In-situ OAM IPv6 Options
draft-ietf-ippm-ioam-ipv6-options-09

ippm                                                    S. Bhandari, Ed.
Internet-Draft                                               Thoughtspot
Intended status: Standards Track                       F. Brockners, Ed.
Expires: 14 April 2023                                             Cisco
                                                         11 October 2022

                        In-situ OAM IPv6 Options
                  draft-ietf-ippm-ioam-ipv6-options-09

Abstract

   In-situ Operations, Administration, and Maintenance (IOAM) records
   operational and telemetry information in the packet while the packet
   traverses a path between two points in the network.  This document
   outlines how IOAM data fields are encapsulated in IPv6.

Status of This Memo

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

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   This Internet-Draft will expire on 14 April 2023.

Copyright Notice

   Copyright (c) 2022 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Contributors  . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     3.2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   3
   4.  In-situ OAM Metadata Transport in IPv6  . . . . . . . . . . .   4
   5.  IOAM Deployment In IPv6 Networks  . . . . . . . . . . . . . .   6
     5.1.  Considerations for IOAM deployment and implementation in
           IPv6 networks . . . . . . . . . . . . . . . . . . . . . .   6
     5.2.  IOAM domains bounded by hosts . . . . . . . . . . . . . .   7
     5.3.  IOAM domains bounded by network devices . . . . . . . . .   8
     5.4.  Deployment options  . . . . . . . . . . . . . . . . . . .   8
       5.4.1.  IP-in-IPv6 encapsulation with ULA . . . . . . . . . .   8
       5.4.2.  x-in-IPv6 Encapsulation that is used Independently  .   9
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  10
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Contributors' Addresses . . . . . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  13

1.  Introduction

   In-situ Operations, Administration, and Maintenance (IOAM) records
   operational and telemetry information in the packet while the packet
   traverses a path between two points in the network.  This document
   outlines how IOAM data fields are encapsulated in the IPv6 [RFC8200]
   and discusses deployment options for networks that use
   IPv6-encapsulated IOAM data fields.  These options have distinct
   deployment considerations; for example, the IOAM domain can either be
   between hosts, or be between IOAM encapsulating and decapsulating
   network nodes that forward traffic, such as routers.

2.  Contributors

   This document was the collective effort of several authors.  The text
   and content were contributed by the editors and the co-authors listed
   below.  The contact information of the co-authors appears at the end
   of this document.

   *  Carlos Pignataro

   *  Hannes Gredler

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   *  John Leddy

   *  Stephen Youell

   *  Tal Mizrahi

   *  Aviv Kfir

   *  Barak Gafni

   *  Petr Lapukhov

   *  Mickey Spiegel

   *  Suresh Krishnan

   *  Rajiv Asati

   *  Mark Smith

3.  Conventions

3.1.  Requirements 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.

3.2.  Abbreviations

   Abbreviations used in this document:

   E2E:       Edge-to-Edge

   IOAM:      In-situ Operations, Administration, and Maintenance as
              defined in [RFC9197]

   OAM:       Operations, Administration, and Maintenance

   POT:       Proof of Transit

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4.  In-situ OAM Metadata Transport in IPv6

   In-situ OAM in IPv6 is used to enhance diagnostics of IPv6 networks.
   It complements other mechanisms designed to enhance diagnostics of
   IPv6 networks, such as the IPv6 Performance and Diagnostic Metrics
   Destination Option described in [RFC8250].

   IOAM data fields can be encapsulated in "option data" fields using
   two types of extension headers in IPv6 packets - either Hop-by-Hop
   Options header or Destination options header.  Multiple options with
   the same Option Type MAY appear in the same Hop-by-Hop Options or
   Destination Options header, with distinct content.

   In order for IOAM to work in IPv6 networks, IOAM MUST be explicitly
   enabled per interface on every node within the IOAM domain.  Unless a
   particular interface is explicitly enabled (i.e., explicitly
   configured) for IOAM, a router MUST ignore IOAM Options.  As
   additional security, IOAM domains MUST provide a mechanism to prevent
   unauthorized injections at ingress or leaks at egress.

   An IPv6 packet carrying IOAM data in an Extension header can have
   other extension headers, compliant with [RFC8200].

   IPv6 Hop-by-Hop and Destination Option format for carrying in-situ
   OAM data fields:

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Option Type  |  Opt Data Len |   Reserved    |   IOAM Type   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
   |                                                               |  |
   .                                                               .  I
   .                                                               .  O
   .                                                               .  A
   .                                                               .  M
   .                                                               .  .
   .                          Option Data                          .  O
   .                                                               .  P
   .                                                               .  T
   .                                                               .  I
   .                                                               .  O
   .                                                               .  N
   |                                                               |  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+

   Option Type:  8-bit option type identifier as defined inSection 7.

   Opt Data Len:  8-bit unsigned integer.  Length of this option, in
      octets, not including the first 2 octets.

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   Reserved:  8-bit field MUST be set to zero upon transmission and
      ignored upon reception.

   IOAM Type:  8-bit field as defined in section 7.1 in [RFC9197].

   Option Data:  Variable-length field.  Option-Type-specific data.

   IOAM Option data is inserted as follows:

   1.  Pre-allocated Trace Option: The in-situ OAM Preallocated Trace
       Option-Type defined in [RFC9197] is represented as an IPv6 option
       in the Hop-by-Hop extension header:

       Option Type:  TBD_1_1 8-bit identifier of the IPv6 Option Type
          for IOAM.

       IOAM Type:  IOAM Pre-allocated Trace Option-Type.

   2.  Incremental Trace Option: The in-situ OAM Incremental Trace
       Option-Type defined in [RFC9197] is represented as an IPv6 option
       in the Hop-by-Hop extension header:

       Option Type:  TBD_1_1 8-bit identifier of the IPv6 Option Type
          for IOAM.

       IOAM Type:  IOAM Incremental Trace Option-Type.

   3.  Proof of Transit Option: The in-situ OAM POT Option-Type defined
       in [RFC9197] is represented as an IPv6 option in the Hop-by-Hop
       extension header:

       Option Type:  TBD_1_1 8-bit identifier of the IPv6 Option Type
          for IOAM.

       IOAM Type:  IOAM POT Option-Type.

   4.  Edge to Edge Option: The in-situ OAM E2E option defined in
       [RFC9197] is represented as an IPv6 option in Destination
       extension header:

       Option Type:  TBD_1_0 8-bit identifier of the IPv6 Option Type
          for IOAM.

       IOAM Type:  IOAM E2E Option-Type.

   5.  Direct Export (DEX) Option: The in-situ OAM Direct Export Option-
       Type defined in [I-D.ietf-ippm-ioam-direct-export] is represented
       as an IPv6 option in the Hop-by-Hop extension header:

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       Option Type:  TBD_1_0 8-bit identifier of the IPv6 Option Type
          for IOAM.

       IOAM Type:  IOAM Direct Export (DEX) Option-Type.

   All the in-situ OAM IPv6 options defined here have alignment
   requirements.  Specifically, they all require 4n alignment.  This
   ensures that fields specified in [RFC9197] are aligned at a multiple-
   of-4 offset from the start of the Hop-by-Hop and Destination Options
   header.  In addition, to maintain IPv6 extension header 8-octet
   alignment and avoid the need to add or remove padding at every hop,
   the Trace-Type for Incremental Trace Option in IPv6 MUST be selected
   such that the IOAM node data length is a multiple of 8-octets.

   IPv6 options can have a maximum length of 255 octets.  Consequently,
   the total length of IOAM Option-Types including all data fields is
   also limited to 255 octets when encapsulated into IPv6.

5.  IOAM Deployment In IPv6 Networks

5.1.  Considerations for IOAM deployment and implementation in IPv6
      networks

   IOAM deployments in IPv6 networks should take the following
   considerations and requirements into account:

   C1  It is desirable that the addition of IOAM data fields neither
      changes the way routers forward packets nor the forwarding
      decisions the routers take.  Packets with added OAM information
      should follow the same path within the domain that an identical
      packet without OAM information would follow, even in the presence
      of ECMP.  Such behavior is particularly important for deployments
      where IOAM data fields are only added "on-demand", e.g., to
      provide further insights in case of undesired network behavior for
      certain flows.  Implementations of IOAM SHOULD ensure that ECMP
      behavior for packets with and without IOAM data fields is the
      same.

   C2  Given that IOAM data fields increase the total size of a packet,
      the size of a packet including the IOAM data could exceed the
      PMTU.  In particular, the incremental trace IOAM Hop-by-Hop (HbH)
      Option, which is intended to support hardware implementations of
      IOAM, changes Option Data Length en-route.  Operators of an IOAM
      domain SHOULD ensure that the addition of OAM information does not
      lead to fragmentation of the packet, e.g., by configuring the MTU
      of transit routers and switches to a sufficiently high value.
      Careful control of the MTU in a network is one of the reasons why

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      IOAM is considered a domain-specific feature (see also [RFC9197]).
      In addition, the PMTU tolerance range in the IOAM domain should be
      identified (e.g., through configuration) and IOAM encapsulation
      operations and/or IOAM data field insertion (in case of
      incremental tracing) should not be performed if it exceeds the
      packet size beyond PMTU.

   C3  Packets with IOAM data or associated ICMP errors, should not
      arrive at destinations that have no knowledge of IOAM.  For
      example, if IOAM is used in in transit devices, misleading ICMP
      errors due to addition and/or presence of OAM data in a packet
      could confuse the host that sent the packet if it did not insert
      the OAM information.  The entities that communicate the errors to
      devices outside of the IOAM domain MUST remove any IOAM data from
      the packet included in the error message.

   C4  OAM data leaks can affect the forwarding behavior and state of
      network elements outside an IOAM domain.  IOAM domains MUST
      provide a mechanism to prevent data leaks or be able to ensure
      that if a leak occurs, network elements outside the domain are not
      affected (i.e., they continue to process other valid packets).

   C5  An Autonomous System (AS) that inserts and leaks the IOAM data
      needs to be easy to identify for the purpose of troubleshooting,
      due to the high complexity in identifying the source of the leak.
      Such a troubleshooting process might require coordination between
      multiple operators, complex configuration verification, packet
      capture analysis, etc.  This requirement may require additional
      option or fields to be defined to identify the domain that
      inserted the IOAM data, this is out of the scope of this document.

   C6  Compliance with [RFC8200] requires OAM data to be encapsulated
      instead of header/option insertion directly into in-flight packets
      using the original IPv6 header.

   C7  The IOAM Incremental Trace Option-Type expands the option length
      that may affect the processing of extension headers and options
      that follow IOAM options.  Hence when the IOAM Incremental Trace
      Option-Type is used in the deployment the RemainingLen field of
      the option MUST follow the guidance in [RFC9197] and must be
      computed and set appropriately.

5.2.  IOAM domains bounded by hosts

   For deployments where the IOAM domain is bounded by hosts, hosts will
   perform the operation of IOAM data field encapsulation and
   decapsulation.  IOAM data is carried in IPv6 packets as Hop-by-Hop or
   Destination options as specified in this document.

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5.3.  IOAM domains bounded by network devices

   For deployments where the IOAM domain is bounded by network devices,
   network devices such as routers form the edge of an IOAM domain.
   Network devices will perform the operation of IOAM data field
   encapsulation and decapsulation.

5.4.  Deployment options

   This section lists out possible deployment options that can be
   employed to meet the requirements listed in Section 5.1.

5.4.1.  IP-in-IPv6 encapsulation with ULA

   The "IP-in-IPv6 encapsulation with ULA" [RFC4193] approach can be
   used to apply IOAM to either an IPv6 or an IPv4 network.  In
   addition, it fulfills requirement C4 (avoid leaks) by using ULA for
   the IOAM Overlay Network.  The original IP packet is preserved.  An
   IPv6 header including IOAM data fields in an extension header is
   added in front of it, to forward traffic within and across the IOAM
   domain.  IPv6 addresses for the IOAM Overlay Network, i.e. the outer
   IPv6 addresses are assigned from the ULA space.  Addressing and
   routing in the IOAM Overlay Network are to be configured so that the
   IP-in-IPv6 encapsulated packets follow the same path as the original,
   non-encapsulated packet would have taken.  This would create an
   internal IPv6 forwarding topology using the IOAM domain's interior
   ULA address space which is parallel with the forwarding topology that
   exists with the non-IOAM address space (the topology and address
   space that would be followed by packets that do not have supplemental
   IOAM information).  Establishment and maintenance of the parallel
   IOAM ULA forwarding topology could be automated, e.g., similar to how
   LDP [RFC5036] is used in MPLS to establish and maintain an LSP
   forwarding topology that is parallel to the network's IGP forwarding
   topology.

   Transit across the IOAM Overlay Network could leverage the transit
   approach for traffic between BGP border routers, as described in
   [RFC1772], "A.2.3 Encapsulation".  Assuming that the operational
   guidelines specified in Section 4 of [RFC4193] are properly followed,
   the probability of leaks in this approach will be almost close to
   zero.  If the packets do leak through IOAM egress device
   misconfiguration or partial IOAM egress device failure, the packets'
   ULA destination address is invalid outside of the IOAM domain.  There
   is no exterior destination to be reached, and the packets will be
   dropped when they encounter either a router external to the IOAM
   domain that has a packet filter that drops packets with ULA
   destinations, or a router that does not have a default route.

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5.4.2.  x-in-IPv6 Encapsulation that is used Independently

   In some cases it is desirable to monitor a domain that uses an
   overlay network that is deployed independently of the need for IOAM,
   e.g., an overlay network that runs Geneve-in-IPv6, or VXLAN-in-IPv6.
   In this case IOAM can be encapsulated in as an extension header in
   the tunnel (outer) IPv6 header.  Thus, the tunnel encapsulating node
   is also the IOAM encapsulating node, and the tunnel end point is also
   the IOAM decapsulating node.

6.  Security Considerations

   This document describes the encapsulation of IOAM data fields in
   IPv6.  Security considerations of the specific IOAM data fields for
   each case (i.e., Trace, Proof of Transit, and E2E) are described and
   defined in [RFC9197].

   As this document describes new options for IPv6, these are similar to
   the security considerations of [RFC8200] and the weakness documented
   in [RFC8250].

7.  IANA Considerations

   This draft requests the following IPv6 Option Type assignments from
   the Destination Options and Hop-by-Hop Options sub-registry of
   Internet Protocol Version 6 (IPv6) Parameters.

   http://www.iana.org/assignments/ipv6-parameters/ipv6-
   parameters.xhtml#ipv6-parameters-2

      Hex Value    Binary Value      Description            Reference
                   act chg rest
      ------------------------------------------------------------------
      TBD_1_0      00   0  TBD_1     IOAM                   [This draft]
                                     destination option
                                     and
                                     IOAM hop-by-hop option
      TBD_1_1      00   1  TBD_1     IOAM                   [This draft]
                                     destination option
                                     and
                                     IOAM hop-by-hop option

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8.  Acknowledgements

   The authors would like to thank Tom Herbert, Eric Vyncke, Nalini
   Elkins, Srihari Raghavan, Ranganathan T S, Karthik Babu Harichandra
   Babu, Akshaya Nadahalli, Stefano Previdi, Hemant Singh, Erik
   Nordmark, LJ Wobker, Mark Smith, Andrew Yourtchenko and Justin Iurman
   for the comments and advice.  For the IPv6 encapsulation, this
   document leverages concepts described in
   [I-D.kitamura-ipv6-record-route].  The authors would like to
   acknowledge the work done by the author Hiroshi Kitamura and people
   involved in writing it.

9.  References

9.1.  Normative References

   [I-D.ietf-ippm-ioam-direct-export]
              Song, H., Gafni, B., Brockners, F., Bhandari, S., and T.
              Mizrahi, "In-situ OAM Direct Exporting", Work in Progress,
              Internet-Draft, draft-ietf-ippm-ioam-direct-export-11, 23
              September 2022, <https://www.ietf.org/archive/id/draft-
              ietf-ippm-ioam-direct-export-11.txt>.

   [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>.

9.2.  Informative References

   [I-D.kitamura-ipv6-record-route]
              Kitamura, H., "Record Route for IPv6 (PR6) Hop-by-Hop
              Option Extension", Work in Progress, Internet-Draft,
              draft-kitamura-ipv6-record-route-00, November 2000,
              <https://tools.ietf.org/id/draft-kitamura-ipv6-record-
              route-00.txt>.

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   [RFC1772]  Rekhter, Y. and P. Gross, "Application of the Border
              Gateway Protocol in the Internet", RFC 1772,
              DOI 10.17487/RFC1772, March 1995,
              <https://www.rfc-editor.org/info/rfc1772>.

   [RFC4193]  Hinden, R. and B. Haberman, "Unique Local IPv6 Unicast
              Addresses", RFC 4193, DOI 10.17487/RFC4193, October 2005,
              <https://www.rfc-editor.org/info/rfc4193>.

   [RFC5036]  Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
              "LDP Specification", RFC 5036, DOI 10.17487/RFC5036,
              October 2007, <https://www.rfc-editor.org/info/rfc5036>.

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,
              <https://www.rfc-editor.org/info/rfc8200>.

   [RFC8250]  Elkins, N., Hamilton, R., and M. Ackermann, "IPv6
              Performance and Diagnostic Metrics (PDM) Destination
              Option", RFC 8250, DOI 10.17487/RFC8250, September 2017,
              <https://www.rfc-editor.org/info/rfc8250>.

Contributors' Addresses

      Carlos Pignataro
      Cisco Systems, Inc.
      7200-11 Kit Creek Road
      Research Triangle Park, NC  27709
      United States
      Email: cpignata@cisco.com

      Hannes Gredler
      RtBrick Inc.
      Email: hannes@rtbrick.com

      John Leddy
      Email: john@leddy.net

      Stephen Youell
      JP Morgan Chase
      25 Bank Street
      London  E14 5JP
      United Kingdom
      Email: stephen.youell@jpmorgan.com

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      Tal Mizrahi
      Huawei Network.IO Innovation Lab
      Israel
      Email: tal.mizrahi.phd@gmail.com

      Aviv Kfir
      Mellanox Technologies, Inc.
      350 Oakmead Parkway, Suite 100
      Sunnyvale, CA  94085
      U.S.A.
      Email: avivk@mellanox.com

      Barak Gafni
      Mellanox Technologies, Inc.
      350 Oakmead Parkway, Suite 100
      Sunnyvale, CA  94085
      U.S.A.
      Email: gbarak@mellanox.com

      Petr Lapukhov
      Facebook
      1 Hacker Way
      Menlo Park, CA  94025
      US
      Email: petr@fb.com

      Mickey Spiegel
      Barefoot Networks, an Intel company
      4750 Patrick Henry Drive
      Santa Clara, CA  95054
      US
      Email: mickey.spiegel@intel.com

      Suresh Krishnan
      Kaloom
      Email: suresh@kaloom.com

      Rajiv Asati
      Cisco Systems, Inc.
      7200 Kit Creek Road
      Research Triangle Park, NC  27709
      US
      Email: rajiva@cisco.com

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      Mark Smith
      PO BOX 521
      HEIDELBERG, VIC  3084
      AU
      Email: markzzzsmith+id@gmail.com

Authors' Addresses

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

   Frank Brockners (editor)
   Cisco Systems, Inc.
   Hansaallee 249, 3rd Floor
   40549 DUESSELDORF
   Germany
   Email: fbrockne@cisco.com

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