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<rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="info" docName="draft-ietf-raw-architecture-30" number="9912" consensus="true" ipr="trust200902" updates="" tocInclude="true" obsoletes="" submissionType="IETF" xml:lang="en" version="3"> version="3" sortRefs="false" symRefs="true">

<front>

<!-- [rfced] *AD, Janos Farkas (document shepherd) sent an email to the RPC on
2026 Jan 16 saying that the [6TiSCH-ARCHI] should be moved from the
normative references section to the informative references section. We
made this change, but please review and let us know if you approve. We
consider changes to normative references to be "beyond editorial".
-->

<!-- [rfced] Please note that the title of the document has been updated as
follows. We have added the abbreviation "RAW" to align with the title of
draft-ietf-raw-technologies-17 (RFC 9913).

Original:
  Reliable and Available Wireless Architecture

Current:
  Reliable and Available Wireless (RAW) Architecture
-->

<!-- [rfced] We have removed "Without Affiliation" from the document header
and Author's Addresses section to align with draft-ietf-raw-technologies
and draft-ietf-roll-dao-projection.

Note: Per Section 4.1.2 of RFC 7322 ("RFC Style Guide"), an author's
affiliation may be left blank or include "Independent", "Individual
Contributor", "Retired", or a similar term. Please let us know if you prefer
to use one of these terms instead, and we will apply that to all documents in
this cluster.
-->

  <title abbrev="RAW Architecture">Reliable and Available Wireless (RAW) Architecture</title>
  <seriesInfo name="RFC" value="9912"/>
  <author initials='P' surname='Thubert' fullname='Pascal Thubert' role='editor'>
      <organization abbrev=''>Without Affiliation</organization>
    <organization></organization>
    <address>
      <postal>
        <city>Roquefort-les-Pins</city>
        <code>06330</code>
        <country>France</country>
      </postal>
      <email>pascal.thubert@gmail.com</email>
    </address>
  </author>

    <date/>
    <area>Routing Area</area>
    <workgroup>DetNet</workgroup>
    <keyword>Draft</keyword>

  <date month="February" year="2026"/>
  <area>RTG</area>
  <workgroup>detnet</workgroup>

<!-- [rfced] Please insert any keywords (beyond those that appear in
the title) for use on https://www.rfc-editor.org/search. -->

<keyword>example</keyword>

    <abstract>
      <t>
      Reliable and Available Wireless (RAW) extends the reliability and
      availability of DetNet Deterministic Networking (DetNet) to networks composed of any combination of wired and
      wireless segments.

      The RAW Architecture architecture leverages and extends RFC 8655, the
      Deterministic 8655 ("Deterministic
      Networking Architecture, Architecture") to adapt to challenges that
      affect prominently affect
      the wireless medium, notably intermittent transmission loss.

      This document defines a network control loop that optimizes the use of
      constrained bandwidth and energy while assuring ensuring the expected
      DetNet services.

      The loop involves a new Point of Local Repair (PLR) function in
      the DetNet Service sub-layer that dynamically selects the DetNet
      path(s) for packets to route around local connectivity degradation.

      </t>
    </abstract>
  </front>
  <middle>

    <section numbered="true" toc="default">
      <name>Introduction</name>

      <t>
   Deterministic Networking (DetNet) aims at providing to provide bounded latency and eliminating eliminate
   congestion loss, even when co-existing coexisting with best-effort traffic.
   It provides the ability to carry
   specified unicast or multicast data flows for real-time applications
   with extremely low packet loss rates and assured ensures maximum end-to-end
   delivery latency.  A description of the general background and
   concepts of DetNet can be found in [RFC8655]. <xref target="RFC8655"/>.
      </t>
   <t>
   DetNet and the related IEEE 802.1
   Time-Sensitive networking Networking (TSN) <xref target="TSN"/> initially focused on wired
   infrastructure, which provides a more stable communication channel
   than wireless networks.
   Wireless networks operate on a shared medium where uncontrolled interference,
   including the self-induced multipath fading, may cause intermittent transmission losses.
   Fixed and mobile obstacles and reflectors may block or alter the signal,
   causing transient and unpredictable variations of the throughput and packet
   delivery ratio Packet
   Delivery Ratio (PDR) of a wireless link. This adds new dimensions to the
   statistical effects that affect the quality and reliability of the link.
   </t>
   <t>
   Nevertheless, deterministic capabilities are required in a number of
   wireless use cases as well <xref target="I-D.ietf-raw-use-cases"/>. target="RFC9450"/>. With scheduled radios
   such as Time Slotted Time-Slotted Channel Hopping (TSCH) and Orthogonal Frequency
   Division
   Frequency-Division Multiple Access (OFDMA) (see <xref target="I-D.ietf-raw-technologies"/> for more on both of these and other technologies as well) being developed
   to provide determinism over wireless links at the lower layers, providing
   DetNet capabilities has become possible. See <xref target="RFC9913"/>
   for more on TSCH, OFDMA, and other technologies.
   </t>
   <t>
   Reliable and Available Wireless (RAW) takes up the challenge of providing
   highly available and reliable end-to-end performances in a DetNet network
   that may include wireless segments. To achieve this, RAW leverages all the
   possible transmission diversity and redundancy to assure ensure packet delivery,
   while optimizing the use of the shared spectrum to preserve bandwidth and
   save energy.  To that effect, RAW defines Protection Paths protection paths that can be activated
   dynamically upon failures and a control loop that dynamically controls the
   activation and deactivation of the feasible Protection Paths protection paths to react
   quickly to intermittent losses.
   </t>

   <t>
      The intent of RAW is to meet Service Level Objectives (SLO) (SLOs) in terms of  packet delivery ratio (PDR), PDR, maximum contiguous losses losses, or latency boundaries for DetNet flows over mixes of wired and wireless networks, including wireless access and meshes (see <xref target="problem"/> for more on the RAW problem).

   This document introduces and/or leverages terminology (see <xref target="terms"/>), principles (see <xref target="raw"/>), and concepts such as protection path paths and recovery graph, graphs to put together a conceptual model for RAW (see <xref target="model"/>), and, based target="model"/>). Based on that model, elaborate this document elaborates on an in-network optimization control loop (see <xref target="control"/>).

   </t>
    </section>
    <!-- Introduction -->
    <!--  000000000000000000000    -->

    <section anchor="problem" numbered="true" toc="default">
      <name>The RAW problem</name> Problem</name>
   <t>
   While the generic <xref target="RFC8557">"Deterministic "Deterministic Networking Problem Statement"</xref> Statement" <xref
   target="RFC8557"/> applies to both the wired and the wireless media, the <xref target="RFC8655">"Deterministic "Deterministic Networking Architecture"
   </xref> <xref
   target="RFC8655"/> must be extended to address less consistent
   transmissions, energy conservation, and shared spectrum efficiency.
   </t>
   <t>
   Operating at Layer-3, Layer 3, RAW does not change the wireless technology at the
   lower layers. OTOH, On the other hand, it can further increase diversity in the
   spatial, time, code, and frequency domains by enabling multiple link-layer
   wired and wireless technologies in parallel or sequentially, for a higher
   resilience and a wider applicability. RAW can also provide homogeneous
   services to critical applications beyond the boundaries of a single
   subnetwork, e.g., using diverse radio access technologies to optimize the
   end-to-end application experience.
   </t>
   <t>
   RAW extends the DetNet services by providing elements that are specialized
   for transporting IP flows over deterministic radio technologies such as
   those listed in <xref target="I-D.ietf-raw-technologies"/>. target="RFC9913"/>.  Conceptually, RAW is agnostic to
   the lower layer, though the capability to control latency is assumed to assure
   ensure the DetNet services that RAW extends.  How the lower layers are
   operated to do so, and, e.g., so (and whether a radio network is single-hop single hop or
   meshed, for example) are opaque to the IP layer and not part of the RAW abstraction.
   Nevertheless, cross-layer optimizations may take place to ensure proper
   link awareness (think, (such as link quality) and packet handling (think, (such as
   scheduling).
      </t>
      <t>
   The RAW Architecture architecture extends the DetNet Network Plane, Plane to accommodate one or
   multiple hops of homogeneous or heterogeneous wired and wireless technologies.
   RAW adds reactivity to the DetNet Forwarding sub-layer to compensate the dynamics
   for the radio links in terms of lossiness and bandwidth. This may apply, for
   instance, to mesh networks as illustrated in <xref target ="FigCPF"/>, ="FigCPF"/> or
   diverse radio access networks as illustrated in <xref target ="Figranp2"/>.
      </t>

    <t>
    As opposed to wired links, the availability and performance of an individual
    wireless link cannot be trusted over the long term; it varies with
    transient service discontinuity, and any path that includes wireless
    hops is bound to face short periods of high loss. On the other hand, being
    broadcast in nature, the wireless medium provides capabilities that are
    atypical on modern wired links and that the RAW Architecture architecture can leverage
    opportunistically to improve the end-to-end reliability over a collection of
    paths.
    </t>
    <t>
    Those capabilities include:
    </t>
    <dl>
    <dt>Promiscuous Overhearing:</dt><dd> overhearing:</dt><dd> Some wired and wireless
    technologies allow for multiple lower-layer attached nodes to receive
    the same packet sent by another node.  This differs from a
    lower-layer network that is physically point-to-point point-to-point, like a wire.
    With overhearing, more than one
    node in the forward direction of the packet may hear or overhear a
    transmission, and the reception by one may compensate the loss by another.
    The concept of path can be revisited in favor of multipoint to multipoint multipoint-to-multipoint
    progress in the forward direction and statistical chances of successful
    reception of any of the transmissions by any of the receivers.
    </dd>
    <dt>L2-aware routing:</dt><dd> As routing:</dt>
    <dd><t>As the quality and speed of a link varies
    over time, the concept of metric must also be revisited. Shortest-path cost loses
    its absolute value, and hop count turns into a bad idea as the link budget
    drops with the physical distance. Routing over radio requires both 1) a both:</t>

    <ol>
      <li>a new and more dynamic sense of link metrics, with new protocols
      such as DLEP the Dynamic Link Exchange Protocol (DLEP) and L2-trigger Layer 2 (L2) triggers to keep L3 Layer 3 (L3) up to date with the link quality
      and availability, and 2) an and</li>
      <li>an approach to multipath routing, where multiple link metrics are
      considered since simple shortest-path cost loses its meaning with the
      instability of the metrics. metrics.</li>
    </ol>
    </dd>
    <dt>Redundant transmissions:</dt><dd>Though
<!-- [rfced] May we update "ack-based" to either "acknowledgment-based" or
"ACK-based" in the text below to clarify its meaning?

Original:

   Redundant transmissions:  Though feasible on any technology,
      proactive (forward) and reactive (ack-based) error correction are
      typical to the wireless media.

Perhaps:

   Redundant transmissions:  Though feasible on any technology,
      proactive (forward) and reactive (acknowledgment-based) error correction is
      typical for wireless media.
-->

    <dt>Redundant transmissions:</dt><dd>Though feasible on any technology, proactive
    (forward) and reactive (ack-based) error correction are typical for wireless
    media. Bounded latency can still be obtained on a wireless link while
    operating those technologies, provided that link latency used in
    path selection allows for the extra transmission, transmission or that the introduced delay is
    compensated along the path. In the case of coded fragments and retries, it
    makes sense to vary all the possible physical properties of the
    transmission to reduce the chances that the same effect causes the loss of
    both original and redundant transmissions.
  </dd>

<!-- [rfced] Should "translate taking" here be updated to "translate to taking"?

Original:
   From a DetNet perspective, this may translate taking into account
   how transmission from one node may interfere with the transmission
   of another node attached to the same wireless sub-layer network.

Perhaps:
   From a DetNet perspective, this may translate to taking into account
   how transmission from one node may interfere with the transmission
   of another node attached to the same wireless sub-layer network.
-->

    <dt>Relay Coordination coordination and constructive interference:</dt><dd>Though it
    can be difficult to achieve at high speed, a fine time synchronization and
    a precise sense of phase allows the energy from multiple coordinated
    senders to add up at the receiver and actually improve the signal quality,
    compensating for either distance or physical objects in the Fresnel zone
    that would reduce the link budget. From a DetNet perspective, this may
    translate taking into account how transmission from one node may interfere
    with the transmission of another node attached to the same wireless
    sub-layer network.
    </dd>
      </dl>
      <t>
    RAW and DetNet enable application flows that require a special treatment along paths that can provide that treatment.
    This may be seen as a form of Path Aware Networking networking and may be subject to
    impediments documented in <xref target="RFC9049"/>.
      </t>
      <t>

<!-- [rfced] Will readers understand what "It" refers to in the second
sentence (e.g., to "path", "mechanism", "RAW")? Also, how may we clarify
"ala"?

Original:
   The mechanisms used to establish a path is not unique to, or
   necessarily impacted by, RAW.  It is expected to be the product of
   the DetNet Controller Plane <xref
   target="I-D.ietf-detnet-controller-plane-framework"/>,
   [I-D.ietf-detnet-controller-plane-framework], and may use a Path
   computation Element (PCE) <xref target="RFC4655"/> [RFC4655] or the DetNet Yang Data Model
   [RFC9633], or may be computed in a distributed fashion ala Resource
   ReSerVation Protocol (RSVP) [RFC2205].

Perhaps:
   The mechanism used to establish a path is not unique to, or
   necessarily impacted by, RAW.  The mechanism is expected to be the product of
   the DetNet Controller Plane [DetNet-PLANE]; it may use a Path
   Computation Element (PCE) [RFC4655] or the DetNet YANG data model
   [RFC9633], or it may be computed in a distributed fashion as per the
   Resource ReSerVation Protocol (RSVP) [RFC2205].
-->

      <t>
   The mechanism used to establish a path is not unique to, or necessarily
   impacted by, RAW. It is expected to be the product of the DetNet Controller
   Plane <xref target="I-D.ietf-detnet-controller-plane-framework"/>; it may
   use a Path Computation Element (PCE) <xref target="RFC4655"/> or the DetNet
   YANG data model <xref target="RFC9633"/>, or it may be computed in a
   distributed fashion ala the Resource ReSerVation Protocol (RSVP) <xref
   target="RFC2205"/>.  Either way, the assumption is that it is slow relative
   to local forwarding operations along the path.  To react fast enough to
   transient changes in the radio transmissions, RAW leverages DetNet Network
   Plane enhancements to optimize the use of the paths and match the quality
   of the transmissions over time.
   </t>
   <t>
   As opposed to wired networks, the action of installing a path over a set of
   wireless links may be very slow relative to the speed at which the radio
   conditions vary,
   and it makes sense vary; thus, in the wireless case case, it makes sense to provide
   redundant forwarding solutions along a alternate paths (see <xref
   target="pt"/>) and to leave it to the Network Plane to select which of
   those forwarding solutions are to be used for a given packet based on the
   current conditions.  The RAW Network Plane operations happen within the
   scope of a recovery graph (see <xref target="trk"/>) that is
   pre-established and installed by means outside of the scope of RAW.

   A recovery graph may be strict or loose depending on whether
   each hop or just a subset of the hops are is observed and controlled by RAW.
      </t>
      <t>
   RAW distinguishes the longer time-scale timescale at which routes are computed from
   the shorter time-scale timescale where forwarding decisions are made (see <xref
   target= "timescale"/>).  The RAW Network Plane operations happen at a time-scale
   timescale that sits timewise between the routing and the forwarding time-scales. Their goal is to select dynamically, within
   timescales. Within the resources delineated by a recovery graph, their
   goal is to dynamically select the protection path(s) that the upcoming
   packets of a DetNet flow shall follow. As they influence the path for entire the
   entirety of the flows or a portion of flows, them, the RAW Network Plane operations may
   affect the metrics used in their rerouting decision, decisions, which could
   potentially lead to oscillations; such effects must be avoided or dampened.
      </t>

    </section>      <!-- The RAW problem -->
   <section anchor="terms" numbered="true" toc="default">
    <name>Terminology</name>

<!-- [rfced] Will readers know what "IETF art of Protection" is? Also, is a
reference needed in this sentence?

Original:
   RAW inherits and
   augments the IETF art of Protection as seen in DetNet and Traffic
   Engineering.
-->

    <t>RAW reuses terminology defined for DetNet in the <xref target="RFC8655"> "Deterministic Networking Architecture"</xref>,
    Architecture" <xref target="RFC8655"/>, e.g., PREOF "PREOF" to stand for Packet "Packet
    Replication, Elimination Elimination, and Ordering Functions. Functions". RAW inherits and
    augments the IETF art of Protection protection as seen in DetNet and Traffic
    Engineering.
    </t>
    <t>RAW also reuses terminology defined for Operations, Administration, and
    Maintenance (OAM) protocols in Section 1.1 of the <xref target="RFC9551"> target="RFC9551" sectionFormat="bare"
    section="1.1"/> of "Framework of OAM for DetNet" </xref> Operations, Administration, and Maintenance
    (OAM) for Deterministic Networking (DetNet)" <xref target="RFC7799">"Active target="RFC9551"/> and in "Active and Passive
    Metrics and Methods (with Hybrid Types In-Between)" </xref>.

   <!-- <xref target="I-D.ietf-opsawg-oam-characterization">"Guidelines for Characterizing OAM"</xref>
   provides additional semantics of
    target="RFC7799"/>.

<!-- [rfced] For clarity, we have replaced the terms Active, Passive, Hybrid, and In-Packet OAM that are consistent comma in the text below with
    <xref target="RFC7799"/>. It
"for". Please review to ensure this update does not change your meaning.

Original:

   RAW also warns about potential inconsistencies reuses terminology defined for MPLS in [RFC4427] such as the way the terms "in-band"
   term recovery as covering both Protection and "out-of-band" are used across the IETF; Restoration, a number
   of recovery types.

Current:

   RAW also reuses terminology defined for MPLS in [RFC4427] such as the DetNet reference
   term "recovery" to cover both protection and restoration for those terms is <xref target="RFC9551"/>. a number
   of recovery types.
-->

    </t>
  <t>
    RAW also reuses terminology defined for MPLS in <xref target=
    "RFC4427" format="default"/> target="RFC4427"
    format="default"/>, such as the term recovery as covering "recovery" to cover both Protection protection
    and Restoration, restoration for a number of recovery types.  That document defines a
    number of concepts concepts, such as the recovery domain domain, that are used in the RAW mechanisms,
    mechanisms and defines the new term recovery graph. "recovery graph".  A recovery graph
    associates a topological graph with usage metadata that represents how the
    paths are built and used within the recovery graph.  The recovery graph
    provides excess bandwidth for the intended traffic over alternate
    potential paths, and the use of that bandwidth is optimized dynamically.
    </t>
    <t>
    RAW also reuses terminology defined for RSVP-TE in <xref target=
    "RFC4090" format="default"/> format="default"/>, such as the Point "Point of Local Repair (PLR). (PLR)".
    The concept of a backup path is generalized with protection path, which is the
    term mostly found in recent standards and used in this document.
    </t>
    <t>
    RAW also reuses terminology defined for 6TiSCH in <xref target=
    "RFC9030" format="default"/> and equates the 6TiSCH concept of a Track with
   that of a recovery graph.
    </t>
    <t>

<!-- [rfced] This sentence appears at the end of Section 3. Please review the
placement, and let us know if this should be added to (or moved to
follow) the third paragraph in Section 3, which also discusses recovery graphs.

Original:
   The concept of recovery graph is agnostic to the underlying
   technology and applies but is not limited to any full or partial
   wireless mesh.  RAW specifies strict and loose recovery graphs
   depending on whether the path is fully controlled by RAW or traverses
   an opaque network where RAW cannot observe and control the individual
   hops.
-->

    <t>
    The concept of a recovery graph is agnostic to
    the underlying technology and applies, but is not limited to, any full or
    partial wireless mesh.
    RAW specifies strict and loose recovery graphs depending on whether the path is fully
    controlled by RAW or traverses an opaque network where RAW cannot observe
    and control the individual hops.
    </t>

<!-- [rfced] Section 3.1: If no objections, we will update this section to use
<dl> instead of a separate subsection for each abbreviation. Note that
this aligns with the format used in draft-ietf-roll-dao-projection-40
(also part of Cluster 538) and is more typical in the RFC Series.
-->

    <section><name>Abbreviations</name>
    <t>
    RAW uses the following terminology and acronyms: abbreviations.
    </t>

    <section><name>Acronyms</name>
    <section><name>ARQ</name>

    <t>
   Automatic Repeat Request, a Request. A well-known mechanism, enabling mechanism that enables an acknowledged
   transmission with retries to mitigate errors and loss. ARQ may be
   implemented at various layers in a network. ARQ is typically implemented at
   Layer-2,
   per hop and not end-to-end (not end to end) at Layer 2 in wireless networks. ARQ improves
   delivery on lossy wireless. Additionally, ARQ retransmission may be further
   limited by a bounded time to meet end-to-end packet latency constraints.
   Additional details and considerations for ARQ are detailed in
   <xref target="RFC3366"/>.
    </t>
    </section>

    <section><name>FEC</name>
    <t>
    Forward Error Correction, adding Correction. Adding redundant data to protect against a partial
    loss without retries.
    </t>
    </section>

    <section><name>HARQ</name>
    <t>
    Hybrid ARQ, combining ARQ. A combination of FEC and ARQ.
    </t>
    </section>

    <section><name>ETX</name>
    <t>
    Expected Transmission Count: a Count. A statistical metric that represents the
    expected total number of packet transmissions (including retransmissions)
    required to successfully deliver a packet along a path, used by 6TiSCH
    <xref target="RFC6551"/>.
    </t>
    </section>
    <section><name>ISM</name>
    <t>

    The industrial, scientific,
    Industrial, Scientific, and medical (ISM) radio band refers Medical. Refers to a
    group of radio bands or parts of the radio spectrum (e.g., 2.4 GHz and 5
    GHz) that are internationally reserved for the use of radio frequency (RF)
    energy intended for industrial, scientific, medical, and industrial requirements, e.g., medical requirements (e.g., by microwaves, depth radars, and medical diathermy machines.
    machines). Cordless phones, Bluetooth and LoWPAN Low-Power Wireless Personal Area Network (LoWPAN) devices, near-field
    communication (NFC) devices, garage door openers, baby monitors, and Wi-Fi
    networks may all use the ISM frequencies, although these low-power
    transmitters are not considered to be ISM devices. In general,
    communications equipment operating in ISM bands must tolerate any
    interference generated by ISM applications, and users have no regulatory
    protection from ISM device operation in these bands.
    </t>
    </section>

    <section><name>PER and PDR</name>

    <section><name>PER</name>
    <t>

    The
    Packet Error Rate (PER) is defined as the Rate. The ratio of the number of
    packets received in error to the total number of transmitted packets. A
    packet is considered to be in error if even a single bit within the packet
    is received incorrectly. In contrast, the Packet incorrectly.</t>
    </section>

    <section><name>PDR</name>
    <t>Packet Delivery Ratio (PDR) indicates the (PDR). The ratio of the number successful delivery of
    successfully delivered data packets to the total number of transmitted
    packets transmitted from the sender to the receiver.
    </t> receiver.</t>
    </section>

    <section><name>RSSI</name>
    <t>
    Received Signal Strength Indication (a.k.a. Energy Indication. Also known as "Energy Detection Level): a Level". A measure of the incoherent (raw) RF power in a channel. The RF power can come from any source: other transmitters using the same technology, other radio technology using the same band, or background radiation. For a single-hop, single hop, RSSI may be used for LQI.
    </t>
    </section>

    <section><name>LQI</name>
    <t>

    The link quality indicator (LQI) is an
    Link Quality Indicator. An indication of the quality of the data packets received by the receiver.
    It is typically derived from packet error statistics, with the exact method depending on the network stack being used.
    LQI values may be exposed to the controller plane for each individual hop or cumulated along segments.
    Outgoing LQI values can be calculated from coherent (demodulated) PER, RSSI RSSI, and incoming LQI values.
    </t>
    </section>

    <section><name>OAM</name>
    <t>
      OAM stands for
      Operations, Administration, and Maintenance, and
      covers Maintenance. Covers the processes,
      activities, tools, and standards involved with operating, administering,
      managing, and maintaining any system.  This document uses the terms Operations, Administration,
      and Maintenance, term
      in conformance with the <xref target="RFC6291">
      'Guidelines "Guidelines for the Use of the "OAM" 'OAM' Acronym in the IETF'</xref> IETF" <xref
      target="RFC6291"/>, and the system observed by the RAW OAM is the
      recovery graph.
     </t>
    </section>
    <section><name>OODA</name>
    <t>
    OODA (Observe,
    Observe, Orient, Decide, Act) is a Act. A generic formalism to represent the
    operational steps in a Control Loop. In the context of RAW, OODA is
    applied to network control and convergence, more in convergence; see <xref target="ooda"/>.
    target="ooda"/> for more.
    </t>
    </section>

    <section><name>SNR</name>
    <t>
    Signal-Noise Ratio (a.k.a. S/N): a
    Signal-to-Noise Ratio. Also known as "S/N Ratio". A measure used in science
    and engineering that compares the level of a desired signal to the level
    of background noise. SNR is defined as the ratio of signal power to noise
    power, often expressed in decibels.
    </t>
    </section>

    </section><!--Acronyms-->
    </section>

<!-- [rfced] May we update these section titles to use the plural "Links" and
"Paths"?

Original:
3.2.  Link and Direction
3.3.  Path and Recovery Graphs

Perhaps:
3.2.  Links and Direction
3.3.  Paths and Recovery Graphs
-->

<!-- [rfced] Introductory text

a) Sections 3.4 and 3.5 contain introductory sentences. We have updated them
as shown below. Please let us know any concerns.

Original:
   This document reuses the terminology in section 2 of [RFC8557] and
   section 4.1.2 of [DetNet-ARCHI] for deterministic networking and
   deterministic networks.
   ...
   In the context of the RAW work, Reliability and Availability are
   defined as follows:

Current:
   This document reuses the terminology in Section 2 of [RFC8557] and
   in Section 4.1.2 of [DetNet-ARCHI] for deterministic networking and
   deterministic networks. This document also uses the following terms.
   ...
   This document uses the following terms relating to reliability and
   availability in the context of the RAW work.

b) Should Sections 3.2 and 3.3 contain similar introductory sentences? If so,
please provide the text.

Perhaps:
   This document uses the following terms relating to links and direction
   in the context of RAW.
   ...
   This document uses the following terms relating to paths and recovery graphs
   in the context of RAW.
-->

    <section><name>Link and Direction</name>

    <section><name>Flapping</name>
    <t>
<!-- [rfced] Will "a subsecond to seconds duration" be clear to readers?

Original:
   In the context of RAW, a link flaps when the reliability of the
   wireless connectivity drops abruptly for a short period of time,
   typically of a subsecond to seconds duration.

Perhaps:
   In the context of RAW, a link flaps when the reliability of the
   wireless connectivity drops abruptly for a short period of time,
   typically a duration of a subsecond or a second.
-->

    <t>
    In the context of RAW, a link flaps when the reliability of the wireless
    connectivity drops abruptly for a short period of time, typically
    a duration of a subsecond to seconds.
    </t>
    </section>

    <section><name>Uplink</name>
    <t>
     Connection
     An uplink is the connection from end-devices end devices to data communication equipment. In the
     context of wireless, uplink refers to the connection between a station
     (STA) and a controller (AP) or a User Equipment (UE) to and a Base Station (BS)
     such as a 3GPP 5G gNodeB (gNb). (gNB).
     </t>
    </section>

    <section><name>Downlink</name>
    <t>
      The
      A downlink is the reverse direction from uplink.
     </t>
    </section>

    <section><name>Downstream</name>
    <t>
     Following
     Downstream refers to the following the direction of the flow data path along a recovery graph.
     </t>
    </section>

    <section><name>Upstream</name>
    <t>
     Against
     Upstream refers to going against the direction of the flow data path along a recovery graph.
     </t>
     </section>

    </section><!-- Link and Direction -->

    </section>

    <section anchor="pt"><name>Path and Recovery Graphs</name>
    <section><name>Path</name>
    <t>
    Quoting section 1.1.3

<!-- [rfced] FYI - We updated the direct quotes in Section 3.3.1 to exactly
match the text in Section 1.3.3 of [INT-ARCHI] and Section 2 of
[RFC9473].
-->

    <xref target="RFC1122"/>: target="RFC1122" section="1.3.3"/> provides a definition of Path:
    </t>
    <blockquote>
    At a given moment, all the IP datagrams from a particular source host to a
    particular destination host will typically traverse the same sequence of
    gateways.  We use the term "path" for this sequence.  Note that a path is
    unidirectional;
    uni-directional; it is not unusual to have different paths in the two
    directions between a given host pair.
    </blockquote>
    <t>
    Section 2 of
    <xref target="RFC9473"/> target="RFC9473" section="2"/> points to a
    longer, more modern definition of path, which begins as follows:
    </t>
    <blockquote>
    <t>
      A sequence of adjacent path elements over which a packet can
      be transmitted, starting and ending with a node.
</t><t>
  Paths are unidirectional and time-dependent, time dependent, i.e., there can be a
  variety of paths from one node to another, and the path over which
  packets are transmitted may change. A path definition can be
      fixed strict
  (i.e., the exact sequence of path elements remains the same) or mutable loose
  (i.e., the start and end node remain the same, but the path elements
  between them may vary over time).
</t><t>

      The representation of a path and its properties may depend on the
      entity considering the path.  On the one hand, the representation
      may differ due to entities having partial visibility of path
      elements comprising a path or their visibility changing over time.
</t>
    </blockquote>
    <t>
    It follows that the general acceptance of a path is a linear sequence of
    links and nodes, as opposed to a multi-dimensional graph, defined by the
    experience of the packet that went from a node A to a node B.
    In the context of this document, a path is observed by following one copy
    or one fragment of a packet that conserves its uniqueness and integrity.

    For instance, if C replicates to E and F and if D eliminates duplicates,
    a packet from A to B can experience 2 paths, two paths: A->C->E->D->B and
    A->C->F->D->B. Those paths are called protection paths. Protection
    paths may be fully non-congruent, and alternatively non-congruent; alternatively, they may intersect at
    replication or elimination points.

    </t>
    <t> With DetNet and RAW,
    a packet may be duplicated, fragmented, and network-coded, network coded, and the various
    byproducts may travel different paths that are not necessarily end-to-end end to end
    between A and B; we B. We refer to that this complex scenario as a DetNet path.
    As such, the DetNet path extends the above description of a path,
    but it still matches the experience of a packet that traverses the network.
    </t>
    <t>
    With RAW, the path experienced by a packet is subject to change from one packet to the next,
    but all the possible experiences are all contained within a finite set.
    Therefore, we introduce below the term of a recovery graph "recovery graph" (see the next section) that coalesces
    that set and covers the overall topology where the possible DetNet paths are
    all contained. As such, the recovery graph coalesces all the possible paths
    a flow
    may experience, each with its own statistical probability to be used.
    </t>
    </section>
    <section anchor="trk"><name>Recovery Graph</name>

    <t>A

<!-- [rfced] Section 3.3.2: Please clarify "represents not an actual but a
potential" in this text.

Original:

   A networking graph that can be followed to transport packets with
   equivalent treatment, associated with usage metadata; as opposed to
   the definition of a path above, a recovery graph represents not an
   actual but a potential, it is not necessarily a linear sequence like
   a simple path, and is not necessarily fully traversed (flooded) by
   all packets of a flow like a DetNet Path.

Perhaps:

   A recovery graph is a networking graph that can be followed to transport packets with
   equivalent treatment and is associated with usage metadata. In contrast to
   the definition of a path above, a recovery graph represents a
   potential path, not an actual one. Also, a recovery graph is not necessarily a
   linear sequence like
   a simple path and is not necessarily fully traversed (flooded) by
   all packets of a flow like a DetNet Path.

-->

    <t>A recovery graph is a networking graph that can be followed to
    transport packets with equivalent treatment and is associated with usage
    metadata. In contrast to the definition of a path above,
    a recovery graph represents not an actual but a potential, is not
    necessarily a linear sequence like a simple path, and is not necessarily
    fully traversed (flooded) by all packets of a flow like a DetNet
    Path. Still, and as a simplification, the casual reader may consider that
    a recovery graph is very much like a DetNet path, aggregating multiple
    paths that may
    overlap, overlap or fork and then rejoin, for instance instance, to enable a
    protection service by the PREOF operations.
    </t>
   <figure anchor="Figtrk">
          <name>Example IoT Recovery Graph to an IoT Gateway with 1+1 Redundancy</name>
       <artwork align="center" name="" type="" alt="">
       <![CDATA[ alt=""><![CDATA[
                _________
               |         |
               | IoT G/W |
               |_________|
                 EGRESS  <<=== Elimination at Egress
                  |  |
      ---+--------+--+--------+--------
         |      Backbone      |
       __|__                __|__
      |     | Backbone     |     | Backbone
      |__ __| Router       |__ __| Router
         |           #        |
      #   \     #            /  <-- protection path
    #      #        #-------#
            \  #   /  #         ( Low-power )
     #   #   \    /      #     ( Lossy Network)
              \  /
        #   INGRESS <<=== Replication at recovery graph Ingress
               |
               # <-- source device
     #: Low-power device

    ]]>
       </artwork>
]]></artwork>
   </figure>

<!-- [rfced] Is "coalescence of the collection" redundant? Also, how may we
revise "for which a flow is assigned to the recovery graph" to improve
clarity?

Original:
   Refining further, a recovery graph is defined as the coalescence of
   the collection of all the feasible DetNet Paths that a packet for
   which a flow is assigned to the recovery graph may be forwarded
   along.

Perhaps:
   Refining further, a recovery graph is defined as the coalescence of
   all the feasible DetNet Paths that a packet with an assigned flow
   may be forwarded along.
-->

   <t>
    Refining further, a recovery graph is defined as the coalescence of the collection
    of all the feasible DetNet Paths that a packet for which a flow is assigned to the
    recovery graph may be forwarded along.
    A packet that is assigned to the recovery graph experiences one of the feasible
    DetNet Paths based on the current selection by the PLR at the time the
    packet traverses the network.
    </t>
    <t>
    Refining even further, the feasible DetNet Paths within the recovery graph may or may
    not be computed in advance, but advance; instead, they may be decided upon the detection of a change from
    a clean slate.
    Furthermore, the PLR decision may be distributed, which yields a large
    combination of possible and dependent decisions, with no node in the network
    capable of reporting which is the current DetNet Path within the recovery graph.
    </t>
    <t>
    In DetNet <xref target="RFC8655"/> terms, a recovery graph has the following
    properties:
    </t>
    <ul>
    <li>
    A recovery graph is a Layer-3 Layer 3 abstraction built upon IP links between routers.
    A router may form multiple IP links over a single radio interface.
    </li><li>
    A recovery graph has one Ingress and one Egress node, which operate as DetNet Edge
    nodes.
    </li><li>

<!-- [rfced] The bulleted list in Section 3.3.2 lists the properties of a
recovery graph. We have the following questions.

a) Is "graph of a recovery graph" correct here?

Original:
   *  The graph of a recovery graph is reversible, meaning that packets
      can be routed against the flow of data packets, e.g., to carry OAM
      measurements or control messages back to the Ingress.

Perhaps:
   *  A recovery graph is reversible, meaning that packets
      can be routed against the flow of data packets, e.g., to carry OAM
      measurements or control messages back to the Ingress.

b) In the first bullet below, should "that graph" be updated to "a recovery
graph"? In the second bullet below, should "of the graph" be updated to "of a
recovery graph"? Or is the current correct in both instances?

Original:
   *  The vertices of that graph are DetNet Relay Nodes that operate at
      the DetNet Service sub-layer and provide the PREOF functions.

   *  The topological edges of the graph are strict sequences of DetNet
      Transit nodes that operate at the DetNet Forwarding sub-layer.

Perhaps:
   *  The vertices of a recovery graph are DetNet Relay Nodes that operate at
      the DetNet Service sub-layer and provide the PREOF functions.

   *  The topological edges of a recovery graph are strict sequences of DetNet
      Transit nodes that operate at the DetNet Forwarding sub-layer.
-->

    The graph of a recovery graph is reversible, meaning that packets can be routed against
    the flow of data packets, e.g., to carry OAM measurements or control
    messages back to the Ingress.
    </li><li>
    The vertices of that graph are DetNet Relay Nodes that operate at the
    DetNet Service sub-layer and provide the PREOF functions.
    </li><li>
    The topological edges of the graph are strict sequences of DetNet Transit
    nodes that operate at the DetNet Forwarding sub-layer.
    </li>
    </ul>

    <t>
    <xref target='TRK'/> illustrates the generic concept of a recovery graph,
   between an Ingress Node and an Egress Node.

    The recovery graph is composed of forward protection paths and paths, forward or Segments, and crossing
    Segments (see the definition for definitions of those terms in the next sections).
    The recovery graph contains at least 2 two protection paths as paths: a main path and a backup path.
    </t>

<!-- [rfced] FYI - For Figure 3, we moved the information about the segments
and paths out of the figure.
-->

<figure anchor='TRK'><name>A Recovery Graph and its Its Components</name>
              <artwork align="center"><![CDATA[
 ------------------- forward direction ---------------------->

       a ==> b ==> C -=- F ==> G ==> h     T1       I: Ingress
     /              \   /      |       \ /          E: Egress
   I                  o        n        E -=- T2    T1, T2, T3:
     \              /   \      |       / \            External
       p ==> q ==> R -=- T ==> U ==> v     T3         Targets

      I: Ingress
      E: Egress
      T1, T2, T3: external targets
      Uppercase: DetNet Relay Nodes
      Lowercase: DetNet Transit nodes

   I
]]></artwork>
</figure>

<t>Of note:</t>
<dl newline="false" spacing="normal">
  <dt>I ==> a ==> b ==> C : A C:</dt><dd>A forward Segment to targets F and o
   C o</dd>
  <dt>C ==> o ==> T: A T:</dt><dd>A forward Segment to target T (and/or U)
   G U)</dd>
  <dt>G | n | U : A U:</dt><dd>A crossing Segment to targets G or U
   I U</dd>
  <dt>I -> F -> E : A E:</dt><dd>A forward Protection Path protection path to targets T1, T2, and T3

   I, T3</dd>
  <dt>I, a, b, C, F, G, h, E : a E:</dt><dd>A path to T1, T2, and/or T3
   I, T3</dd>
  <dt>I, p, q, R, o, F, G, h, E : E:</dt><dd>A segment-crossing protection path

]]></artwork>
</figure> path</dd>
</dl>

    </section>
  <section><name>Forward and Crossing</name>
    <t>
    Forward refers to progress towards the Egress of the recovery graph Egress. graph. Forward links are
    directional, and packets that are forwarded along the recovery graph can only be
    transmitted along the link direction. Crossing links are bidirectional,
    meaning that they can be used in both directions, though a given packet may
    use the link in one direction only. A Segment can be forward, in which
    case it is composed of forward links only, or it can be crossing, in which
    case it is composed of crossing links only. A Protection Path protection path is always forward,
    meaning that it is composed of forward links and Segments.
    </t>
    </section>
  <section><name>Protection Path</name>
    <t>
    An
    A protection path is an end-to-end forward path between the Ingress and Egress Nodes of a
    recovery graph. A protection path in a recovery graph is expressed as a strict sequence
    of DetNet Relay Nodes or as a loose sequence of DetNet Relay Nodes that are
    joined by Segments in the recovery graph Segments. graph.  Background information on the
    concepts related to protection paths can be found in <xref
    target="RFC4427"/> and <xref target="RFC6378"/> target="RFC6378"/>.
    </t>
  </section>
    <section><name>Segment</name>
    <t>
    A Segment is a strict sequence of DetNet Transit nodes between 2 two DetNet Relay Nodes; a
    Segment of a recovery graph is composed topologically of two vertices of the
    recovery graph and one edge of the recovery graph between those vertices.
    </t>
    </section>

    </section><!--Path and recovery graphs-->

    </section>

    <section><name>Deterministic Networking</name>
    <t>This document reuses the terminology in section 2 of
    <xref target="RFC8557"/> target="RFC8557" section="2"/> and section 4.1.2 of <xref target="RFC8655"/> target="RFC8655" section="4.1.2"/>
    for deterministic networking and deterministic networks. This documents also uses the following terms.
    </t>

     <section><name>The DetNet Planes</name>
      <t>
   <xref target="RFC8655"/> defines three planes: the Application (User) Plane, the Controller Plane,
   and the Network Plane.
   The DetNet Network Plane is composed of a Data Plane (packet forwarding) and an
   Operational Plane where OAM operations take place.
   In the Network Plane, the DetNet Service sub-layer
   focuses on flow protection (e.g., using redundancy) and can be fully operated
   at Layer-3, Layer 3, while the DetNet forwarding sub-layer establishes the paths,
   associates the flows to the paths, and ensures the availability of the
   necessary resources, and leverages Layer-2 Layer 2 functionalities for timely delivery
   to the next DetNet system, system. For more in information, see <xref target='problem'/>.
      </t>
    </section>

    <section><name>Flow</name>
    <t>
    A flow is a collection of consecutive IP packets defined by the upper layers and
    signaled by the same 5 5-tuple or 6-tuple (see section 5.1 of
    <xref target="RFC8939"/>). target="RFC8939" section="5.1"/>). Packets of the same flow must be placed
    on the same recovery graph to receive an equivalent treatment from Ingress to Egress
    within the recovery graph. Multiple flows may be transported along the same recovery graph.
    The DetNet Path that is selected for the flow may change over time under the
    control of the PLR.

    </t>
    </section>

    <section><name>Residence Time</name>

    <t>
    A residence time (RT) is defined as the time interval between when the reception
   of a packet starts and the transmission of the packet begins. In the
   context of RAW, RT is useful for a transit node, nodes, not ingress or egress. egress nodes.
    </t>
    </section>

    <section><name>L3 Deterministic Flow Identifier </name>
    <t>
<!-- [rfced] FYI - To improve clarity, we moved the first sentence below to a
parenthetical within the second sentence. Please let us know any
objections.

Original:
   See section 3.3 of <xref target="RFC8938"/>. [DetNet-DP].  The classic IP 5-tuple that
   identifies a flow comprises the source IP, destination IP, source
   port, destination port, and the upper layer protocol (ULP).  DetNet
   uses a 6-tuple where the extra field is the DSCP field in the packet.
   The IPv6 flow label is not used for that purpose.

Perhaps:
   The classic IP 5-tuple that
   identifies a flow comprises the source IP, destination IP, source
   port, destination port, and the Upper-Layer Protocol (ULP).  DetNet
   uses a 6-tuple where the extra field is the Differentiated Services
   Code Point (DSCP) field in the packet (see Section 3.3 of [DetNet-DP]).
   The IPv6 flow label is not used for that purpose.
-->

    <t>
     The classic IP 5-tuple that
     identifies a flow comprises the source IP, destination IP, source port,
     destination port, and
     the Upper-Layer Protocol (ULP). DetNet uses a 6-tuple where the extra field
     is the Differentiated Services Code Point (DSCP) field in the packet (see <xref target="RFC8938" section="3.3"/>). The IPv6 flow label is not used for that
     purpose.
     </t>
     </section>

     <section><name>TSN</name>
    <t>

     <section><name>Time-Sensitive Networking</name>

<!-- [rfced] Updates to Section 3.4.5

a) We made some updates to this sentence (see Current text below). Would
adding a citation to [TSN] also be helpful here (see Perhaps text below)?
Also, please review "the efforts at IEEE 802"? Is the intended meaning "the
IEEE efforts"?

Original:
 3.4.5.  TSN

   TSN stands for Time-Sensitive Networking and denotes the efforts at
   IEEE 802 for deterministic networking, originally for use on
   Ethernet.

Current:
 3.4.5.  Time-Sensitive Networking

   Time-Sensitive Networking (TSN) denotes the efforts at IEEE 802 regarding
   for deterministic networking, originally for use on
   Ethernet. See [TSN].

Perhaps:
 3.4.5.  Time-Sensitive Networking

   Time-Sensitive Networking (TSN) denotes the IEEE efforts regarding
   for deterministic networking, originally for use on
   Ethernet. See [TSN].

b) May we update "the selected RAW technologies [RAW-TECHNOS]" as follows? Or
is another meaning intended?

Original:
   Wireless TSN (WTSN) denotes extensions of the TSN work on
   wireless media such as the selected RAW technologies [RAW-TECHNOS].

Perhaps:
   Wireless TSN (WTSN) denotes extensions of the TSN work on
   wireless media, such as the RAW technologies described in [RAW-TECHNOS].
-->

     <t>
    Time-Sensitive Networking (TSN) denotes the efforts at IEEE
    802 for deterministic networking, originally for use on Ethernet. Wireless
    TSN (WTSN) denotes extensions of the TSN work on wireless media such as
    the selected RAW technologies <xref target="I-D.ietf-raw-technologies"/>. target="RFC9913"/>.
    </t>
    </section>
     <section><name>Lower-Layer API</name>
    <t>
   In addition,
   RAW includes the concept of a lower-layer API (LL
   API),
   API) that provides an interface between the
   lower layer
   lower-layer (e.g., wireless) technology and the DetNet layers. The LL API is
   technology  dependent as what the lower layers expose towards the DetNet layers may vary.
   Furthermore, the different RAW technologies are equipped with
   different reliability features, e.g., short range features (e.g., short-range broadcast, Multiple-User,
   Multiple-Input, and Multiple-Output (MUMIMO),
    Multiple User - Multiple Input Multiple Output (MU-MIMO), PHY rate
   and other Modulation Coding Scheme (MCS) adaptation, coding and
   retransmissions methods, and constructive interference and overhearing, overhearing;
   see <xref target="I-D.ietf-raw-technologies"/> target="RFC9913"/> for details. more details).
   The LL API enables interactions between the
   reliability functions provided by the lower layer and the
   reliability functions provided by DetNet. That is, the LL API makes
   cross-layer optimization possible for the reliability functions of
   different layers depending on the actual exposure provided via the LL API
   by the given RAW technology.
   The <xref target="RFC8175"> Dynamic Link Exchange Protocol (DLEP) </xref> format="title" target="RFC8175"/> <xref target="RFC8175"/> is an
   example of a protocol that can be used to implement the LL API.
    </t>

    </section>
     </section><!--Deterministic Networking -->
     </section>
    <section><name>Reliability and Availability</name>
    <t>
    In
    <t>This document uses the following terms relating to reliability and
   availability in the context of the RAW work, Reliability and Availability are defined as
    follows: work.
</t>

    <section><name>Service Level Agreement</name>
    <t>

<!-- [rfced] This sentence is difficult to parse. How does "the application
flow" connect to the rest of the sentence?

Original:

   In the context of RAW, an SLA (service level agreement) is a contract
   between a provider (the network) and a client, the application flow,
   defining measurable metrics such as latency boundaries, consecutive
   losses, and packet delivery ratio (PDR).

Perhaps:

   In the context of RAW, a Service Level Agreement (SLA) is a contract
   between a provider (the network) and a client that defines the application flow
   and measurable metrics such as latency boundaries, consecutive
   losses, and Packet Delivery Ratio (PDR).

Or:

   In the context of RAW, a Service Level Agreement (SLA) is a contract
   between a provider (the network) and a client (the application flow) that defines
   measurable metrics such as latency boundaries, consecutive
   losses, and Packet Delivery Ratio (PDR).
-->

    <section><name>Service Level Agreement</name>
    <t>
    In the context of RAW, a Service Level Agreement (SLA) is a contract
    between a provider (the network) and a client, the application flow,
    defining measurable metrics such as latency boundaries, consecutive losses,
    and Packet Delivery Ratio (PDR).
    </t>
    </section>
    <section><name>Service Level Objective</name>
    <t>
    A service level objective Service Level Objective (SLO) is one term in the SLA, for which specific
    network setting and operations are implemented. For instance, a dynamic
    tuning of the packet redundancy addresses an SLO of consecutive losses in
    a row by augmenting the chances of delivery of a packet that follows a loss.
    </t>
    </section>

    <section><name>Service Level Indicator</name>
<!-- [rfced] Will "losses in a row as time series" be clear to readers?

Original:
   It can be for instance, the statistics of
   individual losses and losses in a row as time series.

Perhaps:
   For instance, it can be the statistics of
   individual losses or losses in a row during a certain amount of time.
-->

    <t>
    A service level indicator Service Level Indicator (SLI) measures the compliance of an SLO to the
    terms of the contract. It For instance, it can be for instance, the statistics of individual
    losses and losses in a row as time series.
    </t>
    </section>

    <section><name> Precision

    <section><name>Precision Availability Metrics</name>
    <t>
    Precision Availability Metrics (PAMs) <xref target="RFC9544"/> aim
    at capturing
   to capture service levels for a flow, specifically the degree to which
    the flow complies with the SLOs that are in effect.
    </t>
    </section>
    <section><name>Reliability</name>
    <t>
    Reliability is a measure of the probability that an item (e.g., system, system or
   network) will perform its intended function with no failure for a stated
   period of time (or for a stated number of demands or load) under stated environmental
   conditions. In other words, reliability is the probability that an item
   will be in an uptime state (i.e., fully operational or ready to perform)
   for a stated mission, e.g., mission (e.g., to provide an SLA. SLA). See more in
   <xref target="NASA1"/>.
    </t>
    </section>

    <section><name>Availability</name>
<!-- [rfced] This sentence may be difficult to read because of the
parentheticals. Also, does the text starting with "an uptime
state..." refer to availability or mission readiness? Please review.

Original:
   Availability is the probability of an items (e.g., a network's)
   mission readiness (e.g., to provide an SLA), an uptime state with the
   likelihood of a recoverable downtime state.

Perhaps:
   Availability is the probability of an item's
   mission readiness (e.g., probability of a network to provide an SLA);
   it is an uptime state with the
   likelihood of a recoverable downtime state.
-->

    <t>
   Availability is the probability of an item’s item's (e.g., a network’s) network's)
   mission readiness (e.g., to provide an SLA), an uptime state with the
   likelihood of a recoverable downtime state.
   Availability is expressed as
   (uptime)/(uptime+downtime). Note that it is availability that addresses
   downtime (including time for maintenance, repair, and replacement activities)
   and not reliability. See more in <xref target="NASA2"/>.
    </t>
    </section>

    </section><!--Reliability and Availability-->

    </section><!-- Terminology -->
    <!--  1111111111111111    -->

    </section>

    </section>

    <section anchor="raw" numbered="true" toc="default">
      <name>Reliable and Available Wireless</name>

    <!--  2222222222222222    -->

    <section numbered="true" toc="default">
      <name>High Availability Engineering Principles</name>

    <t>
    The reliability criteria of a critical system pervade through its elements,
    and if the system comprises a data network and network, then the data network is also
    subject to the inherited reliability and availability criteria.
    It is only natural to consider the art of high availability engineering and
    apply it to wireless communications in the context of RAW.
    </t>

    <t>
    There are three principles (pillars) of high availability engineering:
    </t>
     <ol spacing="compact">
     <ol>
     <li>elimination of each single point of failure</li>
     <li>reliable crossover</li>
     <li>prompt detection of failures as they occur</li>
     </ol>
     <t>
     These principles are common to all high availability systems, not just ones
     with Internet technology at the center.  Examples of both  Both non-Internet and
     Internet examples are included.
    </t>

    <!--  333333333333333333333   -->

    <section numbered="true" toc="default">
      <name>Elimination of Single Points of Failure</name>

    <t>
    Physical and logical components in a system happen to fail, either as the
    effect of wear and tear, when used beyond acceptable limits, or due to a
    software bug.
    It is necessary to decouple component failure from system failure to avoid
    the latter.
    This allows failed components to be restored while the rest of the system
    continues to function.
    </t>
    <t>
    IP Routers routers leverage routing protocols to reroute to alternate routes in case
    of a failure. When links are cabled through the same conduit, they form a
    shared risk link group (SRLG),
    Shared Risk Link Group (SRLG) and share the same fate if the conduit is
    cut, making the reroute operation ineffective.
    The same effect can happen with virtual links that end up in a the same
    physical transport through the intricacies of nested encapsulation.
    In a the same fashion, an interferer or an obstacle may affect multiple
    wireless transmissions at the same time, even between different sets of peers.
    </t>

<!-- [rfced] FYI - We updated these sentences as follows to improve
readability of "it is thus required to use" and "it is also required to
use". Let us know any concerns.

Original:
   For high availability, it is thus required to use
   physically link-disjoint and node-disjoint paths; in the wireless
   space, it is also required to use the highest possible degree of
   diversity (time, space, code, frequency, and channel width) in the
   transmissions over the air to combat the additional causes of
   transmission loss.

Perhaps:
   Thus, for high availability, the use of
   physically link-disjoint and node-disjoint paths is required; in the wireless
   space, the use of the highest possible degree of
   diversity (time, space, code, frequency, and channel width) in the
   transmissions over the air is also required to combat the additional causes of
   transmission loss.
-->

    <t>
    Intermediate network Nodes such nodes (such as routers, switches and APs, wire bundles,
    and the air medium itself itself) can become single points of failure. For High
    Availability, it is thus required to Thus, for high
    availability, the use of physically link-disjoint and Node-disjoint
    paths; node-disjoint
    paths is required; in the wireless space, it is also required to the use of the highest
    possible degree of diversity (time, space, code, frequency, and channel width)
    in the transmissions over the air is also required to combat the additional causes of
    transmission loss.
    </t>
    <t>
    From an economics standpoint, executing this principle properly generally
    increases capital expense because of the redundant equipment. In a
    constrained network where the waste of energy and bandwidth should be
    minimized, an excessive use of redundant links must be avoided; for RAW RAW, this
    means that the extra bandwidth must be used wisely and efficiently.
    </t>

    </section>
      <!--Elimination of Single Points of Failure-->

    <!--  333333333333333333333   -->

    <section numbered="true" toc="default">
      <name>Reliable Crossover</name>

    <t>
    Having backup
    Backup equipment has a limited value unless it can be reliably
    switched into use within the down-time downtime parameters.
    IP Routers routers execute reliable crossover continuously because
    the routers use any alternate routes that are available <xref target=
    "RFC0791"/>. This is due to the stateless nature of IP datagrams and the
    dissociation of the datagrams from the forwarding routes they take.
    The <xref target="RFC5714">"IP
    "IP Fast Reroute Framework"</xref> Framework" <xref target="RFC5714"/> analyzes
    mechanisms for fast failure detection and path repair for IP Fast-Reroute (FRR), Fast Reroute (FRR)
    and discusses the case of multiple failures and SRLG. Examples of FRR
    techniques include Remote Loop-Free Alternate <xref target="RFC7490"/> and
    backup label-switched path Label Switched Path (LSP) tunnels for the local repair of LSP tunnels
    using RSVP-TE <xref target="RFC4090"/>.
    </t>

    <t>
    Deterministic flows, on the contrary, are attached to specific paths where
    dedicated resources are reserved for each flow. Therefore, each DetNet path
    must inherently provide sufficient redundancy to provide the assured SLOs
    at all times.
    The DetNet PREOF typically leverages 1+1 redundancy whereby a packet is sent
    twice, over non-congruent paths. This avoids the gap during the fast reroute
    operation, FRR
    operation but doubles the traffic in the network.
    </t>
    <t>
    In the case of RAW, the expectation is that multiple transient faults may
    happen in overlapping time windows, in which case the 1+1 redundancy with
    delayed reestablishment of the second path does not provide the required
    guarantees.
    The Data Plane must be configured with a sufficient degree of
    redundancy to select an alternate redundant path immediately upon a fault,
    without the need for a slow intervention from the Controller Plane.
    </t>
    </section>
      <!--Reliable Crossover-->

    <!--  333333333333333333333   -->

    <section numbered="true" toc="default">
      <name>Prompt Notification of Failures</name>
    <t>
    The execution of the two above principles is likely to render a system where
    the end user rarely sees a failure. But However, a failure that occurs must still be detected in order to direct maintenance.
    </t>
    <t>
    There are many reasons for system monitoring (FCAPS for fault, configuration,
    accounting, performance, security (Fault, Configuration, Accounting, Performance, and Security (FCAPS) is a handy mental checklist) checklist), but fault
    monitoring is a sufficient reason.
    </t>
    <t>
    <xref target="RFC9522">
    "Overview and Principles of Internet Traffic Engineering"</xref> Engineering" <xref target="RFC9522"/> discusses
    the importance of measurement for network protection, protection and provides an
   abstract method for network survivability with the analysis of a traffic
   matrix as observed via a network management YANG data model, probing techniques,
   file transfers, IGP link state advertisements, and more.
    </t>

    <t>
    Those measurements are needed in the context of RAW to inform the controller
    and make the long-term reactive decision to rebuild a recovery graph based on
    statistical and aggregated information. RAW itself operates in the DetNet
    Network
    Plane at a faster time-scale timescale with live information on speed, state, etc.
    This live information can be obtained directly from the lower layer, e.g., layer (e.g.,
    using L2 triggers, triggers), read from a protocol such as DLEP,
    or transported over multiple hops using OAM and reverse OAM,
    as illustrated in <xref target="Figlearn"/>.
    </t>

    </section>
      <!--Prompt Notification of Failures-->

   </section>
      <!--Reliability Engineering-->
    <!--  22222222222222222222    -->

    <section numbered="true" toc="default">
      <name>Applying Reliability Concepts to Networking</name>
    <t>
    The terms Reliability "reliability" and Availability "availability" are defined for use in RAW in
    <xref target="terms"/> target="terms"/>, and the reader is invited to read
    <xref target="NASA1"/> and <xref target="NASA2"/>
    for more details on the general definition of Reliability. reliability.
    Practically speaking, a number of nines is often used to indicate the
    reliability of a data link, e.g., link (e.g., 5 nines indicate a
    Packet Delivery Ratio (PDR) of 99.999%. 99.999%).
    </t>
    <t>
    This number is typical in a wired
    environment where the loss is due to a random event such as a solar particle
    that affects the transmission of a particular packet, packet but does not affect the
    previous or packet, the next packet, nor or packets transmitted on other links. Note that the
    QoS requirements in RAW may include a bounded latency, and a packet that
    arrives too late is a fault and not considered as delivered.
    </t>

<!-- [rfced] FYI - To make this text easier to read and understand, we updated
the "e.g., using redundancy..." phrase to be two separate sentences. Please
review and let us know any objections.

Original:
   Packet loss cannot be fully avoided and the systems are built to resist
   some loss, e.g., using redundancy with Retries (as in HARQ), Packet
   Replication and Elimination (PRE) FEC, Network Coding (e.g., using FEC with
   SCHC [RFC8724] fragments), or, in a typical control loop, by linear
   interpolation from the previous measurements.

Perhaps:
   Packet loss cannot be fully
   avoided, and the systems are built to resist some loss.  This can be
   done by using redundancy with retries (as in HARQ), Packet
   Replication and Elimination (PRE) FEC, and Network Coding (e.g.,
   using FEC with Static Context Header Compression (SCHC) [RFC8724]
   fragments).  Also, in a typical control loop, linear interpolation
   from the previous measurements can be used.
-->

    <t>
    For a periodic networking pattern such as an automation control loop, this
    number is proportional to the Mean Time Between Failures (MTBF).
    When a single fault can have dramatic consequences, the MTBF expresses the
    chances that the unwanted fault event occurs. In data networks,
    this is rarely the case. Packet loss cannot be fully avoided avoided, and the
    systems are built to resist some loss, e.g., loss. This can be done by using redundancy with Retries retries
    (as in HARQ), Packet Replication and Elimination (PRE) FEC, and Network Coding (e.g., using
    FEC with SCHC Static Context Header Compression (SCHC) <xref target="RFC8724"/> fragments), or, fragments). Also, in a typical control
    loop, by linear interpolation from the previous measurements. measurements can be used.
    </t>
    <t>
<!-- [rfced] Would updating the text starting with "as a guarantee that
this..." as follows make this test more clear and concise?

Original:
   But the linear interpolation method cannot resist multiple
   consecutive losses, and a high MTBF is desired as a guarantee that
   this does not happen, in other words that the number of losses-in-a-row losses-in-
   a-row can be bounded.

Perhaps:
   However, the linear interpolation method cannot resist multiple
   consecutive losses, and a high MTBF is desired as a guarantee that
   the number of losses in a row is bounded.
-->

<!-- [rfced] The following text points to Section 5.9.5 of RFC 8175
[DLEP]; however, RFC 8175 does not have a Section 5.9.5. What section
would you like to point to?

Original:
   In that case, what is really desired is a
   Maximum Consecutive Loss (MCL).  (See also section Section 5.9.5 of [DLEP].)
-->
    However, the linear interpolation method cannot resist multiple consecutive
    losses, and a high MTBF is desired as a guarantee that this does not happen,
    in other words, that the number of losses in a row can be bounded. In this case, what is
    really desired is a Maximum Consecutive Loss (MCL). (See also
    <xref target="RFC8175"/>.) target="RFC8175" section="5.9.5"/>.)
    If the number of losses in a row passes the MCL, the control loop has to
    abort
    abort, and the system, e.g., system (e.g., the production line, line) may need to enter an
    emergency stop condition.
    </t>
   <t>

<!-- [rfced] Will readers understand "as an MTBF as a proxy" in this sentence?
Also, please confirm that Section 7.4 of [RFC8578] is correct here. We do
not see "reliability", "MTBF", or "MCL" in that section.

Original:
   Engineers that build automated processes may use the network
   reliability expressed in nines as an MTBF as a proxy to indicate an
   MCL, e.g., as described in section 7.4 of the "Deterministic
   Networking Use Cases" [RFC8578].

Perhaps:
   Engineers that build automated processes may use the network
   reliability expressed in nines as the MTBF and as a proxy to indicate an
   MCL, e.g., as described in Section 7.4 of the "Deterministic
   Networking Use Cases" [RFC8578].

Or:
   Engineers that build automated processes may use the network
   reliability expressed in nines as the MTBF, which is then used as a
   proxy to indicate an
   MCL, e.g., as described in Section 7.4 of the "Deterministic
   Networking Use Cases" [RFC8578].
-->

   <t>
    Engineers that build automated processes may use the network reliability
    expressed in nines as an MTBF as a proxy to indicate an MCL, e.g., as
    described in Section <xref target="RFC8578">"Deterministic target="RFC8578" sectionFormat="bare" section="7.4"/> of "Deterministic Networking Use Cases"</xref>. Cases" <xref target="RFC8578"/>.
    </t>
    </section>
      <!--Applying Reliability concepts to Networking-->
    <!--  22222222222222222222    -->

    <section numbered="true" toc="default">
      <name>Wireless Effects Affecting Reliability</name>
    <t>
    In contrast with wired networks, errors in transmission are the predominant
    source of packet loss in wireless networks.
    </t>
    <t>
    The root cause for the loss may be of multiple origins, calling for
    the use of different forms of diversity:
    </t>
    <dl>
    <dt>Multipath Fading:</dt> fading:</dt>
    <dd>
    <t>A destructive interference by a reflection of the original signal.
    </t>
    <t>A radio signal may be received directly
    (line-of-sight) and/or as a reflection on a physical structure (echo).
    The reflections take a longer path and are delayed by the extra distance
    divided by the speed of light in the medium. Depending on the frequency, the
    echo lands with a different phase phase, which may either add up to (constructive
    interference) or cancel (destructive interference) the direct signal.
    </t>
    <t>
    The affected frequencies depend on the relative position of the sender, the
    receiver, and all the reflecting objects in the environment.
    A given hop suffers from multipath fading for multiple packets in a
    row till until a physical movement changes the reflection patterns.
    </t>
    </dd>
    <dt>Co-channel Interference:</dt> interference:</dt>
    <dd>
    <t>
    Energy in the spectrum used for the transmission confuses the receiver.
    </t>
    <t>
    The wireless medium itself is a Shared Risk Link Group (SRLG) for nearby
    users of the same spectrum, as an interference may affect multiple co-channel
    transmissions between different peers within the interference domain of the
    interferer, possibly even when they use different technologies.
    </t>
    </dd>
    <dt>Obstacle in Fresnel Zone:</dt> zone:</dt>
    <dd>

    <t>
    The Fresnel zone is an elliptical region of space between and around the transmit
    and receive antennas in a point-to-point wireless communication.
    The optimal transmission happens when it is free of obstacles.
    </t>
    </dd>
    </dl>
    <t>
    In an environment that is rich in metallic structures and mobile objects, a
    single radio link provides a fuzzy service, meaning that it cannot be
   trusted to transport the traffic reliably over a long period of time.
    </t>
    <t>
    Transmission losses are typically not independent, and their nature and
    duration are unpredictable; as long as a physical object (e.g., a metallic
    trolley between peers) that affects the transmission is not removed, or as
    long as the interferer (e.g., a radar in the ISM band) keeps transmitting, a continuous
    stream of packets are affected.
    </t>
    <t>
    The key technique to combat those unpredictable losses is diversity.
    Different forms of diversity are necessary to combat different causes of
    loss
    loss, and the use of diversity must be maximized to optimize the PDR.
    </t>
    <t>

<!-- [rfced] Please review the series in this sentences (i.e., "on diverse
radio channels... and diverse PHY technologies ... , or diverse
codes"). Should this be a series of two items or three items?

Original:
   A single packet may be sent at different times (time diversity) over
   diverse paths (spatial diversity) that rely on diverse radio channels
   (frequency diversity) and diverse PHY technologies, e.g., narrowband
   vs. spread spectrum, or diverse codes.

Perhaps (two items):
   A single packet may be sent at different times (time diversity) over
   diverse paths (spatial diversity) that rely either on diverse radio channels
   (frequency diversity) and diverse PHY technologies (e.g., narrowband
   versus spread spectrum) or on diverse codes.

Or (three items):
   A single packet may be sent at different times (time diversity) over
   diverse paths (spatial diversity) that rely on diverse radio channels
   (frequency diversity), diverse PHY technologies (e.g., narrowband
   versus spread spectrum), or diverse codes.
-->

    <t>
    A single packet may be sent at different times (time diversity) over diverse
    paths (spatial diversity) that rely on diverse radio channels (frequency
    diversity) and diverse PHY technologies (e.g., narrowband versus spread
    spectrum), or diverse codes.
    Using time diversity defeats short-term interferences;
    spatial diversity combats very local causes of interference such as multipath fading;
    narrowband and spread spectrum are relatively innocuous to one another and
    can be used for diversity in the presence of the other.
    </t>

    </section>
      <!--Reliability in the Context of RAW-->

  </section>   <!-- Reliable and Available Wireless -->

    <!--  000000000000000000000    -->

  <section anchor="model" numbered="true" toc="default">
    <name>The RAW Conceptual Model</name>

<!-- [rfced] Is "point of local reaction" correct here? We ask because we see
"Point of Local Repair" elsewhere in the document, including in Section
6.5 (mentioned in this sentence).

Original:
   The PLR (see Section 6.5) is a point of
   local reaction to provide additional agility against transmission
   loss.

Perhaps:
   The PLR (see Section 6.5)
   provides additional agility against transmission
   loss.
-->

    <t>
    RAW extends the conceptual model described in section 4 Section <xref
    target="RFC8655" sectionFormat="bare" section="4"/> of the DetNet
    Architecture "Deterministic
    Networking Architecture" <xref target="RFC8655"/> with the PLR at the
    Service sub-layer, as illustrated in <xref target='FigLayers'/>. The PLR
    (see <xref target='PLRpce'/>) is a point of local reaction to provide
    additional agility against transmission loss. The For example, the PLR can act, e.g., act
    based on indications from the lower layer or based on OAM.
    </t>

<figure anchor="FigLayers">
          <name>Extended DetNet Data-Plane Data Plane Protocol Stack</name>
       <artwork align="left" name="" type="" alt=""> alt=""><![CDATA[
           |  packets going  |        ^  packets coming   ^
           v down the stack  v        |   up the stack    |
        +-----------------------+   +-----------------------+
        |        Source         |   |      Destination      |
        +-----------------------+   +-----------------------+
        |   Service sub-layer:  |   |   Service sub-layer:  |
        |   Packet sequencing   |   | Duplicate elimination |
        |    Flow replication   |   |      Flow merging     |
        |    Packet encoding    |   |    Packet decoding    |
        | Point of Local Repair |   |                       |
        +-----------------------+   +-----------------------+
        | Forwarding sub-layer: |   | Forwarding sub-layer: |
        |  Resource allocation  |   |  Resource allocation  |
        |    Explicit routes    |   |    Explicit routes    |
        +-----------------------+   +-----------------------+
        |     Lower layers      |   |     Lower layers      |
        +-----------------------+   +-----------------------+
                    v                           ^
                     \_________________________/

</artwork>
]]></artwork>
</figure>

<section anchor="plane" numbered="true" toc="default">
    <name>The RAW Planes</name>
<t>
   The RAW Nodes are DetNet Relay Nodes that operate in the RAW Network Plane and
   are capable of additional diversity mechanisms and measurement functions
   related to the radio interface.
   RAW leverages an Operational Plane orientation function (that typically operates inside the Ingress
   Edge Nodes) to dynamically adapt the path of the packets and optimizes optimize the
   resource usage.
    </t><t>
   In the case of centralized routing operations, the RAW Controller Plane Function (CPF) interacts
   with RAW Nodes over a Southbound API. It consumes data and information from
   the network and generates knowledge and wisdom to help steer the traffic optimally  inside a recovery graph.
    </t>
<figure anchor="FigCPF">
          <name>RAW Nodes (Centralized Routing Case)</name>
       <artwork align="center" name="" type="" alt=""> alt=""><![CDATA[
                         DetNet Routing

        CPF               CPF          CPF                 CPF

                       Southbound API
   _-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-
 _-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-._-

              ___ RAW  ___ RAW  ___ RAW  ___ RAW  __
             /    Node     Node     Node     Node   \
  Ingress __/     / \      /                   \     \____Egress
  End  __        /   \    /       .- -- .       \       ___  End
  Node   \      /     \  /     .-(        ).     \     /    Node
          \_ RAW  ___ RAW  ___(Non-RAW Nodes)__ RAW  _/
             Node     Node   (___.______.____)  Node

</artwork>
]]></artwork>
</figure>
<t>
   When a new flow is defined, the routing function uses its current knowledge of
   the network to build a new recovery graph between an Ingress End System and an Egress
   End System for that flow; it indicates to the RAW Nodes where the PREOF and/or radio
   diversity and reliability operations may be actioned in the Network Plane.
  </t>
  <ul>
  <li>
    The recovery graph may be strict, meaning that the
    DetNet forwarding sub-layer operations are enforced end-to-end end to end.
  </li><li>
    The recovery graph may be expressed loosely to enable traversing a non-RAW subnetwork
    as in <xref target='FigDN3'/>.
    In that case, RAW cannot leverage end-to-end DetNet and cannot provide
    latency guarantees.

    </li>
  </ul>
<!-- [rfced] How may we update "includes may be a time-aggregated (e.g.,
statistical) fashion" for clarity?

Original:
   The information that the orientation function reports to the routing
   function includes may be a time-aggregated, e.g., statistical
   fashion, to match the longer-term operation of the routing function.

Perhaps:
   The information that the orientation function reports to the routing
   function may be time aggregated (e.g., statistical),
   to match the longer-term operation of the routing function.
-->

    <t>
    The information that the orientation function reports to the routing
    function includes may be a time-aggregated, e.g., statistical fashion, to
    match the longer-term operation of the routing function.  Example
    information includes Link-Layer link-layer metrics such as Link link bandwidth (the medium
    speed depends dynamically on the mode of the physical (PHY) PHY layer), number
    of flows (bandwidth that can be reserved for a flow depends on the number
    and size of flows sharing the spectrum) spectrum), and the average and mean squared
    deviation of availability and reliability metrics, such metrics (such as Packet Delivery Ratio (PDR) PDR)
    over long periods of time. It may also report an aggregated expected
    transmission count (ETX),
    Expected Transmission Count (ETX) or a variation of it.  </t><t> Based on
    those metrics, the routing function installs the recovery graph with
    enough redundant forwarding solutions to ensure that the Network Plane can
    reliably deliver the packets within an SLA associated with the flows that
    it transports.  The SLA defines end-to-end reliability and availability
    requirements, in which reliability may be expressed as a successful
    delivery in-order in order and within a bounded delay of at least one copy of a
    packet.  </t><t> Depending on the use case and the SLA, the recovery graph
    may comprise non-RAW segments, either interleaved inside the recovery
    graph (e.g. (e.g., over tunnels), tunnels) or all the way to the Egress End Node (e.g., a
    server in the local wired domain). RAW observes the
    Lower-Layer Links lower-layer links
    between RAW nodes (typically, (typically radio links) and the end-to-end Network Layer network-layer
    operation to decide at all times which of the diversity schemes is
    actioned by which RAW Nodes.  </t><t> Once a recovery graph is
    established, per-segment and end-to-end reliability and availability
    statistics are periodically reported to the routing function to ensure
    that the SLA can be met or met; if not, then have the recovery graph is recomputed.
    </t>
    </section> <!--The RAW Network Plane -->

<section anchor="layers" numbered="true" toc="default">
    <name>RAW vs. Versus Upper and Lower Layers</name>

    <t>RAW builds on DetNet-provided features such as scheduling and shaping.
    In particular, RAW inherits the DetNet guarantees on end-to-end latency,
    which can be tuned to ensure that DetNet and RAW reliability mechanisms have
    no side effect on upper layers, e.g., on transport-layer packet recovery.
    RAW operations include possible rerouting, which in turn may affect
    the ordering of a burst of packets. RAW also inherits PREOF from DetNet,
    which can be used to reorder packets before delivery to the upper layers.
    As a result, DetNet in general and RAW in particular offer a smoother
    transport experience for the upper layers than the Internet at large large,
    with ultra-low jitter and loss.
    </t>
    <t>
<!-- [rfced] Will readers understand what "it" refers to in this sentence?

Original:
   RAW improves the reliability of transmissions and the availability of
   the communication resources, and should be seen as a dynamic
   optimization of the use of redundancy to maintain it within certain
   boundaries.

Perhaps:
   RAW improves the reliability of transmissions and the availability of
   the communication resources and should be seen as a dynamic
   optimization of the use of redundancy to maintain reliability and availability
   within certain boundaries.
-->

    <t>
    RAW improves the reliability of transmissions and the availability of
    communication resources, and should be seen as a dynamic optimization of the use of
    redundancy to maintain it within certain boundaries.
    For instance, ARQ, which ARQ (which provides 1-hop one-hop reliability through acknowledgements and retries, retries)
    and FEC codes such (such as turbo codes which reduce the PER, PER) are typically operated at Layer-2 Layer 2 and Layer-1 Layer 1, respectively.
    In both cases, redundant transmissions improve the 1-hop one-hop reliability at the expense of energy and latency, which are the resources that RAW must control.
    In order to achieve its goals, RAW may leverage the lower-layer operations
    by abstracting the concept and providing hints to the lower layers
    on the desired outcome, e.g., outcome (e.g., in terms of reliability and timeliness, timeliness),
    as opposed to performing the actual operations at Layer-3. Layer 3.
    </t>

    <t>
    Guarantees such as bounded latency depend on the upper layers (Transport (transport or
    Application)
    application) to provide the payload in volumes and at times that match the
    contract with the DetNet sub-layers and the layers below. Excess An excess of
    incoming traffic at the DetNet Ingress may result in dropping or
    queueing of packets, packets and can entail loss, latency, or jitter, and
    therefore, violate jitter; this violates the guarantees that are provided inside the DetNet Network.
    </t>
    <t>
    When the traffic from upper layers matches the expectation of the lower
    layers, RAW still depends on DetNet mechanisms and the
    lower layers to provide the timing and
    physical resource guarantees that are needed to match the traffic SLA.
    When the availability of the physical resource varies, RAW acts on the
    distribution of the traffic to leverage alternates within a finite set of
    potential resources.
    </t>
  <t>
    The Operational Plane elements (Routing (routing and OAM control) may gather
    aggregated information from lower layers (e.g., information about e.g., link quality,
    either quality),
    via measurement or communication with the lower layer.
    This information may be obtained from inside the device using
    specialized APIs (e.g., L2 triggers), triggers) via monitoring and measurement protocols such as BFD  Bidirectional Forwarding Detection (BFD)
    <xref target="RFC5880"/> and STAMP Simple Two-way Active Measurement Protocol (STAMP) <xref target="RFC8762"/>, respectively, or via a control protocol exchange with the
    lower layer via, e.g., (e.g., DLEP <xref target="RFC8175"/>. target="RFC8175"/>). It may then be
    processed and exported through OAM messaging or via a YANG data model, model
    and exposed to the Controller Plane.
    </t>

    </section> <!--The RAW Network Plane -->

<section anchor="DetNet" numbered="true" toc="default">
    <name>RAW and DetNet</name>
<t>
  RAW leverages the DetNet Forwarding sub-layer and requires the support of
  OAM in DetNet Transit Nodes (see Figure 3 of <xref target="RFC8655"/>) for the
  dynamic acquisition of link capacity and state to maintain a strict RAW
  service, end-to-end,
  service end to end over a DetNet Network. In turn, DetNet and thus RAW
  may benefit from / or leverage functionality such as that provided by TSN at the
  lower layers.
</t>
<t>
  RAW extends DetNet to improve the
  protection against link errors such as transient flapping that are far more
  common in wireless links. Nevertheless, for the most part, the RAW methods are for the most part
  applicable to wired links as well, e.g., when energy savings are desirable and
  the available path diversity exceeds 1+1 linear redundancy.
</t>
<t>
  RAW adds sub-layer functions that operate in the DetNet Operational Plane, which is part of the Network Plane.
  The RAW orientation function may run only in the DetNet Edge Nodes (Ingress Edge
  Node or End System), or it can also run in DetNet Relay Nodes
  when the RAW operations are distributed along the recovery graph.
  The RAW Service sub-layer includes the PLR, which decides the DetNet Path for the
  future packets of a flow along the DetNet Path, Maintenance End Points (MEPs)
  on edge nodes, and Maintenance Intermediate Points (MIPs) within. The MEPs
  trigger, and learn from, OAM observations, observations and feed the PLR for its
  next decision.
</t>
<t>
  As illustrated in <xref target='FigDN'/>, RAW extends the DetNet Stack (see
  Figure 4 of <xref target="RFC8655"/> and <xref target='FigLayers'/>) with
  additional functionality at the DetNet Service sub-layer for the actuation of PREOF based on the PLR decision.
  DetNet operates at Layer-3, Layer 3, leveraging abstractions of the
  lower layers and APIs that control those abstractions. For instance,
  DetNet already leverages lower layers for time-sensitive operations such as
  time synchronization and traffic shapers. As the performances of the
  radio layers are subject to rapid changes, RAW needs more dynamic gauges
  and knobs. To that effect, the LL API provides an
  abstraction to the DetNet layer that can be used to push reliability
  and timing hints hints, like suggest suggesting X retries (min, max) within a time window, window or
  send
  sending unicast (one next hop) or multicast (for overhearing).
  In the other direction up the stack, the RAW PLR needs hints about the radio conditions such as L2 triggers (e.g., RSSI, LQI, or ETX) over all the wireless hops.
  </t>

  <t>
  RAW uses various OAM functionalities at the different layers. For instance,
  the OAM function in the DetNet Service sub-layer may perform Active
  and/or Hybrid OAM to estimate the link and path availability, end-to-end either end to end
  or limited to a Segment. The RAW
  functions may be present in the Service sub-layer in DetNet Edge and Relay Nodes.
</t>

<figure anchor="FigDN">
          <name>RAW function placement Function Placement (Centralized Routing Case)</name>
       <artwork align="left" name="" type="" alt=""> alt=""><![CDATA[
  +-----------------+     +-------------------+
  |     Routing     |     |    OAM Control    |
  +-----------------+     +-------------------+

                                          Controller Plane
+-+-+-+-+-+-+-+-+ Southbound Interface -+-+-+-+-+-+-+-+-+-+-+-+
                                           Network Plane

                                                |
                Operational Plane               .   Data Plane
                                                |
  +-----------------+                           .
  |  Orientation    |                           |
  +-----------------+                           .
                                                |
  +-----------------+   +-------------------+   .
  | Point of Local  |   |  OAM Maintenance  |   |
  |   local Repair (PLR)    |   |  End Point (MEP)  |   .
  +-----------------+   +-------------------+   |
                                                .
                                                |

  </artwork>
]]></artwork>
</figure>
<t> There

<!-- [rfced] Please review the paragraphs before Figure 6 (strict model) and
Figure 7 (loose model) and let us know if any changes are needed to place
text about the loose model together before Figure 7.
-->

<t>There are two main proposed models to deploy RAW and DetNet. DetNet: strict (<xref target="FigDN2"/>) and loose (<xref target="FigDN3"/>). In the first
  model (strict) (illustrated
  strict model, illustrated in <xref target="FigDN2"/>), target="FigDN2"/>, RAW operates over a
  continuous DetNet Service end-to-end service end to end between the Ingress and the Egress Edge
  Nodes or End Systems.
</t>
<t>
   sIn
   In the second model (loose), loose model, illustrated in <xref target="FigDN3"/>, RAW may traverse a section of the network that
   is not serviced by DetNet. RAW / OAM may observe the end-to-end traffic and
   make the best of the available resources, but it may not expect the DetNet
   guarantees over all paths.  For instance, the packets between two wireless
   entities may be relayed over a wired infrastructure, in which case RAW
   observes and controls the transmission over the wireless first and last
   hops, as well as end-to-end metrics such as latency, jitter, and delivery
   ratio. This operation is loose since the structure and properties of the
   wired infrastructure are ignored, ignored and may be either controlled by other
   means such as DetNet/TSN, DetNet/TSN or neglected in the face of the wireless hops.

    </t>
<t>
  A minimal Forwarding sub-layer service is provided at all DetNet Nodes
  to ensure that the OAM information flows. DetNet Relay Nodes may or may not support
  RAW services, whereas the DetNet Edge Nodes are required to support RAW in any case.
  DetNet guarantees, such as bounded latency, are provided end-to-end. end to end.
  RAW extends the DetNet Service sub-layer to optimize the use of resources.
</t>

<figure anchor="FigDN2">
          <name>(Strict) RAW
          <name>RAW over DetNet</name> DetNet (Strict Model)</name>
       <artwork align="left" name="" type="" alt=""> alt=""><![CDATA[
--------------------Flow Direction---------------------------------->

+---------+
| RAW     |
| Control |
+---------+                           +---------+        +---------+
| RAW +   |                           | RAW +   |        | RAW +   |
| DetNet  |                           | DetNet  |        | DetNet  |
| Service |                           | Service |        | Service |
+---------+---------------------------+---------+--------+---------+
|                       DetNet                                     |
|                     Forwarding                                   |
+------------------------------------------------------------------+

  Ingress             Transit            Relay              Egress
  Edge      ...       Nodes     ...      Nodes     ...        Edge
  Node                                                        Node

&lt;------------------End-to-End

<------------------End-to-End DetNet Service----------------------->

</artwork>
]]></artwork>
</figure>

<t> In

<t>In the second loose model (loose), illustrated (illustrated in <xref target="FigDN3"/>, target="FigDN3"/>), RAW
  operates over a partial DetNet Service service where typically only the Ingress and
  the Egress End Systems support RAW. The DetNet Domain domain may extend beyond the
  Ingress Node, or there may be a DetNet domain starting at an Ingress
  Edge Node at the first hop after the End System.
</t>
<t>
  In the loose model, RAW cannot observe the hops in the network, and the path
  beyond the first hop is opaque; RAW can still observe the end-to-end
  behavior and use Layer-3 Layer 3 measurements to decide whether to replicate a packet
  and select the first-hop interface(s).
</t>
<!-- [rfced] FYI - We have adjusted the titles of Figures 6 and 7 to make them
consistent with one another; please review.

Original:

  Figure 6: (Strict) RAW over DetNet
  Figure 7: Loose RAW

Current:

  Figure 6: RAW over DetNet (Strict Model)
  Figure 7: RAW over DetNet (Loose Model)
-->

<figure anchor="FigDN3">
          <name>Loose RAW</name>
          <name>RAW over DetNet (Loose Model)</name>
       <artwork align="left" name="" type="" alt=""> alt=""><![CDATA[
--------------------Flow Direction---------------------------------->

+---------+
| RAW     |
| Control |
+---------+            +---------+                       +---------+
| RAW +   |            | DetNet  |                       | RAW +   |
| DetNet  |            |  Only   |                       | DetNet  |
| Service |            | Service |                       | Service |
+---------+----------------------+---+               +---+---------+
|          DetNet                    |_______________|   DetNet    |
|         Forwarding                  _______________  Forwarding  |
+------------------------------------+               +-------------+

 Ingress    Transit       Relay           Tunnel             Egress
 End  ...   Nodes   ...   Nodes    ...                ...       End
 System                                                      System

&lt;---------------Partitioned

<---------------Partitioned DetNet Service------------------------->

</artwork>
]]></artwork>
</figure>

    </section>      <!-- RAW and DetNet -->

    <!--  1111111111111   -->

</section> <!-- The RAW Conceptual Model -->
<section anchor="control" numbered="true" toc="default">
    <name>The RAW Control Loop</name>

      <t>
   The RAW Architecture architecture is based on an abstract OODA
   Loop that controls the operation of a Recovery Graph. recovery graph.  The generic
   concept involves: involves the following:
      </t>
      <ol>
      <li>

<!-- [rfced] Some of the items in the numbered list in Section 6 are complete
sentences and others are not. How may we update to create parallel
structure?

Original:
   1.  Operational Plane measurement protocols for OAM to observe (like
       the first O in OODA) some or all hops along a recovery graph as
       well as the end-to-end packet delivery.

   2.  The DetNet Controller Plane establish primary and protection
       paths for use by the RAW Network Plane. ...

   3.  A PLR operates at the DetNet Service sub-layer and hosts the
       decision function (like the D in OODA) of which DetNet Paths to
       use for the future packets that are routed within the recovery
       graph.

   4.  Service protection actions that are actuated or triggered over
       the LL API by the PLR to increase the reliability of the end-to-
       end transmissions. ...

Perhaps (make #1 and #4 into complete sentences):
   1.  Operational Plane measurement protocols allow OAM to observe (like
       the first "O" in "OODA") some or all hops along a recovery graph as
       well as the end-to-end packet delivery.

   2.  The DetNet Controller Plane establishes primary and protection
       paths for use by the RAW Network Plane. ...

   3.  A PLR operates at the DetNet Service sub-layer and hosts the
       decision function (like the D in OODA). The decision function determines
       which DetNet Paths will be
       used for future packets that are routed within the recovery
       graph.

   4.  Service protection actions are actuated or triggered over
       the LL API by the PLR to increase the reliability of the end-to-
       end transmissions. ...
-->

      <ol>
      <li>Operational Plane measurement protocols for OAM to observe (like
      the first "O" in "OODA") some or all hops along a recovery graph as well as
      the end-to-end packet delivery.
      </li>
      <li>
      The DetNet Controller Plane establish establishes primary and protection
      paths for use by the RAW Network Plane.  The orientation function
      reports data and information such as link statistics to be used by the
      routing function to compute, install, and maintain the recovery
      graphs. The routing function may also generate intelligence such as a
      trained model for link quality prediction, which in turn can be used by
      the orientation function (like the second O "O" in OODA) "OODA") to influence the
      Path selection by the PLR within the RAW OODA loop.
      </li>
      <li> A
      <li>A PLR operates at the DetNet Service sub-layer and hosts the
      decision function (like the D "D" in OODA) of "OODA"). The decision function determines which DetNet Paths to use will be used
      for the future packets that are routed within the recovery graph.
      </li>
      <li> Service
      <li>Service protection actions that are actuated or triggered over the LL API
      by the PLR to increase the reliability of the end-to-end transmissions.
      The RAW architecture also covers in-situ signaling that is embedded
      within live user traffic <xref target="RFC9378"/>, e.g., target="RFC9378"/> (e.g., via OAM, OAM) when
      the decision is acted (like the A "A" in OODA) "OODA") upon by a node that is
      downstream in the recovery graph from the PLR.
      </li>
      </ol>
   <t> The
   <t>The overall OODA Loop optimizes the use of redundancy to achieve the
   required reliability and availability SLO(s) while
   minimizing the use of constrained resources such as spectrum and battery.
   </t>

    <section anchor="timescale" numbered="true" toc="default">
      <name>Routing Time-Scale vs. Timescale Versus Forwarding Time-Scale</name> Timescale</name>
      <t>
   With DetNet, the Controller Plane Function (CPF) handles the routing computation
   and maintenance. With RAW, the routing operation is segregated from the RAW
   Control Loop, so it may reside in the Controller Plane Plane, whereas the control
   loop itself happens in the Network Plane. To achieve RAW capabilities, the
   routing operation is extended to generate the information required by the
   orientation function in the loop.
   The  For example, the routing function may, e.g., may propose
   DetNet Paths to be used as a reflex action in response to network events, events
   or provide an aggregated history that the orientation function can use to
   make a decision.
   </t>
<t>
   In a wireless mesh, the path to a routing function located in the controller
   plane can be expensive and
   slow, possibly going across the whole mesh and back.
   Reaching to the Controller Plane can also be slow in regards regard to the speed
   of events that affect the forwarding operation in the Network Plane at the radio layer.
   Note that a distributed routing protocol may also take time and
   consume excessive wireless resources to reconverge to a new optimized state.

      </t><t>
   As a result, the DetNet routing function is not expected to be aware of and to react to
   very transient changes. The abstraction of a link at the routing level is
   expected to use statistical metrics that aggregate the behavior of a link
   over long periods of time, time and represent its properties as shades of gray as
   opposed to numerical values such as a link quality indicator, indicator or a Boolean
   value for either up or down.
      </t><t>

<!-- [rfced] How may we clarify "builds reports to the routing function"?

Original:
   The interaction between the network nodes and the routing function is
   handled by the orientation function, which builds reports to the
   routing function and sends control information in a digested form ...

Perhaps:
   The interaction between the network nodes and the routing function is
   handled by the orientation function, which builds reports for the
   routing function and sends control information in a digested form ...

Or:
   The interaction between the network nodes and the routing function is
   handled by the orientation function, which reports to the
   routing function and sends control information in a digested form ...
-->

   The interaction between the network nodes and the routing function is handled by the orientation function, which
   builds reports to the routing function and
   sends control information in a digested form back to the RAW node, node to be used inside a forwarding control loop for
   traffic steering.

      </t><t>
   <xref target="Figcontrol"/> illustrates a Network Plane recovery graph
   with links P-Q and N-E flapping, possibly in a transient fashion
   due to a short-term interferences, interferences and possibly for a longer time, e.g., time (e.g.,
   due to obstacles between the sender and the receiver or hardware failures. failures).
   In order to maintain a received redundancy around a value of, say, 2, of 2 (for instance),
   RAW may leverage a higher ARQ on these hops if the overall latency permits the extra delay, delay
   or enable alternate paths between ingress I and egress E.
   For instance, RAW may enable protection path I ==> F ==> N ==> Q ==> M ==> R ==> E
   that routes around both issues and provides some degree of spatial diversity
   with protection path I ==> A ==> B ==> C ==> D ==> E.
         </t>

         <figure anchor="Figcontrol">
          <name>Time-Scales</name>
          <name>Timescales</name>
       <artwork align="center" name="" type="" alt="">
       <![CDATA[ alt=""><![CDATA[
               +----------------+
               |     DetNet     |
               |    Routing     |
               +----------------+
                       ^
                       |
                      Slow
                       |            Controller Plane
   _-._-._-._-._-._-.  |  ._-._-._-._-._-._-._-._-._-._-._-._-
 _-._-._-._-._-._-._-. | _-._-._-._-._-._-._-._-._-._-._-._-
                       |             Network Plane
                    Expensive
                       |
              __...--- | ----.._.
           .(          |          )-._
          (            v              ).
        (     A--------B---C----D       )
    _ -      / \          /      \       --._
   (        I---F--------N--***-- E           -
    -_       \          /        /             )
    (         P--***---Q----M---R             .
      _                                     )- ._
        -    <------ Fast ------->               )
       (                                   -._ .-
        (_.___.._____________.____.._ __-____)

*** =  flapping at this time
    ]]>
       </artwork>
]]></artwork>

     </figure>
      <t>
   In the case of wireless, the changes that affect the forwarding decision can
   happen frequently and often for short durations, e.g., durations. An example of this is a mobile object that moves
   between a transmitter and a receiver, receiver and cancels the line of sight line-of-sight
   transmission for a few seconds, or, a seconds. Another example is radar that measures the depth of a pool using the ISM band, band and
   interferes on a particular channel for a split second.
      </t>
      <t>
   There
   Thus, there is thus a desire to separate the long-term computation of the route and
   the short-term forwarding decision. In that model, the routing operation
   computes a recovery graph that enables multiple Unequal Cost Multi-Path Unequal-Cost Multipath
   (UCMP) forwarding solutions along so-called protection paths, paths and leaves
   it to the Network Plane to make
   the short-term decision of which of these possibilities should be used for which upcoming packets / and flows.
      </t>
      <t>
   In the context of Traffic Engineering (TE), an alternate path can be used
   upon the detection of a failure in the main path, e.g., using OAM in
   Multiprotocol Label Switching - Transport Profile (MPLS-TP) or BFD
   over a collection of Software-Defined Wide Area Network (SD-WAN) tunnels.
      </t>
      <t>
   RAW formalizes a forwarding time-scale timescale that may be order(s) of magnitude shorter
   than the Controller Plane routing time-scale, timescale and separates the protocols
   and metrics that are used at both scales.
   Routing can operate on long-term statistics such as delivery
   ratio over minutes to hours, but as a first approximation approximation, it can ignore the cause of transient losses.
   On the other hand, the RAW forwarding decision is made at the scale of a burst of packets, packets
   and uses information that must be pertinent at the present time for the current transmission(s).
      </t>

    </section >
    <!--Routing time-scale vs. Forwarding time-scale-->

<section anchor="ooda" numbered="true" toc="default">
    <name>OODA Loop</name>
      <t>
    The RAW Architecture architecture applies the generic OODA model to continuously optimize the
   spectrum and energy used to forward packets within a recovery graph, instantiating the
   OODA steps as follows:
      </t>
      <dl>
      <dt>Observe:</dt><dd> Network Plane measurements, including protocols for
      OAM, to Observe observe the local state of the links and some or all hops along a recovery graph as well as
      the end-to-end packet delivery (see more in <xref target = "aom"/>). target="aom"/>).
      Information can also be provided by lower-layer
      interfaces such as DLEP; DLEP.
      </dd>
      <dt>Orient:</dt><dd>
      The orientation function, which function reports data and information such as the link
      statistics,
      statistics and leverages offline-computed wisdom and knowledge to Orient orient
      the PLR for its forwarding decision (see more in <xref target = "pce" />); target="pce"/>).
      </dd>
      <dt>Decide:</dt><dd> A
      <dt>Decide:</dt><dd>A local PLR that decides which DetNet Path to use
      for the future packet(s) that are routed along the recovery graph
       (see more in <xref target = "PLRpce" />); target="PLRpce"/>).
      </dd>
      <dt>Act:</dt><dd> PREOF
      <dt>Act:</dt><dd>PREOF Data Plane actions are controlled by the PLR over
      the LL API to increase the reliability of the end-to-end
      transmission. The RAW architecture also covers in-situ signaling when
      the decision is Acted acted by a node that is down the recovery graph from the
      PLR (see more in <xref target = "reliability" />). target="reliability"/>).
      </dd>
      </dl>
      <figure anchor="oodaloop">
          <name>The RAW OODA Loop</name>
       <artwork align="center" name="" type="" alt="">
<![CDATA[ alt=""><![CDATA[
     +-------> Orientation ---------+
     |        reflex actions        |
     |       pre-trained model      |
     |                              |
   ......................................
     |                              |
     |        Service sub-layer     |
     |                              v
 Observe (OAM)                 Decide (PLR)
     ^                              |
     |                              |
     |                              |
     +------- Act (LL API) <--------+
]]></artwork>
</figure>
   <t> The overall OODA Loop optimizes the use of redundancy to achieve the
   required reliability and availability Service Level Agreement (SLA) while
   minimizing the use of constrained resources such as spectrum and battery.
   </t>

</section > <!-- A OODA Loop -->
<section anchor="aom" numbered="true" toc="default">
    <name>Observe: The RAW OAM </name><t>
    The RAW In-situ in-situ OAM operation in the Network Plane may observe either a full
    recovery graph or the DetNet Path that is being used at this time. As packets may be load
    balanced, replicated, eliminated, and / or and/or fragmented for Network Coding
    FEC, the RAW In-situ in-situ operation needs to be
    able to signal which operation occurred to an individual packet.
    </t>
    <t>
    Active RAW OAM may
    be needed to observe the unused segments and evaluate the desirability of
    a rerouting decision.
    </t>
<!-- [rfced] Will readers understand what "Assurance" means here? We do not
see this used elsewhere in the document.

Original:
   Finally, the RAW Service sub-layer Assurance may observe the
   individual PREOF operation of a DetNet Relay Node to ensure that it
   is conforming;
-->

    <t>
    Finally, the RAW Service sub-layer Assurance may observe the individual PREOF
    operation of a DetNet Relay Node to ensure that it is conforming; this might
    require injecting an OAM packet at an upstream point inside the recovery graph and
    extracting that packet at another point downstream before it reaches the
    egress.
    </t><t>
    This observation feeds the RAW
    PLR that makes the decision on which path is used at which RAW
    Node, for one packet or a small continuous series of packets.
     </t>
   <t>
    In the case of End-to-End Protection end-to-end protection in a Wireless Mesh, wireless mesh, the recovery
   graph is strict and congruent with the path so all links are observed.
    </t>
    <t>
    Conversely, in the case of Radio Access Protection, illustrated in
   <xref target="Figranp2"/>, the recovery graph is Loose loose and only the first
   hop is observed; the rest of the path is abstracted and considered
   infinitely reliable. The loss of a packet is attributed to the first-hop
   Radio Access Network (RAN), even if a particular loss effectively happens
   farther down the path. In that case, RAW enables technology diversity
   (e.g., Wi-Fi and 5G), which in turn improves the diversity in spectrum usage.
    </t>
<figure anchor="Figranp2">
          <name>Observed Links in Radio Access Protection</name>
       <artwork align="center" name="" type="" alt="">
<![CDATA[ alt=""><![CDATA[
                               Opaque to OAM
                       <---------------------------->
                               .-  .. - ..
             RAN 1  --------(              ).__
+-------+  /              (                    ).      +------+
|Ingress|-              __________Tunnel_______________|Egress|
|  End  |------ RAN 2 --_______________________________  End  |
|System |-               (                        )    |System|
+-------+  \            (                        ).    +------+
            RAN n ----(                            )
                     (_______...___.__...____....__..)

        <-------L2------>
         Observed by OAM
        <----------------------L3----------------------->
]]></artwork>
</figure>

<!-- [rfced] What is being connected by "either" in the phrase "either or a
collection of those access links". How should this text be clarified?

Original:
   ; still the RAW OAM measures the end-to-end latency and delivery
   ratio for packets sent via RAN 1, RAN 2, and RAN 3, and determines
   whether a packet should be sent over either or a collection of those
   access links.
-->

    <t>
    The Links links that are not observed by OAM are opaque to it, meaning that the
    OAM information is carried across and possibly echoed as data, but there is
    no information captured in intermediate nodes. In the example above, the
    Tunnel
    tunnel underlay is opaque and not controlled by RAW; still the still, RAW OAM measures the
    end-to-end latency and delivery ratio for packets sent via RAN 1, RAN 2, and
   RAN 3, and determines whether a packet should be sent over either or a
   collection of those access links.
    </t>

</section>
    <!-- Observe: The RAW OAM -->

<section anchor="pce" numbered="true" toc="default">
    <name>Orient: The RAW-extended RAW-Extended DetNet Operational Plane</name>

   <t>
   RAW separates the long time-scale timescale at which a recovery graph is computed and installed, installed
   from the short time-scale timescale at which the forwarding decision is taken for one
   or for a few packets (see <xref target="timescale"/>) that experience the
   same path until the network conditions evolve and another path is selected
   within the same recovery graph.
   </t>
   <t>
   The recovery graph computation is out of scope, but RAW expects that the CPF
   that installs the recovery graph also provides related knowledge
   in the form of metadata about the links, segments, and possible DetNet Paths.
   That metadata can be a pre-digested statistical model, model and may include
   prediction of future flaps and packet loss, as well as recommended actions
   when that happens.
   </t>
   <t>
   The metadata may include:
   </t>
   <ul>
   <li>
   A set of Pre-Determined pre-determined DetNet Paths that are prepared to match
   expected link-degradation profiles, so the DetNet Relay Nodes can take reflex rerouting actions when
   facing a degradation that matches one such profile; and
   </li>
   <li>
   Link-Quality Statistics
   Link-quality statistics history and pre-trained models, e.g., models (e.g., to predict the
   short-term variation of quality of the links in a recovery graph. graph).
   </li>
   </ul>
   <t>
   The recovery graph is installed with measurable objectives that are computed
   by the CPF to achieve the RAW SLA. The objectives can be expressed as any of the
   maximum number of packets lost in a row, bounded latency, maximal jitter,
   maximum number of interleaved out-of-order packets,
   average number of copies received at the elimination point, and maximal
   delay between the first and the last received copy of the same packet.
   </t>
</section>
    <!-- Orient: The Path Computation Engine -->

<section anchor="PLRpce" numbered="true" toc="default">
    <name>Decide: The Point of Local Repair</name>

<!-- [rfced] This sentence does not parse. Please clarify.

Original:
   The OODA Loop controls, within the redundant solutions that are proposed by
   the routing function, which is used for each packet to provide a Reliable and
   Available service while minimizing the waste of constrained resources.

Perhaps:
   Within the redundant solutions that are proposed by
   the routing function, the OODA Loop controls what is used for each packet and
   provides a reliable and
   available service while minimizing the waste of constrained resources.
-->

 <t>
    The RAW OODA Loop operates at the path selection time-scale timescale to provide
    agility vs. versus the brute-force approach of flooding the whole recovery graph.
    The OODA Loop controls, within the redundant solutions that are proposed
    by the routing function, which is used for each packet to provide a Reliable reliable and
   Available
   available service while minimizing the waste of constrained resources.
    </t><t>
    To that effect, RAW defines the Point of Local Repair (PLR), which performs
   rapid local adjustments of the forwarding tables within the path diversity that is
   available in that in the recovery graph. The PLR enables exploitation of
   the richer forwarding capabilities at a faster time-scale timescale over a portion of
   the recovery graph, in either a loose or a strict fashion.
    </t>
   <t>
<!-- [rfced] This sentence is difficult to follow. We updated as shown below.
Please review and to confirm that the updated text accurately conveys the
intended meaning.

Original:
   The PLR operates on metrics that evolve faster, but that need to be
   advertised at a fast rate but only locally, within the recovery
   graph, and reacts on the metric updates by changing the DetNet path
   in use for the affected flows.

Updated:
   The PLR operates on metrics that evolve quickly and need to be
   advertised at a fast rate (but only locally, within the recovery
   graph), and the PLR reacts to the metric updates by changing the DetNet path
   in use for the affected flows.
-->

   <t>
    The PLR operates on metrics that evolve quickly and need to be
    advertised at a fast rate (but only locally, within the recovery graph), and the PLR reacts on
    the metric updates by changing the DetNet path in use for the affected
    flows.
   </t>
   <t>
    The rapid changes in the forwarding decisions are made and contained within
    the scope of a recovery graph graph, and the actions of the PLR are not signaled outside
    the recovery graph. This is as opposed to the routing function that must observe
    the whole network and optimize all the recovery graphs globally, which can only be
    done at a slow pace and using with long-term statistical metrics, as presented in
    <xref target="PCEPLRtable"/>.
    </t>

    <table anchor="PCEPLRtable"><name>Centralized Decision vs. Versus PLR</name>
   <thead>
      <tr>
       <th> </th>
         <th align='center'> Controller Plane      </th>
         <th align='center'> PLR        </th>
	<th></th>
        <th>Controller Plane</th>
        <th>PLR</th>
      </tr>

   </thead><tbody>

         <tr><td>Communication
</td>
             <td align='center'>Slow,
   </thead>
   <tbody>
     <tr><th>Communication</th>
     <td>Slow, distributed</td>
             <td align='center'>Fast,
     <td>Fast, local</td>
     </tr>

         <tr><td>Time-Scale (order)</td>
             <td align='center'>Path
     <tr><th>Timescale (order)</th>
     <td>Path computation + round trip, milliseconds to seconds</td>
             <td align='center'>Lookup
     <td>Lookup + protection switch, micro to milliseconds</td>
     </tr>

         <tr><td>Network Size</td>
             <td align='center'>Large,
     <tr><th>Network Size</th>
     <td>Large, many recovery graphs to optimize globally</td>
             <td align='center'>Small,
     <td>Small, limited set of protection paths</td>
     </tr>

         <tr><td>Considered Metrics</td>
             <td align='center'>Averaged,
     <tr><th>Considered Metrics</th>
     <td>Averaged, statistical, shade of grey</td>
             <td align='center'>Instantaneous
     <td>Instantaneous values / boolean condition</td>
     </tr>
    </tbody>
    </table>
    <t>
    The PLR sits in the DetNet Forwarding sub-layer of Edge and Relay Nodes.
    The PLR operates on the packet flow, learning the recovery graph and
    path-selection information from the packet, packet and possibly making a local decision and
    retagging the packet to indicate so. On the other hand, the PLR interacts
    with the lower layers (through triggers and DLEP) and with its peers
    (through OAM) to obtain up-to-date information about its links and
    the quality of the overall recovery graph, respectively, as illustrated in
    <xref target="Figlearn"/>.
    </t>

<figure anchor="Figlearn">
          <name>PLR Conceptual Interfaces</name>
       <artwork align="center" name="" type="" alt=""><![CDATA[
            |
     packet
     Packet | going
   down the | stack
 +==========v==========+=====================+===================+
 |(In-situ OAM + iCTRL)| (L2 Triggers, triggers, DLEP) |   (Hybrid OAM)    |
 +==========v==========+=====================+===================+
 |     Learn from      |                     |    Learn from     |
 |    packet tagging   >       Maintain      <    end-to-end     |
 +----------v----------+      Forwarding     |    OAM packets    |
 | Forwarding decision <        State        +---------^---------|
 +----------v----------+                     |      Enrich or    |
 +    Retag Packet packet     |  Learn abstracted   >     Regenerate     regenerate    |
 |    and Forward forward      | metrics about Links links |     OAM packets   |
 +..........v..........+..........^..........+........^.v........+
 |                          Lower layers                         |
 +..........v.....................^...................^.v........+
      frame
      Frame | sent          Frame | L2 Ack ack     Active | | OAM
       over | wireless        In        in  |            In            in and | | out
            v                     |                   | v
]]></artwork>
</figure>
</section>
    <!--PCE vs. PLR-->

    <!--  11111111111111111    -->

    <section anchor="reliability" numbered="true" toc="default">
      <name>Act: DetNet Path Selection and Reliability Functions</name>
      <t>
    The main action by the PLR is the swapping of the DetNet Path within the
    recovery graph for the future packets.
    The candidate DetNet Paths represent different energy and spectrum profiles, profiles
    and provide protection against different failures.
      </t>
    <t>The

<!-- [rfced] Please clarify "more typical to wireless than wired".

Original:
   The LL API enriches the DetNet protection services (PREOF) with
   potential possibility to interact with lower-layer one-hop
   reliability functions that are more typical to wireless than wired,
   including ARQ, FEC, and other techniques such as overhearing and
   constructive interferences.

Perhaps:
   The LL API enriches the DetNet protection services (PREOF) with the
   possibility to interact with lower-layer, one-hop
   reliability functions that are more typical with wireless links than with wired ones,
   including ARQ, FEC, and other techniques such as overhearing and
   constructive interferences.
-->

    <t>The LL API enriches the DetNet protection services (PREOF)
    with the possibility to interact with lower-layer, one-hop reliability
   functions that are more typical to wireless than wired, including ARQ, FEC,
   and other techniques such as overhearing and constructive interferences.
   Because RAW may be leveraged on wired links,
   e.g., links
   (e.g., to save power, power), it is not expected that all lower layers support all
   those capabilities.
    </t>
    <t>
    RAW provides hints to the lower-layer services on the desired outcome, and
   the lower layer acts on those hints to provide the best approximation of
   that outcome, e.g., a level of reliability for one-hop transmission within
   a bounded budget of time and/or energy. Thus, the LL API makes possible
   cross-layer optimization for reliability depending on the actual
   abstraction provided. That is, some reliability functions are controlled
   from Layer-3 Layer 3 using an abstract interface, while they are really operated at
   the lower layers.
    </t>
    <t>
    The RAW Path Selection can be implemented in both centralized and
   distributed approaches.
    In the centralized approach, the PLR may obtain a set of pre-computed DetNet
    paths matching a set of expected failures, failures and apply the appropriate DetNet
    paths for the current state of the wireless links.
    In the distributed approach, the signaling in the packet may be more
    abstract than an explicit Path, and the PLR decision might be revised along
    the selected DetNet Path based on a better knowledge of the rest of the way.
    </t>
    <t>
    The dynamic DetNet Path selection in RAW avoids the waste of critical
    resources such as spectrum and energy while providing for the
    assured SLA, e.g., by rerouting and/or adding redundancy only when a
    loss spike is observed.
    </t>

</section>      <!-- Act: The reliability Functions-->

</section>
   <!-- The RAW Control Loop -->

    <!--  000000000000000000000    -->

    <section anchor="SecurityConsiderations" numbered="true" toc="default">
      <name>Security Considerations</name>

    <section numbered="true" toc="default">
      <name>Collocated Denial of Service Denial-of-Service Attacks</name>
    <t>
    RAW leverages diversity (e.g., spatial and time diversity,
    coding diversity, and frequency diversity), possibly using
    heterogeneous wired and wireless networking technologies over different physical paths,
    to increase the reliability and availability in the face of unpredictable
    conditions. While this is not done specifically to defeat an attacker, the
    amount of diversity used in RAW defeats possible attacks that would
    impact a particular technology or a specific path.
    </t>

    <t>
    Physical actions by a collocated attacker such as a radio interference
    may still  lower the reliability of an end-to-end RAW transmission by blocking one segment or one
    possible path. But However, if an alternate path with diverse frequency, location, and/or technology, technology is
    available, then RAW adapts by rerouting the impacted traffic over the preferred alternates,
    which defeats the attack after a limited period of lower reliability.
    Then again, the security benefit is a side-effect side effect of an action that is taken regardless of whether or not the source of the
    issue is voluntary (an attack) or not. attack).
   </t>
   </section><!-- Collocated Denial of Service Attacks -->
   </section>

    <section numbered="true" toc="default">
      <name>Layer-2 encryption</name>
      <name>Layer 2 Encryption</name>
    <t>
    Radio networks typically encrypt at the MAC Media Access Control (MAC) layer to protect the
    transmission. If the encryption is per-pair per pair of peers, then certain
    RAW operations like promiscuous overhearing become impractical.
    </t>

      </section><!-- Layer-2 encryption -->

      </section>
    <section numbered="true" toc="default">
      <name>Forced Access</name>
    <t>

<!-- [rfced] Should "may typically select" be updated to "may select" or
"typically selects"?

Original:
   A RAW policy may typically select the cheapest collection of links
   that matches the requested SLA, e.g., use free Wi-Fi vs. paid 3GPP
   access.

Perhaps:
   A RAW policy may select the cheapest collection of links
   that matches the requested SLA, e.g., use free Wi-Fi vs. paid 3GPP
   access.

Or:
   A RAW policy typically selects the cheapest collection of links
   that matches the requested SLA, e.g., use free Wi-Fi vs. paid 3GPP
   access.
-->

    <t>
    A RAW policy may typically select the cheapest collection of links that
    matches the requested SLA, e.g., use free Wi-Fi versus paid 3GPP access. By
    defeating the cheap connectivity (e.g., PHY-layer interference) the attacker
    can force an End System to use the paid access and increase the cost of the
    transmission for the user.
    </t>
<t>
      Similar attacks may also be used to deplete resources in lower-power
      nodes by forcing additional transmissions for FEC and ARQ, and attack
      metrics such as battery life of the nodes. By affecting the transmissions
      and the associated routing metrics in one area, an attacker may force
      the traffic and cause congestion along a remote path, thus reducing
      the overall throughput of the network.
</t>
      </section><!-- Forced Access -->

    <!--  111111111111111111111    -->
      </section>
      <!--Security Considerations-->
    <!--  000000000000000000000    -->

    </section>

    <section numbered="true" toc="default">
      <name>IANA Considerations</name>
      <t>This document has no IANA actions.
      </t>
    </section>
      <!--IANA Considerations-->
    <!--  000000000000000000000    -->

    <section numbered="true" toc="default">
      <name>Contributors</name>

      <t>The editor wishes to thank the following individuals
         for their contributions to the text and ideas exposed in this document:

      </t>
      <dl>
    <dt>Lou Berger:</dt><dd>LabN Consulting, L.L.C, lberger@labn.net</dd>
    <!--dt>Janos Farkas:</dt><dd>Erisson,    Janos.Farkas@ericsson.com</dd-->
    <dt>Xavi Vilajosana:</dt><dd>Wireless Networks Research Lab, Universitat Oberta de Catalunya, xvilajosana@gmail.com</dd>
    <dt>Geogios Papadopolous:</dt><dd>IMT Atlantique   , georgios.papadopoulos@imt-atlantique.fr</dd>
    <dt>Remous-Aris Koutsiamanis:</dt><dd>IMT Atlantique, remous-aris.koutsiamanis@imt-atlantique.fr </dd>
    <dt>Rex Buddenberg:</dt><dd>retired, buddenbergr@gmail.com</dd>
    <dt>Greg Mirsky:</dt><dd>Ericsson, gregimirsky@gmail.com</dd>
      </dl> actions.</t>
    </section>
      <!--ConTributors-->
    <!--  000000000000000000000    -->

   <section><name>Acknowledgments</name>
   <t>This architecture could never have been completed without the support and
   recommendations from the DetNet Chairs Janos Farkas and Lou Berger, and
   Dave Black, the DetNet Tech Advisor.
   Many thanks to all of you.
   </t>
   <t>The authors wish to thank Ketan Talaulikar, as well as Balazs Varga, Dave Cavalcanti, Don Fedyk,
   Nicolas Montavont, and Fabrice Theoleyre for their in-depth reviews during
   the development of this document.
   </t>
   <t>The authors wish to thank Acee Lindem, Eva Schooler, Rich Salz, Wesley Eddy, Behcet Sarikaya, Brian Haberman,
   Gorry Fairhurst, Eric Vyncke, Erik Kline, Roman Danyliw, and Dave Thaler, for their reviews and comments during the IETF Last Call / IESG review cycle.
      </t>
      <t>
    Special thanks for Mohamed Boucadair, Giuseppe Fioccola, and Benoit Claise, for their help dealing with OAM technologies.
      </t>
   </section>
   <!-- Acknowledgments -->
    <!--  000000000000000000000    -->

  </middle>
  <back>

    <displayreference   target="I-D.ietf-raw-technologies"   target="RFC9913"   to="RAW-TECHNOS"/>
    <displayreference   target="I-D.ietf-raw-use-cases"   target="RFC9450"   to="RAW-USE-CASES"/>
    <displayreference   target="RFC1122"                  to="INT-ARCHI"/>
    <displayreference   target="RFC9522"                  to="TE"/>
    <displayreference   target="RFC8175"                  to="DLEP"/>
    <displayreference   target="RFC7490"                  to="RLFA-FRR"/>
    <displayreference   target="RFC5714"                  to="FRR"/>
    <displayreference   target="RFC8938"                  to="DetNet-DP"/>
<!--displayreference   target="RFC9016"                  to="DetNet-Flow"/-->
    <displayreference   target="RFC8655"                  to="DetNet-ARCHI"/>
    <displayreference   target="RFC9030"                  to="6TiSCH-ARCHI"/>
    <displayreference   target="RFC9551"                  to="DetNet-OAM"/>

    <displayreference target="I-D.ietf-detnet-controller-plane-framework" to="DetNet-PLANE"/>

    <references>
      <name>References</name>
      <references>
    <name>Normative References</name>

<xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml3/reference.I-D.ietf-raw-technologies.xml"/>

<!-- Reliable [rfced] Would you like the references to be alphabetized
or left in their current order?
-->

<!-- [RFC9913 / RAW_TECHNOS]
draft-ietf-raw-technologies-17
companion doc RFC 9913
-->
<reference anchor="RFC9913" target="https://www.rfc-editor.org/info/rfc9913">
  <front>
    <title>Reliable and Available Wireless Technologies --> (RAW) Technologies</title>
    <author initials="P." surname="Thubert" fullname="Pascal Thubert" role="editor">
    </author>
    <author initials="D." surname="Cavalcanti" fullname="Dave Cavalcanti">
      <organization>Intel Corporation</organization>
    </author>
    <author initials="X." surname="Vilajosana" fullname="Xavier Vilajosana">
      <organization>Universitat Oberta de Catalunya</organization>
    </author>
    <author initials="C." surname="Schmitt" fullname="Corinna Schmitt">
      <organization>Research Institute CODE, UniBw M</organization>
    </author>
    <author initials="J." surname="Farkas" fullname="János Farkas">
      <organization>Ericsson</organization>
    </author>
    <date month='February' year='2026'/>
  </front>
  <seriesInfo name="RFC" value="9913"/>
  <seriesInfo name="DOI" value="10.17487/RFC9913"/>
</reference>

    <reference anchor="TSN" target="https://1.ieee802.org/tsn/">
      <front>
        <title>Time-Sensitive Networking (TSN)</title>
        <author>
          <organization>IEEE</organization>
        </author>
        <date/>
      </front>
    </reference>

    <xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9030.xml"/>
<!-- 6TiSCH Architecture -->

<xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.4427.xml"/>
<!-- Internet Architecture --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4427.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.6291.xml"/>
<!-- Guidelines for the Use of the "OAM" Acronym in the IETF  --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6291.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.7799.xml"/>
<!-- Active and Passive Metrics and Methods for OAM  --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7799.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8557.xml"/>
<!-- DetNet problem statement --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8557.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8655.xml"/>
<!-- Deterministic Networking Architecture --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8655.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9551.xml"/> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9551.xml"/>
      </references>
    <!--Normative References-->

      <references>
    <name>Informative References</name>

    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9049.xml"/>
<!-- Path Aware Networking: Obstacles to Deployment  --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9030.xml"/>
    <xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.1122.xml"/>
<!-- Internet Architecture --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9049.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8939.xml"/>
<!-- Deterministic Networking IP dataplane --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.1122.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8578.xml"/>
<!-- Deterministic Networking Use Cases --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8939.xml"/>
    <xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml3/reference.I-D.ietf-raw-use-cases.xml"/> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8578.xml"/>
<!-- RAW use cases [RAW-USE-CASES]

-->
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.0791.xml"/>
<!-- IP --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9450.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.2205.xml"/>
<!-- RSVP --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.0791.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9522.xml"/>
<!-- TE --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2205.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9544.xml"/> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9522.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.4655.xml"/>
<!-- PCE --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9544.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.3366.xml"/>
<!-- Advice to link designers on link Automatic Repeat reQuest (ARQ) --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4655.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.4090.xml"/>
<!-- Fast Reroute Extensions to RSVP-TE --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.3366.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.5880.xml"/>
<!-- BFD --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.4090.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.5714.xml"/>
<!--  IP Fast Reroute Framework --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5880.xml"/>
    <xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.6378.xml"/> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5714.xml"/>
    <xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.6551.xml"/> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6378.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.7490.xml"/>
<!--   Remote Loop-Free Alternate (LFA) Fast Reroute (FRR) --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6551.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8724.xml"/> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7490.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8938.xml"/>
<!--   Deterministic Networking (DetNet) Data Plane Framework --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8724.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8175.xml"/>
 <!--    Dynamic Link Exchange Protocol  -->

<!--xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9016.xml"/-->
 <!-- Flow and Service Information Model for Deterministic Networking (DetNet) --> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8938.xml"/>
    <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8175.xml"/>
    <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9378.xml"/>
    <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8762.xml"/>
    <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9378.xml"/> href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9473.xml"/>
    <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9633.xml"/>
<!-- Framework
draft-ietf-detnet-controller-plane-framework-14
IESG State:  IESG Evaluation::AD Followup as of Operations, Administration, and Maintenance (OAM) 09/18/25
-->

<reference anchor="I-D.ietf-detnet-controller-plane-framework" target="https://datatracker.ietf.org/doc/html/draft-ietf-detnet-controller-plane-framework-14">
   <front>
      <title>A Framework for Deterministic Networking (DetNet) -->

 <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.8762.xml"/>
 <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9473.xml"/>
 <xi:include href="https://xml2rfc.tools.ietf.org/public/rfc/bibxml/reference.RFC.9633.xml"/>
<!--
<xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml3/reference.I-D.ietf-opsawg-oam-characterization"/>
-->
<xi:include href="http://xml2rfc.tools.ietf.org/public/rfc/bibxml3/reference.I-D.ietf-detnet-controller-plane-framework"/> Controller Plane</title>
      <author initials="A. G." surname="Malis" fullname="Andrew G. Malis">
         <organization>Independent</organization>
      </author>
      <author initials="X." surname="Geng" fullname="Xuesong Geng" role="editor">
         <organization>Huawei</organization>
      </author>
      <author initials="M." surname="Chen" fullname="Mach Chen">
         <organization>Huawei</organization>
      </author>
      <author initials="B." surname="Varga" fullname="Balazs Varga">
         <organization>Ericsson</organization>
      </author>
      <author initials="C. J." surname="Bernardos" fullname="Carlos J. Bernardos">
         <organization>Universidad Carlos III de Madrid</organization>
      </author>
      <date month="September" day="9" year="2025" />
   </front>
   <seriesInfo name="Internet-Draft" value="draft-ietf-detnet-controller-plane-framework-14" />

</reference>

    <reference anchor="NASA1" target="https://extapps.ksc.nasa.gov/Reliability/Documents/150814-3bWhatIsReliability.pdf">
      <front>
        <title>RELIABILITY: Definition &amp; Quantitative Illustration</title>
        <author  initials="T." surname="Adams" fullname="Tim Adams" >
          <organization>NASA</organization>
        </author>
        <date/>
      </front>
    </reference>

   <reference anchor="NASA2" target="https://extapps.ksc.nasa.gov/Reliability/Documents/160727.1_Availability_What_is_it.pdf">
      <front>
        <title>Availability</title>
        <author  initials="T." surname="Adams" fullname="Tim Adams" >
          <organization>NASA</organization>
        </author>
        <date/>
      </front>
    </reference>

    <!--Informative References-->

    </references>
    </references>

   <section numbered="false">
     <name>Acknowledgments</name>
   <t>This architecture could never have been completed without the support
   and recommendations from the DetNet chairs <contact fullname="Janos
   Farkas"/> and <contact fullname="Lou Berger"/>, and from <contact fullname="Dave
   Black"/>, the DetNet Tech Advisor.  Many thanks to all of you.
   </t>
   <t>The authors wish to thank <contact fullname="Ketan Talaulikar"/>, as
   well as <contact fullname="Balazs Varga"/>, <contact fullname="Dave
   Cavalcanti"/>, <contact fullname="Don Fedyk"/>, <contact fullname="Nicolas
   Montavont"/>, and <contact fullname="Fabrice Theoleyre"/> for their
   in-depth reviews during the development of this document.
   </t>
   <t>The authors wish to thank <contact fullname="Acee Lindem"/>, <contact
   fullname="Eva Schooler"/>, <contact fullname="Rich Salz"/>, <contact
   fullname="Wesley Eddy"/>, <contact fullname="Behcet Sarikaya"/>, <contact
   fullname="Brian Haberman"/>, <contact fullname="Gorry Fairhurst"/>,
   <contact fullname="Éric Vyncke"/>, <contact fullname="Erik Kline"/>,
   <contact fullname="Roman Danyliw"/>, and <contact fullname="Dave Thaler"/>
   for their reviews and comments during the IETF Last Call and IESG review
   cycle.
   </t>
   <t>
    Special thanks for <contact fullname="Mohamed Boucadair"/>, <contact
    fullname="Giuseppe Fioccola"/>, and <contact fullname="Benoit Claise"/>
    for their help dealing with OAM technologies.
   </t>
   </section>

    <section numbered="false" toc="default">
      <name>Contributors</name>
      <t>The editor wishes to thank the following individuals
         for their contributions to the text and the ideas discussed in this document:
      </t>

    <contact fullname="Lou Berger">
      <organization>LabN Consulting, L.L.C</organization>
      <address>
        <email>lberger@labn.net</email>
      </address>
    </contact>

    <contact fullname="Xavi Vilajosana">
      <organization>Wireless Networks Research Lab, Universitat Oberta de Catalunya</organization>
      <address>
        <email>xvilajosana@gmail.com</email>
      </address>
    </contact>

    <contact fullname="Geogios Papadopolous">
      <organization>IMT Atlantique</organization>
      <address>
        <email>georgios.papadopoulos@imt-atlantique.fr</email>
      </address>
    </contact>

    <contact fullname="Remous-Aris Koutsiamanis">
      <organization>IMT Atlantique</organization>
      <address>
        <email>remous-aris.koutsiamanis@imt-atlantique.fr</email>
      </address>
    </contact>

    <contact fullname="Rex Buddenberg">
      <organization>Retired</organization>
      <address>
        <email>buddenbergr@gmail.com</email>
      </address>
    </contact>

    <contact fullname="Greg Mirsky">
      <organization>Ericsson</organization>
      <address>
        <email>gregimirsky@gmail.com</email>
      </address>
    </contact>
    </section>
  </back>
</rfc>

<!-- [rfced] Terminology:

a) "sub-layer" (with hyphen) is used consistently in this document, but
"sublayer" (no hyphen) is used in the other documents in cluster 538
(draft-ietf-raw-technologies and draft-ietf-roll-dao-projection). May we
update usage in this document to align with the other documents in the
cluster? Note that we see mixed usage in past RFCs; for example, RFC 9030
uses "sublayer", but RFC 8655 uses "sub-layer".

b) We note the following capitalization inconsistencies in the names of
nodes. Please review and let us know how to update for consistency.

RAW Node
RAW node

Ingress Node
Ingress node

Egress Node
Egress node

DetNet Edge nodes
DetNet Edge Nodes
edge nodes

DetNet Transit Nodes
DetNet Transit nodes
transit node

DetNet Relay Node

c) We also note inconsistencies in the terms below throughout the text. Should
these be uniform? If so, please let us know which form is preferred.

RAW OAM
RAW / OAM

DetNet Path
DetNet path

Protection Path
protection path

path selection
Path selection (i.e., DetNet Path selection)
Path Selection (i.e., RAW Path Selection)

Control Loop
control loop

OODA Loop
OODA loop

Segment
segment

Ingress
ingress

Egress
egress

DetNet Forwarding sub-layer
DetNet forwarding sub-layer

Controller Plane
controller plane

d) FYI - We updated "gNb" to "gNB" to align with usage in RFC-to-be 9913 aka
draft-ietf-raw-technologies-17 and other documents in the RFC Series.
-->

<!-- [rfced] Abbreviations

a) Below is the first instance of "PHY" in this document. How should this be
expanded? As "Physical"?

Original:
   Furthermore, the different RAW technologies are equipped with
   different reliability features, e.g., short range broadcast,
   Multiple-User, Multiple-Input, and Multiple-Output (MUMIMO), PHY rate
   and other Modulation Coding Scheme (MCS) adaptation, coding and
   retransmissions methods, constructive interference and overhearing,
   see [RAW-TECHNOS] for details.

b) FYI - We updated the expansion of SNR as follows to align with the
expansion used in previous RFCs.

Original:
  Signal-Noise Ratio

Updated:
  Signal-to-Noise Ratio

c) FYI - We have added expansions for abbreviations upon first use
per Section 3.6 of RFC 7322 ("RFC Style Guide"). Please review each
expansion in the document carefully to ensure correctness.

Deterministic Networking (DetNet)
Dynamic Link Exchange Protocol (DLEP)
Differentiated Services Code Point (DSCP)
Static Context Header Compression (SCHC)
Bidirectional Forwarding Detection (BFD)
Media Access Control (MAC)
-->

<!-- [rfced] Please review the "Inclusive Language" portion of the online
Style Guide <https://www.rfc-editor.org/styleguide/part2/#inclusive_language>
and let us know if any changes are needed.  Updates of this nature typically
result in more precise language, which is helpful for readers.

Note that our script did not flag any words in particular, but this should
still be reviewed as a best practice.
-->