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<!DOCTYPE rfc [
 <!ENTITY filename "draft-ietf-manet-dlep-da-credit-extension-21">
  <!ENTITY nbsp    "&#160;">
 <!ENTITY zwsp   "&#8203;">
 <!ENTITY nbhy   "&#8209;">
 <!ENTITY wj     "&#8288;">
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<?rfc toc="yes" ?>
<?rfc symrefs="yes" ?>
<?rfc sortrefs="yes"?>
<?rfc iprnotified="no" ?>
<?rfc strict="yes" ?>

<rfc xmlns:xi="http://www.w3.org/2001/XInclude" category="std" ipr="trust200902"
	docName="&filename;" docName="draft-ietf-manet-dlep-da-credit-extension-21" number="9894" consensus="true" obsoletes="" updates="" submissionType="IETF" xml:lang="en" tocInclude="true" symRefs="true" sortRefs="true" version="3">
  <!-- xml2rfc v2v3 conversion 3.19.4 -->

  <front>
    <title abbrev="DLEP DA Credit Extension">DLEP DiffServ Extension">Dynamic Link Exchange Protocol (DLEP) Diffserv Aware Credit
    Window Extension</title>

<!-- [rfced] Document title: FYI, for ease of the reader and per our
process, we expanded "DLEP" in the title. Please review.

Original:
 DLEP DiffServ Aware Credit Window Extension

Currently:
 Dynamic Link Exchange Protocol (DLEP) Diffserv Aware Credit Window
 Extension
-->

    <seriesInfo name="Internet-Draft"
		value="&filename;"/> name="RFC" value="9894"/>
    <author initials="B." surname="Cheng" fullname="Bow-Nan Cheng">
      <organization>MIT Lincoln Laboratory</organization>
      <address>
        <postal>
          <street>Massachusetts Institute of Technology</street>
          <street>244 Wood Street</street>
          <city>Lexington</city>
          <region>MA</region>
          <code>02421-6426</code>
	  <country>United States of America</country>
        </postal>
        <email>bcheng@ll.mit.edu</email>
      </address>
    </author>
    <author initials="D." surname="Wiggins" fullname="David Wiggins">
      <organization/>
      <address>
        <email>david@none.org</email>
      </address>
    </author>
    <author initials="L." surname="Berger" fullname="Lou Berger">
      <organization>LabN Consulting, L.L.C.</organization>
      <address>
        <email>lberger@labn.net</email>
      </address>
    </author>
   <author fullname="Donald E. Eastlake 3rd" initials="D."
           surname="Eastlake"
           surname="Eastlake 3rd" role="editor">
     <organization>Independent</organization>
     <address>
       <postal>
         <street>2386 Panoramic Circle</street>
         <city>Apopka</city>
         <region>Florida</region>
         <region>FL</region>
         <code>32703</code>
         <country>USA</country>
         <country>United States of America</country>
       </postal>
       <phone>+1-508-333-2270</phone>
       <email>d3e3e3@gmail.com</email>
     </address>
   </author>
    <date/>
    <area>Routing</area>
    <workgroup>MANET</workgroup>
    <date month="November" year="2025"/>
    <area>RTG</area>
    <workgroup>manet</workgroup>

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

<!-- [rfced] For ease of the reader, we expanded "CLI" where first
used, per Section 3.6 of RFC 7322 ("RFC Style Guide" -
<https://www.rfc-editor.org/info/rfc7322>).  Please review, and
let us know any objections.

CLI: Command-Line Interface -->

    <abstract>
      <t>
  This document defines an extension to the Dynamic Link Exchange
  Protocol (DLEP) that enables a DiffServ Diffserv aware credit-window scheme
  for destination-specific and shared flow control.
      </t>
    </abstract>
  </front>
  <middle>
    <section anchor="sec-1" numbered="true" toc="default">
      <name>Introduction</name>
      <t>
  The Dynamic Link Exchange Protocol (DLEP) is defined in <xref
  target="RFC8175"/>.  The protocol provides the exchange of link
  related link-related control information between DLEP peers.  DLEP peers consist of
  a modem and a router.  DLEP defines a base set of mechanisms as well
  as support for possible extensions.  This document defines one such
  extension.
      </t>
      <t>
  The DLEP specification does not include any flow control capability.
  There are various
  Various flow control techniques are theoretically possible with
  DLEP.  This document defines a DLEP extension which that provides a
  DiffServ-based
  Diffserv-based flow control mechanism for traffic sent from a router
  to a modem. Flow control is provided using one or more logical "Credit
  Windows", each of which will typically be supported by an associated
  virtual or physical queue.  A router will use traffic flow
  classification information provided by the modem to identify which
  traffic is associated with each credit window.  Credit windows may be
  shared or dedicated on a per-flow basis.  See <xref
  target="I-D.ietf-manet-dlep-ether-credit-extension"/>
  target="RFC9895"/> for an
  Ethernet-based version of credit window flow control.  As specified in
  Section 2.3.1 of
  <xref
  target="I-D.ietf-manet-dlep-traffic-classification"/>, section="2.3.1"
  target="RFC9892"/>, when both
  DiffServ
  Diffserv and Ethernet traffic classification are specified for a flow,
  the Ethernet information takes precedence.
      </t>
      <t>
  This document uses the traffic classification and credit window
  control mechanisms defined in <xref
  target="I-D.ietf-manet-dlep-traffic-classification"/>
  target="RFC9892"/> and <xref
  target="I-D.ietf-manet-dlep-credit-flow-control"/>
  target="RFC9893"/> to provide credit
  window based credit-window-based flow control based on DLEP destinations and DiffServ Differentiated Services Code Points (DSCPs) <xref target="RFC2475"/> DSCPs (differentiated services codepoints). target="RFC2475"/>.
  The defined mechanism allows for credit windows to be shared across
  traffic sent to multiple DLEP destinations and DSCPs, or used
  exclusively for traffic sent to a particular destination and/or DSCP.
  The extension also supports the "wildcard" matching of any DSCP.
      </t>
      <t>
  The extension defined in this document is referred to as "DiffServ the "Diffserv
  Aware Credit Window" or, more simply, the "DA Credit" extension. The
  reader should be familiar with both the traffic classification and
  credit window control mechanisms defined in <xref
  target="I-D.ietf-manet-dlep-traffic-classification"/>
  target="RFC9892"/> and <xref
  target="I-D.ietf-manet-dlep-credit-flow-control"/>.
  target="RFC9893"/>.
      </t>
      <t>
  This document defines a new DLEP Extension Type Value in <xref
  target="sec-ext-type"/> which
  that is used to indicate support for the
  extension.  See <xref target="sec-ext-type"/>.
      </t>
      <section anchor="sec-1.1" numbered="true">
        <name>Key Words</name>
        <t>
   The
         <t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", "<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>",
         "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>",
         "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>",
         "<bcp14>SHOULD NOT</bcp14>",
         "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>",
         "<bcp14>MAY</bcp14>", and
   "OPTIONAL" "<bcp14>OPTIONAL</bcp14>" in this document
         are to be interpreted as described in BCP
   14 BCP&nbsp;14
         <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only
         when, they appear in all capitals, as shown here.
	</t> here.</t>
      </section>
    </section>
    <section anchor="sec-ext-type" numbered="true">
      <name>Extension Usage and Identification</name>
      <t>
   The extension defined in this document is composed of the mechanisms
   and processing defined in <xref
   target="I-D.ietf-manet-dlep-traffic-classification"/>
   target="RFC9892"/> and <xref
   target="I-D.ietf-manet-dlep-credit-flow-control"/>.
   target="RFC9893"/>.  To indicate that
   the DiffServ Diffserv Aware Credit Window Extension is to be used, an
   implementation MUST <bcp14>MUST</bcp14> include the DiffServ Diffserv Aware Credit Window Type
   Value in the Extensions Supported Data Item (see Section 13.6 of
   <xref target="RFC8175"/>). target="RFC8175" section="13.6"/>).  The Extensions Supported Data Item is
   sent and processed according to <xref target="RFC8175"/>.  Any
   implementation that indicates the use of the DiffServ Diffserv Aware Credit Window
   Extension MUST <bcp14>MUST</bcp14> support all Messages, message types, Data Items, the DiffServ Diffserv Traffic
   Classification Sub-Data Item, and all related processing defined in
   <xref target="I-D.ietf-manet-dlep-traffic-classification"/> target="RFC9892"/> and <xref
   target="I-D.ietf-manet-dlep-credit-flow-control"/>.
   target="RFC9893"/>.
      </t>

      <t>
  The DiffServ Diffserv Aware Credit Window Extension Type Value is TBA1, see 6. See
  <xref target="sec-iana"/>.
      </t>
    </section>
    <section anchor="sec-mgmnt" numbered="true">
      <name>Management Considerations</name>
      <t>
    This section provides several network management guidelines
    to
    for implementations supporting the DiffServ Diffserv Aware Credit Window
    Extension.
      </t>
      <t>
    If this extension is supported, that support MUST <bcp14>MUST</bcp14> be declared
    using the Extensions Supported Data Item (see Section 13.6 of
    <xref target="RFC8175"/>). DiffServ target="RFC8175" section="13.6"/>). Diffserv Aware Credit Window Extension
    Data Items MUST NOT <bcp14>MUST NOT</bcp14> be emitted by a DLEP participant unless such
    support was specified in the initialization message received from
    its peer.  The use of the extension defined in this document
    SHOULD
    <bcp14>SHOULD</bcp14> be configurable on both modems and routers. That
    configuration can be implemented using a proprietary CLI Command-Line Interface (CLI) or by
    implementing a YANG module. The definition of the YANG module is
    out of the scope of for this document.
      </t>
      <t>
    Modems SHOULD <bcp14>SHOULD</bcp14> support the configuration of mapping a DSCP to a credit window (queue) mapping. (queue).
      </t>
      <t>
    Modems MAY <bcp14>MAY</bcp14> support the configuration of the number of credit
    windows (queues) to advertise to a router.
      </t>
      <t>
    Routers may have limits on the number of queues that they can
    support and limits on supported credit window combinations. Per
    destination
    Per-destination queues might not be supported at all.  When
    modem-provided
    credit window information provided by a modem exceeds the capabilities of
    a router, the router SHOULD <bcp14>SHOULD</bcp14> use a subset of the provided credit
    windows.  Alternatively, a router MAY <bcp14>MAY</bcp14> reset the session and indicate
    that the extension is not supported.  In either case, any mismatch
    in capabilities <bcp14>SHOULD</bcp14> be reported to the user via normal network
    management mechanisms, such as user interface messages or error
    logging.

<!-- [rfced] Section 3:  We changed "the mismatch of capabilities" to
"any mismatch in capabilities" per
draft-ietf-manet-dlep-ether-credit-extension.  Please let us know any
objections.

Original:
 In either case, the mismatch of capabilities SHOULD be
 reported to the user via normal network management mechanisms such as
 user interface messages or error logging.

Currently:
 In either case, any mismatch in capabilities SHOULD be
 reported to the user via normal network management mechanisms, such
 as user interface messages or error logging. -->

      </t>
      <t>
    In all cases, if credit windows are in use, traffic for which
    credits are not available MUST NOT <bcp14>MUST NOT</bcp14> be sent to the modem by the
    router.
      </t>
    </section>
    <section anchor="sec-sec" numbered="true">
      <name>Security Considerations</name>
      <t>
    This document defines a DLEP extension that uses DLEP mechanisms and
    the credit window control and flow mechanisms defined in <xref
    target="I-D.ietf-manet-dlep-traffic-classification"/>
    target="RFC9892"/> and <xref
    target="I-D.ietf-manet-dlep-credit-flow-control"/>.
    target="RFC9893"/>.  See
    also the Security Considerations sections of those documents.
      </t>
      <t>
    The defined extension is exposed to vulnerabilities similar to
    existing DLEP messages and discussed in the Security Considerations
    section of <xref target="RFC8175"/> target="RFC8175"/>, such as an injected message
    resizing a credit window to a value that results in a denial of
    service.  The security mechanisms documented in <xref
    target="RFC8175"/> can be applied equally to the mechanism defined
    in this document.
      </t>
      <t>
    Wildcards for matching Priority Code point Point (PCP) and VLAN ID Identifier (VID)
    fields (see <xref
    target="I-D.ietf-manet-dlep-ether-credit-extension"/>)
    target="RFC9895"/>) are provided
    which provided.  Note that wildcards
    may be convenient to match for matching a number of packet flows but could
    inadvertently match unexpected flows or new flows that appear after
    the wildcard matching has been set up. It is therefore RECOMMENDED <bcp14>RECOMMENDED</bcp14>
    that wildcards not be used unless needed.
      </t>
    </section>

    <section anchor="sec-iana" numbered="true" toc="default">
      <name>IANA Considerations</name>
      <t>
  IANA is requested to assign one has assigned the following code point in the "Extension Type Values"
  registry in the "Dynamic Link Exchange Protocol (DLEP) Parameters"
  registry group as follows: group:
      </t>
        <t keepWithNext="true"/>
        <table anchor="table_et" align="center">
          <name>Requested Extension
          <name>Extension Type Value</name>
          <thead>
            <tr>
              <th align="left">Code</th>
              <th align="left">Description</th>
            </tr>
          </thead>
          <tbody>
            <tr>
              <td align="left">TBA1</td> align="left">6</td>
              <td align="left">DiffServ align="left">Diffserv Aware Credit Window</td>
            </tr>
          </tbody>
        </table>
        <t keepWithPrevious="true"/>
    </section>
  </middle>
  <back>
    <references>
      <name>References</name>
      <references>
        <name>Normative References</name>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8175.xml"/>

<!-- draft-ietf-manet-dlep-credit-flow-control-19 (RFC 9893) -->
        <reference anchor="I-D.ietf-manet-dlep-credit-flow-control"
		 target="https://datatracker.ietf.org/doc/draft-ietf-manet-dlep-credit-flow-control"> anchor="RFC9893" target="https://www.rfc-editor.org/info/rfc9893">
          <front>
            <title>Dynamic Link Exchange Protocol (DLEP) Credit-Based Flow Control Messages and Data Items</title>
            <author fullname="Bow-Nan Cheng" initials="B."
		  surname="Cheng"> surname="Cheng" fullname="Bow-Nan Cheng">
              <organization>MIT Lincoln Laboratory</organization>
            </author>
            <author fullname="David Wiggins" initials="D."
		  surname="Wiggins"/> surname="Wiggins" fullname="David Wiggins">
            </author>
            <author initials="S." surname="Ratliff" fullname="Stan Ratliff">
            </author>
            <author fullname="Lou Berger" initials="L." surname="Berger"> surname="Berger" fullname="Lou Berger">
              <organization>LabN Consulting, L.L.C.</organization>
            </author>
            <author fullname="Stan Ratliff" initials="S."
		  surname="Ratliff"/>
	  <author initials="E." surname="Kinzie" fullname="Eric Kinzie" initials="E." surname="Kinzie"> role="editor">
              <organization>LabN Consulting, L.L.C.</organization>
            </author>
            <date day="3" month="January" year="2025"/> month="November" year="2025" />
          </front>
         <seriesInfo name="Internet-Draft"
		    value="draft-ietf-manet-dlep-credit-flow-control"/> name="RFC" value="9893"/>
         <seriesInfo name="DOI" value="10.17487/RFC9893"/>
        </reference>

<!-- draft-ietf-manet-dlep-traffic-classification-17 (RFC 9892) -->
        <reference anchor="I-D.ietf-manet-dlep-traffic-classification"
		 target="https://datatracker.ietf.org/doc/draft-ietf-manet-dlep-traffic-classification"> anchor="RFC9892" target="https://www.rfc-editor.org/info/rfc9892">
          <front>
            <title>Dynamic Link Exchange Protocol (DLEP) Traffic Classification Data Item</title>
            <author fullname="Bow-Nan Cheng" initials="B."
		  surname="Cheng"> surname="Cheng" fullname="Bow-Nan Cheng">
              <organization>MIT Lincoln Laboratory</organization>
            </author>
            <author fullname="David Wiggins" initials="D."
		  surname="Wiggins"/> surname="Wiggins" fullname="David Wiggins">
            </author>
            <author fullname="Lou Berger" initials="L." surname="Berger"> surname="Berger" fullname="Lou Berger">
              <organization>LabN Consulting, L.L.C.</organization>
            </author>
            <author initials="D." surname="Fedyk" fullname="Don Fedyk" initials="D." surname="Fedyk"> role="editor">
              <organization>LabN Consulting, L.L.C.</organization>
            </author>
            <date day="19" month="November" year="2024"/> month='November' year='2025'/>
          </front>
          <seriesInfo name="Internet-Draft"
		    value="draft-ietf-manet-dlep-traffic-classification"/> name="RFC" value="9892"/>
          <seriesInfo name="DOI" value="10.17487/RFC9892"/>
        </reference>

      </references>
      <references>
        <name>Informative References</name>
        <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2475.xml"/>

<!-- draft-ietf-manet-dlep-ether-credit-extension-09 (RFC 9895) -->
<reference anchor="I-D.ietf-manet-dlep-ether-credit-extension"
		   target="https://datatracker.ietf.org/doc/draft-ietf-manet-dlep-ether-credit-extension/"> anchor="RFC9895" target="https://www.rfc-editor.org/info/rfc9895">
   <front>
	    <title>DLEP
      <title>Dynamic Link Exchange Protocol (DLEP) IEEE 802.1Q Aware Credit Window Extension</title>
      <author fullname="David Wiggins" initials="D."
		    surname="Wiggins"/> surname="Wiggins" fullname="David Wiggins">
         </author>
      <author fullname="Lou Berger" initials="L."
		    surname="Berger"> surname="Berger" fullname="Lou Berger">
         <organization>LabN Consulting, L.L.C.</organization>
      </author>
      <author initials="D." surname="Eastlake 3rd" fullname="Donald E. Eastlake 3rd" initials="D. E."
		    surname="Eastlake"> role="editor">
         <organization>Independent</organization>
      </author>
      <date day="15" month="December" year="2024"/> month="November" year="2025" />
   </front>
   <seriesInfo name="Internet-Draft"
		      value="draft-ietf-manet-dlep-ether-credit-extension"/> name="RFC" value="9895"/>
   <seriesInfo name="DOI" value="10.17487/RFC9895"/>
</reference>

      </references>
    </references>
    <section numbered="true"> numbered="false">
      <name>Acknowledgments</name>
      <t>
     The Sub-Data item Item format was inspired by Rick Taylor's <contact fullname="Rick Taylor"/>'s "Data Item
     Containers".  He also proposed the separation of credit windows from
     traffic classification at IETF 98. Many useful comments were
     received from contributors to the MANET working group, Working Group, notably
     Ronald in't Velt.
     <contact fullname="Ronald in 't Velt"/>.
      </t>
      <t>
     We had the honor of working too briefly with David Wiggins <contact fullname="David Wiggins"/> on this
     and related DLEP work. His contribution to the IETF and publication
     of the first and definitive open source open-source DLEP implementation have
     been critical to the acceptance of DLEP. We mourn his passing on
     November 23, 26, 2023.  We wish to recognize his guidance, leadership leadership,
     and professional excellence.  We were fortunate to benefit from his
     leadership and friendship. He shall be missed.
      </t>
    </section>
  </back>

<!-- [rfced] Please review the "Inclusive Language" portion of the
online Style Guide at
<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. -->

<!-- [rfced] Please let us know if any changes are needed for the
following:

a) The following term was used inconsistently in this document.
We chose to use the latter form.  Please let us know any objections.

 Sub-Data item / Sub-Data Item (as used elsewhere in this document
  and per the other documents in this group (Cluster 541 /
  https://www.rfc-editor.org/cluster_info.php?cid=C541) of documents)

b) The following term appears to be used inconsistently in this document.
Please let us know which form is preferred. (Note that we updated "Diffserv"
to "DiffServ".)

 DiffServ Aware Credit Window Type Value /
   DiffServ Aware Credit Window Extension Type Value -->

</rfc>