(44)
			4539435A39494E4462642B326552516F7A59717162513279584C564B42392B786370724D462B34345531673D
	# "E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g="		# "E9CZ9INDbd+2eRQozYqqbQ2yXLVKB9+xcprMF+44U1g="
	02 # unsigned(2)		02 # unsigned(2)
	81 # array(1)		81 # array(1)
	A4 # map(4)		A4 # map(4)
	03 # unsigned(3)		03 # unsigned(3)
	19 302C # unsigned(12332)		19 302C # unsigned(12332)
	04 # unsigned(4)		04 # unsigned(4)
	82 # array(2)		82 # array(2)
	70 # text(16)		70 # text(16)
	323030313A6462383A363430313A3A31 # "2001:db8:6401::1"		323030313A6462383A363430313A3A31 # "2001:db8:6401::1"
	skipping to change at page 21, line 4 ¶		skipping to change at page 21, line 32 ¶
	83 # array(3)		83 # array(3)
	A1 # map(1)		A1 # map(1)
	06 # unsigned(6)		06 # unsigned(6)
	18 50 # unsigned(80)		18 50 # unsigned(80)
	A1 # map(1)		A1 # map(1)
	06 # unsigned(6)		06 # unsigned(6)
	19 01BB # unsigned(443)		19 01BB # unsigned(443)
	A1 # map(1)		A1 # map(1)
	06 # unsigned(6)		06 # unsigned(6)
	19 1F90 # unsigned(8080)		19 1F90 # unsigned(8080)
	08 # unsigned(8)		08 # unsigned(8)
	81 # array(1)		81 # array(1)
	06 # unsigned(6)		06 # unsigned(6)
	Figure 6: PUT for DOTS signal		Figure 6: PUT for DOTS signal
	The DOTS server indicates the result of processing the PUT request		The DOTS server indicates the result of processing the PUT request
	using CoAP response codes. CoAP 2.xx codes are success. CoAP 4.xx		using CoAP response codes. CoAP 2.xx codes are success. CoAP 4.xx
	codes are some sort of invalid requests. Figure 7 shows a PUT		codes are some sort of invalid requests. Figure 7 shows a PUT
	response for CoAP 2.xx response codes.		response for CoAP 2.xx response codes.
	{		{
	"mitigation-scope": {		"mitigation-scope": {
	"client-identifer": "string",		"client-identifier": [
			"string"
			],
	"scope": [		"scope": [
	{		{
	"mitigation-id": integer,		"mitigation-id": integer,
	"lifetime": integer		"lifetime": integer
	}		}
	]		]
	}		}
	}		}
	Figure 7: 2.xx response body		Figure 7: 2.xx response body
	skipping to change at page 22, line 12 ¶		skipping to change at page 22, line 48 ¶
	contains invalid or unknown parameters then 4.02 (Invalid query) is		contains invalid or unknown parameters then 4.02 (Invalid query) is
	returned in the response.		returned in the response.
	For a mitigation request to continue beyond the initial negotiated		For a mitigation request to continue beyond the initial negotiated
	lifetime, the DOTS client need to refresh the current mitigation		lifetime, the DOTS client need to refresh the current mitigation
	request by sending a new PUT request. The PUT request MUST use the		request by sending a new PUT request. The PUT request MUST use the
	same 'mitigation-id' value, and MUST repeat all the other parameters		same 'mitigation-id' value, and MUST repeat all the other parameters
	as sent in the original mitigation request apart from a possible		as sent in the original mitigation request apart from a possible
	change to the lifetime parameter value.		change to the lifetime parameter value.
			A DOTS gateway MUST update the 'client-identifier' list in the
			response to remove the 'client-identifier' value it had added in the
			corresponding request before forwarding the response to the DOTS
			client.
	5.3.2. Withdraw a DOTS Signal		5.3.2. Withdraw a DOTS Signal
	A DELETE request is used to withdraw a DOTS signal from a DOTS server		A DELETE request is used to withdraw a DOTS signal from a DOTS server
	(Figure 8).		(Figure 8).
	Header: DELETE (Code=0.04)		Header: DELETE (Code=0.04)
	Uri-Host: "host"		Uri-Host: "host"
	Uri-Path: "version"		Uri-Path: "version"
	Uri-Path: "dots-signal"		Uri-Path: "dots-signal"
	Uri-Path: "signal"		Uri-Path: "signal"
	Content-Format: "application/cbor"		Content-Format: "application/cbor"
	{		{
	"mitigation-scope": {		"mitigation-scope": {
	"client-identifer": "string",		"client-identifier": [
			"string"
			],
	"scope": [		"scope": [
	{		{
	"mitigation-id": integer		"mitigation-id": integer
	}		}
	]		]
	}		}
	}		}
	Figure 8: Withdraw DOTS signal		Figure 8: Withdraw DOTS signal
	skipping to change at page 23, line 13 ¶		skipping to change at page 24, line 9 ¶
	DOTS server MAY exponentially increase the active-but-terminating		DOTS server MAY exponentially increase the active-but-terminating
	timeout up to a maximum of 240 seconds (4 minutes). After the		timeout up to a maximum of 240 seconds (4 minutes). After the
	active-but-terminating period expires, the DOTS server MUST treat the		active-but-terminating period expires, the DOTS server MUST treat the
	mitigation as terminated. That is, the DOTS client is no longer		mitigation as terminated. That is, the DOTS client is no longer
	responsible for the mitigation. For example, if there is a financial		responsible for the mitigation. For example, if there is a financial
	relationship between the DOTS client and server domains, the DOTS		relationship between the DOTS client and server domains, the DOTS
	client ceases incurring cost at this point.		client ceases incurring cost at this point.
	5.3.3. Retrieving a DOTS Signal		5.3.3. Retrieving a DOTS Signal
	A GET request is used to retrieve information (inclduding status) of		A GET request is used to retrieve information (including status) of a
	a DOTS signal from a DOTS server (Figure 9). If the DOTS server does		DOTS signal from a DOTS server (Figure 9). If the DOTS server does
	not find the 'mitigation-id' parameter value conveyed in the GET		not find the 'mitigation-id' parameter value conveyed in the GET
	request in its configuration data, then it responds with a 4.04 (Not		request in its configuration data, then it responds with a 4.04 (Not
	Found) error response code. The 'c' (content) parameter and its		Found) error response code. The 'c' (content) parameter and its
	permitted values defined in [I-D.ietf-core-comi] can be used to		permitted values defined in [I-D.ietf-core-comi] can be used to
	retrieve non-configuration data or configuration data or both.		retrieve non-configuration data (attack mitigation status) or
			configuration data or both.
	1) To retrieve all DOTS signals signaled by the DOTS client.		1) To retrieve all DOTS signals signaled by the DOTS client.
	Header: GET (Code=0.01)		Header: GET (Code=0.01)
	Uri-Host: "host"		Uri-Host: "host"
	Uri-Path: "version"		Uri-Path: "version"
	Uri-Path: "dots-signal"		Uri-Path: "dots-signal"
	Uri-Path: "signal"		Uri-Path: "signal"
	Observe : 0		Observe : 0
	{		{
	"mitigation-scope": {		"mitigation-scope": {
	"client-identifer": "string",		"client-identifier": [
			"string"
			]
	}		}
	}		}
	2) To retrieve a specific DOTS signal signaled by the DOTS client.		2) To retrieve a specific DOTS signal signaled by the DOTS client.
	The configuration data in the response will be formatted in the		The configuration data in the response will be formatted in the
	same order it was processed at the DOTS server.		same order it was processed at the DOTS server.
	Header: GET (Code=0.01)		Header: GET (Code=0.01)
	Uri-Host: "host"		Uri-Host: "host"
	Uri-Path: "version"		Uri-Path: "version"
	Uri-Path: "dots-signal"		Uri-Path: "dots-signal"
	Uri-Path: "signal"		Uri-Path: "signal"
	Observe : 0		Observe : 0
	Content-Format: "application/cbor"		Content-Format: "application/cbor"
	{		{
	"mitigation-scope": {		"mitigation-scope": {
	"client-identifer": "string",		"client-identifier": [
			"string"
			],
	"scope": [		"scope": [
	{		{
	"mitigation-id": integer		"mitigation-id": integer
	}		}
	]		]
	}		}
	}		}
	Figure 9: GET to retrieve the rules		Figure 9: GET to retrieve the rules
	skipping to change at page 26, line 8 ¶		skipping to change at page 27, line 8 ¶
	relative to 1970-01-01T00:00Z in UTC time (Section 2.4.1 of		relative to 1970-01-01T00:00Z in UTC time (Section 2.4.1 of
	[RFC7049]). The encoding is modified so that the leading tag 1		[RFC7049]). The encoding is modified so that the leading tag 1
	(epoch-based date/time) MUST be omitted.		(epoch-based date/time) MUST be omitted.
	bytes-dropped: The total dropped byte count for the mitigation		bytes-dropped: The total dropped byte count for the mitigation
	request since the attack mitigation is triggered. The count wraps		request since the attack mitigation is triggered. The count wraps
	around when it reaches the maximum value of unsigned integer.		around when it reaches the maximum value of unsigned integer.
	This is an optional attribute.		This is an optional attribute.
	bps-dropped: The average dropped bytes per second for the mitigation		bps-dropped: The average dropped bytes per second for the mitigation
	request since the attack mitigation is triggered. This is an		request since the attack mitigation is triggered. This SHOULD be
	optional attribute.		a five-minute average. This is an optional attribute.
	pkts-dropped: The total dropped packet count for the mitigation		pkts-dropped: The total dropped packet count for the mitigation
	request since the attack mitigation is triggered. This is an		request since the attack mitigation is triggered. This is an
	optional attribute.		optional attribute.
	pps-dropped: The average dropped packets per second for the		pps-dropped: The average dropped packets per second for the
	mitigation request since the attack mitigation is triggered. This		mitigation request since the attack mitigation is triggered. This
	is an optional attribute.		SHOULD be a five-minute average. This is an optional attribute.
	status: Status of attack mitigation. The 'status' parameter is a		status: Status of attack mitigation. The 'status' parameter is a
	mandatory attribute.		mandatory attribute.
	The various possible values of 'status' parameter are explained		The various possible values of 'status' parameter are explained
	below:		below:
	/--------------------+---------------------------------------------------\		/--------------------+---------------------------------------------------\
	| Parameter value | Description |		| Parameter value | Description |
	+--------------------+---------------------------------------------------+		+--------------------+---------------------------------------------------+
	skipping to change at page 27, line 8 ¶		skipping to change at page 28, line 8 ¶
	The observe option defined in [RFC7641] extends the CoAP core		The observe option defined in [RFC7641] extends the CoAP core
	protocol with a mechanism for a CoAP client to "observe" a resource		protocol with a mechanism for a CoAP client to "observe" a resource
	on a CoAP server: the client retrieves a representation of the		on a CoAP server: the client retrieves a representation of the
	resource and requests this representation be updated by the server as		resource and requests this representation be updated by the server as
	long as the client is interested in the resource. A DOTS client		long as the client is interested in the resource. A DOTS client
	conveys the observe option set to 0 in the GET request to receive		conveys the observe option set to 0 in the GET request to receive
	unsolicited notifications of attack mitigation status from the DOTS		unsolicited notifications of attack mitigation status from the DOTS
	server. Unidirectional notifications within the bidirectional signal		server. Unidirectional notifications within the bidirectional signal
	channel allows unsolicited message delivery, enabling asynchronous		channel allows unsolicited message delivery, enabling asynchronous
	notifications between the agents. A DOTS client that is no longer		notifications between the agents. Due to the higher likelihood of
			packet loss during a DDoS attack, DOTS server periodically sends
			attack mitigation status to the DOTS client and also notifies the
			DOTS client whenever the status of the attack mitigation changes. If
			the DOTS server cannot maintain a RTT estimate then it SHOULD NOT
			send more than one unsolicited notification every 3 seconds, and
			SHOULD use an even less aggressive rate when possible (case 2 in
			Section 3.1.3 of [RFC8085]). A DOTS client that is no longer
	interested in receiving notifications from the DOTS server can simply		interested in receiving notifications from the DOTS server can simply
	"forget" the observation. When the DOTS server then sends the next		"forget" the observation. When the DOTS server then sends the next
	notification, the DOTS client will not recognize the token in the		notification, the DOTS client will not recognize the token in the
	message and thus will return a Reset message. This causes the DOTS		message and thus will return a Reset message. This causes the DOTS
	server to remove the associated entry. Alternatively, the DOTS		server to remove the associated entry. Alternatively, the DOTS
	client can explicitly deregister by issuing a GET request that has		client can explicitly deregister by issuing a GET request that has
	the Token field set to the token of the observation to be cancelled		the Token field set to the token of the observation to be cancelled
	and includes an Observe Option with the value set to 1 (deregister).		and includes an Observe Option with the value set to 1 (deregister).
	DOTS Client DOTS Server		DOTS Client DOTS Server
	skipping to change at page 28, line 20 ¶		skipping to change at page 29, line 27 ¶
	A DOTS client should react to the status of the attack from the DOTS		A DOTS client should react to the status of the attack from the DOTS
	server and not the fact that it has recognized, using its own means,		server and not the fact that it has recognized, using its own means,
	that the attack has been mitigated. This ensures that the DOTS		that the attack has been mitigated. This ensures that the DOTS
	client does not recall a mitigation request in a premature fashion		client does not recall a mitigation request in a premature fashion
	because it is possible that the DOTS client does not sense the DDOS		because it is possible that the DOTS client does not sense the DDOS
	attack on its resources but the DOTS server could be actively		attack on its resources but the DOTS server could be actively
	mitigating the attack and the attack is not completely averted.		mitigating the attack and the attack is not completely averted.
	5.3.4. Efficacy Update from DOTS Client		5.3.4. Efficacy Update from DOTS Client
	While DDoS mitigation is active, a DOTS client MAY frequently		While DDoS mitigation is active, due to the likelihood of packet
	transmit DOTS mitigation efficacy updates to the relevant DOTS		loss, a DOTS client MAY periodically transmit DOTS mitigation
	server. A PUT request (Figure 12) is used to convey the mitigation		efficacy updates to the relevant DOTS server. A PUT request
	efficacy update to the DOTS server.		(Figure 12) is used to convey the mitigation efficacy update to the
			DOTS server.
	The PUT request MUST include all the parameters used in the PUT		The PUT request MUST include all the parameters used in the PUT
	request to convey the DOTS signal (Section 5.3.1) unchanged apart		request to convey the DOTS signal (Section 5.3.1) unchanged apart
	from the lifetime parameter value. If this is not the case, the DOTS		from the lifetime parameter value. If this is not the case, the DOTS
	server MUST reject the request with a 4.02 error response code.		server MUST reject the request with a 4.02 error response code.
	The If-Match Option (Section 5.10.8.1 of [RFC7252]) with an empty		The If-Match Option (Section 5.10.8.1 of [RFC7252]) with an empty
	value is used to make the PUT request conditional on the current		value is used to make the PUT request conditional on the current
	existence of the mitigation request. If UDP is used as transport,		existence of the mitigation request. If UDP is used as transport,
	CoAP requests may arrive out-of-order. For example, the DOTS client		CoAP requests may arrive out-of-order. For example, the DOTS client
	skipping to change at page 29, line 13 ¶		skipping to change at page 30, line 13 ¶
	silently ignored.		silently ignored.
	Header: PUT (Code=0.03)		Header: PUT (Code=0.03)
	Uri-Host: "host"		Uri-Host: "host"
	Uri-Path: "version"		Uri-Path: "version"
	Uri-Path: "dots-signal"		Uri-Path: "dots-signal"
	Uri-Path: "signal"		Uri-Path: "signal"
	Content-Format: "application/cbor"		Content-Format: "application/cbor"
	{		{
	"mitigation-scope": {		"mitigation-scope": {
	"client-identifer": "string",		"client-identifier": [
			"string"
			],
	"scope": [		"scope": [
	{		{
	"mitigation-id": integer,		"mitigation-id": integer,
	"target-ip": [		"target-ip": [
	"string"		"string"
	],		],
	"target-port-range": [		"target-port-range": [
	{		{
	"lower-port": integer,		"lower-port": integer,
	"upper-port": integer		"upper-port": integer
	skipping to change at page 29, line 47 ¶		skipping to change at page 30, line 49 ¶
	],		],
	"lifetime": integer,		"lifetime": integer,
	"attack-status": integer		"attack-status": integer
	}		}
	]		]
	}		}
	}		}
	Figure 12: Efficacy Update		Figure 12: Efficacy Update
	The 'attack-status' parameter is a mandatory attribute. The various		The 'attack-status' parameter is a mandatory attribute when doing a
	possible values contained in the 'attack-status' parameter are		efficacy update. The various possible values contained in the
	described below:		'attack-status' parameter are described below:
	/--------------------+------------------------------------------------------\		/--------------------+------------------------------------------------------\
	| Parameter value | Description |		| Parameter value | Description |
	+--------------------+------------------------------------------------------+		+--------------------+------------------------------------------------------+
	| 1 | DOTS client determines that it is still under attack.|		| 1 | DOTS client determines that it is still under attack.|
	+--------------------+------------------------------------------------------+		+--------------------+------------------------------------------------------+
	| 2 | DOTS client determines that the attack is |		| 2 | DOTS client determines that the attack is |
	| | successfully mitigated |		| | successfully mitigated |
	| | (e.g., attack traffic is not seen). |		| | (e.g., attack traffic is not seen). |
	\--------------------+------------------------------------------------------/		\--------------------+------------------------------------------------------/
	skipping to change at page 30, line 28 ¶		skipping to change at page 31, line 28 ¶
	update. The error response code 5.03 (Service Unavailable) is		update. The error response code 5.03 (Service Unavailable) is
	returned if the DOTS server has erred or is incapable of performing		returned if the DOTS server has erred or is incapable of performing
	the mitigation.		the mitigation.
	5.4. DOTS Signal Channel Session Configuration		5.4. DOTS Signal Channel Session Configuration
	The DOTS client can negotiate, configure, and retrieve the DOTS		The DOTS client can negotiate, configure, and retrieve the DOTS
	signal channel session behavior. The DOTS signal channel can be		signal channel session behavior. The DOTS signal channel can be
	used, for example, to configure the following:		used, for example, to configure the following:
	a. Heartbeat interval: DOTS agents regularly send heartbeats (Ping/		a. Heartbeat interval: DOTS agents regularly send heartbeats (CoAP
	Pong) to each other after mutual authentication in order to keep		Ping/Pong) to each other after mutual authentication in order to
	the DOTS signal channel open, heartbeat messages are exchanged		keep the DOTS signal channel open, heartbeat messages are
	between the DOTS agents every heartbeat-interval seconds to		exchanged between the DOTS agents every heartbeat-interval
	detect the current status of the DOTS signal channel session.		seconds to detect the current status of the DOTS signal channel
			session.
	b. Missing heartbeats allowed: This variable indicates the maximum		b. Missing heartbeats allowed: This variable indicates the maximum
	number of consecutive heartbeat messages for which a DOTS agent		number of consecutive heartbeat messages for which a DOTS agent
	did not receive a response before concluding that the session is		did not receive a response before concluding that the session is
	disconnected or defunct.		disconnected or defunct.
	c. Acceptable signal loss ratio: Maximum retransmissions,		c. Acceptable signal loss ratio: Maximum retransmissions,
	retransmission timeout value and other message transmission		retransmission timeout value and other message transmission
	parameters for the DOTS signal channel.		parameters for the DOTS signal channel.
	skipping to change at page 31, line 42 ¶		skipping to change at page 32, line 43 ¶
	configuration parameters for the server.		configuration parameters for the server.
	Header: GET (Code=0.01)		Header: GET (Code=0.01)
	Uri-Host: "host"		Uri-Host: "host"
	Uri-Path: "version"		Uri-Path: "version"
	Uri-Path: "dots-signal"		Uri-Path: "dots-signal"
	Uri-Path: "config"		Uri-Path: "config"
	Figure 13: GET to retrieve configuration		Figure 13: GET to retrieve configuration
	The DOTS server in the 2.05 (Content) response conveys the minimum		The DOTS server in the 2.05 (Content) response conveys the current,
	and maximum attribute values acceptable by the DOTS server.		minimum and maximum attribute values acceptable by the DOTS server.
	Content-Format: "application/cbor"		Content-Format: "application/cbor"
	{		{
	"heartbeat-interval": {		"heartbeat-interval": {
	"CurrentValue": integer,		"CurrentValue": integer,
	"MinValue": integer,		"MinValue": integer,
	"MaxValue" : integer,		"MaxValue" : integer,
	},		},
	"missing-hb-allowed": {		"missing-hb-allowed": {
	"CurrentValue": integer,		"CurrentValue": integer,
	skipping to change at page 32, line 27 ¶		skipping to change at page 33, line 27 ¶
	"max-retransmit": {		"max-retransmit": {
	"CurrentValue": integer,		"CurrentValue": integer,
	"MinValue": integer,		"MinValue": integer,
	"MaxValue" : integer,		"MaxValue" : integer,
	},		},
	"ack-timeout": {		"ack-timeout": {
	"CurrentValue": integer,		"CurrentValue": integer,
	"MinValue": integer,		"MinValue": integer,
	"MaxValue" : integer,		"MaxValue" : integer,
	},		},
	"ack-random-factor": {		"ack-random-factor": {
	"CurrentValue": number,		"CurrentValue": number,
	"MinValue": number,		"MinValue": number,
	"MaxValue" : number,		"MaxValue" : number,
			},
			"trigger-mitigation": {
			"CurrentValue": boolean,
	}		}
	}		}
	Figure 14: GET response body		Figure 14: GET response body
	Figure 15 shows an example of acceptable and current configuration		Figure 15 shows an example of acceptable and current configuration
	parameters on the DOTS server for DOTS signal channel session		parameters on the DOTS server for DOTS signal channel session
	configuration.		configuration.
	Content-Format: "application/cbor"		Content-Format: "application/cbor"
	skipping to change at page 33, line 31 ¶		skipping to change at page 34, line 31 ¶
	},		},
	"ack-timeout": {		"ack-timeout": {
	"CurrentValue": 2,		"CurrentValue": 2,
	"MinValue": 1,		"MinValue": 1,
	"MaxValue" : 30,		"MaxValue" : 30,
	},		},
	"ack-random-factor": {		"ack-random-factor": {
	"CurrentValue": 1.5,		"CurrentValue": 1.5,
	"MinValue": 1.1,		"MinValue": 1.1,
	"MaxValue" : 4.0,		"MaxValue" : 4.0,
			},
			"trigger-mitigation": {
			"CurrentValue": true,
	}		}
	}		}
	Figure 15: configuration response body		Figure 15: configuration response body
	5.4.2. Convey DOTS Signal Channel Session Configuration		5.4.2. Convey DOTS Signal Channel Session Configuration
	A PUT request is used to convey the configuration parameters for the		A PUT request is used to convey the configuration parameters for the
	signaling channel (e.g., heartbeat interval, maximum		signaling channel (e.g., heartbeat interval, maximum
	retransmissions). Message transmission parameters for CoAP are		retransmissions). Message transmission parameters for CoAP are
	skipping to change at page 33, line 50 ¶		skipping to change at page 35, line 4 ¶
	retransmissions). Message transmission parameters for CoAP are		retransmissions). Message transmission parameters for CoAP are
	defined in Section 4.8 of [RFC7252]. The RECOMMENDED values of		defined in Section 4.8 of [RFC7252]. The RECOMMENDED values of
	transmission parameter values are ack_timeout (2 seconds), max-		transmission parameter values are ack_timeout (2 seconds), max-
	retransmit (3), ack-random-factor (1.5). In addition to those		retransmit (3), ack-random-factor (1.5). In addition to those
	parameters, the RECOMMENDED specific DOTS transmission parameter		parameters, the RECOMMENDED specific DOTS transmission parameter
	values are heartbeat-interval (30 seconds) and missing-hb-allowed		values are heartbeat-interval (30 seconds) and missing-hb-allowed
	(5).		(5).
	Note: heartbeat-interval should be tweaked to also assist DOTS		Note: heartbeat-interval should be tweaked to also assist DOTS
	messages for NAT traversal (SIG-010 of		messages for NAT traversal (SIG-010 of
	[I-D.ietf-dots-requirements]). According to [RFC8085], keepalive		[I-D.ietf-dots-requirements]). According to [RFC8085], keepalive
	messages must not be sent more frequently than once every 15		messages must not be sent more frequently than once every 15
	seconds and should use longer intervals when possible.		seconds and should use longer intervals when possible.
	Furthermore, [RFC4787] recommends NATs to use a state timeout of 2		Furthermore, [RFC4787] recommends NATs to use a state timeout of 2
	minutes or longer, but experience shows that sending packets every		minutes or longer, but experience shows that sending packets every
	15 to 30 seconds is necessary to prevent the majority of		15 to 30 seconds is necessary to prevent the majority of
	middleboxes from losing state for UDP flows. From that		middleboxes from losing state for UDP flows. From that
	standpoint, this specification recommends a minimum heartbeat-		standpoint, this specification recommends a minimum heartbeat-
	interval of 15 seconds and a maximum heartbeat-interval of 240		interval of 15 seconds and a maximum heartbeat-interval of 240
	seconds. The recommended value of 30 seconds is selected to		seconds. The recommended value of 30 seconds is selected to
	anticipate the expiry of NAT state.		anticipate the expiry of NAT state.
	A heartbeat-interval of 30 second may be seen as too chatty in		A heartbeat-interval of 30 second may be seen as too chatty in
	some deployments. For such deployments, DOTS agents may negotiate		some deployments. For such deployments, DOTS agents may negotiate
	longer heartbeat-interval values to avoid overloading the network		longer heartbeat-interval values to avoid overloading the network
	with too frequent keepalives.		with too frequent keepalives.
	For the recommended transmission parameters, if the DOTS agent does		When a confirmable "CoAP ping" is sent, and if there is no response,
	not receive any response from the peer DOTS agent for five (missing-		the "CoAP ping" will get retransmitted max-retransmit number of times
	hb-allowed) consecutive "CoAP ping" confirmable messages, then it		by the CoAP layer using an initial timeout set to a random duration
	concludes that the DOTS signal channel session is disconnected, and a		between ack_timeout and (ack-timeout*ack-random-factor) and
	"CoAP ping" confirmable message is retransmitted three (max-		exponential back-off between retransmissions. By choosing the
	retransmit) times using an initial timeout set to a random duration		recommended transmission parameters, the "CoAP ping" will timeout
	between 2 (ack_timeout) and 3 seconds (ack-timeout*ack-random-factor)		after 45 seconds. If the DOTS agent does not receive any response
	and exponential back-off between retransmissions.		from the peer DOTS agent for missing-hb-allowed number of consecutive
			"CoAP ping" confirmable messages, then it concludes that the DOTS
			signal channel session is disconnected. A DOTS client MUST NOT
			transmit a "CoAP ping" while waiting for the previous "CoAP ping"
			response from the same DOTS server.
	If the DOTS agent wishes to change the default values of message		If the DOTS agent wishes to change the default values of message
	transmission parameters, then it should follow the guidance given in		transmission parameters, then it should follow the guidance given in
	Section 4.8.1 of [RFC7252]. The DOTS agents MUST use the negotiated		Section 4.8.1 of [RFC7252]. The DOTS agents MUST use the negotiated
	values for message transmission parameters and default values for		values for message transmission parameters and default values for
	non-negotiated message transmission parameters.		non-negotiated message transmission parameters.
	The signaling channel session configuration is applicable to a single		The signaling channel session configuration is applicable to a single
	DOTS signal channel session between the DOTS agents.		DOTS signal channel session between the DOTS agents.
	skipping to change at page 36, line 7 ¶		skipping to change at page 37, line 7 ¶
	ack-timeout: Timeout value in seconds used to calculate the initial		ack-timeout: Timeout value in seconds used to calculate the initial
	retransmission timeout value (referred to as ACK_TIMEOUT parameter		retransmission timeout value (referred to as ACK_TIMEOUT parameter
	in CoAP). This is an optional attribute.		in CoAP). This is an optional attribute.
	ack-random-factor: Random factor used to influence the timing of		ack-random-factor: Random factor used to influence the timing of
	retransmissions (referred to as ACK_RANDOM_FACTOR parameter in		retransmissions (referred to as ACK_RANDOM_FACTOR parameter in
	CoAP). This is an optional attribute.		CoAP). This is an optional attribute.
	trigger-mitigation: If the parameter value is set to 'false', then		trigger-mitigation: If the parameter value is set to 'false', then
	DDoS mitigation is triggered only when the DOTS signal channel		DDoS mitigation is triggered only when the DOTS signal channel
	session is lost. Automated mtigation on loss of signal is		session is lost. Automated mitigation on loss of signal is
	discussed in Section 3.3.3 of [I-D.ietf-dots-architecture]. If		discussed in Section 3.3.3 of [I-D.ietf-dots-architecture]. If
	the DOTS client ceases to respond to heartbeat messages, then the		the DOTS client ceases to respond to heartbeat messages, then the
	DOTS server can detect that the DOTS session is lost. The default		DOTS server can detect that the DOTS session is lost. The default
	value of the parameter is 'true'. This is an optional attribute.		value of the parameter is 'true'. This is an optional attribute.
	In the PUT request at least one of the attributes heartbeat-interval,		In the PUT request at least one of the attributes heartbeat-interval,
	missing-hb-allowed, max-retransmit, ack-timeout, ack-random-factor,		missing-hb-allowed, max-retransmit, ack-timeout, ack-random-factor,
	and trigger-mitigation MUST be present. The PUT request with higher		and trigger-mitigation MUST be present. The PUT request with higher
	numeric session-id value over-rides the DOTS signal channel session		numeric session-id value over-rides the DOTS signal channel session
	configuration data installed by a PUT request with a lower numeric		configuration data installed by a PUT request with a lower numeric
	skipping to change at page 37, line 18 ¶		skipping to change at page 38, line 18 ¶
	4.00 (Bad Request) is returned in the response.		4.00 (Bad Request) is returned in the response.
	o If the request contains one or more invalid or unknown parameters,		o If the request contains one or more invalid or unknown parameters,
	then 4.02 (Invalid query) code is returned in the response.		then 4.02 (Invalid query) code is returned in the response.
	o Response code 4.22 (Unprocessable Entity) is returned in the		o Response code 4.22 (Unprocessable Entity) is returned in the
	response, if any of the heartbeat-interval, missing-hb-allowed,		response, if any of the heartbeat-interval, missing-hb-allowed,
	max-retransmit, target-protocol, ack-timeout, and ack-random-		max-retransmit, target-protocol, ack-timeout, and ack-random-
	factor attribute values are not acceptable to the DOTS server.		factor attribute values are not acceptable to the DOTS server.
	Upon receipt of the 4.22 error response code, the DOTS client		Upon receipt of the 4.22 error response code, the DOTS client
	should request the maximum and minumum attribute values acceptable		should request the maximum and minimum attribute values acceptable
	to the DOTS server (Section 5.4.1). The DOTS client may re-try		to the DOTS server (Section 5.4.1). The DOTS client may re-try
	and send the PUT request with updated attribute values acceptable		and send the PUT request with updated attribute values acceptable
	to the DOTS server.		to the DOTS server.
	5.4.3. Delete DOTS Signal Channel Session Configuration		5.4.3. Delete DOTS Signal Channel Session Configuration
	A DELETE request is used to delete the installed DOTS signal channel		A DELETE request is used to delete the installed DOTS signal channel
	session configuration data (Figure 18).		session configuration data (Figure 18).
	Header: DELETE (Code=0.04)		Header: DELETE (Code=0.04)
	Uri-Host: "host"		Uri-Host: "host"
	Uri-Path: "version"		Uri-Path: "version"
	Uri-Path: "dots-signal"		Uri-Path: "dots-signal"
	Uri-Path: "config"		Uri-Path: "config"
	Content-Format: "application/cbor"		Content-Format: "application/cbor"
	{
	"signal-config": {
	"session-id": integer
	}
	}
	Figure 18: DELETE configuration		Figure 18: DELETE configuration
	If the DOTS server does not find the session-id parameter value		The DOTS server resets the DOTS signal channel session configuration
	conveyed in the DELETE request in its configuration data, then it		back to the default values and acknowledges a DOTS client's request
	responds with a 4.04 (Not Found) error response code. The DOTS		to remove the DOTS signal channel session configuration using 2.02
	server successfully acknowledges a DOTS client's request to remove		(Deleted) response code.
	the DOTS signal channel session configuration using 2.02 (Deleted)
	response code.
	5.4.4. Retrieving DOTS Signal Channel Session Configuration
	A GET request is used to retrieve the installed DOTS signal channel
	session configuration data from a DOTS server. Figure 19 shows how
	to retrieve the DOTS signal channel session configuration data.
	Header: GET (Code=0.01)
	Uri-Host: "host"
	Uri-Path: "version"
	Uri-Path: "dots-signal"
	Uri-Path: "config"
	Content-Format: "application/cbor"
	{
	"signal-config": {
	"session-id": integer
	}
	}
	Figure 19: GET to retrieve configuration
	5.5. Redirected Signaling		5.5. Redirected Signaling
	Redirected Signaling is discussed in detail in Section 3.2.2 of		Redirected Signaling is discussed in detail in Section 3.2.2 of
	[I-D.ietf-dots-architecture]. If the DOTS server wants to redirect		[I-D.ietf-dots-architecture]. If the DOTS server wants to redirect
	the DOTS client to an alternative DOTS server for a signaling session		the DOTS client to an alternative DOTS server for a signaling session
	then the response code 3.00 (alternate server) will be returned in		then the response code 3.00 (alternate server) will be returned in
	the response to the client. The DOTS server can return the error		the response to the client. The DOTS server can return the error
	response code 3.00 in response to a PUT request from the DOTS client		response code 3.00 in response to a PUT request from the DOTS client
	or convey the error response code 3.00 in a unidirectional		or convey the error response code 3.00 in a unidirectional
	skipping to change at page 38, line 50 ¶		skipping to change at page 39, line 19 ¶
	{		{
	"alt-server": "string",		"alt-server": "string",
	"alt-server-record": [		"alt-server-record": [
	{		{
	"addr": "string",		"addr": "string",
	"ttl" : integer,		"ttl" : integer,
	}		}
	]		]
	}		}
	Figure 20: Error response body		Figure 19: Error response body
	The parameters are described below:		The parameters are described below:
	alt-server: FQDN of an alternate DOTS server.		alt-server: FQDN of an alternate DOTS server.
	addr: IP address of an alternate DOTS server.		addr: IP address of an alternate DOTS server.
	ttl: Time to live (TTL) represented as an integer number of seconds.		ttl: Time to live (TTL) represented as an integer number of seconds.
	Figure 21 shows a 3.00 response example to convey the DOTS alternate		Figure 20 shows a 3.00 response example to convey the DOTS alternate
	server www.example-alt.com, its IP addresses 2001:db8:6401::1 and		server www.example-alt.com, its IP addresses 2001:db8:6401::1 and
	2001:db8:6401::2, and TTL values 3600 and 1800.		2001:db8:6401::2, and TTL values 3600 and 1800.
	{		{
	"alt-server": "www.example-alt.com",		"alt-server": "www.example-alt.com",
	"alt-server-record": [		"alt-server-record": [
	{		{
	"ttl" : 3600,		"ttl" : 3600,
	"addr": "2001:db8:6401::1"		"addr": "2001:db8:6401::1"
	},		},
	{		{
	"ttl" : 1800,		"ttl" : 1800,
	"addr": "2001:db8:6401::2"		"addr": "2001:db8:6401::2"
	}		}
	]		]
	}		}
	Figure 21: Example of error response body		Figure 20: Example of error response body
	When the DOTS client receives 3.00 response, it considers the current		When the DOTS client receives 3.00 response, it considers the current
	request as having failed, but SHOULD try the request with the		request as having failed, but SHOULD try the request with the
	alternate DOTS server. During a DDOS attack, the DNS server may be		alternate DOTS server. During a DDOS attack, the DNS server may be
	subjected to DDOS attack, alternate DOTS server IP addresses conveyed		subjected to DDOS attack, alternate DOTS server IP addresses conveyed
	in the 3.00 response help the DOTS client to skip DNS lookup of the		in the 3.00 response help the DOTS client to skip DNS lookup of the
	alternate DOTS server and can try to establish UDP or TCP session		alternate DOTS server and can try to establish UDP or TCP session
	with the alternate DOTS server IP addresses. The DOTS client SHOULD		with the alternate DOTS server IP addresses. The DOTS client SHOULD
	implement DNS64 function to handle the scenario where IPv6-only DOTS		implement DNS64 function to handle the scenario where IPv6-only DOTS
	client communicates with IPv4-only alternate DOTS server.		client communicates with IPv4-only alternate DOTS server.
	skipping to change at page 40, line 21 ¶		skipping to change at page 40, line 39 ¶
	[RFC7252]. Concretely, the DOTS agent sends an Empty Confirmable		[RFC7252]. Concretely, the DOTS agent sends an Empty Confirmable
	message and the peer DOTS agent will respond by sending an Reset		message and the peer DOTS agent will respond by sending an Reset
	message.		message.
	In DOTS over TCP, heartbeat messages can be exchanged between the		In DOTS over TCP, heartbeat messages can be exchanged between the
	DOTS agents using the Ping and Pong messages specified in Section 4.4		DOTS agents using the Ping and Pong messages specified in Section 4.4
	of [I-D.ietf-core-coap-tcp-tls]. That is, the DOTS agent sends a		of [I-D.ietf-core-coap-tcp-tls]. That is, the DOTS agent sends a
	Ping message and the peer DOTS agent would respond by sending a		Ping message and the peer DOTS agent would respond by sending a
	single Pong message.		single Pong message.
	A DOTS client MUST NOT transmit a heartbeat message while a previous
	heartbeat message has not been responded by the remote DOTS server.
	6. Mapping parameters to CBOR		6. Mapping parameters to CBOR
	All parameters in the payload in the DOTS signal channel MUST be		All parameters in the payload in the DOTS signal channel MUST be
	mapped to CBOR types as follows and are given an integer key to save		mapped to CBOR types as follows and are given an integer key to save
	space. The recipient of the payload MAY reject the information if it		space. The recipient of the payload MAY reject the information if it
	is not suitably mapped.		is not suitably mapped.
	/--------------------+------------------------+--------------------------\		/--------------------+------------------------+--------------------------\
	| Parameter name | CBOR key | CBOR major type of value |		| Parameter name | CBOR key | CBOR major type of value |
	+--------------------+------------------------+--------------------------+		+--------------------+------------------------+--------------------------+
	skipping to change at page 41, line 42 ¶		skipping to change at page 41, line 42 ¶
	| pps-dropped | 25 | 0 |		| pps-dropped | 25 | 0 |
	| session-id | 26 | 0 |		| session-id | 26 | 0 |
	| trigger-mitigation | 27 | 7 (simple types) |		| trigger-mitigation | 27 | 7 (simple types) |
	| missing-hb-allowed | 28 | 0 |		| missing-hb-allowed | 28 | 0 |
	| CurrentValue | 29 | 0 |		| CurrentValue | 29 | 0 |
	| mitigation-start | 30 | 7 (floating-point) |		| mitigation-start | 30 | 7 (floating-point) |
	| target-prefix | 31 | 4 (array) |		| target-prefix | 31 | 4 (array) |
	| client-identifier | 32 | 2 (byte string) |		| client-identifier | 32 | 2 (byte string) |
	\--------------------+------------------------+--------------------------/		\--------------------+------------------------+--------------------------/
	Figure 22: CBOR mappings used in DOTS signal channel message		Figure 21: CBOR mappings used in DOTS signal channel message
	7. (D)TLS Protocol Profile and Performance considerations		7. (D)TLS Protocol Profile and Performance considerations
	This section defines the (D)TLS protocol profile of DOTS signal		This section defines the (D)TLS protocol profile of DOTS signal
	channel over (D)TLS and DOTS data channel over TLS.		channel over (D)TLS and DOTS data channel over TLS.
	There are known attacks on (D)TLS, such as machine-in-the-middle and		There are known attacks on (D)TLS, such as machine-in-the-middle and
	protocol downgrade. These are general attacks on (D)TLS and not		protocol downgrade. These are general attacks on (D)TLS and not
	specific to DOTS over (D)TLS; please refer to the (D)TLS RFCs for		specific to DOTS over (D)TLS; please refer to the (D)TLS RFCs for
	discussion of these security issues. DOTS agents MUST adhere to the		discussion of these security issues. DOTS agents MUST adhere to the
	skipping to change at page 43, line 42 ¶		skipping to change at page 43, line 42 ¶
	send DOTS signal message on its first flight, thus reducing		send DOTS signal message on its first flight, thus reducing
	handshake latency. 0-RTT only works if the DOTS client has		handshake latency. 0-RTT only works if the DOTS client has
	previously communicated with that DOTS server, which is very		previously communicated with that DOTS server, which is very
	likely with the DOTS signal channel. The DOTS client SHOULD		likely with the DOTS signal channel. The DOTS client SHOULD
	establish a (D)TLS session with the DOTS server during peacetime		establish a (D)TLS session with the DOTS server during peacetime
	and share a PSK. During DDOS attack, the DOTS client can use the		and share a PSK. During DDOS attack, the DOTS client can use the
	(D)TLS session to convey the DOTS signal message and if there is		(D)TLS session to convey the DOTS signal message and if there is
	no response from the server after multiple re-tries then the DOTS		no response from the server after multiple re-tries then the DOTS
	client can resume the (D)TLS session in 0-RTT mode using PSK. A		client can resume the (D)TLS session in 0-RTT mode using PSK. A
	simplified TLS 1.3 handshake with 0-RTT DOTS signal message		simplified TLS 1.3 handshake with 0-RTT DOTS signal message
	exchange is shown in Figure 23.		exchange is shown in Figure 22.
	DOTS Client DOTS Server		DOTS Client DOTS Server
	ClientHello		ClientHello
	(Finished)		(Finished)
	(0-RTT DOTS signal message)		(0-RTT DOTS signal message)
	(end_of_early_data) -------->		(end_of_early_data) -------->
	ServerHello		ServerHello
	{EncryptedExtensions}		{EncryptedExtensions}
	{ServerConfiguration}		{ServerConfiguration}
	{Certificate}		{Certificate}
	{CertificateVerify}		{CertificateVerify}
	{Finished}		{Finished}
	<-------- [DOTS signal message]		<-------- [DOTS signal message]
	{Finished} -------->		{Finished} -------->
	[DOTS signal message] <-------> [DOTS signal message]		[DOTS signal message] <-------> [DOTS signal message]
	Figure 23: TLS 1.3 handshake with 0-RTT		Figure 22: TLS 1.3 handshake with 0-RTT
	9. Mutual Authentication of DOTS Agents & Authorization of DOTS Clients		9. Mutual Authentication of DOTS Agents & Authorization of DOTS Clients
	(D)TLS based on client certificate can be used for mutual		(D)TLS based on client certificate can be used for mutual
	authentication between DOTS agents. If a DOTS gateway is involved,		authentication between DOTS agents. If a DOTS gateway is involved,
	DOTS clients and DOTS gateway MUST perform mutual authentication;		DOTS clients and DOTS gateway MUST perform mutual authentication;
	only authorized DOTS clients are allowed to send DOTS signals to a		only authorized DOTS clients are allowed to send DOTS signals to a
	DOTS gateway. DOTS gateway and DOTS server MUST perform mutual		DOTS gateway. DOTS gateway and DOTS server MUST perform mutual
	authentication; DOTS server only allows DOTS signals from authorized		authentication; DOTS server only allows DOTS signals from authorized
	DOTS gateway, creating a two-link chain of transitive authentication		DOTS gateway, creating a two-link chain of transitive authentication
	between the DOTS client and the DOTS server.		between the DOTS client and the DOTS server.
	+-------------------------------------------------+		+-------------------------------------------------+
	| example.com domain +---------+ |		| example.com domain +---------+ |
	| | AAA | |		| | AAA | |
	| +---------------+ | Server | |		| +---------------+ | Server | |
	| | Application | +------+--+ |		| | Application | +------+--+ |
	| | server + ^		| | server + ^
	| | (DOTS client) |<-----------------+ | |		| | (DOTS client) |<-----------------+ | |
	| +---------------+ + | | example.net domain		| +---------------+ | | | example.net domain
	| V V |		| V V |
	| +-------------+ | +---------------+		| +-------------+ | +---------------+
	| +--------------+ | | | | |		| +--------------+ | | | | |
	| | Guest +<-----x----->+ +<---------------->+ DOTS |		| | Guest +<-----x----->+ +<---------------->+ DOTS |
	| | (DOTS client)| | DOTS | | | Server |		| | (DOTS client)| | DOTS | | | Server |
	| +--------------+ | Gateway | | | |		| +--------------+ | Gateway | | | |
	| +----+--------+ | +---------------+		| +----+--------+ | +---------------+
	| ^ |		| ^ |
	| | |		| | |
	| +----------------+ | |		| +----------------+ | |
	| | DDOS detector | | |		| | DDOS detector | | |
	| | (DOTS client) +<--------------+ |		| | (DOTS client) +<--------------+ |
	| +----------------+ |		| +----------------+ |
	| |		| |
	+-------------------------------------------------+		+-------------------------------------------------+
	Figure 24: Example of Authentication and Authorization of DOTS Agents		Figure 23: Example of Authentication and Authorization of DOTS Agents
	In the example depicted in Figure 24, the DOTS gateway and DOTS		In the example depicted in Figure 23, the DOTS gateway and DOTS
	clients within the 'example.com' domain mutually authenticate with		clients within the 'example.com' domain mutually authenticate with
	each other. After the DOTS gateway validates the identity of a DOTS		each other. After the DOTS gateway validates the identity of a DOTS
	client, it communicates with the AAA server in the 'example.com'		client, it communicates with the AAA server in the 'example.com'
	domain to determine if the DOTS client is authorized to request DDOS		domain to determine if the DOTS client is authorized to request DDOS
	mitigation. If the DOTS client is not authorized, a 4.01		mitigation. If the DOTS client is not authorized, a 4.01
	(Unauthorized) is returned in the response to the DOTS client. In		(Unauthorized) is returned in the response to the DOTS client. In
	this example, the DOTS gateway only allows the application server and		this example, the DOTS gateway only allows the application server and
	DDOS detector to request DDOS mitigation, but does not permit the		DDOS detector to request DDOS mitigation, but does not permit the
	user of type 'guest' to request DDOS mitigation.		user of type 'guest' to request DDOS mitigation.
	Also, DOTS gateway and DOTS server located in different domains MUST		Also, DOTS gateway and DOTS server located in different domains MUST
	perform mutual authentication (e.g., using certificates). A DOTS		perform mutual authentication (e.g., using certificates). A DOTS
	server will only allow a DOTS gateway with a certificate for a		server will only allow a DOTS gateway with a certificate for a
	particular domain to request mitigation for that domain. In		particular domain to request mitigation for that domain. In
	reference to Figure 24, the DOTS server only allows the DOTS gateway		reference to Figure 23, the DOTS server only allows the DOTS gateway
	to request mitigation for 'example.com' domain and not for other		to request mitigation for 'example.com' domain and not for other
	domains.		domains.
	10. IANA Considerations		10. IANA Considerations
	This specification registers new CoAP response code, new parameters		This specification registers new CoAP response code, new parameters
	for DOTS signal channel and establishes registries for mappings to		for DOTS signal channel and establishes registries for mappings to
	CBOR.		CBOR.
	10.1. CoAP Response Code		10.1. CoAP Response Code
	The following entry is added to the "CoAP Response Codes" sub-		The following entry is added to the "CoAP Response Codes" sub-
	registry:		registry:
	+------+------------------------------+-----------+		+------+------------------------------+-----------+
	| Code | Description | Reference |		| Code | Description | Reference |
	+------+------------------------------+-----------+		+------+------------------------------+-----------+
	| 3.00 | Alternate server | [RFCXXXX] |		| 3.00 | Alternate server | [RFCXXXX] |
	+------+------------------------------+-----------+		+------+------------------------------+-----------+
	Figure 25: CoAP Response Code		Figure 24: CoAP Response Code
	[Note to RFC Editor: Please replace XXXX with the RFC number of this		[Note to RFC Editor: Please replace XXXX with the RFC number of this
	specification.]		specification.]
	10.2. DOTS signal channel CBOR Mappings Registry		10.2. DOTS signal channel CBOR Mappings Registry
	A new registry will be requested from IANA, entitled "DOTS signal		A new registry will be requested from IANA, entitled "DOTS signal
	channel CBOR Mappings Registry". The registry is to be created as		channel CBOR Mappings Registry". The registry is to be created as
	Expert Review Required.		Expert Review Required.
	skipping to change at page 54, line 49 ¶		skipping to change at page 54, line 49 ¶
	Veillette, M., Pelov, A., Somaraju, A., Turner, R., and A.		Veillette, M., Pelov, A., Somaraju, A., Turner, R., and A.
	Minaburo, "CBOR Encoding of Data Modeled with YANG",		Minaburo, "CBOR Encoding of Data Modeled with YANG",
	draft-ietf-core-yang-cbor-05 (work in progress), August		draft-ietf-core-yang-cbor-05 (work in progress), August
	2017.		2017.
	[I-D.ietf-dots-architecture]		[I-D.ietf-dots-architecture]
	Mortensen, A., Andreasen, F., Reddy, T.,		Mortensen, A., Andreasen, F., Reddy, T.,
	christopher_gray3@cable.comcast.com, c., Compton, R., and		christopher_gray3@cable.comcast.com, c., Compton, R., and
	N. Teague, "Distributed-Denial-of-Service Open Threat		N. Teague, "Distributed-Denial-of-Service Open Threat
	Signaling (DOTS) Architecture", draft-ietf-dots-		Signaling (DOTS) Architecture", draft-ietf-dots-
	architecture-04 (work in progress), July 2017.		architecture-05 (work in progress), October 2017.
	[I-D.ietf-dots-data-channel]		[I-D.ietf-dots-data-channel]
	Reddy, T., Boucadair, M., Nishizuka, K., Xia, L., Patil,		Reddy, T., Boucadair, M., Nishizuka, K., Xia, L., Patil,
	P., Mortensen, A., and N. Teague, "Distributed Denial-of-		P., Mortensen, A., and N. Teague, "Distributed Denial-of-
	Service Open Threat Signaling (DOTS) Data Channel", draft-		Service Open Threat Signaling (DOTS) Data Channel", draft-
	ietf-dots-data-channel-04 (work in progress), October		ietf-dots-data-channel-05 (work in progress), October
	2017.		2017.
	[I-D.ietf-dots-requirements]		[I-D.ietf-dots-requirements]
	Mortensen, A., Moskowitz, R., and T. Reddy, "Distributed		Mortensen, A., Moskowitz, R., and T. Reddy, "Distributed
	Denial of Service (DDoS) Open Threat Signaling		Denial of Service (DDoS) Open Threat Signaling
	Requirements", draft-ietf-dots-requirements-06 (work in		Requirements", draft-ietf-dots-requirements-06 (work in
	progress), July 2017.		progress), July 2017.
	[I-D.ietf-dots-use-cases]		[I-D.ietf-dots-use-cases]
	Dobbins, R., Migault, D., Fouant, S., Moskowitz, R.,		Dobbins, R., Migault, D., Fouant, S., Moskowitz, R.,
	Teague, N., Xia, L., and K. Nishizuka, "Use cases for DDoS		Teague, N., Xia, L., and K. Nishizuka, "Use cases for DDoS
	Open Threat Signaling", draft-ietf-dots-use-cases-07 (work		Open Threat Signaling", draft-ietf-dots-use-cases-08 (work
	in progress), July 2017.		in progress), October 2017.
	[I-D.ietf-tls-tls13]		[I-D.ietf-tls-tls13]
	Rescorla, E., "The Transport Layer Security (TLS) Protocol		Rescorla, E., "The Transport Layer Security (TLS) Protocol
	Version 1.3", draft-ietf-tls-tls13-21 (work in progress),		Version 1.3", draft-ietf-tls-tls13-21 (work in progress),
	July 2017.		July 2017.
	[I-D.rescorla-tls-dtls13]		[I-D.rescorla-tls-dtls13]
	Rescorla, E., Tschofenig, H., and N. Modadugu, "The		Rescorla, E., Tschofenig, H., and N. Modadugu, "The
	Datagram Transport Layer Security (DTLS) Protocol Version		Datagram Transport Layer Security (DTLS) Protocol Version
	1.3", draft-rescorla-tls-dtls13-01 (work in progress),		1.3", draft-rescorla-tls-dtls13-01 (work in progress),
	March 2017.		March 2017.
	[proto_numbers]		[proto_numbers]
	"IANA, "Protocol Numbers"", 2011,		"IANA, "Protocol Numbers"", 2011,
	<http://www.iana.org/assignments/protocol-numbers>.		<http://www.iana.org/assignments/protocol-numbers>.
	[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,		[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
	DOI 10.17487/RFC0791, September 1981,		DOI 10.17487/RFC0791, September 1981,
	<https://www.rfc-editor.org/info/rfc791>.		<https://www.rfc-editor.org/info/rfc791>.
			[RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram
			Congestion Control Protocol (DCCP)", RFC 4340,
			DOI 10.17487/RFC4340, March 2006,
			<https://www.rfc-editor.org/info/rfc4340>.
	[RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing		[RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing
	(CIDR): The Internet Address Assignment and Aggregation		(CIDR): The Internet Address Assignment and Aggregation
	Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August		Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August
	2006, <https://www.rfc-editor.org/info/rfc4632>.		2006, <https://www.rfc-editor.org/info/rfc4632>.
	[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet		[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
	Denial-of-Service Considerations", RFC 4732,		Denial-of-Service Considerations", RFC 4732,
	DOI 10.17487/RFC4732, December 2006,		DOI 10.17487/RFC4732, December 2006,
	<https://www.rfc-editor.org/info/rfc4732>.		<https://www.rfc-editor.org/info/rfc4732>.
	[RFC4787] Audet, F., Ed. and C. Jennings, "Network Address		[RFC4787] Audet, F., Ed. and C. Jennings, "Network Address
	Translation (NAT) Behavioral Requirements for Unicast		Translation (NAT) Behavioral Requirements for Unicast
	UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January		UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January
	2007, <https://www.rfc-editor.org/info/rfc4787>.		2007, <https://www.rfc-editor.org/info/rfc4787>.
			[RFC4960] Stewart, R., Ed., "Stream Control Transmission Protocol",
			RFC 4960, DOI 10.17487/RFC4960, September 2007,
			<https://www.rfc-editor.org/info/rfc4960>.
	[RFC4987] Eddy, W., "TCP SYN Flooding Attacks and Common		[RFC4987] Eddy, W., "TCP SYN Flooding Attacks and Common
	Mitigations", RFC 4987, DOI 10.17487/RFC4987, August 2007,		Mitigations", RFC 4987, DOI 10.17487/RFC4987, August 2007,
	<https://www.rfc-editor.org/info/rfc4987>.		<https://www.rfc-editor.org/info/rfc4987>.
	[RFC5077] Salowey, J., Zhou, H., Eronen, P., and H. Tschofenig,		[RFC5077] Salowey, J., Zhou, H., Eronen, P., and H. Tschofenig,
	"Transport Layer Security (TLS) Session Resumption without		"Transport Layer Security (TLS) Session Resumption without
	Server-Side State", RFC 5077, DOI 10.17487/RFC5077,		Server-Side State", RFC 5077, DOI 10.17487/RFC5077,
	January 2008, <https://www.rfc-editor.org/info/rfc5077>.		January 2008, <https://www.rfc-editor.org/info/rfc5077>.
	[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for		[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
	skipping to change at page 56, line 33 ¶		skipping to change at page 56, line 42 ¶
	[RFC6555] Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with		[RFC6555] Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with
	Dual-Stack Hosts", RFC 6555, DOI 10.17487/RFC6555, April		Dual-Stack Hosts", RFC 6555, DOI 10.17487/RFC6555, April
	2012, <https://www.rfc-editor.org/info/rfc6555>.		2012, <https://www.rfc-editor.org/info/rfc6555>.
	[RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,		[RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
	"Default Address Selection for Internet Protocol Version 6		"Default Address Selection for Internet Protocol Version 6
	(IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,		(IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,
	<https://www.rfc-editor.org/info/rfc6724>.		<https://www.rfc-editor.org/info/rfc6724>.
			[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
			"Enrollment over Secure Transport", RFC 7030,
			DOI 10.17487/RFC7030, October 2013,
			<https://www.rfc-editor.org/info/rfc7030>.
	[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object		[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
	Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,		Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
	October 2013, <https://www.rfc-editor.org/info/rfc7049>.		October 2013, <https://www.rfc-editor.org/info/rfc7049>.
	[RFC7413] Cheng, Y., Chu, J., Radhakrishnan, S., and A. Jain, "TCP		[RFC7413] Cheng, Y., Chu, J., Radhakrishnan, S., and A. Jain, "TCP
	Fast Open", RFC 7413, DOI 10.17487/RFC7413, December 2014,		Fast Open", RFC 7413, DOI 10.17487/RFC7413, December 2014,
	<https://www.rfc-editor.org/info/rfc7413>.		<https://www.rfc-editor.org/info/rfc7413>.
	[RFC7589] Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the		[RFC7589] Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
	NETCONF Protocol over Transport Layer Security (TLS) with		NETCONF Protocol over Transport Layer Security (TLS) with
End of changes. 72 change blocks.
	175 lines changed or deleted		213 lines changed or added
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