Individual Submission                                            J. Yang
Internet-Draft                                                  W. Cheng
Intended status: Standards Track                                  T. Han
Expires: 3 May 2027                                         China Mobile
                                                                 J. Wang
                                                                 L. Wang
                                                                  Centec
                                                         30 October 2026


              IPFIX Export of RoCEv2 Sequence Observations
               draft-yang-opsawg-ipfix-rocev2-sequence-00

Abstract

   This document specifies an IP Flow Information Export (IPFIX)
   metering and export profile for bounded Packet Sequence Number (PSN)
   observations on provisioned RoCEv2 Reliable Connection SEND and RDMA
   WRITE request streams.  It defines cumulative observations of
   skipped, subsequently observed, expired, repeated, and unclassified
   sequence positions, with explicit observation epochs and
   qualification flags.

   The profile requires complete observation of the provisioned stream
   and defines no packet-loss estimator, retransmission detector, or
   congestion-control action.  Twelve Information Elements describe the
   observation state.  Existing RoCEv2 header Information Elements
   identify the monitored stream.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 3 May 2027.






Yang, et al.               Expires 3 May 2027                   [Page 1]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


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 (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Revised BSD License text as
   described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Revised BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   3
   3.  Applicability and Provisioning  . . . . . . . . . . . . . . .   3
   4.  Identity and Epoch Lifecycle  . . . . . . . . . . . . . . . .   4
   5.  Bounded Sequence Observation Algorithm  . . . . . . . . . . .   5
   6.  Export Profile and Template . . . . . . . . . . . . . . . . .   7
   7.  Collector Processing  . . . . . . . . . . . . . . . . . . . .   9
   8.  Information Element Definitions . . . . . . . . . . . . . . .  10
     8.1.  rdmaSequenceEpochId . . . . . . . . . . . . . . . . . . .  10
     8.2.  rdmaSequenceReportId  . . . . . . . . . . . . . . . . . .  11
     8.3.  rdmaSequenceWindow  . . . . . . . . . . . . . . . . . . .  12
     8.4.  rdmaSequenceFlags . . . . . . . . . . . . . . . . . . . .  12
     8.5.  skippedPsnTotalCount  . . . . . . . . . . . . . . . . . .  13
     8.6.  filledPsnTotalCount . . . . . . . . . . . . . . . . . . .  14
     8.7.  expiredPsnTotalCount  . . . . . . . . . . . . . . . . . .  14
     8.8.  abandonedPsnTotalCount  . . . . . . . . . . . . . . . . .  15
     8.9.  pendingPsnCount . . . . . . . . . . . . . . . . . . . . .  16
     8.10. repeatedPsnTotalCount . . . . . . . . . . . . . . . . . .  16
     8.11. requestPacketTotalCount . . . . . . . . . . . . . . . . .  17
     8.12. unclassifiedLatePacketTotalCount  . . . . . . . . . . . .  18
     8.13. Qualification Flags . . . . . . . . . . . . . . . . . . .  18
   9.  Verification Examples . . . . . . . . . . . . . . . . . . . .  19
   10. Security Considerations . . . . . . . . . . . . . . . . . . .  20
   11. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
   12. Normative References  . . . . . . . . . . . . . . . . . . . .  21
   13. Informative References  . . . . . . . . . . . . . . . . . . .  21
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  22








Yang, et al.               Expires 3 May 2027                   [Page 2]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


1.  Introduction

   Two metering implementations can see the same PSNs yet report
   different gap counts if they use different history, initialization,
   or closure rules.  A common export profile is useful when a collector
   consumes such observations from multiple implementations and must
   distinguish unresolved history from observed packets.  The
   interoperability target is the interpretation of exported
   measurements, not an implementation-specific packet-processing
   architecture.

   [I-D.lin-opsawg-ipfix-rocev2] defines raw RoCEv2 BTH Information
   Elements.  Those fields remain useful for packet traces and
   validation.  This document reuses its destination QP and partition
   identifiers and adds an explicitly specified summary.  A raw-field
   export need not export every packet; however, a sampled packet trace
   cannot reconstruct the exact state of this profile.  No throughput or
   export-volume improvement is claimed without measurement.

   A shared collector may correlate queue and sequence observations, but
   such correlation alone does not establish which link lost a packet or
   whether an ECN policy is effective.  A sequence position may be
   observed after reordering, a retry, duplication, or a capture fault.
   These causes cannot in general be distinguished by the counters
   defined here.

2.  Requirements Language

   The key words MUST, MUST NOT, REQUIRED, SHOULD, SHOULD 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.

3.  Applicability and Provisioning

   The profile covers only a provisioned, unidirectional RoCEv2 Reliable
   Connection request stream using BTH OpCodes 0x00 through 0x0B: SEND
   and RDMA WRITE, including the immediate-data variants in that range.
   Originally transmitted requests advance by one PSN modulo 2^24.
   Other RC operations, UC, UD, XRC, and inferred READ spans are outside
   this profile.  Provisioning MUST establish the operation restriction
   for the whole connection, rather than merely filter the listed
   opcodes.

   RDMA READ can reserve sequence space for response packets;
   [LINUX-RXE] provides a public implementation example.  Filtering READ
   from a mixed stream does not make its remaining request PSNs
   consecutive.  An observed unsupported request or malformed request



Yang, et al.               Expires 3 May 2027                   [Page 3]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   attributable to the provisioned connection MUST close the epoch with
   profileViolation and disable metering for that connection until
   explicitly reprovisioned.  The offending packet is not counted.  A
   subsequent SEND or WRITE MUST NOT automatically re-enable the
   profile.  Response packets and CNPs do not change this request state.

   The observation point MUST process all request packets in the
   provisioned scope, without sampling, selective omission, or known
   capture loss, and MUST cover all paths carrying that stream.  A
   single ECMP branch without complete coverage is not sufficient.
   Deployment provisioning MUST establish namespace separation and path
   coverage.  If capture completeness cannot be established, this
   profile MUST NOT be enabled.  A capture gap closes affected epochs
   with captureDiscontinuity; metering resumes only after complete
   observation has been re-established and starts fresh state.  An
   unclassifiable capture fault affecting several contexts closes all
   contexts that may be affected.

   Serial interpretation also requires that a packet cannot legitimately
   be separated from the current high-water position by half or more of
   the PSN serial space, including very old retries.  This is an
   applicability condition, not something a 24-bit field alone can
   verify.  If endpoint behavior or retention bounds cannot establish
   it, this profile MUST NOT be used for that connection.  Known
   violations close the epoch.  An exactly half-space distance is always
   treated as ambiguous.

4.  Identity and Epoch Lifecycle

   The record key comprises the IPFIX Transport Session, Observation
   Domain ID, observationPointId, source and destination IP addresses of
   the RoCEv2 packet, rdmaDestinationQP, rdmaPartitionKey, any
   additional tenant or tunnel namespace required to avoid collisions,
   and rdmaSequenceEpochId.  A physical interface identifier alone is
   not a tenant namespace.  Address family and encapsulation layer MUST
   be fixed and unambiguous in each Template.  UDP source port MUST NOT
   split a connection context.














Yang, et al.               Expires 3 May 2027                   [Page 4]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   The Exporting Process MUST allocate a nonzero, monotonically
   increasing epoch ID across all contexts in each Transport Session and
   Observation Domain when the first report of that epoch is serialized.
   Thus first reports are serialized in increasing epoch-ID order; the
   ID does not order the first packet times.  An ID MUST NOT be reused
   in that scope.  IDs need not be consecutive at a collector.  A new
   Transport Session starts fresh metering state.  An epoch is closed on
   a known connection-generation change, idle expiration, policy or
   window change, capture discontinuity, profile violation, resource
   eviction, serial discontinuity, or impending counter/report-ID
   exhaustion.

   Unless connection generation is independently established by trusted
   provisioning or endpoint integration, every report MUST set
   generationUnverified.  A local epoch is not proof of a connection
   lifetime.  Neither an idle timer nor an apparently new initial PSN
   proves that destination QP reuse was detected.  Known connection
   restarts MUST NOT be joined even if addresses, QP, and PSN repeat.

   A serial discontinuity caused by a valid eligible request closes the
   old epoch before counting that request, then starts a new epoch with
   that request.  The request is counted exactly once.  Other closure
   causes require the applicable validity conditions to be re-
   established before restart.  A final snapshot abandons all pending
   positions.  If it cannot be exported because of failure or resource
   exhaustion, the collector sees an incomplete epoch; a final record is
   never fabricated by the collector.

5.  Bounded Sequence Observation Algorithm

   Let M=2^24 and 1<=W<=2^22.  The exporter maintains a local extended
   integer H, a fixed initial extended position S, and a retained
   interval [L,H], where L=max(S,H-W+1).  Retained positions are either
   SEEN or PENDING.  Positions before S or before L are unclassified,
   including positions numerically within W of H but preceding the first
   observed request.  No initialized prefix is presumed seen or pending.
   Local extended integers are not exported PSN values.

   For an arriving PSN p, compute u=(p-(H mod M)) mod M.  If u=M/2,
   comparison is ambiguous.  Otherwise d=u for u<M/2, and d=u-M for
   u>M/2.  This uses the serial comparison boundary in [RFC1982].
   Implementations MUST use checked arithmetic for counters and local
   extended positions; they MUST close and restart before overflow
   rather than wrap a cumulative counter.







Yang, et al.               Expires 3 May 2027                   [Page 5]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


    +===========+=====================================================+
    | Condition | Required action                                     |
    +===========+=====================================================+
    | No active | Set S=H=p; retain only p as SEEN; requests=1; all   |
    | epoch     | other counters=0.                                   |
    +-----------+-----------------------------------------------------+
    | u=M/2 or  | Close with serialDiscontinuity; start fresh state   |
    | d>W       | with p; do not account p to the old epoch.          |
    +-----------+-----------------------------------------------------+
    | 1<=d<=W   | Count request; add H+1 through H+d-1 as PENDING and |
    |           | add d-1 to skipped; advance H by d; mark H SEEN;    |
    |           | expire each pending position below new L once.      |
    +-----------+-----------------------------------------------------+
    | d<=0 and  | Count request; change that position to SEEN;        |
    | H+d in    | increment filled once.                              |
    | [L,H] is  |                                                     |
    | PENDING   |                                                     |
    +-----------+-----------------------------------------------------+
    | d<=0 and  | Count request; increment repeated.                  |
    | H+d in    |                                                     |
    | [L,H] is  |                                                     |
    | SEEN      |                                                     |
    +-----------+-----------------------------------------------------+
    | d<=0 and  | Count request; increment unclassifiedLate; do not   |
    | H+d<L     | change H or retained state.                         |
    +-----------+-----------------------------------------------------+

                      Table 1: Per-Request Transitions

   At most W position labels are retained.  Ordinary reports do not
   reset counters or pending state.  On closure, add the number of
   pending positions to abandoned and clear pending.  A position can be
   filled or expired or abandoned, never more than one of these.  Expiry
   is caused by high-water advance, not by an elapsed-time estimate of
   network loss.

   skipped = filled + expired + abandoned + pending
   0 <= pending <= W - 1
   repeated + unclassifiedLate + filled <= requests - 1

   These relationships MUST hold at every snapshot.  Abandoned is zero
   in an active epoch and pending is zero in a final epoch.  Their
   validity establishes internal accounting only.  A malicious exporter
   can satisfy them with fabricated measurements.







Yang, et al.               Expires 3 May 2027                   [Page 6]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


6.  Export Profile and Template

   This profile uses IPFIX over TCP [RFC7011] to order reports from an
   Exporting Process.  A profile implementation MUST support this
   binding.  Selecting TCP for this profile does not remove the general
   implementation requirements of RFC 7011, including its SCTP
   requirement, and does not update that RFC.  Reconnection creates a
   new session and new epochs.  TCP reliability does not guarantee
   delivery of a final report after process or connection failure.

   Each Data Record MUST contain every field listed in Table 2, plus any
   required namespace keys.  It MUST be an atomic snapshot of a single
   epoch.  All counters are cumulative from the first accounted request.
   The report ID starts at one and increments once per serialized
   snapshot; retransmission of an identical snapshot retains its ID.
   The ID and each total counter MUST NOT wrap. flowStartMilliseconds
   and flowEndMilliseconds are the first and last accounted packet
   arrival times; they do not measure the export delay or the final
   closure time.

   A Template MUST use exactly one address family.  A field is not
   conditionally omitted within a record.  All named fields occur once
   in this profile.  The exporter MUST advertise the Flow Keys using the
   Flow Keys Options Template in RFC 7011, including record-level
   namespace and epoch identifiers but excluding report ID.  The
   Transport Session and Observation Domain are outer context.  An
   observationPointId change requires a new epoch.  The unassigned
   identifiers in this draft and its dependency are not usable wire
   numbers.






















Yang, et al.               Expires 3 May 2027                   [Page 7]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


       +=================================================+========+
       | Information Element                             | Octets |
       +=================================================+========+
       | observationPointId                              | 8      |
       +-------------------------------------------------+--------+
       | sourceIPv4Address / sourceIPv6Address           | 4 / 16 |
       +-------------------------------------------------+--------+
       | destinationIPv4Address / destinationIPv6Address | 4 / 16 |
       +-------------------------------------------------+--------+
       | rdmaDestinationQP                               | 4      |
       +-------------------------------------------------+--------+
       | rdmaPartitionKey                                | 2      |
       +-------------------------------------------------+--------+
       | flowStartMilliseconds                           | 8      |
       +-------------------------------------------------+--------+
       | flowEndMilliseconds                             | 8      |
       +-------------------------------------------------+--------+
       | rdmaSequenceEpochId                             | 8      |
       +-------------------------------------------------+--------+
       | rdmaSequenceReportId                            | 8      |
       +-------------------------------------------------+--------+
       | rdmaSequenceWindow                              | 4      |
       +-------------------------------------------------+--------+
       | rdmaSequenceFlags                               | 2      |
       +-------------------------------------------------+--------+
       | skippedPsnTotalCount                            | 8      |
       +-------------------------------------------------+--------+
       | filledPsnTotalCount                             | 8      |
       +-------------------------------------------------+--------+
       | expiredPsnTotalCount                            | 8      |
       +-------------------------------------------------+--------+
       | abandonedPsnTotalCount                          | 8      |
       +-------------------------------------------------+--------+
       | pendingPsnCount                                 | 4      |
       +-------------------------------------------------+--------+
       | repeatedPsnTotalCount                           | 8      |
       +-------------------------------------------------+--------+
       | requestPacketTotalCount                         | 8      |
       +-------------------------------------------------+--------+
       | unclassifiedLatePacketTotalCount                | 8      |
       +-------------------------------------------------+--------+

                 Table 2: Profile Fields in Example Order

   With assigned standard IEs, no extra namespace fields, and full-
   length encodings as shown, there are 19 fields: 120 octets per IPv4
   Data Record or 144 per IPv6 Data Record.  The Template Record is 80
   octets (4+19*4); its containing Template Set is 84 octets before any



Yang, et al.               Expires 3 May 2027                   [Page 8]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   padding.  These are distinct from the IPFIX Message length.  An
   enterprise-specific field adds a four-octet PEN to its Field
   Specifier; therefore these Template lengths do not apply unchanged to
   experimental PEN mappings.  No Template ID is reserved by this
   profile.  Other legal integer lengths require explicit agreement and
   MUST retain the same semantics.

   The destination QP uses the unsigned32 definition from
   [I-D.lin-opsawg-ipfix-rocev2], with its upper eight bits zero.
   rdmaPartitionKey is unsigned16.  Both remain dependent on the
   referenced individual proposal; its progression or allocation is not
   assumed.  Prior to publication, the definitions and assignments must
   be resolved with that work or replaced through explicit review,
   rather than silently inventing competing fields.

7.  Collector Processing

   The collector MUST validate Template bindings, field ranges, required
   keys, and the arithmetic relationships in Section 5.  It compares
   cumulative counters only for an identical full epoch key.  Window,
   connection-generation qualification, flow start time, and namespace
   are immutable within the epoch.  Closure-reason flags appear only in
   final records.  Each final record has pending zero; each non-final
   record has abandoned zero.  Unknown flag bits make the record an
   unsupported qualification; the collector MUST preserve the raw record
   and MUST NOT derive unqualified measurements from it.

   For a retained epoch, a larger report ID is processed only if total
   counters do not decrease and immutable fields agree.  A report gap,
   including a first received ID greater than one, marks missing report
   coverage.  It does not invalidate an otherwise self-consistent
   cumulative total, but differences across the gap MUST NOT be assigned
   to the missing subintervals.  An identical repeat of the latest
   report ID is ignored; different decoded content for that ID
   invalidates the epoch.  A smaller report ID is stale and MUST NOT
   modify already published values.  An implementation MAY keep older
   raw records for offline validation.

   After an accepted final record, no larger report ID can extend that
   epoch.  A conflicting or extending record received while closure
   state is retained invalidates it.  Collectors MUST set finite
   resource and retention limits and expose those limits to their
   operators.  On retirement, they MUST preserve an outcome of complete,
   incomplete, or invalid in the stored result.  Offline recomputation
   from an explicit archive is a separate operation.






Yang, et al.               Expires 3 May 2027                   [Page 9]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   For bounded retirement, the collector retains an epoch-admission
   high-water ID per Transport Session and Observation Domain.  It first
   looks up retained context by epoch ID, rejecting a changed full key
   for that ID.  For an unknown epoch, an ID at or below the high-water
   ID is an orphan and MUST NOT create or reopen context.  An unknown
   larger ID advances the high-water ID, including when admission is
   refused because of resource limits.  It can create a new context with
   missing initial reports explicitly qualified.  This rule relies on
   the specified ordering of first reports.  Retirement therefore needs
   no unbounded tombstone set.  The high-water ID is cleared only with a
   new Transport Session.  A collector MUST NOT silently forget it while
   continuing that session.

   Silence alone is not a final report.  A session failure or configured
   inactivity timeout without finalEpoch leaves the epoch incomplete.
   Complete report coverage requires reports from ID one through a valid
   final record without report gaps; metering qualifications still apply
   and this does not imply coverage of an entire connection lifetime.  A
   missing final does not erase useful observed counters, but
   outstanding positions remain unresolved.  Collectors MUST distinguish
   metering qualifications, report gaps, and collector resource drops
   from network loss.

   Expired positions MUST NOT be labeled lost packets.  Repeated PSNs
   MUST NOT be labeled confirmed retransmissions.  Filled positions MUST
   NOT be labeled proven reorderings.  Aggregate counters from different
   observation points MUST NOT be subtracted to claim a loss location:
   the records lack common event identities, and windows, paths, and
   epochs may differ.

8.  Information Element Definitions

   The following definitions follow [RFC7012] and [RFC7013].  Each
   requested IE has status current and reference RFC XXXX.  TBD labels
   denote unassigned Element IDs.  The units none are intentional for
   sequence-position quantities; packets is used only for counts of
   observed packet arrivals.

8.1.  rdmaSequenceEpochId

   Nonzero epoch identifier allocated monotonically across contexts in a
   Transport Session and Observation Domain.  It is never reused within
   that scope.








Yang, et al.               Expires 3 May 2027                  [Page 10]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD1                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | identifier                                  |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                      Table 3: Registration Properties

8.2.  rdmaSequenceReportId

   Snapshot identifier starting at one and increasing per serialized
   report within an epoch.  Retransmission of an identical snapshot
   retains the identifier.

   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD2                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | identifier                                  |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                      Table 4: Registration Properties




Yang, et al.               Expires 3 May 2027                  [Page 11]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


8.3.  rdmaSequenceWindow

   Configured history width W in PSN positions, 1 through 4194304;
   constant throughout an epoch.  A position is a serial-space value,
   not a claim about a distinct network packet.

   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD3                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned32                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | quantity                                    |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                      Table 5: Registration Properties

8.4.  rdmaSequenceFlags

   Numeric qualification masks defined in the flags table; serialized in
   network byte order.




















Yang, et al.               Expires 3 May 2027                  [Page 12]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD4                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned16                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | flags                                       |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                      Table 6: Registration Properties

8.5.  skippedPsnTotalCount

   Number of sequence positions introduced as PENDING by bounded forward
   advances since epoch creation.

   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD5                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | totalCounter                                |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                      Table 7: Registration Properties





Yang, et al.               Expires 3 May 2027                  [Page 13]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


8.6.  filledPsnTotalCount

   Number of PENDING positions changed to SEEN while retained.  A
   position contributes at most once.

   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD6                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | totalCounter                                |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                      Table 8: Registration Properties

8.7.  expiredPsnTotalCount

   Number of PENDING positions retired by high-water advance outside the
   retained window.





















Yang, et al.               Expires 3 May 2027                  [Page 14]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD7                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | totalCounter                                |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                      Table 9: Registration Properties

8.8.  abandonedPsnTotalCount

   Number of PENDING positions retired at epoch closure.  Zero before
   closure.

   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD8                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | totalCounter                                |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                     Table 10: Registration Properties





Yang, et al.               Expires 3 May 2027                  [Page 15]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


8.9.  pendingPsnCount

   Current PENDING positions; at most W-1 and zero on closure.

   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD9                                        |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned32                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | quantity                                    |
   +---------------------+---------------------------------------------+
   | Units               | none                                        |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                     Table 11: Registration Properties

8.10.  repeatedPsnTotalCount

   Number of accounted packets whose PSN maps to an already SEEN
   retained position.






















Yang, et al.               Expires 3 May 2027                  [Page 16]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD10                                       |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | totalCounter                                |
   +---------------------+---------------------------------------------+
   | Units               | packets                                     |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                     Table 12: Registration Properties

8.11.  requestPacketTotalCount

   All eligible requests accounted to the epoch, including its first
   request, repeated arrivals, and unclassified late arrivals.  Excludes
   offending profile-violation packets and responses.

   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD11                                       |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | totalCounter                                |
   +---------------------+---------------------------------------------+
   | Units               | packets                                     |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                     Table 13: Registration Properties




Yang, et al.               Expires 3 May 2027                  [Page 17]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


8.12.  unclassifiedLatePacketTotalCount

   Accounted requests that map before L, including before the first
   observed position S.  Their earlier observation status is not known.

   +=====================+=============================================+
   | Property            | Value                                       |
   +=====================+=============================================+
   | Element ID          | TBD12                                       |
   +---------------------+---------------------------------------------+
   | Abstract Data Type  | unsigned64                                  |
   +---------------------+---------------------------------------------+
   | Data Type Semantics | totalCounter                                |
   +---------------------+---------------------------------------------+
   | Units               | packets                                     |
   +---------------------+---------------------------------------------+
   | Range               | As specified in the                         |
   |                     | description and profile                     |
   +---------------------+---------------------------------------------+
   | Status              | current                                     |
   +---------------------+---------------------------------------------+
   | Reference           | RFC XXXX                                    |
   +---------------------+---------------------------------------------+

                     Table 14: Registration Properties

8.13.  Qualification Flags

   The following hexadecimal masks, not bit positions in a drawing,
   define the wire value.  Closure causes can be combined.
   generationUnverified is set in every report unless generation was
   independently established.  Other defined reason bits MUST be zero in
   non-final reports; finalEpoch alone permits ordinary closure.
   Senders MUST set undefined bits to zero.

















Yang, et al.               Expires 3 May 2027                  [Page 18]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


     +========+======================+===============================+
     | Mask   | Name                 | Meaning                       |
     +========+======================+===============================+
     | 0x0001 | finalEpoch           | Epoch is closed.              |
     +--------+----------------------+-------------------------------+
     | 0x0002 | profileViolation     | Unsupported or malformed      |
     |        |                      | request/profile violation.    |
     +--------+----------------------+-------------------------------+
     | 0x0004 | captureDiscontinuity | Complete observation          |
     |        |                      | interrupted.                  |
     +--------+----------------------+-------------------------------+
     | 0x0008 | stateExhaustion      | Context resource eviction.    |
     +--------+----------------------+-------------------------------+
     | 0x0010 | serialDiscontinuity  | Unsupported jump or ambiguous |
     |        |                      | serial interpretation.        |
     +--------+----------------------+-------------------------------+
     | 0x0020 | generationUnverified | Connection generation not     |
     |        |                      | independently established.    |
     +--------+----------------------+-------------------------------+
     | 0xFFC0 | Unassigned           | Reserved for future IANA      |
     |        |                      | assignment.                   |
     +--------+----------------------+-------------------------------+

                          Table 15: Defined Masks

9.  Verification Examples

   With W=4 and PSNs 100,102,101,103,102: requests=5, skipped=1,
   filled=1, repeated=1, pending=expired=abandoned=unclassifiedLate=0.
   These observations are compatible with multiple network histories.

   With W=4 and PSNs 100,99,100: position 99 precedes S even though it
   lies inside the nominal width.  The result is requests=3,
   unclassifiedLate=1, repeated=1, skipped=filled=pending=0.  Treating
   99 as an initialized missing or previously seen position is
   incorrect.

   With W=4 and PSNs 100,102,106: skipped=4, expired=1, pending=3.
   Closing produces abandoned=3 and pending=0.  A later packet cannot
   fill the closed result.

   PSNs 16777214,16777215,0,1 advance continuously with no skipped
   positions.  A jump of 2^23 closes as ambiguous.  With W=1, any
   forward advance greater than one starts a fresh epoch; no pending
   positions exist.






Yang, et al.               Expires 3 May 2027                  [Page 19]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   An observed READ disables the provisioned profile, including after
   subsequent SEND packets.  A capture fault requires a fresh epoch
   after capture validity returns.  Neither mechanism carries pending
   state across the interruption.

10.  Security Considerations

   The IPFIX security considerations in [RFC7011] apply.  Exporters and
   collectors for this profile MUST support TLS 1.3 [RFC8446] over TCP
   and MUST use mutually authenticated, confidential export sessions
   with explicitly authorized peers.  Current TLS deployment guidance is
   in [RFC9325].  A transport reconnect changes the epoch scope even
   when certificates identify the same exporter.

   Addresses, QP identifiers, partition identifiers, and times can
   reveal tenant activity.  Operators SHOULD restrict observation and
   retention to the required scope and authorize collector access.
   Malformed packets and fabricated identities can exhaust state or
   induce closure storms.  Exporters MUST bound concurrent contexts and
   window size, restrict provisioning to authorized scopes, and expose
   capture/resource failures.  Resource controls can lose reports; they
   MUST NOT silently convert incomplete observations into complete
   results.

   An authenticated exporter may still be faulty or compromised.
   Arithmetic validation does not establish truth.  This profile
   supplies no instructions to endpoints and MUST NOT be used as
   authoritative evidence to force retransmission or disable congestion
   feedback.

11.  IANA Considerations

   IANA is requested to allocate the twelve IEs in Section 8 in the
   IPFIX Information Elements registry [IANA-IPFIX].  No numeric IDs are
   requested.  Experimental implementations MUST use enterprise-specific
   IEs under an assigned PEN and an explicitly shared mapping; they MUST
   NOT use TBD labels or unassigned standard numbers as wire values.

   IANA is also requested to create an rdmaSequenceFlags registry within
   IPFIX assignments.  Entries are individual unsigned16 masks,
   description, and reference.  Initial entries are masks 0x0001 through
   0x0020 in Table 15; individual masks 0x0040 through 0x8000 are
   unassigned.  The registration policy is Specification Required
   [RFC8126].  Review must verify a nonoverlapping mask and define
   epoch/collector compatibility.  A change to the observation algorithm
   or a new operation profile requires explicit version or IE
   separation; a flag alone MUST NOT silently redefine existing
   counters.



Yang, et al.               Expires 3 May 2027                  [Page 20]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


12.  Normative References

   [I-D.lin-opsawg-ipfix-rocev2]
              Lin, C. and H. Zhang, "Export of RoCEv2 Base Transport
              Header (BTH) Information Using IP Flow Information Export
              (IPFIX)", Work in Progress, Internet-Draft, draft-lin-
              opsawg-ipfix-rocev2-01, 1 September 2026,
              <https://datatracker.ietf.org/doc/html/draft-lin-opsawg-
              ipfix-rocev2-01>.

   [RFC1982]  Elz, R. and R. Bush, "Serial Number Arithmetic", RFC 1982,
              DOI 10.17487/RFC1982, August 1996,
              <https://www.rfc-editor.org/info/rfc1982>.

   [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>.

   [RFC7011]  Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
              "Specification of the IP Flow Information Export (IPFIX)
              Protocol for the Exchange of Flow Information", STD 77,
              RFC 7011, DOI 10.17487/RFC7011, September 2013,
              <https://www.rfc-editor.org/info/rfc7011>.

   [RFC7012]  Claise, B., Ed. and B. Trammell, Ed., "Information Model
              for IP Flow Information Export (IPFIX)", RFC 7012,
              DOI 10.17487/RFC7012, September 2013,
              <https://www.rfc-editor.org/info/rfc7012>.

   [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>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

13.  Informative References

   [IANA-IPFIX]
              IANA, "IP Flow Information Export (IPFIX) Entities",
              <https://www.iana.org/assignments/ipfix>.








Yang, et al.               Expires 3 May 2027                  [Page 21]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   [LINUX-RXE]
              Linux Kernel Organization, "Linux Kernel Soft-RoCE (RXE)
              Requester PSN Allocation Implementation",
              <https://github.com/torvalds/linux/blob/master/drivers/infiniband/
              sw/rxe/rxe_req.c>.

   [RFC7013]  Trammell, B. and B. Claise, "Guidelines for Authors and
              Reviewers of IP Flow Information Export (IPFIX)
              Information Elements", BCP 184, RFC 7013,
              DOI 10.17487/RFC7013, September 2013,
              <https://www.rfc-editor.org/info/rfc7013>.

   [RFC8126]  RFC Editor, "Guidelines for Writing an IANA Considerations
              Section in RFCs", RFC 8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [RFC9325]  RFC Editor, "Recommendations for Secure Use of Transport
              Layer Security (TLS) and Datagram Transport Layer Security
              (DTLS)", RFC 9325, November 2022,
              <https://www.rfc-editor.org/info/rfc9325>.

Authors' Addresses

   Jin Yang
   China Mobile
   Beijing
   100053
   China
   Email: yangjinwl@chinamobile.com


   Weiqiang Cheng
   China Mobile
   Beijing
   100053
   China
   Email: chengweiqiang@chinamobile.com


   Tingting Han
   China Mobile
   Beijing
   100053
   China
   Email: hantingting@chinamobile.com






Yang, et al.               Expires 3 May 2027                  [Page 22]

Internet-Draft        RoCEv2 Sequence Observations          October 2026


   Junjie Wang
   Centec
   Suzhou
   215000
   China
   Email: wangjj@centec.com


   Li Wang
   Centec
   Suzhou
   215000
   China
   Email: wangl@centec.com





































Yang, et al.               Expires 3 May 2027                  [Page 23]