draft-ietf-detnet-oam-framework-06.txt		draft-ietf-detnet-oam-framework-07.txt
	DetNet G. Mirsky		DetNet G. Mirsky
	Internet-Draft Ericsson		Internet-Draft Ericsson
	Intended status: Informational F. Theoleyre		Intended status: Informational F. Theoleyre
	Expires: 15 December 2022 CNRS		Expires: 7 April 2023 CNRS
	G.Z. Papadopoulos		G.Z. Papadopoulos
	IMT Atlantique		IMT Atlantique
	CJ. Bernardos		CJ. Bernardos
	UC3M		UC3M
	B. Varga		B. Varga
	J. Farkas		J. Farkas
	Ericsson		Ericsson
	13 June 2022		4 October 2022
	Framework of Operations, Administration and Maintenance (OAM) for		Framework of Operations, Administration and Maintenance (OAM) for
	Deterministic Networking (DetNet)		Deterministic Networking (DetNet)
	draft-ietf-detnet-oam-framework-06		draft-ietf-detnet-oam-framework-07
	Abstract		Abstract
	Deterministic Networking (DetNet), as defined in RFC 8655, is aimed		Deterministic Networking (DetNet), as defined in RFC 8655, is aimed
	to provide a bounded end-to-end latency on top of the network		to provide a bounded end-to-end latency on top of the network
	infrastructure, comprising both Layer 2 bridged and Layer 3 routed		infrastructure, comprising both Layer 2 bridged and Layer 3 routed
	segments. This document's primary purpose is to detail the specific		segments. This document's primary purpose is to detail the specific
	requirements of the Operation, Administration, and Maintenance (OAM)		requirements of the Operation, Administration, and Maintenance (OAM)
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	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 15 December 2022.		This Internet-Draft will expire on 7 April 2023.
	Copyright Notice		Copyright Notice
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	1.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 4		1.2. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . 4
	1.3. Requirements Language . . . . . . . . . . . . . . . . . . 5		1.3. Requirements Language . . . . . . . . . . . . . . . . . . 5
	2. Role of OAM in DetNet . . . . . . . . . . . . . . . . . . . . 5		2. Role of OAM in DetNet . . . . . . . . . . . . . . . . . . . . 5
	3. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 6		3. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 6
	3.1. Information Collection . . . . . . . . . . . . . . . . . 7		3.1. Information Collection . . . . . . . . . . . . . . . . . 7
	3.2. Continuity Check . . . . . . . . . . . . . . . . . . . . 7		3.2. Continuity Check . . . . . . . . . . . . . . . . . . . . 7
	3.3. Connectivity Verification . . . . . . . . . . . . . . . . 7		3.3. Connectivity Verification . . . . . . . . . . . . . . . . 7
	3.4. Route Tracing . . . . . . . . . . . . . . . . . . . . . . 8		3.4. Route Tracing . . . . . . . . . . . . . . . . . . . . . . 8
	3.5. Fault Verification/detection . . . . . . . . . . . . . . 8		3.5. Fault Verification/Detection . . . . . . . . . . . . . . 8
	3.6. Fault Localization and Characterization . . . . . . . . . 8		3.6. Fault Localization and Characterization . . . . . . . . . 8
	3.7. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . 9		3.7. Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . . 8
	4. Administration . . . . . . . . . . . . . . . . . . . . . . . 9		4. Administration . . . . . . . . . . . . . . . . . . . . . . . 9
	4.1. Collection of metrics . . . . . . . . . . . . . . . . . . 10		4.1. Collection of metrics . . . . . . . . . . . . . . . . . . 9
	4.2. Worst-case metrics . . . . . . . . . . . . . . . . . . . 10		4.2. Worst-case metrics . . . . . . . . . . . . . . . . . . . 10
	5. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 10		5. Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . 10
	5.1. Replication / Elimination . . . . . . . . . . . . . . . . 10		5.1. Replication / Elimination . . . . . . . . . . . . . . . . 10
	5.2. Resource Reservation . . . . . . . . . . . . . . . . . . 11		5.2. Resource Reservation . . . . . . . . . . . . . . . . . . 11
	6. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 11		6. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 11
	6.1. Requirements on OAM for DetNet Forwarding Sub-layer . . . 12		6.1. Requirements on OAM for DetNet Forwarding Sub-layer . . . 12
	6.2. Requirements on OAM for DetNet Service Sub-layer . . . . 12		6.2. Requirements on OAM for DetNet Service Sub-layer . . . . 12
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
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	SLO: Service Level Objective		SLO: Service Level Objective
	1.3. Requirements Language		1.3. Requirements Language
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and		"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
	"OPTIONAL" in this document are to be interpreted as described in BCP		"OPTIONAL" in this document are to be interpreted as described in BCP
	14 [RFC2119] [RFC8174] when, and only when, they appear in all		14 [RFC2119] and [RFC8174] when, and only when, they appear in all
	capitals, as shown here.		capitals, as shown here. The requirements language is used in
			Section 6 and applies to future implementations of DetNet OAM.
	2. Role of OAM in DetNet		2. Role of OAM in DetNet
	DetNet networks expect to provide communications with predictable low		DetNet networks expect to provide communications with predictable low
	packet delay and packet loss. Most critical applications will define		packet delay and packet loss. Most critical applications will define
	an SLO to be required for the DetNet flows it generates.		an SLO to be required for the DetNet flows it generates.
	To respect strict guarantees, DetNet can use an orchestrator able to		To respect strict guarantees, DetNet can use an orchestrator able to
	monitor and maintain the network. Typically, a Software-Defined		monitor and maintain the network. Typically, a Software-Defined
	Network (SDN) controller places DetNet flows in the deployed network		Network controller places DetNet flows in the deployed network based
	based on their SLO. Thus, resources have to be provisioned a priori		on their SLO. Thus, resources have to be provisioned a priori for
	for the regular operation of the network. OAM represents the		the regular operation of the network. OAM represents the essential
	essential elements of the network operation and necessary for OAM		elements of the network operation and necessary for OAM resources
	resources that need to be accounted for to maintain the network		that need to be accounted for to maintain the network operational.
	operational.
	Many legacy OAM tools can be used in DetNet networks, but they are		Many legacy OAM tools can be used in DetNet networks, but they are
	not able to cover all the aspects of deterministic networking.		not able to cover all the aspects of deterministic networking.
	Fulfilling strict guarantees is essential for DetNet flows, resulting		Fulfilling strict guarantees is essential for DetNet flows, resulting
	in new DetNet specific functionalities that must be covered with OAM.		in new DetNet specific functionalities that must be covered with OAM.
	Filling these gaps is inevitable and needs accurate consideration of		Filling these gaps is inevitable and needs accurate consideration of
	DetNet specifics. Similar to DetNet flows itself, their OAM needs		DetNet specifics. Similar to DetNet flows itself, their OAM needs
	careful end-to-end engineering as well.		careful end-to-end engineering as well.
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	recognize/discover DetNet relay nodes, to get information about their		recognize/discover DetNet relay nodes, to get information about their
	configuration, and to check their operation or status.		configuration, and to check their operation or status.
	DetNet service sub-layer functions using a sequence number. That		DetNet service sub-layer functions using a sequence number. That
	creates a challenge for inserting OAM packets in the DetNet flow.		creates a challenge for inserting OAM packets in the DetNet flow.
	Fault tolerance also assumes that multiple paths could be provisioned		Fault tolerance also assumes that multiple paths could be provisioned
	to maintain an end-to-end circuit by adapting to the existing		to maintain an end-to-end circuit by adapting to the existing
	conditions. The central controller/orchestrator typically controls		conditions. The DetNet Controller Plane, e.g., central controller/
	the PREOF on a node. OAM is expected to support monitoring and		orchestrator, controls the PREOF on a node. OAM is expected to
	troubleshooting PREOF on a particular node and within the domain.		support monitoring and troubleshooting PREOF on a particular node and
			within the domain.
	Note that distributed controllers can also control PREOF in those		Note that a distributed architecture of of the DetNet Control Plane
	scenarios where DetNet solutions involve more than one single central		can also control PREOF in those scenarios where DetNet solutions
	controller.		involve more than one single central controller.
	DetNet forwarding sub-layer is based on legacy technologies and has a		DetNet forwarding sub-layer is based on legacy technologies and has a
	much better coverage regarding OAM. However, the forwarding sub-		much better coverage regarding OAM. However, the forwarding sub-
	layer is terminated at DetNet relay nodes, so the end-to-end OAM		layer is terminated at DetNet relay nodes, so the end-to-end OAM
	state of forwarding may be created only based on the status of		state of forwarding may be created only based on the status of
	multiple forwarding sub-layer segments serving a given DetNet flow		multiple forwarding sub-layer segments serving a given DetNet flow
	(e.g., in case of DetNet MPLS, there may be no end-to-end LSP below		(e.g., in case of DetNet MPLS, there may be no end-to-end LSP below
	the DetNet PW).		the DetNet PW).
	3. Operation		3. Operation
	OAM features will enable DetNet with robust operation both for		OAM features will enable DetNet with robust operation both for
	forwarding and routing purposes.		forwarding and routing purposes.
	It is worth noting that the test and data packets MUST follow the		It is worth noting that the test and data packets are expected to
	same path, i.e., the connectivity verification has to be conducted		follow the same path, i.e., the connectivity verification has to be
	in-band without impacting the data traffic. Test packets MUST share		conducted in-band without impacting the data traffic. It is expected
	fate with the monitored data traffic without introducing congestion		that test packets share fate with the monitored data traffic without
	in normal network conditions.		introducing congestion in normal network conditions.
	3.1. Information Collection		3.1. Information Collection
	Information about the state of the network can be collected using		Information about the state of the network can be collected using
	several mechanisms. Some protocols, e.g., Simple Network Management		several mechanisms. Some protocols, e.g., Simple Network Management
	Protocol, send queries. Others, e.g., YANG-based data models,		Protocol, send queries. Others, e.g., YANG-based data models,
	generate notifications based on the publish-subscribe method. In		generate notifications based on the publish-subscribe method. In
	either way, information is collected and sent to the controller.		either way, information is collected and sent using the DetNet
			Controller Plane.
	Also, we can characterize methods of transporting OAM information		Also, we can characterize methods of transporting OAM information
	relative to the path of data. For instance, OAM information may be		relative to the path of data. For instance, OAM information may be
	transported in-band or out-of-band relative to the DetNet flow. In		transported in-band or out-of-band relative to the DetNet flow. In
	case of the former, the telemetry information uses resources		case of the former, the telemetry information uses resources
	allocated for the monitored DetNet flow. If an in-band method of		allocated for the monitored DetNet flow. If an in-band method of
	transporting telemetry is used, the amount of generated information		transporting telemetry is used, the amount of generated information
	needs to be carefully analyzed, and additional resources must be		needs to be carefully analyzed, and additional resources must be
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	constraints, i.e., the absence of misconnection. The misconnection		constraints, i.e., the absence of misconnection. The misconnection
	error state is entered after several consecutive test packets from		error state is entered after several consecutive test packets from
	other DetNet flows are received. The definition of the conditions of		other DetNet flows are received. The definition of the conditions of
	entry and exit for misconnection error state is outside the scope of		entry and exit for misconnection error state is outside the scope of
	this document.		this document.
	3.4. Route Tracing		3.4. Route Tracing
	Ping and traceroute are two ubiquitous tools that help localize and		Ping and traceroute are two ubiquitous tools that help localize and
	characterize a failure in the network. They help to identify a		characterize a failure in the network. They help to identify a
	subset of the list of routers in the route. However, to be		subset of the list of routers in the route. However, to be
	predictable, resources are reserved per flow in DetNet. Thus, DetNet		predictable, resources are reserved per flow in DetNet. Thus, DetNet
	needs to define route tracing tools able to track the route for a		needs to define route tracing tools able to track the route for a
	specific flow. Also, tracing can be used for the discovery of the		specific flow. Also, tracing can be used for the discovery of the
	Path Maximum Transmission Unit or location of elements of PREOF for		Path Maximum Transmission Unit or location of elements of PREOF for
	the particular route in the DetNet domain.		the particular route in the DetNet domain.
	DetNet is NOT RECOMMENDED to use multiple paths or links, i.e.,		DetNet is not expected to use Equal-Cost Multipath (ECMP) [RFC8939].
	Equal-Cost Multipath (ECMP) [RFC8939]. As the result, OAM in ECMP		As the result, DetNet OAM in ECMP environment is outside the scope of
	environment is outside the scope of this document.		this document.
	3.5. Fault Verification/detection		3.5. Fault Verification/Detection
	DetNet expects to operate fault-tolerant networks. Thus, mechanisms		DetNet expects to operate fault-tolerant networks. Thus, mechanisms
	able to detect faults before they impact the network performance are		able to detect faults before they impact the network performance are
	needed.		needed.
	The network has to detect when a fault occurred, i.e., the network		The network has to detect when a fault occurred, i.e., the network
	has deviated from its expected behavior. While the network must		has deviated from its expected behavior. While the network must
	report an alarm, the cause may not be identified precisely. For		report an alarm, the cause may not be identified precisely. For
	instance, the end-to-end reliability has decreased significantly, or		instance, the end-to-end reliability has decreased significantly, or
	a buffer overflow occurs.		a buffer overflow occurs.
	DetNet OAM mechanisms SHOULD allow a fault detection in real time.
	They MAY, when possible, predict faults based on current network
	conditions. They MAY also identify and report the cause of the
	actual/predicted network failure.
	3.6. Fault Localization and Characterization		3.6. Fault Localization and Characterization
	An ability to localize the network defect and provide its		An ability to localize the network defect and provide its
	characterization are necessary elements of network operation.		characterization are necessary elements of network operation.
	Fault localization, a process of deducing the location of a		Fault localization, a process of deducing the location of a
	network failure from a set of observed failure indications, might		network failure from a set of observed failure indications, might
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	fault localization can correlate reports of failures from a set of		fault localization can correlate reports of failures from a set of
	interleaving sessions monitoring path continuity.		interleaving sessions monitoring path continuity.
	Fault characterization is a process of identifying the root cause		Fault characterization is a process of identifying the root cause
	of the problem. For instance, misconfiguration or malfunction of		of the problem. For instance, misconfiguration or malfunction of
	PREOF elements can be the cause of erroneous packet replication or		PREOF elements can be the cause of erroneous packet replication or
	extra packets being flooded in the DetNet domain.		extra packets being flooded in the DetNet domain.
	3.7. Use of Hybrid OAM in DetNet		3.7. Use of Hybrid OAM in DetNet
	Hybrid OAM methods are used in performance monitoring and defined in		Hybrid OAM methods are used in performance monitoring and defined in
	[RFC7799] as:		[RFC7799] as:
	Hybrid Methods are Methods of Measurement that use a combination		Hybrid Methods are Methods of Measurement that use a combination
	of Active Methods and Passive Methods.		of Active Methods and Passive Methods.
	A hybrid measurement method may produce metrics as close to passive,		A hybrid measurement method may produce metrics as close to passive,
	but it still alters something in a data packet even if that is the		but it still alters something in a data packet even if that is the
	value of a designated field in the packet encapsulation. One example		value of a designated field in the packet encapsulation. One example
	of such a hybrid measurement method is the Alternate Marking method		of such a hybrid measurement method is the Alternate Marking method
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	to a data flow, measured metrics are directly applicable to the		to a data flow, measured metrics are directly applicable to the
	DetNet flow. AMM minimizes the additional load on the DetNet domain		DetNet flow. AMM minimizes the additional load on the DetNet domain
	by using nodal collection and computation of performance metrics in		by using nodal collection and computation of performance metrics in
	combination with optionally using out-of-band telemetry collection		combination with optionally using out-of-band telemetry collection
	for further network analysis.		for further network analysis.
	4. Administration		4. Administration
	The network SHOULD expose a collection of metrics to support an		The ability to expose a collection of metrics to support an operator
	operator making proper decisions, including:		making proper decisions is essential. Following perfromence metris
			are useful:
	* Queuing Delay: the time elapsed between a packet enqueued and its		* Queuing Delay: the time elapsed between a packet enqueued and its
	transmission to the next hop.		transmission to the next hop.
	* Buffer occupancy: the number of packets present in the buffer, for		* Buffer occupancy: the number of packets present in the buffer, for
	each of the existing flows.		each of the existing flows.
	The following metrics SHOULD be collected:
	* per a DetNet flow to measure the end-to-end performance for a		* Per a DetNet flow to measure the end-to-end performance for a
	given flow. Each of the paths has to be isolated in multipath		given flow. Each of the paths has to be isolated in multipath
	routing strategies.		routing strategies.
	* per path to detect misbehaving path when multiple paths are		* Per path to detect misbehaving path(s) when multiple paths are
	applied.		used for the service protection.
	* per device to detect misbehaving device, when it relays the		* Per device to detect misbehaving device, when it relays the
	packets of several flows.		packets of several flows.
	4.1. Collection of metrics		4.1. Collection of metrics
	DetNet OAM SHOULD optimize the number of statistics / measurements to		The optimization of the number of statistics / measurements to
	collected, frequency of collecting. Distributed and centralized		collected, frequency of collecting using a distributed and/or
	mechanisms MAY be used in combination. Periodic and event-triggered		centralized mechanisms is an important operational function.
	collection information characterizing the state of a network MAY be		Periodic and event-triggered collection information characterizing
	used.		the state of a network is an example of of of mechanisms to achieve
			the optimization.
	4.2. Worst-case metrics		4.2. Worst-case metrics
	DetNet aims to enable real-time communications on top of a		DetNet aims to enable real-time communications on top of a
	heterogeneous multi-hop architecture. To make correct decisions, the		heterogeneous multi-hop architecture. To make correct decisions, the
	controller needs to know the distribution of packet losses/delays for		DetNet Controller Plane [RFC8655] needs timely information about
	each flow, and each hop of the paths. In other words, the average		packet losses/delays for each flow, and each hop of the paths. In
	end-to-end statistics are not enough. The collected information must		other words, just the average end-to-end statistics are not enough.
	be sufficient to allow the controller to predict the worst-case.		The collected information must be sufficient to allow a systemto
			predict the worst-case scenario.
	5. Maintenance		5. Maintenance
			Service protection (provided by the DetNet Service sub-layer) is
			designed to cope with simple network failures and mitigates the
			DetNet Controller Plane's immediate reaction to network events. In
	In the face of events that impact the network operation (e.g., link		the face of events that impact the network operation (e.g., link up/
	up/down, device crash/reboot, flows starting and ending), the DetNet		down, device crash/reboot, flows starting and ending), the DetNet
	Controller need to perform repair and re-optimization actions in		Controller Plane needs to perform repair and re-optimization actions
	order to permanently ensure the SLO of all active flows with minimal		in order to permanently ensure the SLO of all active flows with
	waste of resources The controller MUST be able to continuously		minimal waste of resources. The Controller Plane is expected to be
	retrieve the state of the network, to evaluate conditions and trends		able to continuously retrieve the state of the network, to evaluate
	about the relevance of a reconfiguration, quantifying:		conditions and trends about the relevance of a reconfiguration,
			quantifying:
	the cost of the sub-optimality: resources may not be used		the cost of the sub-optimality: resources may not be used
	optimally (e.g., a better path exists).		optimally (e.g., a better path exists).
	the reconfiguration cost: the controller needs to trigger some		the reconfiguration cost: the DetNet Controller Plane needs an
	reconfigurations. For this transient period, resources may be		ability to trigger some reconfigurations. For this transient
	twice reserved, and control packets have to be transmitted.		period, resources may be twice reserved, and control packets have
			to be transmitted.
	Thus, reconfiguration may only be triggered if the gain is		Thus, reconfiguration may only be triggered if the gain is
	significant.		significant.
	5.1. Replication / Elimination		5.1. Replication / Elimination
	When multiple paths are reserved between two MEPs, packet replication		When multiple paths are reserved between two MEPs, packet replication
	may be used to introduce redundancy and alleviate transmission errors		may be used to introduce redundancy and alleviate transmission errors
	and collisions. For instance, in Figure 1, the source device S is		and collisions. For instance, in Figure 1, the source device S is
	transmitting a packet to devices A and B.		transmitting a packet to devices A and B.
	===> (A) => (C) => (E) ===		===> (A) => (C) => (E) ===
	// \\// \\// \\		// \\// \\// \\
	source (S) //\\ //\\ (R) (root)		source (S) //\\ //\\ (R) (root)
	\\ // \\ // \\ //		\\ // \\ // \\ //
	===> (B) => (D) => (F) ===		===> (B) => (D) => (F) ===
	Figure 1: Packet Replication: S transmits twice the same data		Figure 1: Packet Replication: S transmits twice the same data
	packet, to nodes A and B.		packet, to nodes A and B.
	5.2. Resource Reservation		5.2. Resource Reservation
	Because the quality of service criteria associated with a path may		Because the quality of service criteria associated with a path may
	degrade, the network has to provision additional resources along the		degrade, the network has to provision additional resources along the
	path. We need to provide mechanisms to patch the network		path.
	configuration.
	6. Requirements		6. Requirements
	According to [RFC8655], DetNet functionality is divided into		According to [RFC8655], DetNet functionality is divided into
	forwarding and service sub-layers. The DetNet forwarding sub-layer		forwarding and service sub-layers. The DetNet forwarding sub-layer
	includes DetNet transit nodes and may allocate resources for a DetNet		includes DetNet transit nodes and may allocate resources for a DetNet
	flow over paths provided by the underlay network. The DetNet service		flow over paths provided by the underlay network. The DetNet service
	sub-layer includes DetNet relay nodes and provides a DetNet service		sub-layer includes DetNet relay nodes and provides a DetNet service
	(e.g., service protection). This section lists general requirements		(e.g., service protection). This section lists general requirements
	for DetNet OAM as well as requirements in each of the DetNet sub-		for DetNet OAM as well as requirements in each of the DetNet sub-
	layers of a DetNet domain.		layers of a DetNet domain.
	1. It MUST be possible to initiate a DetNet OAM session from a MEP		1. It MUST be possible to initiate a DetNet OAM session from a MEP
	located at a DetNet node towards downstream MEP(s) within the		located at a DetNet node towards downstream MEP(s) within the
	given domain at a particular DetNet sub-layer.		given domain at a particular DetNet sub-layer.
	2. It MUST be possible to initialize a DetNet OAM session from a		2. It MUST be possible to initialize a DetNet OAM session from
			using any of DetNet Controller Plane solution, e.g., centralized
	centralized controller.		controller.
	3. DetNet OAM MUST support proactive OAM monitoring and measurement		3. DetNet OAM MUST support proactive OAM monitoring and measurement
	methods.		methods.
	4. DetNet OAM MUST support on-demand OAM monitoring and measurement		4. DetNet OAM MUST support on-demand OAM monitoring and measurement
	methods.		methods.
	5. DetNet OAM MUST support unidirectional OAM methods, continuity		5. DetNet OAM MUST support unidirectional OAM methods, continuity
	check, connectivity verification, and performance measurement.		check, connectivity verification, and performance measurement.
	6. OAM methods MAY combine in-band monitoring or measurement in the		6. OAM methods MAY combine in-band monitoring or measurement in the
	forward direction and out-of-bound notification in the reverse		forward direction and out-of-bound notification in the reverse
	direction, i.e., towards the ingress MEP.		direction, i.e., towards the ingress MEP.
	7. DetNet OAM MUST support bi-directional DetNet flows.		7. DetNet OAM MUST support bi-directional DetNet flows.
	8. DetNet OAM MAY support bi-directional OAM methods for bi-		8. DetNet OAM MAY support bi-directional OAM methods for bi-
	directional DetNet flows. OAM test packets used for monitoring		directional DetNet flows. OAM test packets used for monitoring
	and measurements MUST be in-band in both directions.		and measurements MUST be in-band in both directions.
	9. DetNet OAM MUST support proactive monitoring of a DetNet device		9. DetNet OAM MUST support proactive monitoring of a DetNet device
	reachability for a given DetNet flow.		reachability for a given DetNet flow.
	10. DetNet OAM MUST support hybrid performance measurement methods.		10. DetNet OAM MUST support hybrid performance measurement methods.
	11. Calculated performance metrics MUST include but are not limited		11. Calculated performance metrics MUST include but are not limited
	to throughput, packet loss, out of order, delay, and delay		to throughput, packet loss, out of order, delay, and delay
	Skipping		Skipping
	2. DetNet OAM MUST support the discovery of DetNet relay nodes in a		2. DetNet OAM MUST support the discovery of DetNet relay nodes in a
	DetNet network.		DetNet network.
	3. DetNet OAM MUST support the discovery of Packet Replication,		3. DetNet OAM MUST support the discovery of Packet Replication,
	Elimination, and Order preservation sub-functions locations in		Elimination, and Order preservation sub-functions locations in
	the domain.		the domain.
	4. DetNet OAM MUST support the collection of the DetNet service sub-		4. DetNet OAM MUST support the collection of the DetNet service sub-
	layer specific (e.g., configuration/operation/status) information		layer specific (e.g., configuration/operation/status) information
	from DetNet relay nodes.		from DetNet relay nodes.
	5. DetNet OAM MUST support excercising functionality of Packet		5. DetNet OAM MUST support excercising functionality of Packet
	Replication, Elimination, and Order preservation sub-functions in		Replication, Elimination, and Order preservation sub-functions in
	the domain.		the domain.
	6. DetNet OAM MUST work for DetNet data planes - MPLS and IP.		6. DetNet OAM MUST work for DetNet data planes - MPLS and IP.
	7. DetNet OAM MUST support defect notification mechanism, like Alarm		7. DetNet OAM MUST support defect notification mechanism, like Alarm
	Skipping		Skipping
	Requirement Levels", BCP 14, RFC 2119,		Requirement Levels", BCP 14, RFC 2119,
	DOI 10.17487/RFC2119, March 1997,		DOI 10.17487/RFC2119, March 1997,
	<https://www.rfc-editor.org/info/rfc2119>.		<https://www.rfc-editor.org/info/rfc2119>.
	[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC		[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
	2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,		2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
	May 2017, <https://www.rfc-editor.org/info/rfc8174>.		May 2017, <https://www.rfc-editor.org/info/rfc8174>.
	[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,		[RFC8655] Finn, N., Thubert, P., Varga, B., and J. Farkas,
	"Deterministic Networking Architecture", RFC 8655,		"Deterministic Networking Architecture", RFC 8655,
	DOI 10.17487/RFC8655, October 2019,		DOI 10.17487/RFC8655, October 2019,
	<https://www.rfc-editor.org/info/rfc8655>.		<https://www.rfc-editor.org/info/rfc8655>.
	10.2. Informative References		10.2. Informative References
	[I-D.ietf-ippm-ioam-direct-export]		[I-D.ietf-ippm-ioam-direct-export]
	Song, H., Gafni, B., Brockners, F., Bhandari, S., and T.		Song, H., Gafni, B., Brockners, F., Bhandari, S., and T.
	Mizrahi, "In-situ OAM Direct Exporting", Work in Progress,		Mizrahi, "In-situ OAM Direct Exporting", Work in Progress,
	Internet-Draft, draft-ietf-ippm-ioam-direct-export-08, 29		Internet-Draft, draft-ietf-ippm-ioam-direct-export-11, 23
	May 2022, <https://datatracker.ietf.org/doc/html/draft-		September 2022, <https://datatracker.ietf.org/doc/html/
	ietf-ippm-ioam-direct-export-08>.		draft-ietf-ippm-ioam-direct-export-11>.
	[I-D.mirsky-ippm-hybrid-two-step]		[I-D.mirsky-ippm-hybrid-two-step]
	Mirsky, G., Lingqiang, W., Zhui, G., Song, H., and P.		Mirsky, G., Lingqiang, W., Zhui, G., Song, H., and P.
	Thubert, "Hybrid Two-Step Performance Measurement Method",		Thubert, "Hybrid Two-Step Performance Measurement Method",
	Work in Progress, Internet-Draft, draft-mirsky-ippm-		Work in Progress, Internet-Draft, draft-mirsky-ippm-
	hybrid-two-step-13, 25 April 2022,		hybrid-two-step-13, 25 April 2022,
	<https://datatracker.ietf.org/doc/html/draft-mirsky-ippm-		<https://datatracker.ietf.org/doc/html/draft-mirsky-ippm-
	hybrid-two-step-13>.		hybrid-two-step-13>.
	Skipping		Skipping
	and Maintenance (OAM) Tools", RFC 7276,		and Maintenance (OAM) Tools", RFC 7276,
	DOI 10.17487/RFC7276, June 2014,		DOI 10.17487/RFC7276, June 2014,
	<https://www.rfc-editor.org/info/rfc7276>.		<https://www.rfc-editor.org/info/rfc7276>.
	[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with		[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
	Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,		Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
	May 2016, <https://www.rfc-editor.org/info/rfc7799>.		May 2016, <https://www.rfc-editor.org/info/rfc7799>.
	[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,		[RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
	L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,		L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
	"Alternate-Marking Method for Passive and Hybrid		"Alternate-Marking Method for Passive and Hybrid
	Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,		Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
	January 2018, <https://www.rfc-editor.org/info/rfc8321>.		January 2018, <https://www.rfc-editor.org/info/rfc8321>.
	[RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.		[RFC8939] Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
	Bryant, "Deterministic Networking (DetNet) Data Plane:		Bryant, "Deterministic Networking (DetNet) Data Plane:
	IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,		IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,
	<https://www.rfc-editor.org/info/rfc8939>.		<https://www.rfc-editor.org/info/rfc8939>.
	[RFC9055] Grossman, E., Ed., Mizrahi, T., and A. Hacker,		[RFC9055] Grossman, E., Ed., Mizrahi, T., and A. Hacker,
	"Deterministic Networking (DetNet) Security		"Deterministic Networking (DetNet) Security
	Skipping		Skipping
	Office B00 - 102A		Office B00 - 102A
	2 Rue de la Châtaigneraie		2 Rue de la Châtaigneraie
	35510 Cesson-Sévigné - Rennes		35510 Cesson-Sévigné - Rennes
	France		France
	Phone: +33 299 12 70 04		Phone: +33 299 12 70 04
	Email: georgios.papadopoulos@imt-atlantique.fr		Email: georgios.papadopoulos@imt-atlantique.fr
	Carlos J. Bernardos		Carlos J. Bernardos
	Universidad Carlos III de Madrid		Universidad Carlos III de Madrid
	Av. Universidad, 30		Av. Universidad, 30
	28911 Leganes, Madrid		28911 Leganes, Madrid
	Spain		Spain
	Phone: +34 91624 6236		Phone: +34 91624 6236
	Email: cjbc@it.uc3m.es		Email: cjbc@it.uc3m.es
	URI: http://www.it.uc3m.es/cjbc/		URI: http://www.it.uc3m.es/cjbc/
	Balazs Varga		Balazs Varga
	Ericsson		Ericsson
	Budapest		Budapest
	Magyar Tudosok krt. 11.		Magyar Tudosok krt. 11.
	Skipping		Skipping