IPPM                                                             H. Song
Internet-Draft                                                 Futurewei
Intended status: Standards Track                                B. Gafni
Expires: 19 February 2023                                         Nvidia
                                                            F. Brockners
                                                                   Cisco
                                                             S. Bhandari
                                                             Thoughtspot
                                                              T. Mizrahi
                                                                  Huawei
                                                          18 August 2022


                      In-situ OAM Direct Exporting
                 draft-ietf-ippm-ioam-direct-export-10

Abstract

   In-situ Operations, Administration, and Maintenance (IOAM) is used
   for recording and collecting operational and telemetry information.
   Specifically, IOAM allows telemetry data to be pushed into data
   packets while they traverse the network.  This document introduces a
   new IOAM option type (denoted IOAM-Option-Type) called the Direct
   Export (DEX) Option-Type, which is used as a trigger for IOAM data to
   be directly exported or locally aggregated without being pushed into
   in-flight data packets.  The exporting method and format are outside
   the scope of this document.

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 19 February 2023.







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Copyright Notice

   Copyright (c) 2022 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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirement Language  . . . . . . . . . . . . . . . . . .   3
     2.2.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  The Direct Exporting (DEX) IOAM-Option-Type . . . . . . . . .   3
     3.1.  Overview  . . . . . . . . . . . . . . . . . . . . . . . .   4
       3.1.1.  DEX Packet Selection  . . . . . . . . . . . . . . . .   5
       3.1.2.  Responding to the DEX Trigger . . . . . . . . . . . .   6
     3.2.  The DEX Option-Type Format  . . . . . . . . . . . . . . .   7
   4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     4.1.  IOAM Type . . . . . . . . . . . . . . . . . . . . . . . .   9
     4.2.  IOAM DEX Flags  . . . . . . . . . . . . . . . . . . . . .   9
     4.3.  IOAM DEX Extension-Flags  . . . . . . . . . . . . . . . .   9
   5.  Performance Considerations  . . . . . . . . . . . . . . . . .  10
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  12
   Appendix A.  Notes About the History of this Document . . . . . .  14
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

   IOAM [RFC9197] is used for monitoring traffic in the network, and for
   incorporating IOAM data fields (denoted IOAM-Data-Fields) into in-
   flight data packets.







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   IOAM makes use of four possible IOAM-Option-Types, defined in
   [RFC9197]: Pre-allocated Trace Option-Type, Incremental Trace Option-
   Type, Proof of Transit (POT) Option-Type, and Edge-to-Edge Option-
   Type.

   This document defines a new IOAM-Option-Type called the Direct Export
   (DEX) Option-Type.  This Option-Type is used as a trigger for IOAM
   nodes to locally aggregate and process IOAM data, and/or to export it
   to a receiving entity (or entities).  Throughout the document this
   functionality is referred to as collection and/or exporting.  A
   "receiving entity" in this context is an entity that resides within
   the IOAM domain such as a collector, analyzer, controller,
   decapsulating node, or a software module in one of the IOAM nodes.

   Note that even though the IOAM-Option-Type is called "Direct Export",
   it depends on the deployment whether the receipt of a packet with DEX
   Option-Type leads to the creation of another packet.  Some
   deployments might simply use the packet with the DEX Option-Type to
   trigger local processing of OAM data.  The functionality of this
   local processing is not within the scope of this document.

2.  Conventions

2.1.  Requirement Language

   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.

2.2.  Terminology

   Abbreviations used in this document:

   IOAM:      In-situ Operations, Administration, and Maintenance

   OAM:       Operations, Administration, and Maintenance [RFC6291]

   DEX:       Direct EXporting

3.  The Direct Exporting (DEX) IOAM-Option-Type









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3.1.  Overview

   The DEX Option-Type is used as a trigger for collecting IOAM data
   locally or for exporting it to a receiving entity (or entities).
   Specifically, the DEX Option-Type can be used as a trigger for
   collecting IOAM data by an IOAM node and locally aggregating it;
   thus, this aggregated data can be periodically pushed to a receiving
   entity, or pulled by a receiving entity on-demand.

   This Option-Type is incorporated into data packets by an IOAM
   encapsulating node, and removed by an IOAM decapsulating node, as
   illustrated in Figure 1.  The Option-Type can be read but not
   modified by transit nodes.  Note: the terms IOAM encapsulating,
   decapsulating and transit nodes are as defined in [RFC9197].

                                      ^
                                      |Exported IOAM data
                                      |
                                      |
                                      |
                +--------------+------+-------+--------------+
                |              |              |              |
                |              |              |              |
  User      +---+----+     +---+----+     +---+----+     +---+----+
  packets   |Encapsu-|     | Transit|     | Transit|     |Decapsu-|
  --------->|lating  |====>| Node   |====>| Node   |====>|lating  |---->
            |Node    |     | A      |     | B      |     |Node    |
            +--------+     +--------+     +--------+     +--------+
            Insert DEX       Export         Export       Remove DEX
            option and      IOAM data      IOAM data     option and
            export data                                  export data


                        Figure 1: DEX Architecture

   The DEX Option-Type is used as a trigger to collect and/or export
   IOAM data.  The trigger applies to transit nodes, the decapsulating
   node, and the encapsulating node:













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   *  An IOAM encapsulating node configured to incorporate the DEX
      Option-Type encapsulates (possibly a subset of) the packets it
      forwards with the DEX Option-Type, and MAY export and/or collect
      the requested IOAM data immediately.  Only IOAM encapsulating
      nodes are allowed to add the DEX Option-Type to a packet.  An IOAM
      encapsulating node can generate probe packets that incorporate the
      DEX Option-Type.  These probe packets can be generated
      periodically or on-demand (for example triggered by the management
      plane).  The specification of such probe packets is outside the
      scope of this document.

   *  A transit node that processes a packet with the DEX Option-Type
      MAY export and/or collect the requested IOAM data.

   *  An IOAM decapsulating node that processes a packet with the DEX
      Option-Type MAY export and/or collect the requested IOAM data, and
      MUST decapsulate the IOAM header.

   As in [RFC9197], the DEX Option-Type can be incorporated into all or
   a subset of the traffic that is forwarded by the encapsulating node,
   as further discussed in Section 3.1.1 below.  Moreover, IOAM nodes
   respond to the DEX trigger by exporting and/or collecting IOAM data
   either for all traversing packets that carry the DEX Option-Type, or
   selectively only for a subset of these packets, as further discussed
   in Section 3.1.2 below.

3.1.1.  DEX Packet Selection

   If an IOAM encapsulating node incorporates the DEX Option-Type into
   all the traffic it forwards it may lead to an excessive amount of
   exported data, which may overload the network and the receiving
   entity.  Therefore, an IOAM encapsulating node that supports the DEX
   Option-Type MUST support the ability to incorporate the DEX Option-
   Type selectively into a subset of the packets that are forwarded by
   it.

   Various methods of packet selection and sampling have been previously
   defined, such as [RFC7014] and [RFC5475].  Similar techniques can be
   applied by an IOAM encapsulating node to apply DEX to a subset of the
   forwarded traffic.

   The subset of traffic that is forwarded or transmitted with a DEX
   Option-Type SHOULD NOT exceed 1/N of the interface capacity on any of
   the IOAM encapsulating node's interfaces.  It is noted that this
   requirement applies to the total traffic that incorporates a DEX
   Option-Type, including traffic that is forwarded by the IOAM
   encapsulating node and probe packets that are generated by the IOAM
   encapsulating node.  In this context N is a parameter that can be



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   configurable by network operators.  If there is an upper bound, M, on
   the number of IOAM transit nodes in any path in the network, then it
   is RECOMMENDED to use an N such that N >> M (i.e., N is much greater
   than M).  The rationale is that a packet that includes a DEX Option-
   Type may trigger an exported packet from each IOAM transit node along
   the path for a total of M exported packets.  Thus, if N >> M then the
   number of exported packets is significantly lower than the number of
   data packets forwarded by the IOAM encapsulating node.  If there is
   no prior knowledge about the network topology or size, it is
   RECOMMENDED to use N>100.

3.1.2.  Responding to the DEX Trigger

   The DEX Option-Type specifies which IOAM-Data-Fields should be
   exported and/or collected, as specified in Section 3.2.  As mentioned
   above, the data can be locally collected, and optionally can be
   aggregated and exported to a receiving entity, either proactively or
   on-demand.  If IOAM data is exported, the format and encapsulation of
   the packet that contains the exported data is not within the scope of
   the current document.  For example, the export format can be based on
   [I-D.spiegel-ippm-ioam-rawexport].

   An IOAM node that performs DEX-triggered exporting MUST support the
   ability to limit the rate of the exported packets.  The rate of
   exported packets SHOULD be limited so that the number of exported
   packets is significantly lower than the number of packets that are
   forwarded by the device.  The exported data rate SHOULD NOT exceed 1/
   N of the interface capacity on any of the IOAM node's interfaces.  It
   is RECOMMENDED to use N>100.  Depending on the IOAM node's
   architecture considerations, the export rate may be limited to a
   lower number in order to avoid loading the IOAM node.  An IOAM node
   MAY maintain a counter or a set of counters that count the events in
   which the IOAM node receives a packet with the DEX Option-Type and
   does not collect and/or export data due to the rate limits.

   IOAM nodes SHOULD NOT be configured to export packets over a path or
   a tunnel that is subject to IOAM direct exporting.  Furthermore, IOAM
   encapsulating nodes that can identify a packet as an IOAM exported
   packet MUST NOT push a DEX Option-Type into such a packet.  This
   requirement is intended to prevent nested exporting and/or exporting
   loops.

   A transit or decapsulating IOAM node that receives an unknown IOAM-
   Option-Type ignores it (as defined in [RFC9197]), and specifically
   nodes that do not support the DEX Option-Type ignore it.  Note that
   as per [RFC9197] a decapsulating node removes the IOAM encapsulation
   and all its IOAM-Option-Types.  Specifically, this applies to the
   case where one of these options is a (possibly unknown) DEX Option-



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   Type.  The ability to skip over a (possibly unknown) DEX Option-Type
   in the parsing or in the decapsulation procedure is dependent on the
   specific encapsulation, which is outside the scope of this document.
   For example, when IOAM is encapsulated in IPv6
   [I-D.ietf-ippm-ioam-ipv6-options] the DEX Option-Type is incorporated
   either in a Hop-by-Hop options header or in a Destination options
   header, and thus can be skipped using the length field in the options
   header.

3.2.  The DEX Option-Type Format

   The format of the DEX Option-Type is depicted in Figure 2.  The
   length of the DEX Option-Type is at least 8 octets.  The DEX Option-
   Type MAY include one or more optional fields.  The existence of the
   optional fields is indicated by the corresponding flags in the
   Extension-Flags field.  Two optional fields are defined in this
   document, the Flow ID and the Sequence Number fields.  Every optional
   field MUST be exactly 4 octets long.  Thus, the Extension-Flags field
   explicitly indicates the length of the DEX Option-Type.  Defining a
   new optional field requires an allocation of a corresponding flag in
   the Extension-Flags field, as specified in Section 4.2.



       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        Namespace-ID           |     Flags     |Extension-Flags|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |               IOAM-Trace-Type                 |   Reserved    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Flow ID (optional)                    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                     Sequence Number  (Optional)               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 2: DEX Option-Type Format

   Namespace-ID    A 16-bit identifier of the IOAM namespace, as defined
                   in [RFC9197].

   Flags           An 8-bit field, comprised of 8 one-bit subfields.
                   Flags are allocated by IANA, as defined in
                   Section 4.2.

   Extension-Flags  An 8-bit field, comprised of 8 one-bit subfields.





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                   Extension-Flags are allocated by IANA, as defined in
                   Section 4.3.  Every bit in the Extension-Flag field
                   that is set to 1 indicates the existence of a
                   corresponding optional 4-octet field.  An IOAM node
                   that receives a DEX Option-Type with an unknown flag
                   set to 1 MUST ignore the corresponding optional
                   field.

   IOAM-Trace-Type  A 24-bit identifier which specifies which IOAM-Data-
                   Fields should be exported.  The format of this field
                   is as defined in [RFC9197].  Specifically, the bit
                   that corresponds to the Checksum Complement IOAM-
                   Data-Field SHOULD be assigned to be zero by the IOAM
                   encapsulating node, and ignored by transit and
                   decapsulating nodes.  The reason for this is that the
                   Checksum Complement is intended for in-flight packet
                   modifications and is not relevant for direct
                   exporting.

   Reserved        This field MUST be ignored by the receiver.

   Optional fields  The optional fields, if present, reside after the
                   Reserved field.  The order of the optional fields is
                   according to the order of the respective bits,
                   starting from the most significant bit, that are
                   enabled in the Extension-Flags field.  Each optional
                   field is 4 octets long.

   Flow ID         An optional 32-bit field representing the flow
                   identifier.  If the actual Flow ID is shorter than 32
                   bits, it is zero padded in its most significant bits.
                   The field is set at the encapsulating node.  The Flow
                   ID can be used to correlate the exported data of the
                   same flow from multiple nodes and from multiple
                   packets.  Flow ID values are expected to be allocated
                   in a way that avoids collisions.  For example, random
                   assignment of Flow ID values can be subject to
                   collisions, while centralized allocation can avoid
                   this problem.  The specification of the Flow ID
                   allocation method is not within the scope of this
                   document.

   Sequence Number  An optional 32-bit sequence number starting from 0
                   and incremented by 1 for each packet from the same
                   flow at the encapsulating node that includes the DEX
                   option.  The Sequence Number, when combined with the
                   Flow ID, provides a convenient approach to correlate
                   the exported data from the same user packet.



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4.  IANA Considerations

4.1.  IOAM Type

   The "IOAM Option-Type Registry" was defined in Section 7.1 of
   [RFC9197].  IANA is requested to allocate the following code point
   from the "IOAM Option-Type Registry" as follows:

   TBD-type   IOAM Direct Export (DEX) Option-Type

   If possible, IANA is requested to allocate code point 4 (TBD-type).
   The "Description" for the new option should be "Direct exporting" and
   the "Reference" should be the current document.

4.2.  IOAM DEX Flags

   IANA is requested to define an "IOAM DEX Flags" registry.  This
   registry includes 8 flag bits.  Allocation is based on the "IETF
   Review" procedure, as defined in [RFC8126].

   New registration requests MUST use the following template:

   Bit:  Desired bit to be allocated in the 8 bit Flags field of the DEX
      Option-Type.

   Description:  Brief description of the newly registered bit.

   Reference:  Reference to the document that defines the new bit.

4.3.  IOAM DEX Extension-Flags

   IANA is requested to define an "IOAM DEX Extension-Flags" registry.
   This registry includes 8 flag bits.  Bit 0 (the most significant bit)
   and bit 1 in the registry are allocated by this document, and
   described in Section 3.2.  Allocation of the other bits should be
   performed based on the "IETF Review" procedure, as defined in
   [RFC8126].

   Bit 0  "Flow ID [RFC XXXX] [RFC Editor: please replace with the RFC
      number of the current document]"

   Bit 1  "Sequence Number [RFC XXXX] [RFC Editor: please replace with
      the RFC number of the current document]"

   New registration requests MUST use the following template:

   Bit:  Desired bit to be allocated in the 8 bit Extension-Flags field
      of the DEX Option-Type.



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   Description:  Brief description of the newly registered bit.

   Reference:  Reference to the document that defines the new bit.

5.  Performance Considerations

   The DEX Option-Type triggers IOAM data to be collected and/or
   exported packets to be exported to a receiving entity (or entities).
   In some cases this may impact the receiving entity's performance, or
   the performance along the paths leading to it.

   Therefore, the performance impact of these exported packets is
   limited by taking two measures: at the encapsulating nodes, by
   selective DEX encapsulation (Section 3.1.1), and at the transit
   nodes, by limiting exporting rate (Section 3.1.2).  These two
   measures ensure that direct exporting is used at a rate that does not
   significantly affect the network bandwidth, and does not overload the
   receiving entity.  Moreover, it is possible to load balance the
   exported data among multiple receiving entities, although the
   exporting method is not within the scope of this document.

   It should be noted that in some networks DEX data may be exported
   over an out-of-band network, in which a large volume of exported
   traffic does not compromise user traffic.  In this case an operator
   may choose to disable the exporting rate limiting.

6.  Security Considerations

   The security considerations of IOAM in general are discussed in
   [RFC9197].  Specifically, an attacker may try to use the
   functionality that is defined in this document to attack the network.

   An attacker may attempt to overload network devices by injecting
   synthetic packets that include the DEX Option-Type.  Similarly, an
   on-path attacker may maliciously incorporate the DEX Option-Type into
   transit packets, or maliciously remove it from packets in which it is
   incorporated.

   Forcing DEX, either in synthetic packets or in transit packets may
   overload the IOAM nodes and/or the receiving entity (or entities).
   Since this mechanism affects multiple devices along the network path,
   it potentially amplifies the effect on the network bandwidth, on the
   storage of the devices that collect the data, and on the receiving
   entity's load.

   The amplification effect of DEX may be worse in wide area networks in
   which there are multiple IOAM domains.  For example, if DEX is used
   in IOAM domain 1 for exporting IOAM data to a receiving entity, then



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   the exported packets of domain 1 can be forwarded through IOAM domain
   2, in which they are subject to DEX.  The exported packets of domain
   2 may in turn be forwarded through another IOAM domain (or through
   domain 1), and theoretically this recursive amplification may
   continue infinitely.

   In order to mitigate the attacks described above, the following
   requirements (Section 3) have been defined:

   *  Selective DEX (Section 3.1.1) is applied by IOAM encapsulating
      nodes in order to limit the potential impact of DEX attacks to a
      small fraction of the traffic.

   *  Rate limiting of exported traffic (Section 3.1.2) is applied by
      IOAM nodes in order to prevent overloading attacks and in order to
      significantly limit the scale of amplification attacks.

   *  IOAM encapsulating nodes are required to avoid pushing the DEX
      Option-Type into IOAM exported packets (Section 3.1.2), thus
      preventing some of the amplification and export loop scenarios.

   Although the exporting method is not within the scope of this
   document, any exporting method MUST secure the exported data from the
   IOAM node to the receiving entity.  Specifically, an IOAM node that
   performs DEX exporting MUST send the exported data to a pre-
   configured trusted receiving entity that is in the same IOAM domain
   as the exporting IOAM node.  Furthermore, an IOAM node MUST gain
   explicit consent to export data to a receiving entity before starting
   to send exported data.

   An attacker may keep track of the information sent in DEX headers as
   a means of reconnaissance.  This form of recon can be mitigated to
   some extent by careful allocation of the Flow ID and Sequence Number
   space, in a way that does not compromise privacy aspects such as
   customer identities.

   The integrity of the DEX Option-Type can be protected through a
   mechanism of the encapsulating protocol.  While
   [I-D.ietf-ippm-ioam-data-integrity] introduces an integrity
   protection mechanism that protects the integrity of IOAM-Data-Fields,
   the DEX Option-Type does not include IOAM-Data-Fields, and therefore
   these integrity protection mechanisms are not applicable to the DEX
   Option-Type.  As discussed in the threat analysis of
   [I-D.ietf-ippm-ioam-data-integrity], injection or modification of
   IOAM-Option-Type headers are threats that are not addressed in IOAM.






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   IOAM is assumed to be deployed in a restricted administrative domain,
   thus limiting the scope of the threats above and their affect.  This
   is a fundamental assumption with respect to the security aspects of
   IOAM, as further discussed in [RFC9197].

7.  Acknowledgments

   The authors thank Martin Duke, Tommy Pauly, Meral Shirazipour, Colin
   Perkins, Stephen Farrell, Linda Dunbar, Justin Iurman, Greg Mirsky,
   and other members of the IPPM working group for many helpful
   comments.

8.  References

8.1.  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>.

   [RFC9197]  Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi,
              Ed., "Data Fields for In Situ Operations, Administration,
              and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197,
              May 2022, <https://www.rfc-editor.org/info/rfc9197>.

8.2.  Informative References

   [I-D.ietf-ippm-ioam-data-integrity]
              Brockners, F., Bhandari, S., Mizrahi, T., and J. Iurman,
              "Integrity of In-situ OAM Data Fields", Work in Progress,
              Internet-Draft, draft-ietf-ippm-ioam-data-integrity-02, 5
              July 2022, <https://www.ietf.org/archive/id/draft-ietf-
              ippm-ioam-data-integrity-02.txt>.

   [I-D.ietf-ippm-ioam-flags]
              Mizrahi, T., Brockners, F., Bhandari, S., Gafni, B., and
              M. Spiegel, "In-situ OAM Loopback and Active Flags", Work
              in Progress, Internet-Draft, draft-ietf-ippm-ioam-flags-
              09, 15 June 2022, <https://www.ietf.org/archive/id/draft-
              ietf-ippm-ioam-flags-09.txt>.






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   [I-D.ietf-ippm-ioam-ipv6-options]
              Bhandari, S. and F. Brockners, "In-situ OAM IPv6 Options",
              Work in Progress, Internet-Draft, draft-ietf-ippm-ioam-
              ipv6-options-08, 16 June 2022,
              <https://www.ietf.org/archive/id/draft-ietf-ippm-ioam-
              ipv6-options-08.txt>.

   [I-D.song-ippm-postcard-based-telemetry]
              Song, H., Mirsky, G., Filsfils, C., Abdelsalam, A., Zhou,
              T., Li, Z., Graf, T., Mishra, G., Shin, J., and K. Lee,
              "Marking-based Direct Export for On-path Telemetry", Work
              in Progress, Internet-Draft, draft-song-ippm-postcard-
              based-telemetry-13, 16 August 2022,
              <https://datatracker.ietf.org/api/v1/doc/document/draft-
              song-ippm-postcard-based-telemetry/>.

   [I-D.spiegel-ippm-ioam-rawexport]
              Spiegel, M., Brockners, F., Bhandari, S., and R.
              Sivakolundu, "In-situ OAM raw data export with IPFIX",
              Work in Progress, Internet-Draft, draft-spiegel-ippm-ioam-
              rawexport-06, 21 February 2022,
              <https://www.ietf.org/archive/id/draft-spiegel-ippm-ioam-
              rawexport-06.txt>.

   [RFC5475]  Zseby, T., Molina, M., Duffield, N., Niccolini, S., and F.
              Raspall, "Sampling and Filtering Techniques for IP Packet
              Selection", RFC 5475, DOI 10.17487/RFC5475, March 2009,
              <https://www.rfc-editor.org/info/rfc5475>.

   [RFC6291]  Andersson, L., van Helvoort, H., Bonica, R., Romascanu,
              D., and S. Mansfield, "Guidelines for the Use of the "OAM"
              Acronym in the IETF", BCP 161, RFC 6291,
              DOI 10.17487/RFC6291, June 2011,
              <https://www.rfc-editor.org/info/rfc6291>.

   [RFC7014]  D'Antonio, S., Zseby, T., Henke, C., and L. Peluso, "Flow
              Selection Techniques", RFC 7014, DOI 10.17487/RFC7014,
              September 2013, <https://www.rfc-editor.org/info/rfc7014>.

   [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>.








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Appendix A.  Notes About the History of this Document

   This document evolved from combining some of the concepts of PBT-I
   from [I-D.song-ippm-postcard-based-telemetry] with immediate
   exporting from early versions of [I-D.ietf-ippm-ioam-flags].

   In order to help correlate and order the exported packets, it is
   possible to include the Hop_Lim/Node_ID IOAM-Data-Field in exported
   packets; if the IOAM-Trace-Type [RFC9197] has the Hop_Lim/Node_ID bit
   set, then exported packets include the Hop_Lim/Node_ID IOAM-Data-
   Field, which contains the TTL/Hop Limit value from a lower layer
   protocol.  An alternative approach was considered during the design
   of this document, according to which a 1-octet Hop Count field would
   be included in the DEX header (presumably by claiming some space from
   the Flags field).  The Hop Limit would starts from 0 at the
   encapsulating node and be incremented by each IOAM transit node that
   supports the DEX Option-Type.  In this approach the Hop Count field
   value would also be included in the exported packet.

Contributors

   The Editors would like to recognize the contributions of the
   following individuals to this document.




























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      Tianran Zhou
      Huawei
      156 Beiqing Rd.
      Beijing  100095
      China

      Email: zhoutianran@huawei.com


      Zhenbin Li
      Huawei
      156 Beiqing Rd.
      Beijing  100095
      China

      Email: lizhenbin@huawei.com


      Ramesh Sivakolundu
      Cisco Systems, Inc.
      170 West Tasman Dr.
      SAN JOSE, CA 95134
      U.S.A.

      Email: sramesh@cisco.com

Authors' Addresses

   Haoyu Song
   Futurewei
   2330 Central Expressway
   Santa Clara,  95050
   United States of America
   Email: haoyu.song@futurewei.com


   Barak Gafni
   Nvidia
   350 Oakmead Parkway, Suite 100
   Sunnyvale, CA
   Email: gbarak@nvidia.com


   Frank Brockners
   Cisco Systems, Inc.
   Hansaallee 249, 3rd Floor
   40549 DUESSELDORF
   Germany



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   Email: fbrockne@cisco.com


   Shwetha Bhandari
   Thoughtspot
   3rd Floor, Indiqube Orion, 24th Main Rd, Garden Layout, HSR Layout
   Bangalore, KARNATAKA 560 102
   India
   Email: shwetha.bhandari@thoughtspot.com


   Tal Mizrahi
   Huawei
   8-2 Matam
   Haifa 3190501
   Israel
   Email: tal.mizrahi.phd@gmail.com


































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