In-situ OAM IPv6 Options
draft-ietf-ippm-ioam-ipv6-options-03

ippm                                                         S. Bhandari
Internet-Draft                                              F. Brockners
Intended status: Standards Track                            C. Pignataro
Expires: March 22, 2021                                            Cisco
                                                              H. Gredler
                                                            RtBrick Inc.
                                                                J. Leddy
                                                                 Comcast
                                                               S. Youell
                                                                    JMPC
                                                              T. Mizrahi
                                        Huawei Network.IO Innovation Lab
                                                                 A. Kfir
                                                                B. Gafni
                                             Mellanox Technologies, Inc.
                                                             P. Lapukhov
                                                                Facebook
                                                              M. Spiegel
                                     Barefoot Networks, an Intel company
                                                             S. Krishnan
                                                                  Kaloom
                                                                R. Asati
                                                                   Cisco
                                                                M. Smith
                                                      September 18, 2020

                        In-situ OAM IPv6 Options
                  draft-ietf-ippm-ioam-ipv6-options-03

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.

   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/.

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   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on March 22, 2021.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     2.2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   3
   3.  In-situ OAM Metadata Transport in IPv6  . . . . . . . . . . .   3
   4.  IOAM Deployment In IPv6 Networks  . . . . . . . . . . . . . .   6
     4.1.  Considerations for IOAM deployment in IPv6 networks . . .   6
     4.2.  IOAM domains bounded by hosts . . . . . . . . . . . . . .   7
     4.3.  IOAM domains bounded by network devices . . . . . . . . .   7
     4.4.  Deployment options  . . . . . . . . . . . . . . . . . . .   7
       4.4.1.  IPv6-in-IPv6 encapsulation  . . . . . . . . . . . . .   7
       4.4.2.  IP-in-IPv6 encapsulation with ULA . . . . . . . . . .   8
       4.4.3.  x-in-IPv6 Encapsulation that is used Independently  .   9
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

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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 which leverage IOAM
   data fields encapsulated in the IPv6 protocol.  Deployment
   considerations differ, whether the IOAM domain starts and ends on
   hosts or whether the IOAM encapsulating and decapsulating nodes are
   network devices that forward traffic, such as routers.

2.  Conventions

2.1.  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.

2.2.  Abbreviations

   Abbreviations used in this document:

   E2E:       Edge-to-Edge

   IOAM:      In-situ Operations, Administration, and Maintenance

   ION:       IOAM Overlay Network

   OAM:       Operations, Administration, and Maintenance

   POT:       Proof of Transit

3.  In-situ OAM Metadata Transport in IPv6

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

   IOAM data fields are encapsulated in "option data" fields of two
   types of extension headers in IPv6 packets - either Hop-by-Hop
   Options header or Destination options header.  The selection of a
   particular extension header type depends on IOAM usage, as described
   in section 4 of [I-D.ietf-ippm-ioam-data].  Multiple options with the

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   same Option Type MAY appear in the same Hop-by-Hop Options or
   Destination Options header, with varying 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 drop packets which contain
   extension headers carrying IOAM data-fields.  This is the default
   behavior and is independent of whether the Hop-by-Hop options or
   Destination options are used to encode the IOAM data.  This ensures
   that IOAM data does not unintentionally get forwarded outside the
   IOAM domain.

   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 6.

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

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

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   IOAM Type:  8-bit field as defined in section 7.2 in
      [I-D.ietf-ippm-ioam-data].

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

   In-situ OAM Options are inserted as Option data as follows:

   1.  Pre-allocated Trace Option: The in-situ OAM Preallocated Trace
       option defined in [I-D.ietf-ippm-ioam-data] is represented as an
       IPv6 option in Hop-by-Hop extension header:

       Option Type:  001xxxxx 8-bit identifier of the IOAM type of
          option. xxxxx=TBD.

       IOAM Type:  IOAM Pre-allocated Trace Option Type.

   2.  Incremental Trace Option: The in-situ OAM Incremental Trace
       option defined in [I-D.ietf-ippm-ioam-data] is represented as an
       IPv6 option in Hop-by-Hop extension header:

       Option Type:  001xxxxx 8-bit identifier of the IOAM type of
          option. xxxxx=TBD.

       IOAM Type:  IOAM Incremental Trace Option Type.

   3.  Proof of Transit Option: The in-situ OAM POT option defined in
       [I-D.ietf-ippm-ioam-data] is represented as an IPv6 option in
       Hop-by-Hop extension header:

       Option Type:  001xxxxx 8-bit identifier of the IOAM type of
          option. xxxxx=TBD.

       IOAM Type:  IOAM POT Option Type.

   4.  Edge to Edge Option: The in-situ OAM E2E option defined in
       [I-D.ietf-ippm-ioam-data] is represented as an IPv6 option in
       Destination extension header:

       Option Type:  000xxxxx 8-bit identifier of the IOAM type of
          option. xxxxx=TBD.

       IOAM Type:  IOAM E2E 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 [I-D.ietf-ippm-ioam-data] 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

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   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.

4.  IOAM Deployment In IPv6 Networks

4.1.  Considerations for IOAM deployment in IPv6 networks

   IOAM deployment in an IPv6 network 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 the packets, nor the forwarding
      decision the routers takes.  The packet with the added OAM
      information should follow the same path within the domain that the
      same packet without the OAM information would follow within the
      domain even in the presence of ECMP.  Such a behavior is
      particularly interesting 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 the packet,
      the size of the packet including the IOAM data could exceed the
      PMTU.  In particular, the incremental trace IOAM HbH Option, which
      is proposed to support hardware implementations of IOAM, changes
      Option Data Length en-route.  Operators of an IOAM domain are to
      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
      IOAM is considered a domain specific feature, see also
      [I-D.ietf-ippm-ioam-data].  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 which have no knowledge of IOAM.  Consider
      using IOAM in transit devices; misleading ICMP errors due to
      addition and/or presence of OAM data in the packet can confuse a
      source of the packet that did not insert the OAM information.

   C4 OAM data leaks may affect the forwarding behavior and state of
      network elements outside an IOAM domain.  IOAM domains SHOULD

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      provide a mechanism to prevent data leaks or be able to assure
      that upon leak network elements outside the domain are not
      affected i.e they continue to process other valid packets.

   C5 The source of that inserted and leaked the IOAM data must be easy
      to identify for the purpose of troubleshooting, due to the high
      complexity of troubleshooting a source that inserted the IOAM data
      and did not remove it when the packet traversed across an AS.
      Such a troubleshooting process may require coordination between
      multiple operators, complicated configuration verification, packet
      capture analysis, etc.

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

4.2.  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.

4.3.  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.

4.4.  Deployment options

   This section lists out possible deployment options that can be
   employed to meet the requirements listed in Section 4.1.

4.4.1.  IPv6-in-IPv6 encapsulation

   Leverage an IPv6-in-IPv6 approach: Preserve the original IP packet
   and add an IPv6 header including IOAM data fields in an extension
   header in front of it, to forward traffic within and across the IOAM
   domain.  The overlay network formed by the additional IPv6 header
   with the IOAM data fields included in an extension header is referred
   to as IOAM Overlay Network (ION) in this document.

   1.  Perform an IPv6-in-IPv6 approach.  The source address of the
       outer IPv6 header is that of the IOAM encapsulating node.  The
       destination address of the outer IPv6 header is the same as the

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       inner IPv6 destination address, i.e. the destination address of
       the packet does not change.

   2.  To simplify debugging in case of leaked IOAM data fields in
       packets, consider a new IOAM E2E destination option to identify
       the Source IOAM domain (AS, v6 prefix).  Insert this option into
       the IOAM destination options EH attached to the outer IPv6
       header.  This additional information would allow for easy
       identification of an AS operator that is the source of packets
       with leaked IOAM information.  Note that leaked packets with IOAM
       data fields would only occur in case a router would be
       misconfigured.

   3.  All the IOAM options are defined with type "00 - skip over this
       option and continue processing the header.  So presence of the
       options must not cause packet drop in the network elements that
       do not understand the option.  In addition
       [I-D.ietf-6man-hbh-header-handling] should be considered.

4.4.2.  IP-in-IPv6 encapsulation with ULA

   The "IP-in-IPv6 encapsulation with ULA" [RFC4193] approach can be
   used to apply IOAM to an IPv6 as well as an IPv4 network.  In
   addition, it fulfills requirement C4 (avoid leaks) by using ULA for
   the ION.  Similar to the IPv6-in-IPv6 encapsulation approach above,
   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 ION, i.e. the outer IPv6 addresses are assigned from the ULA
   space.  Addressing and routing in the ION 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 ION 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

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   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.

4.4.3.  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.

5.  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 [I-D.ietf-ippm-ioam-data].

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

6.  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]
      TBD_1_1      00   1  TBD_1     IOAM                  [This draft]

7.  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

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   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.

8.  References

8.1.  Normative References

   [I-D.ietf-ippm-ioam-data]
              Brockners, F., Bhandari, S., Pignataro, C., Gredler, H.,
              Leddy, J., Youell, S., Mizrahi, T., Mozes, D., Lapukhov,
              P., Chang, R., and d. daniel.bernier@bell.ca, "Data Fields
              for In-situ OAM", draft-ietf-ippm-ioam-data-01 (work in
              progress), October 2017.

   [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>.

8.2.  Informative References

   [I-D.ietf-6man-hbh-header-handling]
              Baker, F. and R. Bonica, "IPv6 Hop-by-Hop Options
              Extension Header", March 2016.

   [I-D.kitamura-ipv6-record-route]
              Kitamura, H., "Record Route for IPv6 (PR6) Hop-by-Hop
              Option Extension", draft-kitamura-ipv6-record-route-00
              (work in progress), November 2000.

   [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>.

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   [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>.

Authors' Addresses

   Shwetha Bhandari
   Cisco Systems, Inc.
   Cessna Business Park, Sarjapura Marathalli Outer Ring Road
   Bangalore, KARNATAKA 560 087
   India

   Email: shwethab@cisco.com

   Frank Brockners
   Cisco Systems, Inc.
   Kaiserswerther Str. 115,
   RATINGEN, NORDRHEIN-WESTFALEN  40880
   Germany

   Email: fbrockne@cisco.com

   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

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   John Leddy
   Comcast

   Email: John_Leddy@cable.comcast.com

   Stephen Youell
   JP Morgan Chase
   25 Bank Street
   London  E14 5JP
   United Kingdom

   Email: stephen.youell@jpmorgan.com

   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

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   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

   Mark Smith
   PO BOX 521
   HEIDELBERG, VIC  3084
   AU

   Email: markzzzsmith+id@gmail.com

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