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ippm                                                        F. Brockners
Internet-Draft                                               S. Bhandari
Intended status: Standards Track                             V. Govindan
Expires: September 12, 2019                                 C. Pignataro
                                                                   Cisco
                                                              H. Gredler
                                                            RtBrick Inc.
                                                                J. Leddy
                                                                 Comcast
                                                               S. Youell
                                                                    JMPC
                                                              T. Mizrahi
                                        Huawei Network.IO Innovation Lab
                                                             P. Lapukhov
                                                                Facebook
                                                                B. Gafni
                                                                 A. Kfir
                                             Mellanox Technologies, Inc.
                                                              M. Spiegel
                                                       Barefoot Networks
                                                          March 11, 2019


               Geneve encapsulation for In-situ OAM Data
                  draft-brockners-ippm-ioam-geneve-02

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 Geneve.

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 http://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."




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   This Internet-Draft will expire on September 12, 2019.

Copyright Notice

   Copyright (c) 2019 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions . . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Requirement Language  . . . . . . . . . . . . . . . . . .   3
     2.2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   3
   3.  IOAM Data Field Encapsulation in Geneve . . . . . . . . . . .   3
   4.  Considerations  . . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Discussion of the encapsulation approach  . . . . . . . .   5
     4.2.  IOAM and the use of the Geneve O-bit  . . . . . . . . . .   6
     4.3.  Transit devices . . . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   In-situ OAM (IOAM) records OAM information within the packet while
   the packet traverses a particular network domain.  The term "in-situ"
   refers to the fact that the IOAM data fields are added to the data
   packets rather than is being sent within packets specifically
   dedicated to OAM.  This document defines how IOAM data fields are
   transported as part of the Geneve [I-D.ietf-nvo3-geneve]
   encapsulation.  The IOAM data fields are defined in
   [I-D.ietf-ippm-ioam-data].







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2.  Conventions

2.1.  Requirement Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

2.2.  Abbreviations

   Abbreviations used in this document:

   IOAM:      In-situ Operations, Administration, and Maintenance

   OAM:       Operations, Administration, and Maintenance

   Geneve:    Generic Network Virtualization Encapsulation

3.  IOAM Data Field Encapsulation in Geneve

   Geneve is defined in [I-D.ietf-nvo3-geneve].  IOAM data fields are
   carried in the Geneve header as a tunnel option, using a single
   Geneve Option Class TBD_IOAM.  The different IOAM data fields defined
   in [I-D.ietf-ippm-ioam-data] are added as TLVs using that Geneve
   Option Class.  In an administrative domain where IOAM is used,
   insertion of the IOAM header in Geneve is enabled at the Geneve
   tunnel endpoints, which also serve as IOAM encapsulating/
   decapsulating nodes by means of configuration.























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    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+
   |Ver|  Opt Len  |O|C|    Rsvd.  |          Protocol Type        |  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Hdr
   |        Virtual Network Identifier (VNI)       |    Reserved   |  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+--+
   |  Option Class  =  TBD_IOAM    |     Type      |R|R|R| Length  |  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+  I
   !                                                               |  O
   !                                                               |  A
   ~                 IOAM Option and Data Space                    ~  M
   |                                                               |  |
   |                                                               |  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+<-+
   |                                                               |
   |                                                               |
   |                 Payload + Padding (L2/L3/ESP/...)             |
   |                                                               |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 1: IOAM data encapsulation in Geneve

   The Geneve header and fields are defined in [I-D.ietf-nvo3-geneve].
   The Geneve Option Class value for use with IOAM is TBD_IOAM.

   The fields related to the encapsulation of IOAM data fields in Geneve
   are defined as follows:

   Option Class:  16-bit unsigned integer that determines the IOAM
      option class.  The value is from the IANA registry setup for
      Geneve option classes as defined in [I-D.ietf-nvo3-geneve].

   Type:  8-bit field defining the IOAM Option type, as defined in
      Section 7.2 of [I-D.ietf-ippm-ioam-data].

   R (3 bits):  Option control flags reserved for future use.  MUST be
      zero on transmission and ignored on receipt.

   Length:  5-bit unsigned integer.  Length of the IOAM HDR in 4-octet
      units.

   IOAM Option and Data Space:  IOAM option header and data is present
      as defined by the Type field, and is defined in Section 4 of
      [I-D.ietf-ippm-ioam-data].




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   Multiple IOAM options MAY be included within the Geneve
   encapsulation.  For example, if a Geneve encapsulation contains two
   IOAM options before a data payload, there would be two fields with
   TBD_IOAM Option Class each, differentiated by the Type field which
   specifies the type of the IOAM data included.

4.  Considerations

   This section summarizes a set of considerations on the overall
   approach taken for IOAM data encapsulation in Geneve, as well as
   deployment considerations.

4.1.  Discussion of the encapsulation approach

   This section is to support the working group discussion in selecting
   the most appropriate approach for encapsulating IOAM data fields in
   Geneve.

   An encapsulation of IOAM data fields in Geneve should be friendly to
   an implementation in both hardware as well as software forwarders and
   support a wide range of deployment cases, including large networks
   that desire to leverage multiple IOAM data fields at the same time.

      Hardware and software friendly implementation: Hardware forwarders
      benefit from an encapsulation that minimizes iterative look-ups of
      fields within the packet: Any operation which looks up the value
      of a field within the packet, based on which another lookup is
      performed, consumes additional gates and time in an implementation
      - both of which are desired to be kept to a minimum.  This means
      that flat TLV structures are to be preferred over nested TLV
      structures.  IOAM data fields are grouped into three option
      categories: Trace, proof-of-transit, and edge-to-edge.  Each of
      these three options defines a TLV structure.  A hardware-friendly
      encapsulation approach avoids grouping these three option
      categories into yet another TLV structure, but would rather carry
      the options as a serial sequence.

      Total length of the IOAM data fields: The total length of IOAM
      data can grow quite large in case multiple different IOAM data
      fields are used and large path-lengths need to be considered.  If
      for example an operator would consider using the IOAM trace option
      and capture node-id, app_data, egress/ingress interface-id,
      timestamp seconds, timestamps nanoseconds at every hop, then a
      total of 20 octets would be added to the packet at every hop.  In
      case this particular deployment would have a maximum path length
      of 15 hops in the IOAM domain, then a maximum of 300 octets of
      IOAM data were to be encapsulated in the packet.




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   Concerns with the current encapsulation approach:

      Hardware support: Using Geneve tunnel options to encapsulate IOAM
      data fields leads to a nested TLV structure.  Each IOAM data field
      option (trace, proof-of-transit, and edge-to-edge) represents a
      type, with the different IOAM data fields being TLVs within this
      the particular option type.  Nested TLVs require iterative look-
      ups, a fact that creates potential challenges for implementations
      in hardware.  It would be desirable to offer a way to encapsulate
      IOAM in a way that keeps TLV nesting to a minimum.

      Length: Geneve tunnel option length is a 5-bit field in the
      current specification [I-D.ietf-nvo3-geneve] resulting in a
      maximum option length of 128 (2^5 x 4) octets which constrains the
      use of IOAM to either small domains or a few IOAM data fields
      only.  Support for large domains with a variety of IOAM data
      fields would be desirable.

4.2.  IOAM and the use of the Geneve O-bit

   [I-D.ietf-nvo3-geneve] defines an "O bit" for OAM packets.  Per
   [I-D.ietf-nvo3-geneve] the O bit indicates that the packet contains a
   control message instead of data payload.  Packets that carry IOAM
   data fields in addition to regular data payload / customer traffic
   must not set the O bit.  Packets that carry only IOAM data fields
   without any payload must set the O bit.

4.3.  Transit devices

   If IOAM is deployed in domains where UDP port numbers are not
   controlled and do not have a domain-wide meaning, such as on the
   global Internet, transit devices MUST NOT attempt to modify the IOAM
   data contained in the IOAM option class.  In case UDP port numbers
   are not controlled there might be UDP packets, which leverage the UDP
   port number that Geneve utilizes, i.e. 6081, but the payload of these
   packets isn't Geneve.  The scenario and associated reasoning is
   discussed in [RFC7605] which states that "it is important to
   recognize that any interpretation of port numbers -- except at the
   endpoints -- may be incorrect, because port numbers are meaningful
   only at the endpoints."

5.  IANA Considerations

   IANA is requested to allocate a Geneve "option class" numbers for
   IOAM:






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                 +---------------+-------------+---------------+
                 | Option Class  | Description | Reference     |
                 +---------------+-------------+---------------+
                 | x             | TBD_IOAM    | This document |
                 +---------------+-------------+---------------+


6.  Security Considerations

   The security considerations of Geneve are discussed in
   [I-D.ietf-nvo3-geneve], and the security considerations of IOAM in
   general are discussed in [I-D.ietf-ippm-ioam-data].

   IOAM is considered a "per domain" feature, where one or several
   operators decide on leveraging and configuring IOAM according to
   their needs.  Still, operators need to properly secure the IOAM
   domain to avoid malicious configuration and use, which could include
   injecting malicious IOAM packets into a domain.

7.  Acknowledgements

   The authors would like to thank Eric Vyncke, Nalini Elkins, Srihari
   Raghavan, Ranganathan T S, Karthik Babu Harichandra Babu, Akshaya
   Nadahalli, Stefano Previdi, Hemant Singh, Erik Nordmark, LJ Wobker,
   and Andrew Yourtchenko for the comments and advice.

8.  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., daniel.bernier@bell.ca, d., and J. Lemon,
              "Data Fields for In-situ OAM", draft-ietf-ippm-ioam-
              data-04 (work in progress), October 2018.

   [I-D.ietf-nvo3-geneve]
              Gross, J., Ganga, I., and T. Sridhar, "Geneve: Generic
              Network Virtualization Encapsulation", draft-ietf-
              nvo3-geneve-11 (work in progress), March 2019.

   [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>.







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   [RFC2784]  Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
              Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
              DOI 10.17487/RFC2784, March 2000, <https://www.rfc-
              editor.org/info/rfc2784>.

   [RFC3232]  Reynolds, J., Ed., "Assigned Numbers: RFC 1700 is Replaced
              by an On-line Database", RFC 3232, DOI 10.17487/RFC3232,
              January 2002, <https://www.rfc-editor.org/info/rfc3232>.

   [RFC7605]  Touch, J., "Recommendations on Using Assigned Transport
              Port Numbers", BCP 165, RFC 7605, DOI 10.17487/RFC7605,
              August 2015, <https://www.rfc-editor.org/info/rfc7605>.

Authors' Addresses

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

   Email: fbrockne@cisco.com


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

   Email: shwethab@cisco.com


   Vengada Prasad Govindan
   Cisco Systems, Inc.

   Email: venggovi@cisco.com


   Carlos Pignataro
   Cisco Systems, Inc.
   7200-11 Kit Creek Road
   Research Triangle Park, NC  27709
   United States

   Email: cpignata@cisco.com





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   Hannes Gredler
   RtBrick Inc.

   Email: hannes@rtbrick.com


   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


   Petr Lapukhov
   Facebook
   1 Hacker Way
   Menlo Park, CA  94025
   US

   Email: petr@fb.com


   Barak Gafni
   Mellanox Technologies, Inc.
   350 Oakmead Parkway, Suite 100
   Sunnyvale, CA  94085
   U.S.A.

   Email: gbarak@mellanox.com







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   Aviv Kfir
   Mellanox Technologies, Inc.
   350 Oakmead Parkway, Suite 100
   Sunnyvale, CA  94085
   U.S.A.

   Email: avivk@mellanox.com


   Mickey Spiegel
   Barefoot Networks
   2185 Park Boulevard
   Palo Alto, CA  94306
   US

   Email: mspiegel@barefootnetworks.com



































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