DLEP traffic classes: Dynamic Link Exchange Protocol (DLEP) Traffic Classification Data Item

Internet Engineering Task Force (IETF)                          B. Cheng
Request for Comments: 9892                        MIT Lincoln Laboratory
Category: Standards Track                                     D. Wiggins
ISSN: 2070-1721
                                                               L. Berger
                                                           D. Fedyk, Ed.
                                                 LabN Consulting, L.L.C.
                                                            January 2026


 Dynamic Link Exchange Protocol (DLEP) Traffic Classification Data Item

Abstract

   This document defines a new Data Item for the Dynamic Link Exchange
   Protocol (DLEP) to support traffic classification.  Traffic
   classification information identifies traffic flows based on frame/
   packet content such as a destination address.  The Data Item is
   defined in an extensible and reusable fashion.  Its use will be
   mandated in other documents defining specific DLEP extensions.  This
   document also introduces DLEP Sub-Data Items and defines two new Sub-
   Data Items to support Diffserv and Ethernet traffic classification.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc9892.

Copyright Notice

   Copyright (c) 2026 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
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   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
     1.1.  Key Words
   2.  Traffic Classification
     2.1.  Traffic Classification Data Item
       2.1.1.  Traffic Classification Sub-Data Item
     2.2.  Diffserv Traffic Classification Sub-Data Item
       2.2.1.  Router Receive Processing
     2.3.  Ethernet Traffic Classification Sub-Data Item
       2.3.1.  Router Receive Processing
   3.  Compatibility
   4.  Security Considerations
   5.  IANA Considerations
     5.1.  Data Item Type Values
     5.2.  Traffic Classification Sub-Data Item Type Values
     5.3.  Registration Guidance
   6.  References
     6.1.  Normative References
     6.2.  Informative References
   Acknowledgments
   Authors' Addresses

1.  Introduction

   The Dynamic Link Exchange Protocol (DLEP) is defined in [RFC8175].
   This protocol provides the exchange of link-related control
   information between DLEP peers.  DLEP peers are comprised of a modem
   and a router.  DLEP defines a base set of mechanisms as well as
   support for possible extensions.  DLEP defines Data Items, which are
   sets of information that can be reused in DLEP messaging.  The DLEP
   specification does not include any flow identification beyond DLEP
   endpoints, i.e., flows are identified based on their DLEP endpoint.

   This document defines DLEP Data Item formats that provide flow
   identification on a more granular basis.  Specifically, it enables a
   router to use traffic flow classification information provided by the
   modem to identify traffic flows based on a combination of information
   found in a data plane header.  (For general background on traffic
   classification, see Section 2.3 of [RFC2475].)  The Data Item is
   structured to allow for the use of the defined traffic classification
   information with applications such as credit window flow control as
   specified in [RFC9893].  [RFC9893] provides an example of combining
   traffic classification and credit window flow control.

   This document defines traffic classification based on a DLEP
   destination and flows identified by either Differentiated Services
   Code Points (DSCPs) [RFC2475] or IEEE 802.1Q Ethernet Priority Code
   Points (PCPs) [IEEE8021Q].  The defined mechanism allows for flows to
   be described in a flexible fashion and, when combined with
   applications such as credit window flow control, allows credit
   windows to be (1) shared across traffic sent to multiple DLEP
   destinations and as part of multiple flows or (2) used exclusively
   for traffic sent to a particular destination and/or belonging to a
   particular flow.  The extension also supports the "wildcard" matching
   of any flow (DSCP or PCP).  Traffic classification information is
   provided such that it can be readily extended to support other
   traffic classification techniques or can be used by extensions that
   are not related to credit windows, such as the extension defined in
   [RFC8651] or even 5-tuple IP flows.

   This document defines support for traffic classification using a
   single new Data Item (see Section 2.1) for general support and
   defines two new Sub-Data Items to support identification of flows
   based on DSCPs and PCPs (see Sections 2.2 and 2.3).

1.1.  Key Words

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

2.  Traffic Classification

   The Traffic Classification Data Item represents a list of flows that
   may be used at the same time to provide different service classes for
   traffic sent from a router to a modem.  The data plane information
   used to identify each flow is represented in a separate Sub-Data
   Item.  The Data Item and Sub-Data Item structures are intended to be
   independent of any specific usage of the flow identification, e.g.,
   flow control.  The Sub-Data Item structure is also intended to allow
   for future traffic classification types, e.g., 5-tuple flows.  While
   the structure of the Data Items is extensible, actual flow
   information is expected to be used in an extension-dependent manner.
   Support for DSCP and PCP-based flows is defined via individual Sub-
   Data Items; see below.  Other types of flow identification, e.g.,
   based on IP transport-layer protocol and ports, may be defined in the
   future via new Sub-Data Items.  Note that when extensions supporting
   multiple Sub-Data Item types are negotiated, these types MAY be
   combined in a single Data Item.

   Each list of flows is identified using a "Traffic Classification
   Identifier" or "TID" and is expected to represent a valid combination
   of data plane identifiers that may be used at the same time.  Each
   flow is identified via a "Flow Identifier" or "FID".  Each FID is
   defined in a Sub-Data Item that carries the data plane identifier or
   identifiers used to associate traffic with the flow.  A DLEP
   destination address is also needed to complete traffic classification
   information used in extensions such as flow control.  This
   information is expected to be provided in an extension-specific
   manner.  For example, this address can be provided by a modem when it
   identifies the traffic classification set in a Destination Up Message
   using the Credit Window Association Data Item defined in [RFC9893].
   TID and FID values have modem-local scope.

2.1.  Traffic Classification Data Item

   This section defines the Traffic Classification Data Item.  This Data
   Item is used by a modem to provide a router with traffic
   classification information.  When an extension requires the use of
   any Data Item, the Data Items, including this Traffic Classification
   Data Item, SHOULD be included by a modem in any Session
   Initialization Response Message (e.g., see [RFC9893]).  Updates to
   previously provided traffic classifications or new traffic
   classifications MAY be sent by a modem by including the Data Item in
   Session Update Messages.  More than one Data Item MAY be included in
   a message to provide information on multiple traffic classifiers.

   The set of traffic classification information provided in the Data
   Item is identified using a TID.  The actual information related to
   data planes that is used in traffic classification is provided in a
   variable list of Traffic Classification Sub-Data Items.

   The format of the Traffic Classification Data Item is as follows:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Data Item Type                | Length                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Traffic Class. Identifier (TID)|   Num SDIs    |   Reserved    |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~           Traffic Classification Sub-Data Item 1              ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                              ...                              ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~           Traffic Classification Sub-Data Item n              ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Data Item Type:
      29

   Length:
      Variable

      Per Section 11.3 of [RFC8175], Length is the number of octets in
      the Data Item, excluding the Data Item Type and Length fields.
      The length here is limited by the packet data unit (PDU) length
      supported.  For example, if the packet is limited to 1400 bytes,
      then the length MUST NOT exceed this value.  If larger packets are
      supported, the maximum MUST be adjusted to be smaller than or
      equal to the maximum PDU.  Multiple messages can be used if there
      is more data than will fit in a single TLV.

   Traffic Classification Identifier (TID):
      A 16-bit unsigned integer identifying a traffic classification
      set.  There is no restriction on values used by a modem, and there
      is no requirement for sequential or ordered values.

   Num SDIs:
      An 8-bit unsigned integer indicating the number of Traffic
      Classification Sub-Data Items included in the Data Item.  A value
      of zero (0) is allowed and indicates that no traffic should be
      matched against this TID.

   Reserved:
      For the Traffic Classification Data Item, this reserved field is
      currently unused.  It MUST be set to all zeros for this version of
      the Data Item and is currently ignored on reception.  This allows
      for future extensions of the Data Item if needed.

   Traffic Classification Sub-Data Item:
      Zero or more Traffic Classification Sub-Data Items of the format
      defined in Section 2.1.1 MAY be included.  The number MUST match
      the value carried in the Num SDIs field.

   A router receiving the Traffic Classification Data Item MUST locate
   the traffic classification information that is associated with the
   TID indicated in each received Data Item.  If no associated traffic
   classification information is found, the router MUST initialize a new
   information set using the values carried in the Data Item.  If the
   associated traffic classification information is found, the router
   MUST replace the corresponding information using the values carried
   in the Data Item.  In both cases, a router MUST also ensure that any
   data plane state (e.g., see [RFC9893]) that is associated with the
   TID is updated as needed.

2.1.1.  Traffic Classification Sub-Data Item

   All Traffic Classification Sub-Data Items share a common format that
   is patterned after the standard DLEP Data Item format.  See
   Section 11.3 of [RFC8175].  There is no requirement on, or meaning
   to, Sub-Data Item ordering.  Any errors or inconsistencies
   encountered in parsing Sub-Data Items are handled in the same fashion
   as any other Data Item parsing error encountered in DLEP.  See
   [RFC8175].

   The format of the Traffic Classification Sub-Data Item is as follows:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Sub-Data Item Type            | Length                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       ~                           Value...                            ~
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Sub-Data Item Type:
      A 16-bit unsigned integer that indicates the type and
      corresponding format of the Sub-Data Item's Value field.  Sub-Data
      Item Types are scoped within the Data Item in which they are
      carried, i.e., the Sub-Data Item Type field MUST be used together
      with the Traffic Classification Data Item Type to identify the
      format of the Sub-Data Item.  Traffic Classification Sub-Data Item
      Types are managed according to the IANA registry described in
      Section 5.2.

   Length:
      Variable

      Per Section 11.3 of [RFC8175], Length is a 16-bit unsigned integer
      that is the number of octets in the Sub-Data Item, excluding the
      Data Item Type and Length fields.  Each Sub-Data Item has its own
      Length field.

   Value:
      A field of <Length> octets that contains data specific to a
      particular Data Item.

2.2.  Diffserv Traffic Classification Sub-Data Item

   The Diffserv Traffic Classification Sub-Data Item identifies the set
   of DSCPs that should be treated as a single flow, i.e., receive the
   same traffic treatment.  DSCPs are identified in a list of Diffserv
   fields.  An implementation that does not support DSCPs and wants the
   same traffic treatment for all traffic to a destination or
   destinations would indicate 0 DSCPs.

   The format of the Diffserv Traffic Classification Sub-Data Item is as
   follows:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Sub-Data Item Type (1)        |  Length                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Flow Identifier (FID)         |   Num DSCPs   |   DS Field 1  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   DS Field 2  |      ...      |   DS Field n  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Sub-Data Item Type:
      Sub-Data Item Type with value one (1) identifies the Diffserv
      Traffic Classification Sub-Data Item Type in the format defined in
      Section 2.1.1.

   Length:
      Variable

      Length is defined above.  For this Sub-Data Item, it is equal to
      three (3) octets plus the value of the Num DSCPs field.  This
      means that the maximum Length value is 3 + 64 or 67 octets.  The
      definition can be in multiple Sub-Data Items that are much smaller
      than this.

   Flow Identifier (FID):
      A 16-bit unsigned integer representing the data plane information
      carried in the Sub-Data Item that is to be used in identifying a
      flow.  The value 0xFFFF is reserved and MUST NOT be used in this
      field.

   Num DSCPs:
      An 8-bit unsigned integer indicating the number of DSCPs carried
      in the Sub-Data Item.  A zero (0) indicates a (wildcard) match
      against any DSCP value that does not have an explicit match to a
      FID.  A typical use of this is mapping any DSCPs that are not
      explicitly mapped to a default queue.

   DS Field:
      Each DS Field is 8 bits long and carries the DSCP field as defined
      in [RFC2474].

                  0   1   2   3   4   5   6   7
                +---+---+---+---+---+---+---+---+
                |         DSCP          |  MBZ  |
                +---+---+---+---+---+---+---+---+

      DSCP:  Differentiated Services Code Point [RFC2474]
      MBZ:  Must Be Zero - set to zero when transmitted

2.2.1.  Router Receive Processing

   A router receiving the Traffic Classification Sub-Data Item MUST
   validate the information on receipt, prior to using the carried
   information, including potentially updating the data behavior as
   determined by the extension requiring the use of the Sub-Data Item.
   Validation failures MUST be treated as an error as described in
   Section 2.1.1.

   Once validated, the receiver MUST ensure that each DS Field value is
   listed only once across the whole Traffic Classification Data Item.
   Note that this check is across the Data Item and not the individual
   Sub-Data Items.  If the same DS Field value is listed more than once
   within the same Traffic Classification Data Item, the Data Item MUST
   be treated as an error as described in Section 2.1.1.

2.3.  Ethernet Traffic Classification Sub-Data Item

   The Ethernet Traffic Classification Sub-Data Item identifies the VLAN
   and PCPs that should be treated as a single flow, i.e., receive the
   same traffic treatment.  Ethernet PCP support is defined as part of
   the IEEE 802.1Q tag format [IEEE8021Q] and includes a 3-bit "PCP"
   field.  The tag format also includes a 12-bit "VLAN Identifier (VID)"
   field.  PCPs are identified in a list of Priority Fields.  An
   implementation that does not support PCPs and wants the same traffic
   treatment for all traffic to a destination or destinations would
   indicate 0 PCPs.  Such an implementation could identify a VLAN to use
   per destination.

   The format of the Ethernet Traffic Classification Sub-Data Item is as
   follows:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Sub-Data Item Type (2)        | Length                        |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Flow Identifier (FID)         |NumPCPs| VLAN Identifier (VID) |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       | Pri. 1| Pri. 2| ..... | ..... | ..... |  Pad  |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Sub-Data Item Type:
      Sub-Data Item Type with value two (2) identifies the Ethernet
      Traffic Classification Sub-Data Item Type in the format defined in
      Section 2.1.1.

   Length:
      Variable

      Length is defined above.  For this Sub-Data Item, it is equal to
      four (4) plus the number of octets needed to accommodate the
      number of Priority Fields indicated by the NumPCPs field.  Note
      that as the length is in octets and each Priority Field is 4 bits,
      the total length of this Sub-Data Item is the 2 octets of Flow
      Identifier, plus the 2 octets for NumPCPs and VLAN Identifier plus
      the number of octets for PCPs.  The number of octets for the PCPs
      is computed by rounding up NumPCPs to the nearest even value and
      dividing by 2.  This TLV has maximum length of 4 plus 8 divided by
      2 or 8 octets.

   Flow Identifier (FID):
      A 16-bit unsigned integer representing the data plane information
      carried in the Sub-Data Item that is to be used in identifying a
      flow.  The value 0xFFFF is reserved and MUST NOT be used in this
      field.

   NumPCPs:
      A 4-bit unsigned integer indicating the number of Priority Fields
      carried in the Sub-Data Item.  A zero (0) indicates a (wildcard)
      match against any PCP value that does not have an explicit match
      to a FID.  A typical use of a wildcard is mapping any PCPs that
      are not explicitly mapped to a default queue.  The maximum number
      of PCPs is 8.

   VLAN Identifier (VID):
      A 12-bit unsigned integer field indicating the VLAN to be used in
      traffic classification.  VID value zero (0x000) is used to
      indicate that the VID is to be ignored.  VID 0xFFF is reserved.
      Any other VID value from 0x001 through 0xFFE can be used in
      traffic classification.  Any explicitly mapped VLANs are matched
      first.  Any VLANs that do not have a mapping will then map to this
      default mapping.

   Priority:
      Each Priority Field is 4 bits long and indicates a PCP field as
      defined in [IEEE8021Q].  Note that zero (0) is a valid value for
      PCP.

                0   1   2   3
              +---+---+---+---+
              |    PCP    |MBZ|
              +---+---+---+---+

      PCP:  Priority Code Point [IEEE8021Q]
      MBZ:  Must Be Zero - set to zero when transmitted

   Pad:
      A field that is 4 bits long and is included when NumPCPs is an odd
      number.  This field MUST be set to zero by the sender and MUST be
      ignored on receipt.

2.3.1.  Router Receive Processing

   A router receiving the Traffic Classification Sub-Data Item MUST
   validate the information on receipt, prior to using the carried
   information, including potentially updating the data behavior as
   determined by the extension requiring the use of the Sub-Data Item.
   Note that validation can include usage-specific semantics such as
   those found in [RFC9893].  Any failures MUST be treated as an error
   as described in Section 2.1.1.

   After successful validation, the receiver MUST ensure that each
   Priority Field value is listed only once across the whole Traffic
   Classification Data Item.  Note that this check is across the Data
   Item and not the individual Sub-Data Items.  If the same Priority
   Field value is listed more than once within the same Traffic
   Classification Data Item, the Data Item MUST be treated as an error
   as described in Section 2.1.1.

   In cases where both Traffic Classification Sub-Data Item Types are
   defined, matching on Ethernet information takes precedence.  More
   specifically, when a packet matches both a DSCP indicated in a
   Diffserv Traffic Classification Sub-Data Item (Section 2.2) and a
   VID/PCP identified in an Ethernet Traffic Classification Sub-Data
   Item (Section 2.3), the TID associated with the matching VLAN/PCP
   MUST be used.

3.  Compatibility

   The formats defined in this document will only be used when
   extensions require their use.

   The DLEP specification [RFC8175] defines the handling of unexpected
   appearances of any Data Items, including those defined in this
   document.

4.  Security Considerations

   This document introduces finer-grained flow identification mechanisms
   for DLEP.  These mechanisms expose vulnerabilities similar to
   existing DLEP messages.  An example of a threat to which traffic
   classification might be susceptible is where a malicious actor
   masquerading as a DLEP peer could inject an alternate Traffic
   Classification Data Item, changing the mapping of traffic to queues;
   this would in turn cause delay, congestion, or loss in one or more
   service classes.  Other possible threats are discussed in the
   Security Considerations section of [RFC8175] and are also applicable,
   but not specific, to traffic classification.

   The transport-layer security mechanisms documented in [RFC8175],
   along with the latest versions of [BCP195], [IEEE-802.1AE], and
   [IEEE-802.1X] at the time of this writing, can be applied to this
   document.  Implementations following the "networked deployment" model
   described in Section 4 ("Implementation Scenarios") of [RFC8175]
   SHOULD refer to [BCP195] for additional details.  The Layer 2
   security mechanisms documented in [RFC8175] can also, with some
   updates, be applied to the mechanisms defined in this document.
   Examples of technologies that can be deployed to secure the Layer 2
   link include [IEEE-802.1AE] and [IEEE-802.1X].

5.  IANA Considerations

5.1.  Data Item Type Values

   IANA has assigned the following value from the "Specification
   Required" range [RFC8126] in the DLEP "Data Item Type Values"
   registry:

                  +===========+========================+
                  | Type Code | Description            |
                  +===========+========================+
                  | 29        | Traffic Classification |
                  +-----------+------------------------+

                    Table 1: New Data Item Type Value

5.2.  Traffic Classification Sub-Data Item Type Values

   IANA has created a new DLEP registry named "Traffic Classification
   Sub-Data Item Type Values".

   Table 2 shows the registration policies [RFC8126] for the registry:

                 +=============+=========================+
                 | Range       | Registration Procedures |
                 +=============+=========================+
                 | 1-65407     | Specification Required  |
                 +-------------+-------------------------+
                 | 65408-65534 | Private Use             |
                 +-------------+-------------------------+

                       Table 2: Registration Policies

   Table 3 shows the initial contents of the registry:

      +=============+=================================+=============+
      | Type Code   | Description                     | Reference   |
      +=============+=================================+=============+
      | 0           | Reserved                        | RFC 9892    |
      +-------------+---------------------------------+-------------+
      | 1           | Diffserv Traffic Classification | [RFC2474]   |
      +-------------+---------------------------------+-------------+
      | 2           | Ethernet Traffic Classification | [IEEE8021Q] |
      +-------------+---------------------------------+-------------+
      | 3-65407     | Unassigned                      |             |
      +-------------+---------------------------------+-------------+
      | 65408-65534 | Reserved for Private Use        | RFC 9892    |
      +-------------+---------------------------------+-------------+
      | 65535       | Reserved                        | RFC 9892    |
      +-------------+---------------------------------+-------------+

                     Table 3: Initial Registry Contents

   This registry encompasses packet traffic classification, where
   standard packet header identifiers in packets or data frames indicate
   Quality of Service (QoS) treatment.  It includes two specific entries
   for widely recognized identifiers used in QoS management for IP and
   Ethernet networks.  Reserved values are set aside for similar future
   identifiers that may emerge to denote QoS treatment.  However,
   requests for new entries are not expected to be frequent.

   Allocations within the registry are subject to the following
   requirements:

   1.  Documentation of the intended use of the requested value, in
       compliance with the "Specification Required" policy defined in
       [RFC8126].

   2.  Approval by the designated expert (DE) appointed by the IESG.
       The DE must do the following:

       *  Verify that the requested value is clearly documented and its
          purpose and usage are unambiguous.

       *  Ensure that the proposed value does not conflict with existing
          work or ongoing efforts within the IETF.

       *  Confirm that any specification requesting a code point has
          undergone review by the MANET Working Group (or a successor
          mailing list designated by the IESG).

       *  Validate that external specifications requesting code points
          are publicly available, are permanently archived, and do not
          conflict with active or published IETF work.

       *  Ensure that the review process is conducted in a timely
          manner, with any disputes resolved through consultation with
          the appropriate working groups.

5.3.  Registration Guidance

   This section provides guidance for registrations in the "Traffic
   Classification Sub-Data Item Type Values" registry.  To simplify
   future registrations in DLEP-related registries, it is recommended
   that the guidance in this section apply to all registries within the
   "Dynamic Link Exchange Protocol (DLEP) Parameters" registry group
   that use the "Specification Required" policy [RFC8126].  Future
   specifications may point to the guidance in this document.

6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8175]  Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B.
              Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175,
              DOI 10.17487/RFC8175, June 2017,
              <https://www.rfc-editor.org/info/rfc8175>.

6.2.  Informative References

   [BCP195]   Best Current Practice 195,
              <https://www.rfc-editor.org/info/bcp195>.
              At the time of writing, this BCP comprises the following:

              Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS
              1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021,
              <https://www.rfc-editor.org/info/rfc8996>.

              Sheffer, Y., Saint-Andre, P., and T. Fossati,
              "Recommendations for Secure Use of Transport Layer
              Security (TLS) and Datagram Transport Layer Security
              (DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
              2022, <https://www.rfc-editor.org/info/rfc9325>.

   [IEEE-802.1AE]
              IEEE, "IEEE Standard for Local and metropolitan area
              networks-Media Access Control (MAC) Security",
              DOI 10.1109/IEEESTD.2018.8585421, IEEE Std 802.1AE-2018,
              December 2018,
              <https://ieeexplore.ieee.org/document/8585421>.

   [IEEE-802.1X]
              IEEE, "802.1X-2020 - IEEE Standard for Local and
              Metropolitan Area Networks--Port-Based Network Access
              Control", DOI 10.1109/IEEESTD.2020.9018454, IEEE Std IEEE-
              802.1X-2020, February 2020,
              <https://ieeexplore.ieee.org/document/9018454>.

   [IEEE8021Q]
              IEEE, "IEEE Standard for Local and Metropolitan Area
              Networks--Bridges and Bridged Networks",
              DOI 10.1109/IEEESTD.2022.10004498, IEEE Std 802.1Q-2022,
              December 2022,
              <https://ieeexplore.ieee.org/document/10004498>.

   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              DOI 10.17487/RFC2474, December 1998,
              <https://www.rfc-editor.org/info/rfc2474>.

   [RFC2475]  Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
              and W. Weiss, "An Architecture for Differentiated
              Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
              <https://www.rfc-editor.org/info/rfc2475>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [RFC8651]  Cheng, B., Wiggins, D., and L. Berger, Ed., "Dynamic Link
              Exchange Protocol (DLEP) Control-Plane-Based Pause
              Extension", RFC 8651, DOI 10.17487/RFC8651, October 2019,
              <https://www.rfc-editor.org/info/rfc8651>.

   [RFC9893]  Cheng, B., Wiggins, D., Ratliff, S., Berger, L., and E.
              Kinzie, Ed., "Dynamic Link Exchange Protocol (DLEP)
              Credit-Based Flow Control Messages and Data Items",
              RFC 9893, DOI 10.17487/RFC9893, January 2026,
              <https://www.rfc-editor.org/info/rfc9893>.

   [RFC9894]  Cheng, B., Wiggins, D., Berger, L., and D. Eastlake 3rd,
              Ed., "Dynamic Link Exchange Protocol (DLEP) Diffserv Aware
              Credit Window Extension", RFC 9894, DOI 10.17487/RFC9894,
              January 2026, <https://www.rfc-editor.org/info/rfc9894>.

Acknowledgments

   The Sub-Data Item format was inspired by Rick Taylor's "Data Item
   Containers".  He also proposed the separation of credit windows from
   traffic classification at IETF 98.  This document was derived from
   [RFC9894] as a result of discussions at IETF 101.  Many useful
   comments were received from contributors to the MANET Working Group,
   notably Ronald in 't Velt and David Black.

   We had the honor of working too briefly with David Wiggins on this
   and related DLEP work.  His contribution to the IETF and publication
   of the first and definitive open-source DLEP implementation have been
   critical to the acceptance of DLEP.  We mourn his passing on November
   26, 2023.  We wish to recognize his guidance, leadership, and
   professional excellence.  We were fortunate to benefit from his
   leadership and friendship.  He shall be missed.

Authors' Addresses

   Bow-Nan Cheng
   MIT Lincoln Laboratory
   Massachusetts Institute of Technology
   244 Wood Street
   Lexington, MA 02421-6426
   United States of America
   Email: bcheng@ll.mit.edu


   David Wiggins


   Lou Berger
   LabN Consulting, L.L.C.
   Email: lberger@labn.net


   Don Fedyk (editor)
   LabN Consulting, L.L.C.
   Email: dfedyk@labn.net