draft-ietf-ippm-ipsec-05.txt		draft-ietf-ippm-ipsec-06.txt
	IPPM WG K. Pentikousis, Ed.		IPPM WG K. Pentikousis, Ed.
	Internet-Draft EICT		Internet-Draft EICT
	Intended status: Standards Track E. Zhang		Intended status: Standards Track E. Zhang
	Expires: March 23, 2015 Y. Cui		Expires: May 14, 2015 Y. Cui
	Huawei Technologies		Huawei Technologies
	September 19, 2014		November 10, 2014
	IKEv2-based Shared Secret Key for O/TWAMP		IKEv2-based Shared Secret Key for O/TWAMP
	draft-ietf-ippm-ipsec-05		draft-ietf-ippm-ipsec-06
	Abstract		Abstract
	The O/TWAMP security mechanism requires that both the client and		The O/TWAMP security mechanism requires that both the client and
	server endpoints possess a shared secret. Since the currently-		server endpoints possess a shared secret. Since the currently-
	standardized O/TWAMP security mechanism only supports a pre-shared		standardized O/TWAMP security mechanism only supports a pre-shared
	key mode, large scale deployment of O/TWAMP is hindered		key mode, large scale deployment of O/TWAMP is hindered
	significantly. At the same time, recent trends point to wider IKEv2		significantly. At the same time, recent trends point to wider IKEv2
	deployment which, in turn, calls for mechanisms and methods that		deployment which, in turn, calls for mechanisms and methods that
	enable tunnel end-users, as well as operators, to measure one-way and		enable tunnel end-users, as well as operators, to measure one-way and
	skipping to change at page 1, line 45		skipping to change at page 1, line 45
	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 http://datatracker.ietf.org/drafts/current/.		Drafts is at http://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 March 23, 2015.		This Internet-Draft will expire on May 14, 2015.
	Copyright Notice		Copyright Notice
	Copyright (c) 2014 IETF Trust and the persons identified as the		Copyright (c) 2014 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	carefully, as they describe your rights and restrictions with respect		carefully, as they describe your rights and restrictions with respect
	to this document. Code Components extracted from this document must		to this document. Code Components extracted from this document must
	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 . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
	3. O/TWAMP Security . . . . . . . . . . . . . . . . . . . . . . 4		3. Scope and Applicability . . . . . . . . . . . . . . . . . . . 4
	3.1. O/TWAMP-Control Security . . . . . . . . . . . . . . . . 4		4. O/TWAMP Security . . . . . . . . . . . . . . . . . . . . . . 4
	3.2. O/TWAMP-Test Security . . . . . . . . . . . . . . . . . . 5		4.1. O/TWAMP-Control Security . . . . . . . . . . . . . . . . 4
	3.3. O/TWAMP Security Root . . . . . . . . . . . . . . . . . . 6		4.2. O/TWAMP-Test Security . . . . . . . . . . . . . . . . . . 6
	4. O/TWAMP for IPsec Networks . . . . . . . . . . . . . . . . . 6		4.3. O/TWAMP Security Root . . . . . . . . . . . . . . . . . . 7
	4.1. Shared Key Derivation . . . . . . . . . . . . . . . . . . 6		5. O/TWAMP for IPsec Networks . . . . . . . . . . . . . . . . . 7
	4.2. Server Greeting Message Update . . . . . . . . . . . . . 7		5.1. Shared Key Derivation . . . . . . . . . . . . . . . . . . 7
	4.3. Set-Up-Response Update . . . . . . . . . . . . . . . . . 9		5.2. Server Greeting Message Update . . . . . . . . . . . . . 8
	4.4. O/TWAMP over an IPsec tunnel . . . . . . . . . . . . . . 10		5.3. Set-Up-Response Update . . . . . . . . . . . . . . . . . 9
	5. Security Considerations . . . . . . . . . . . . . . . . . . . 10		5.4. O/TWAMP over an IPsec tunnel . . . . . . . . . . . . . . 11
	6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10		6. Security Considerations . . . . . . . . . . . . . . . . . . . 11
	7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
	8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11		8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
	8.1. Normative References . . . . . . . . . . . . . . . . . . 11		9. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
	8.2. Informative References . . . . . . . . . . . . . . . . . 11		9.1. Normative References . . . . . . . . . . . . . . . . . . 12
			9.2. Informative References . . . . . . . . . . . . . . . . . 12
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
	1. Introduction		1. Introduction
	The One-way Active Measurement Protocol (OWAMP) [RFC4656] and the		The One-way Active Measurement Protocol (OWAMP) [RFC4656] and the
	Two-Way Active Measurement Protocol (TWAMP) [RFC5357] can be used to		Two-Way Active Measurement Protocol (TWAMP) [RFC5357] can be used to
	measure network performance parameters, such as latency, bandwidth,		measure network performance parameters, such as latency, bandwidth,
	and packet loss by sending probe packets and monitoring their		and packet loss by sending probe packets and monitoring their
	experience in the network. In order to guarantee the accuracy of		experience in the network. In order to guarantee the accuracy of
	network measurement results, security aspects must be considered.		network measurement results, security aspects must be considered.
	skipping to change at page 3, line 47		skipping to change at page 3, line 49
	traffic using O/TWAMP layer security established using the PSK		traffic using O/TWAMP layer security established using the PSK
	derived from IKEv2 but bypassing the IPsec tunnel. Protecting		derived from IKEv2 but bypassing the IPsec tunnel. Protecting
	unauthenticated O/TWAMP control and/or test traffic via AH or ESP		unauthenticated O/TWAMP control and/or test traffic via AH or ESP
	cannot provide various security options, e.g. it cannot authenticate		cannot provide various security options, e.g. it cannot authenticate
	part of a O/TWAMP packet as mentioned in [RFC4656]. For measuring		part of a O/TWAMP packet as mentioned in [RFC4656]. For measuring
	latency, timestamp is carried in O/TWAMP traffic. The sender has to		latency, timestamp is carried in O/TWAMP traffic. The sender has to
	fetch the timestamp, encrypt it, and send it. In this case, the		fetch the timestamp, encrypt it, and send it. In this case, the
	middle step can be skipped, potentially improving accuracy as the		middle step can be skipped, potentially improving accuracy as the
	sequence number can be encrypted and authenticated before the		sequence number can be encrypted and authenticated before the
	timestamp is fetched. It is the same case for the receiver since it		timestamp is fetched. It is the same case for the receiver since it
	can obtain the timstamp by skipping the decryption step. In such		can obtain the timestamp by skipping the decryption step. In such
	cases, protecting O/TWAMP traffic using O/TWAMP layer security but		cases, protecting O/TWAMP traffic using O/TWAMP layer security but
	bypassing IPsec tunnel has its advantages. This document describes		bypassing IPsec tunnel has its advantages. This document describes
	how to derive the shared secret key from the IKEv2 SA and employ the		how to derive the shared secret key from the IKEv2 SA and employ the
	security service at the O/TWAMP layer. This method SHOULD be used		security service at the O/TWAMP layer. This method SHOULD be used
	when O/TWAMP traffic is bypassing IPsec protection and is running		when O/TWAMP traffic is bypassing IPsec protection and is running
	over an external network exactly between two IKEv2 systems.		over an external network exactly between two IKEv2 systems.
	The remainder of this document is organized as follows. Section 3		After clarifying the terminology and scope in the subsequent
	summarizes O/TWAMP protocol operation with respect to security.		sections, the remainder of this document is organized as follows.
	Section 4 presents a method of binding O/TWAMP and IKEv2 for network		Section 4 summarizes O/TWAMP protocol operation with respect to
	measurements between the client and the server which both support		security. Section 5 presents the method for binding TWAMP and IKEv2
	IKEv2. Finally, Section 5 discusses the security considerations		for network measurements between the client and the server which both
	arising from the proposed mechanisms.		support IKEv2. Finally, Section 6 discusses the security
			considerations arising from the proposed mechanisms.
	2. Terminology		2. Terminology
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in [RFC2119].		document are to be interpreted as described in [RFC2119].
	3. O/TWAMP Security		3. Scope and Applicability
			This document specifies a method for enabling network measurements
			between a TWAMP client and a TWAMP server which both support IPsec.
			In short, the shared key used for securing TWAMP traffic is derived
			using IKEv2 [RFC7296]. This document reserves from the TWAMP-Modes
			registry the Mode value IANA.TBA.TWAMP.IKEv2Derived which MUST be
			used by TWAMP implementations compatible with this specification.
			Although the control procedures described in this document are
			applicable to OWAMP per se, the lack of an established IANA registry
			for OWAMP Mode values technically prevents us from extending OWAMP
			Mode values. Therefore, independent OWAMP implementations SHOULD be
			checked for full compatibility with respect to the use of this Mode
			value. Until an IANA registry for OWAMP Mode values is established,
			the use this feature in OWAMP implementations MUST be arranged
			privately among consenting OWAMP users.
			4. O/TWAMP Security
	Security for O/TWAMP-Control and O/TWAMP-Test are briefly reviewed in		Security for O/TWAMP-Control and O/TWAMP-Test are briefly reviewed in
	the following subsections.		the following subsections.
	3.1. O/TWAMP-Control Security		4.1. O/TWAMP-Control Security
	O/TWAMP uses a simple cryptographic protocol which relies on		O/TWAMP uses a simple cryptographic protocol which relies on
	o AES in Cipher Block Chaining (AES-CBC) for confidentiality		o AES in Cipher Block Chaining (AES-CBC) for confidentiality
	o HMAC-SHA1 truncated to 128 bits for message authentication		o HMAC-SHA1 truncated to 128 bits for message authentication
	Three modes of operation are supported in the OWAMP-Control protocol:		Three modes of operation are supported in the OWAMP-Control protocol:
	unauthenticated, authenticated, and encrypted. In addition to these		unauthenticated, authenticated, and encrypted. In addition to these
	modes, the TWAMP-Control protocol also supports a mixed mode, i.e.		modes, the TWAMP-Control protocol also supports a mixed mode, i.e.
	the TWAMP-Control protocol operates in encrypted mode while TWAMP-		the TWAMP-Control protocol operates in encrypted mode while TWAMP-
	Test protocol operates in unauthenticated mode. The authenticated,		Test protocol operates in unauthenticated mode. The authenticated,
	encrypted and mixed modes require that endpoints possess a shared		encrypted and mixed modes require that endpoints possess a shared
	secret, typically a passphrase. The secret key is derived from the		secret, typically a passphrase. The secret key is derived from the
	passphrase using a password-based key derivation function PBKDF2		passphrase using a password-based key derivation function PBKDF2
	skipping to change at page 5, line 45		skipping to change at page 6, line 18
	with Client- IV as the IV. Correspondingly, the server encrypts its		with Client- IV as the IV. Correspondingly, the server encrypts its
	side of the connection using Server-IV as the IV. The IVs themselves		side of the connection using Server-IV as the IV. The IVs themselves
	are transmitted in cleartext. Encryption starts with the block		are transmitted in cleartext. Encryption starts with the block
	immediately following that containing the IV.		immediately following that containing the IV.
	The AES Session-key and HMAC Session-key are generated randomly by		The AES Session-key and HMAC Session-key are generated randomly by
	the client. The HMAC Session-key is communicated along with the AES		the client. The HMAC Session-key is communicated along with the AES
	Session-key during O/TWAMP-Control connection setup. The HMAC		Session-key during O/TWAMP-Control connection setup. The HMAC
	Session-key is derived independently of the AES Session-key.		Session-key is derived independently of the AES Session-key.
	3.2. O/TWAMP-Test Security		4.2. O/TWAMP-Test Security
	The O/TWAMP-Test protocol runs over UDP, using the client and server		The O/TWAMP-Test protocol runs over UDP, using the client and server
	IP and port numbers that were negotiated during the Request-Session		IP and port numbers that were negotiated during the Request-Session
	exchange. O/TWAMP- Test has the same mode with O/TWAMP-Control and		exchange. O/TWAMP- Test has the same mode with O/TWAMP-Control and
	all O/TWAMP-Test sessions inherit the corresponding O/TWAMP-Control		all O/TWAMP-Test sessions inherit the corresponding O/TWAMP-Control
	session mode except when operating in mixed mode.		session mode except when operating in mixed mode.
	The O/TWAMP-Test packet format is the same in authenticated and		The O/TWAMP-Test packet format is the same in authenticated and
	encrypted modes. The encryption and authentication operations are,		encrypted modes. The encryption and authentication operations are,
	however, different. Similarly with the respective O/TWAMP-Control		however, different. Similarly with the respective O/TWAMP-Control
	skipping to change at page 6, line 28		skipping to change at page 7, line 5
	the session identifier (SID), which serve as inputs of the		the session identifier (SID), which serve as inputs of the
	key derivation function (KDF). The O/TWAMP-Test AES Session-		key derivation function (KDF). The O/TWAMP-Test AES Session-
	key is generated using the O/TWAMP- Control AES Session-key,		key is generated using the O/TWAMP- Control AES Session-key,
	with the 16-octet session identifier (SID), for encrypting		with the 16-octet session identifier (SID), for encrypting
	and decrypting the packets of the particular O/TWAMP-Test		and decrypting the packets of the particular O/TWAMP-Test
	session. The O/TWAMP-Test HMAC Session-key is generated		session. The O/TWAMP-Test HMAC Session-key is generated
	using the O/TWAMP-Control HMAC Session-key, with the 16-octet		using the O/TWAMP-Control HMAC Session-key, with the 16-octet
	session identifier (SID), for authenticating the packets of		session identifier (SID), for authenticating the packets of
	the particular O/TWAMP-Test session.		the particular O/TWAMP-Test session.
	3.3. O/TWAMP Security Root		4.3. O/TWAMP Security Root
	As discussed above, the AES Session-key and HMAC Session-key used by		As discussed above, the AES Session-key and HMAC Session-key used by
	the O/TWAMP-Test protocol are derived from the AES Session-key and		the O/TWAMP-Test protocol are derived from the AES Session-key and
	HMAC Session-key which are used in O/TWAMP-Control protocol. The AES		HMAC Session-key which are used in O/TWAMP-Control protocol. The AES
	Session-key and HMAC Session-key used in the O/TWAMP-Control protocol		Session-key and HMAC Session-key used in the O/TWAMP-Control protocol
	are generated randomly by the client, and encrypted with the shared		are generated randomly by the client, and encrypted with the shared
	secret associated with KeyID. Therefore, the security root is the		secret associated with KeyID. Therefore, the security root is the
	shared secret key. Thus, for large deployments, key provision and		shared secret key. Thus, for large deployments, key provision and
	management may become overly complicated. Comparatively, a		management may become overly complicated. Comparatively, a
	certificate-based approach using IKEv2 can automatically manage the		certificate-based approach using IKEv2 can automatically manage the
	security root and solve this problem, as we explain in Section 4.		security root and solve this problem, as we explain in Section 5.
	4. O/TWAMP for IPsec Networks		5. O/TWAMP for IPsec Networks
	This section presents a method of binding O/TWAMP and IKEv2 for		This section presents a method of binding O/TWAMP and IKEv2 for
	network measurements between a client and a server which both support		network measurements between a client and a server which both support
	IPsec. In short, the shared key used for securing O/TWAMP traffic is		IPsec. In short, the shared key used for securing O/TWAMP traffic is
	derived using IKEv2 [RFC5996].		derived using IKEv2 [RFC7296].
	4.1. Shared Key Derivation		5.1. Shared Key Derivation
	In the authenticated, encrypted and mixed modes, the shared secret		In the authenticated, encrypted and mixed modes, the shared secret
	key MUST be derived from the IKEv2 Security Association (SA). Note		key MUST be derived from the IKEv2 Security Association (SA). Note
	that we explicitly opt to derive the shared secret key from the IKEv2		that we explicitly opt to derive the shared secret key from the IKEv2
	SA, rather than the child SA, since the use case whereby an IKEv2 SA		SA, rather than the child SA, since the use case whereby an IKEv2 SA
	can be created without generating any child SA is possible [RFC6023].		can be created without generating any child SA is possible [RFC6023].
	When the shared secret key is derived from the IKEv2 SA, SK_d must be		When the shared secret key is derived from the IKEv2 SA, SK_d must be
	generated first. SK_d MUST be computed as per [RFC5996].		generated first. SK_d MUST be computed as per [RFC7296].
	The shared secret key MUST be generated as follows:		The shared secret key MUST be generated as follows:
	Shared secret key = PRF( SK_d, "IPPM" )		Shared secret key = PRF( SK_d, "IPPM" )
	Wherein the string "IPPM" comprises four ASCII characters and prf is		Wherein the string "IPPM" comprises four ASCII characters and prf is
	a pseudorandom function. It is recommended that the shared secret		a pseudorandom function. It is recommended that the shared secret
	key is derived in the IPsec layer. This way, the IPsec keying		key is derived in the IPsec layer. This way, the IPsec keying
	material is not exposed to the O/TWAMP client. Note, however, that		material is not exposed to the O/TWAMP client. Note, however, that
	the interaction between the O/TWAMP and IPsec layers is host-internal		the interaction between the O/TWAMP and IPsec layers is host-internal
	skipping to change at page 7, line 41		skipping to change at page 8, line 18
	Alternatively, the O/TWAMP client does not initiate the establishment		Alternatively, the O/TWAMP client does not initiate the establishment
	of the IKEv2 SA, logs an error for operational management purposes,		of the IKEv2 SA, logs an error for operational management purposes,
	and proceeds with the modes defined in [RFC4656][RFC5357][RFC5618].		and proceeds with the modes defined in [RFC4656][RFC5357][RFC5618].
	Again, although both alternatives are feasible, they are in fact		Again, although both alternatives are feasible, they are in fact
	implementation-specific.		implementation-specific.
	If rekeying for the IKEv2 SA or deletion of the IKEv2 SA occurs, the		If rekeying for the IKEv2 SA or deletion of the IKEv2 SA occurs, the
	corresponding shared secret key generated from the SA can continue to		corresponding shared secret key generated from the SA can continue to
	be used until the O/TWAMP session terminates.		be used until the O/TWAMP session terminates.
	4.2. Server Greeting Message Update		5.2. Server Greeting Message Update
	To achieve a binding association between the key generated from IKEv2		To achieve a binding association between the key generated from IKEv2
	and the O/TWAMP shared secret key, Server Greeting Message should be		and the O/TWAMP shared secret key, Server Greeting Message should be
	updated as in Figure 2.		updated as in Figure 2.
	0 1 2 3		0 1 2 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	| Unused (12 octets) |		| Unused (12 octets) |
	skipping to change at page 8, line 34		skipping to change at page 9, line 6
	| Count (4 octets) |		| Count (4 octets) |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	| MBZ (12 octets) |		| MBZ (12 octets) |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 2: Server Greeting format		Figure 2: Server Greeting format
	The Modes field in Figure 2 will need to allow for support of key		The Modes field in Figure 2 will need to allow for support of key
	derivation as discussed in Section 4.1. As such, the Modes value		derivation as discussed in Section 5.1. As such, the Modes value
	extension MUST be supported by implementations compatible with this		extension MUST be supported by implementations compatible with this
	document, indicating support for deriving the shared key from the		document, indicating support for deriving the shared key from the
	IKEv2 SA. The new Modes value indicating support for this		IKEv2 SA. The new Modes value indicating support for this
	specification is IANA.TBA.TWAMP.IKEv2Derived (note to IANA: 128 is		specification is IANA.TBA.TWAMP.IKEv2Derived (note to IANA: 128 is
	preferred, i.e. bit in position 7). Clearly, an implementation		preferred, i.e. bit in position 7). Clearly, an implementation
	compatible with this specification MUST support the authenticated,		compatible with this specification MUST support the authenticated,
	encrypted and mixed modes as per [RFC4656][RFC5357][RFC5618].		encrypted and mixed modes as per [RFC4656][RFC5357][RFC5618].
	The choice of this set of Modes values poses no backwards		The choice of this set of Modes values poses no backwards
	compatibility problems to existing O/TWAMP clients. Robust legacy		compatibility problems to existing O/TWAMP clients. Robust legacy
	client implementations would disregard the fact that the		client implementations would disregard the fact that the
	IANA.TBA.TWAMP.IKEv2Derived Modes bit in the Server Greeting is set.		IANA.TBA.TWAMP.IKEv2Derived Modes bit in the Server Greeting is set.
	On the other hand, a client compatible with this specification can		On the other hand, a client compatible with this specification can
	easily identify that the O/TWAMP server contacted does not support		easily identify that the O/TWAMP server contacted does not support
	this specification. If the server supports other Modes, as one could		this specification. If the server supports other Modes, as one could
	assume, the client would then decide which Mode to use and indicate		assume, the client would then decide which Mode to use and indicate
	such accordingly as per [RFC4656][RFC5357]. A client compatible with		such accordingly as per [RFC4656][RFC5357]. A client compatible with
	this specification which decides not to employ IKEv2 derivation, can		this specification which decides not to employ IKEv2 derivation, can
	simply behave as a purely [RFC4656]/[RFC5357] compatible client.		simply behave as a purely [RFC4656]/[RFC5357] compatible client.
	4.3. Set-Up-Response Update		5.3. Set-Up-Response Update
	The Set-Up-Response Message should be updated as in Figure 3. When a		The Set-Up-Response Message should be updated as in Figure 3. When a
	O/TWAMP client compatible with this specification receives a Server		O/TWAMP client compatible with this specification receives a Server
	Greeting indicating support for Mode IANA.TBA.TWAMP.IKEv2Derived it		Greeting indicating support for Mode IANA.TBA.TWAMP.IKEv2Derived it
	SHOULD reply to the O/TWAMP server with a Set-Up response that		SHOULD reply to the O/TWAMP server with a Set-Up response that
	indicates so. For example, a compatible O/TWAMP client choosing the		indicates so. For example, a compatible O/TWAMP client choosing the
	authenticated mode with IKEv2 shared secret key derivation should set		authenticated mode with IKEv2 shared secret key derivation should set
	Mode to 130, i.e. set the bits in positions 1 and 7 (TBD IANA) to		Mode to 130, i.e. set the bits in positions 1 and 7 (TBD IANA) to
	one.		one.
	skipping to change at page 9, line 40		skipping to change at page 10, line 27
	| |		| |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| |		| |
	| Client-IV (12 octets) |		| Client-IV (12 octets) |
	| |		| |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	Figure 3: Set-Up-Response Message		Figure 3: Set-Up-Response Message
	The Security Parameter Index (SPI)(see [RFC4301] [RFC5996]) can		The Security Parameter Index (SPI)(see [RFC4301] [RFC7296]) can
	uniquely identify the Security Association (SA). If the client		uniquely identify the Security Association (SA). If the client
	supports the derivation of shared secret key from IKEv2 SA, it will		supports the derivation of shared secret key from IKEv2 SA, it will
	choose the corresponding mode value and carry SPIi and SPIr in the		choose the corresponding mode value and carry SPIi and SPIr in the
	Key ID field. SPIi and SPIr MUST be included in the Key ID field of		Key ID field. SPIi and SPIr MUST be included in the Key ID field of
	Set-Up-Response Message to indicate the IKEv2 SA from which the O/		Set-Up-Response Message to indicate the IKEv2 SA from which the O/
	TWAMP shared secret key derived from. The length of SPI is 4 octets.		TWAMP shared secret key derived from. The length of SPI is 4 octets.
	Therefore, the first 4 octets of Key ID field MUST carry SPIi and the		Therefore, the first 4 octets of Key ID field MUST carry SPIi and the
	second 4 octets MUST carry SPIr. The remaining bits of the Key ID		second 4 octets MUST carry SPIr. The remaining bits of the Key ID
	field MUST set to zero.		field MUST set to zero.
	skipping to change at page 10, line 17		skipping to change at page 11, line 5
	remaining octets of the Key ID field. Then, the client and the		remaining octets of the Key ID field. Then, the client and the
	server can derive the shared secret key based on the mode value and		server can derive the shared secret key based on the mode value and
	SPI. If the O/TWAMP server cannot find the IKEv2 SA corresponding to		SPI. If the O/TWAMP server cannot find the IKEv2 SA corresponding to
	the SPIi and SPIr received, it MUST log the event for operational		the SPIi and SPIr received, it MUST log the event for operational
	management purposes. In addition, the O/TWAMP server SHOULD set the		management purposes. In addition, the O/TWAMP server SHOULD set the
	Accept field of the Server-Start message to the value 6 to indicate		Accept field of the Server-Start message to the value 6 to indicate
	that server is not willing to conduct further transactions in this O/		that server is not willing to conduct further transactions in this O/
	TWAMP-Control session since it can not find the corresponding IKEv2		TWAMP-Control session since it can not find the corresponding IKEv2
	SA.		SA.
	4.4. O/TWAMP over an IPsec tunnel		5.4. O/TWAMP over an IPsec tunnel
	IPsec AH [RFC4302] and ESP [RFC4303] provide confidentiality and		IPsec AH [RFC4302] and ESP [RFC4303] provide confidentiality and
	data integrity to IP datagrams. Thus an IPsec tunnel can be used to		data integrity to IP datagrams. Thus an IPsec tunnel can be used to
	provide the protection needed for O/TWAMP Control and Test packets,		provide the protection needed for O/TWAMP Control and Test packets,
	even if the peers choose the unauthenticated mode of operation. If		even if the peers choose the unauthenticated mode of operation. If
	the two endpoints are already connected through an IPSec tunnel it is		the two endpoints are already connected through an IPSec tunnel it is
	RECOMMENDED that the O/TWAMP measurement packets are forwarded over		RECOMMENDED that the O/TWAMP measurement packets are forwarded over
	the IPSec tunnel if the peers choose the unauthenticated mode in		the IPSec tunnel if the peers choose the unauthenticated mode in
	order to ensure authenticity and security.		order to ensure authenticity and security.
	5. Security Considerations		6. Security Considerations
	As the shared secret key is derived from the IKEv2 SA, the key		As the shared secret key is derived from the IKEv2 SA, the key
	derivation algorithm strength and limitations are as per [RFC5996].		derivation algorithm strength and limitations are as per [RFC7296].
	The strength of a key derived from a Diffie-Hellman exchange using		The strength of a key derived from a Diffie-Hellman exchange using
	any of the groups defined here depends on the inherent strength of		any of the groups defined here depends on the inherent strength of
	the group, the size of the exponent used, and the entropy provided by		the group, the size of the exponent used, and the entropy provided by
	the random number generator employed. The strength of all keys and		the random number generator employed. The strength of all keys and
	implementation vulnerabilities, particularly Denial of Service (DoS)		implementation vulnerabilities, particularly Denial of Service (DoS)
	attacks are as defined in [RFC5996].		attacks are as defined in [RFC7296].
	As a more general note, the IPPM community may want to revisit the		As a more general note, the IPPM community may want to revisit the
	arguments listed in [RFC4656], Sec. 6.6. Other widely-used Internet		arguments listed in [RFC4656], Sec. 6.6. Other widely-used Internet
	security mechanisms, such as TLS and DTLS, may also be considered for		security mechanisms, such as TLS and DTLS, may also be considered for
	future use over and above of what is already specified in [RFC4656]		future use over and above of what is already specified in [RFC4656]
	[RFC5357].		[RFC5357].
	6. IANA Considerations		7. IANA Considerations
	IANA is requested to allocate the IANA.TBA.TWAMP.IKEv2Derived Modes		IANA is requested to allocate the IANA.TBA.TWAMP.IKEv2Derived Modes
	value in the TWAMP-Modes registry.		value in the TWAMP-Modes registry.
	7. Acknowledgments		8. Acknowledgments
	We thank Eric Chen, Yaakov Stein, Brian Trammell, Emily Bi, John		We thank Eric Chen, Yaakov Stein, Brian Trammell, Emily Bi, John
	Mattsson, and Steve Baillargeon for their comments and text		Mattsson, and Steve Baillargeon for their comments and text
	suggestions. Al Morton deserves a special mention for his text		suggestions.
	contributions and the good discussion and pointers to earlier related
	work in IPPM WG.
	8. References		Al Morton deserves a special mention for his thorough reviews and
			text contributions to this document as well as the constructive
			discussions over several IPPM meetings.
	8.1. Normative References		9. References
			9.1. Normative References
	[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[RFC4302] Kent, S., "IP Authentication Header", RFC 4302, December		[RFC4302] Kent, S., "IP Authentication Header", RFC 4302, December
	2005.		2005.
	[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", RFC		[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", RFC
	4303, December 2005.		4303, December 2005.
	skipping to change at page 11, line 38		skipping to change at page 12, line 27
	(OWAMP)", RFC 4656, September 2006.		(OWAMP)", RFC 4656, September 2006.
	[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.		[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
	Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",		Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
	RFC 5357, October 2008.		RFC 5357, October 2008.
	[RFC5618] Morton, A. and K. Hedayat, "Mixed Security Mode for the		[RFC5618] Morton, A. and K. Hedayat, "Mixed Security Mode for the
	Two-Way Active Measurement Protocol (TWAMP)", RFC 5618,		Two-Way Active Measurement Protocol (TWAMP)", RFC 5618,
	August 2009.		August 2009.
	[RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,		[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
	"Internet Key Exchange Protocol Version 2 (IKEv2)", RFC		Kivinen, "Internet Key Exchange Protocol Version 2
	5996, September 2010.		(IKEv2)", STD 79, RFC 7296, October 2014.
	8.2. Informative References		9.2. Informative References
	[RFC2898] Kaliski, B., "PKCS #5: Password-Based Cryptography		[RFC2898] Kaliski, B., "PKCS #5: Password-Based Cryptography
	Specification Version 2.0", RFC 2898, September 2000.		Specification Version 2.0", RFC 2898, September 2000.
	[RFC4301] Kent, S. and K. Seo, "Security Architecture for the		[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
	Internet Protocol", RFC 4301, December 2005.		Internet Protocol", RFC 4301, December 2005.
	[RFC6023] Nir, Y., Tschofenig, H., Deng, H., and R. Singh, "A		[RFC6023] Nir, Y., Tschofenig, H., Deng, H., and R. Singh, "A
	Childless Initiation of the Internet Key Exchange Version		Childless Initiation of the Internet Key Exchange Version
	2 (IKEv2) Security Association (SA)", RFC 6023, October		2 (IKEv2) Security Association (SA)", RFC 6023, October
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