DetNet                                                         G. Mirsky
Internet-Draft                                                 ZTE Corp.
Intended status: Informational                              F. Theoleyre
Expires: 20 November 29 December 2021                                           CNRS
                                                       G.Z. Papadopoulos
                                                          IMT Atlantique
                                                           CJ. Bernardos
                                                             19 May
                                                            27 June 2021

   Framework of Operations, Administration and Maintenance (OAM) for
                   Deterministic Networking (DetNet)


   Deterministic Networking (DetNet), as defined in RFC 8655, is aimed
   to provide a bounded end-to-end latency on top of the network
   infrastructure, comprising both Layer 2 bridged and Layer 3 routed
   segments.  This document's primary purpose is to detail the specific
   requirements of the Operation, Administration, and Maintenance (OAM)
   recommended to maintain a deterministic network.  With the
   implementation of the OAM framework in DetNet, an operator will have
   a real-time view of the network infrastructure regarding the
   network's ability to respect the Service Level Objective, such as
   packet delay, delay variation, and packet loss ratio, assigned to
   each data DetNet flow.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  Acronyms  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.3.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  Role of OAM in DetNet . . . . . . . . . . . . . . . . . . . .   4
   3.  Operation . . . . . . . . . . . . . . . . . . . . . . . . . .   5   6
     3.1.  Information Collection  . . . . . . . . . . . . . . . . .   5   6
     3.2.  Continuity Check  . . . . . . . . . . . . . . . . . . . .   6   7
     3.3.  Connectivity Verification . . . . . . . . . . . . . . . .   6   7
     3.4.  Route Tracing . . . . . . . . . . . . . . . . . . . . . .   6   7
     3.5.  Fault Verification/detection  . . . . . . . . . . . . . .   6   8
     3.6.  Fault Localization and Characterization . . . . . . . . .   7   8
     3.7.  Use of Hybrid OAM in DetNet . . . . . . . . . . . . . . .   7   8
   4.  Administration  . . . . . . . . . . . . . . . . . . . . . . .   8   9
     4.1.  Collection of metrics . . . . . . . . . . . . . . . . . .   8   9
     4.2.  Worst-case metrics  . . . . . . . . . . . . . . . . . . .   8   9
   5.  Maintenance . . . . . . . . . . . . . . . . . . . . . . . . .   9  10
     5.1.  Replication / Elimination . . . . . . . . . . . . . . . .   9  10
     5.2.  Resource Reservation  . . . . . . . . . . . . . . . . . .   9  10
     5.3.  Soft transition after reconfiguration . . . . . . . . . .  10  11
   6.  Requirements  . . . . . . . . . . . . . . . . . . . . . . . .  10  11
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11  12
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  11  13
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  11  13
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12  13
     10.1.  Normative References . . . . . . . . . . . . . . . . . .  12  13
     10.2.  Informative References . . . . . . . . . . . . . . . . .  12  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13  15

1.  Introduction

   Deterministic Networking (DetNet) [RFC8655] has proposed to provide a
   bounded end-to-end latency on top of the network infrastructure,
   comprising both Layer 2 bridged and Layer 3 routed segments.  That
   work encompasses the data plane, OAM, time synchronization,
   management, control, and security aspects.

   Operations, Administration, and Maintenance (OAM) Tools are of
   primary importance for IP networks [RFC7276].  DetNet OAM should
   provide a toolset for fault detection, localization, and performance

   This document's primary purpose is to detail the specific
   requirements of the OAM features recommended to maintain a
   deterministic/reliable network.  Specifically, it investigates the
   requirements for a deterministic network, supporting critical flows.

   In this document, the term OAM will be used according to its
   definition specified in [RFC6291].  DetNet expects to implement an
   OAM framework to maintain a real-time view of the network
   infrastructure, and its ability to respect the Service Level
   Objectives (SLO), such as in-order packet delivery, packet delay,
   delay variation, and packet loss ratio, assigned to each data DetNet flow.

   This document lists the functional requirements toward OAM for DetNet
   domain.  The list can further be used for gap analysis of available
   OAM tools to identify possible enhancements of existing or whether
   new OAM tools are required to support proactive and on-demand path
   monitoring and service validation.

1.1.  Terminology

   This document uses definitions, particularly of a DetNet flow,
   provided in Section 2.1 [RFC8655].  The following terms are used
   throughout this document as defined below:

   *  DetNet OAM entity: domain: a data flow to be DetNet network used by the monitored DetNet
      flow.  A DetNet OAM domain (also referred to in this document as
      "OAM domain") may have MEPs on its edge and MIPs within.

   *  DetNet OAM instance: a function that monitors a DetNet flow for
      defects and/or measures its performance metrics measured. metrics.  Within this
      document, a shorter version, OAM instance, is used

   *  Maintenance End Point (MEP): an OAM systems traversed by a data flow
      when entering/exiting the network.  In DetNet, it corresponds with instance that is capable of
      generating OAM test packets in the source and destination particular sub-layer of a data flow. the
      DetNet OAM messages can be
      exchanged between two MEPs. domain.

   *  Maintenance Intermediate endPoint (MIP): an OAM system instance along the
      flow; a
      DetNet flow in the particular sub-layer of the DetNet OAM domain.
      A MIP MAY respond to an OAM message generated by the MEP. MEP at its
      sub-layer of the same DetNet OAM domain.

   *  Control and management plane: the control and management planes
      are used to configure and control the network (long-term).
      Relative to a data DetNet flow, the control and/or management plane can
      be out-of-band.

   *  Active measurement methods (as defined in [RFC7799]) modify a
      normal data
      DetNet flow by inserting novel fields, injecting specially
      constructed test packets [RFC2544]).

   *  Passive measurement methods [RFC7799] infer information by
      observing unmodified existing flows.

   *  Hybrid measurement methods [RFC7799] is the combination of
      elements of both active and passive measurement methods.

1.2.  Acronyms

   OAM: Operations, Administration, and Maintenance

   DetNet: Deterministic Networking

   SLO: Service Level Objective

   SNMP: Simple Network Management Protocol

   SDN: Software Defined Network

   <TODO> we need here an exhaustive list, to be completed after the
   document has evolved.

1.3.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  Role of OAM in DetNet

   DetNet networks expect to provide communications with predictable low
   packet delay and packet loss.  Most critical applications will define
   an SLO to be required for the data DetNet flows it generates.

   To respect strict guarantees, DetNet can use an orchestrator able to
   monitor and maintain the network.  Typically, a Software-Defined
   Network (SDN) controller places DetNet flows in the deployed network
   based on their SLO.  Thus, resources have to be provisioned a priori
   for the regular operation of the network.  Because  OAM is an represents the
   essential element elements of the network operation, resources, operation and necessary for
   resources that need to be accounted for to maintain the network

   Many legacy OAM tools can be used in addition DetNet networks, but they are
   not able to cover all the aspects of deterministic networking.
   Fulfilling strict guarantees is essential for DetNet flows.

   Fault-tolerance flows, resulting
   in new DetNet specific functionalities that must be covered with OAM.
   Filling these gaps is inevitable and needs accurate consideration of
   DetNet specifics.  Similar to DetNet flows itself, their OAM needs
   careful end-to-end engineering as well.

   For example, appropriate placing of MEPs along the path of a DetNet
   flow is not always a trivial task and may require proper design
   together with the design of the service component of a given DetNet

   There are several DetNet specific challenges for OAM.  Bounded
   network characteristics (e.g., delay, loss) are inseparable service
   parameters; therefore, PM is a key topic for DetNet.  OAM tools are
   needed to prove the SLO without impacting the DetNet flow
   characteristics.  A further challenge is the strict resource
   allocation.  Resources used by OAM must be considered and allocated
   to avoid disturbing DetNet flow(s).

   The DetNet Working Group has defined two sub-layers: (1) DetNet
   service sub-layer, at which a DetNet service (e.g., service
   protection) is provided and (2) DetNet forwarding sub-layer, which
   optionally provides resource allocation for DetNet flows over paths
   provided by the underlying network.  OAM mechanisms exist for the
   DetNet forwarding sub-layer, nonetheless, OAM for the service sub-
   layer requires new OAM procedures.  These new OAM functions must
   allow, for example, to recognize/discover DetNet relay nodes, to get
   information about their configuration, and to check their operation
   or status.

   DetNet service sub-layer functions using a sequence number.  That
   creates a challenge for inserting OAM packets in the DetNet flow.

   Fault tolerance also assumes that multiple paths could be provisioned
   so that
   to maintain an end-to-end circuit is maintained by adapting to the existing
   conditions.  The central controller/orchestrator typically controls
   the Packet Replication, Elimination, and Ordering Functions (PREOF)
   on a node.  OAM is expected to support monitoring and troubleshooting
   PREOF on a particular node and within the domain.

   Note that PREOF distributed controllers can also be controlled by a set of distributed
   controllers, control PREOF in those
   scenarios where DetNet solutions involve more than one single central

   DetNet forwarding sub-layer is based on legacy technologies and has a
   much better coverage regarding OAM.  However, the forwarding sub-
   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
   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
   the DetNet PW).

3.  Operation

   OAM features will enable DetNet with robust operation both for
   forwarding and routing purposes.

   It is worth noting that the test and data packets MUST follow the
   same path, i.e., the connectivity verification has to be conducted
   in-band without impacting the data traffic.  Test packets MUST share
   fate with the monitored data traffic without introducing congestion
   in normal network conditions.

3.1.  Information Collection

   Information about the state of the network can be collected using
   several mechanisms.  Some protocols, e.g., Simple Network Management
   Protocol (SNMP),
   Protocol, send queries.  Others, e.g., YANG-based data models,
   generate notifications based on the publish-subscribe method.  In
   either way, information is collected and sent to the controller.

   Also, we can characterize methods of transporting OAM information
   relative to the path of data.  For instance, OAM information may be
   transported in-band or out-of-band with relative to the data DetNet flow.  In
   case of the former, the telemetry information uses resources
   allocated for the monitored DetNet flow.  If an in-band method of
   transporting telemetry is used, the amount of generated information
   needs to be carefully analyzed, and additional resources must be
   reserved.  [I-D.ietf-ippm-ioam-data] defines the in-band transport
   mechanism where telemetry information is collected in the data packet
   on which information is generated.  Two tracing methods are described
   - end-
   to-end, end-to-end, i.e., from the ingress and egress nodes, and hop-by-hop, hop-by-
   hop, i.e., like end-to-end with additional information from transit
   nodes.  [I-D.ietf-ippm-ioam-direct-export] and
   [I-D.mirsky-ippm-hybrid-two-step] are examples of out-of-band
   telemetry transport.  In the former case, information is transported
   by each node traversed by the data packet of the monitored DetNet
   flow in a specially constructed packet.  In the latter, information
   is collected in a sequence of follow-up packets that traverse the
   same path as the data packet of the monitored DetNet flow.  In both
   methods, transport of the telemetry can avoid using resources
   allocated for the DetNet domain.

3.2.  Continuity Check

   Continuity check is used to monitor the continuity of a path, i.e.,
   that there exists a way to deliver the packets between two endpoints MEP A and
   MEP B.  The continuity check detects a network failure in one
   direction, from the MEP transmitting test packets to the remote
   egress MEP.

3.3.  Connectivity Verification

   In addition to the Continuity Check, DetNet solutions have to verify
   the connectivity.  This verification considers additional
   constraints, i.e., the absence of misconnection.  The misconnection
   error state is entered after several consecutive test packets from
   other DetNet flows are received.  The definition of the conditions of
   entry and exit for misconnection error state is outside the scope of
   this document.

3.4.  Route Tracing

   Ping and traceroute are two ubiquitous tools that help localize and
   characterize a failure in the network.  They help to identify a
   subset of the list of routers in the route.  However, to be
   predictable, resources are reserved per flow in DetNet.  Thus, DetNet
   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
   Path Maximum Transmission Unit or location of elements of PREOF for
   the particular route in the DetNet domain.

   DetNet with IP data plane is NOT RECOMMENDED to use multiple paths or links, i.e.,
   Equal-Cost Multipath (ECMP) [RFC8939].  As the result, OAM in IP ECMP
   environment is outside the scope of this document.

3.5.  Fault Verification/detection

   DetNet expects to operate fault-tolerant networks.  Thus, mechanisms
   able to detect faults before they impact the network performance are

   The network has to detect when a fault occurred, i.e., the network
   has deviated from its expected behavior.  While the network must
   report an alarm, the cause may not be identified precisely.  For
   instance, the end-to-end reliability has decreased significantly, or
   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

   An ability to localize the network defect and provide its
   characterization are necessary elements of network operation.

      Fault localization, a process of deducing the location of a
      network failure from a set of observed failure indications, might
      be achieved, for example, by tracing the route of the DetNet flow
      in which the network failure was detected.  Another method of
      fault localization can correlate reports of failures from a set of
      interleaving sessions monitoring path continuity.

      Fault characterization is a process of identifying the root cause
      of the problem.  For instance, misconfiguration or malfunction of
      PREOF elements can be the cause of erroneous packet replication or
      extra packets being flooded in the DetNet domain.

3.7.  Use of Hybrid OAM in DetNet

   Hybrid OAM methods are used in performance monitoring and defined in
   [RFC7799] as:

      Hybrid Methods are Methods of Measurement that use a combination
      of Active Methods and Passive Methods.

   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
   value of a designated field in the packet encapsulation.  One example
   of such a hybrid measurement method is the Alternate Marking method
   (AMM) described in [RFC8321].  As with all on-path telemetry methods,
   AMM in a DetNet domain with the IP data plane is natively in-band in
   respect to the monitored DetNet flow.  Because the marking is applied
   to a data flow, measured metrics are directly applicable to the
   DetNet flow.  AMM minimizes the additional load on the DetNet domain
   by using nodal collection and computation of performance metrics in
   combination with optionally using out-of-band telemetry collection
   for further network analysis.

4.  Administration

   The network SHOULD expose a collection of metrics to support an
   operator making proper decisions, including:

   *  Queuing Delay: the time elapsed between a packet enqueued and its
      transmission to the next hop.

   *  Buffer occupancy: the number of packets present in the buffer, for
      each of the existing flows.

   The following metrics SHOULD be collected:

   *  per virtual circuit a DetNet flow to measure the end-to-end performance for a
      given flow.  Each of the paths has to be isolated in multipath
      routing strategies.

   *  per path to detect misbehaving path when multiple paths are

   *  per device to detect misbehaving node, device, when it relays the
      packets of several flows.

4.1.  Collection of metrics

   DetNet OAM SHOULD optimize the number of statistics / measurements to
   collected, frequency of collecting.  Distributed and centralized
   mechanisms MAY be used in combination.  Periodic and event-triggered
   collection information characterizing the state of a network MAY be

4.2.  Worst-case metrics

   DetNet aims to enable real-time communications on top of a
   heterogeneous multi-hop architecture.  To make correct decisions, the
   controller needs to know the distribution of packet losses/delays for
   each flow, and each hop of the paths.  In other words, the average
   end-to-end statistics are not enough.  The collected information must
   be sufficient to allow the controller to predict the worst-case.

5.  Maintenance

   In the face of events that impact the network operation (e.g., link
   up/down, node device crash/reboot, flows starting and ending), the DetNet
   Controller need to perform repair and re-optimization actions in
   order to permanently ensure the SLO of all active flows with minimal
   waste of resources The controller MUST be able to continuously
   retrieve the state of the network, to evaluate conditions and trends
   about the relevance of a reconfiguration, quantifying:

      the cost of the sub-optimality: resources may not be used
      optimally (e.g., a better path exists).

      the reconfiguration cost: the controller needs to trigger some
      reconfigurations.  For this transient period, resources may be
      twice reserved, and control packets have to be transmitted.

   Thus, reconfiguration may only be triggered if the gain is

5.1.  Replication / Elimination

   When multiple paths are reserved between two maintenance endpoints, MEPs, packet replication
   may be used to introduce redundancy and alleviate transmission errors
   and collisions.  For instance, in Figure 1, the source node device S is
   transmitting the packet to both parents, nodes devices A and B.  Each maintenance endpoint MEP
   will decide to trigger the packet replication, elimination or the
   ordering process when a set of metrics passes a threshold value.

                          ===> (A) => (C) => (E) ===
                        //        \\//   \\//       \\
              source (S)          //\\   //\\         (R) (root)
                        \\       //  \\ //  \\      //
                          ===> (B) => (D) => (F) ===

       Figure 1: Packet Replication: S transmits twice the same data
                        packet, to DP(A) and AP (B).

5.2.  Resource Reservation

   Because the quality of service criteria associated with a path may
   degrade, the network has to provision additional resources along the
   path.  We need to provide mechanisms to patch the network

5.3.  Soft transition after reconfiguration

   Since DetNet expects to support real-time flows, DetNet OAM MUST
   support soft-reconfiguration, where the novel the additional resources are
   reserved before the ancient ones those previously reserved but not in use are
   released.  Some mechanisms have to be proposed so that packets are
   forwarded through the novel track only when the resources are ready
   to be used, while maintaining the global state consistent (no packet
   reordering, duplication, etc.)

6.  Requirements

   This section lists requirements for OAM in a DetNet domain:

   1.   It MUST be possible to initiate a DetNet OAM session from any a MEP
        located at a DetNet node towards another DetNet node(s) downstream MEP(s) within the
        given domain. domain at a particular DetNet sub-layer.  [Ed.note: FT: A
        MEP may be inside the detnet domain: for instance, for PREOF, an
        OAM session may be maintained between any pair of replicator /
        eliminator / egress / ingress.]

   2.   It MUST be possible to initialize a DetNet OAM session from a
        centralized controller.

   3.   DetNet OAM MUST support proactive and on-demand OAM monitoring
        and measurement methods.

   4.   DetNet OAM packets MUST be in-band, i.e., follow precisely the
        same path as DetNet data plane traffic.

   5.   DetNet OAM MUST support unidirectional OAM methods, continuity
        check, connectivity verification, and performance measurement.

   6.   DetNet OAM MUST support bi-directional OAM methods.  Such

   5.   OAM methods MAY combine in-band monitoring or measurement in the
        forward direction and out-of-bound notification in the reverse
        direction, i.e., from egress to ingress end point of towards the ingress MEP.

   6.   DetNet OAM
        test session. MUST support bi-directional DetNet flows.

   7.   DetNet OAM MAY support bi-directional OAM methods for
        bidirectional DetNet flows.  OAM test packets used for
        monitoring and measurements MUST be in-band in both directions.

   8.   DetNet OAM MUST support proactive monitoring of a DetNet node
        availability in the device
        reachability for a given DetNet domain.

   8. flow.

   9.   DetNet OAM MUST support Path Maximum Transmission Unit


   10.  DetNet OAM MUST support the discovery of PREOF along a route in
        the given DetNet domain.


   11.  DetNet OAM MUST support Remote Defect Indication (RDI)
        notification to the DetNet node OAM instance performing continuity

   11.  DetNet OAM MUST support performance measurement methods.

   12.  DetNet OAM MAY support hybrid performance measurement methods.

   13.  DetNet OAM MUST support unidirectional performance measurement
        methods.  Calculated performance metrics MUST include but are
        not limited to throughput, packet loss, out of order, delay and
        delay variation metrics.  [RFC6374] provides detailed
        information on performance measurement and performance metrics.

   14.  DetNet OAM MUST be able to measure metrics (e.g. delay) inside a
        collection of OAM sessions, specially for complex DetNet flows,
        with PREOF features.

   15.  DetNet OAM MUST support defect notification mechanism, like
        Alarm Indication Signal.  Any DetNet node in device within the given
        domain flow MAY originate a defect notification addressed to any
        subset of nodes DetNet devices within the domain.

   15. that flow.

   16.  DetNet OAM MUST support methods to enable survivability availability of the
        DetNet domain.  These recovery methods MAY use protection
        switching and restoration.


   17.  DetNet OAM MUST support the discovery of Packet Replication,
        Elimination, and Order preservation sub-functions locations in
        the domain.


   18.  DetNet OAM MUST support testing of Packet Replication,
        Elimination, and Order preservation sub-functions in the domain.


   19.  DetNet OAM MUST support monitoring levels of resources allocated
        for the particular DetNet flow.  Such resources include but not
        limited to buffer utilization, scheduler transmission calendar.


   20.  DetNet OAM MUST support monitoring any sub-set of paths
        traversed through the DetNet domain by the DetNet flow.

7.  IANA Considerations

   This document has no actionable requirements for IANA.  This section
   can be removed before the publication.

8.  Security Considerations

   This document lists the OAM requirements for a DetNet domain and does
   not raise any security concerns or issues in addition to ones common
   to networking and those specific to a DetNet discussed in

9.  Acknowledgments

   The authors express their appreciation and gratitude to Pascal
   Thubert for the review, insightful questions, and helpful comments.

10.  References

10.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <>.

   [RFC8655]  Finn, N., Thubert, P., Varga, B., and J. Farkas,
              "Deterministic Networking Architecture", RFC 8655,
              DOI 10.17487/RFC8655, October 2019,

10.2.  Informative References

              Grossman, E., Mizrahi, T., and A. J. Hacker,
              "Deterministic Networking (DetNet) Security
              Considerations", Work in Progress, Internet-Draft, draft-
              ietf-detnet-security-16, 2 March 2021,

              Brockners, F., Bhandari, S., and T. Mizrahi, "Data Fields
              for In-situ OAM", Work in Progress, Internet-Draft, draft-
              ietf-ippm-ioam-data-12, 21 February
              ietf-ippm-ioam-data-14, 24 June 2021,

              Song, H., Gafni, B., Zhou, T., Li, Z., Brockners, F.,
              Bhandari, S., Sivakolundu, R., and T. Mizrahi, "In-situ
              OAM Direct Exporting", Work in Progress, Internet-Draft,
              draft-ietf-ippm-ioam-direct-export-03, 17 February 2021,

              Mirsky, G., Lingqiang, W., Zhui, G., and H. Song, "Hybrid
              Two-Step Performance Measurement Method", Work in
              Progress, Internet-Draft, draft-mirsky-ippm-hybrid-two-
              step-10, 17 May 2021, <

   [RFC2544]  Bradner, S. and J. McQuaid, "Benchmarking Methodology for
              Network Interconnect Devices", RFC 2544,
              DOI 10.17487/RFC2544, March 1999,

   [RFC6291]  Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
              D., and S. Mansfield, "Guidelines for the Use of the "OAM"
              Acronym in the IETF", BCP 161, RFC 6291,
              DOI 10.17487/RFC6291, June 2011,

   [RFC6374]  Frost, D. and S. Bryant, "Packet Loss and Delay
              Measurement for MPLS Networks", RFC 6374,
              DOI 10.17487/RFC6374, September 2011,

   [RFC7276]  Mizrahi, T., Sprecher, N., Bellagamba, E., and Y.
              Weingarten, "An Overview of Operations, Administration,
              and Maintenance (OAM) Tools", RFC 7276,
              DOI 10.17487/RFC7276, June 2014,

   [RFC7799]  Morton, A., "Active and Passive Metrics and Methods (with
              Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
              May 2016, <>.

   [RFC8321]  Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli,
              L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi,
              "Alternate-Marking Method for Passive and Hybrid
              Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321,
              January 2018, <>.

   [RFC8655]  Finn, N., Thubert, P., Varga, B., and J. Farkas,
              "Deterministic Networking Architecture", RFC 8655,
              DOI 10.17487/RFC8655, October 2019,

   [RFC8939]  Varga, B., Ed., Farkas, J., Berger, L., Fedyk, D., and S.
              Bryant, "Deterministic Networking (DetNet) Data Plane:
              IP", RFC 8939, DOI 10.17487/RFC8939, November 2020,

Authors' Addresses

   Greg Mirsky
   ZTE Corp.


   Fabrice Theoleyre
   300 boulevard Sebastien Brant - CS 10413
   67400 Illkirch - Strasbourg

   Phone: +33 368 85 45 33

   Georgios Z. Papadopoulos
   IMT Atlantique
   Office B00 - 102A
   2 Rue de la Châtaigneraie
   35510 Cesson-Sévigné - Rennes

   Phone: +33 299 12 70 04

   Carlos J. Bernardos
   Universidad Carlos III de Madrid
   Av. Universidad, 30
   28911 Leganes, Madrid

   Phone: +34 91624 6236