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Simple TWAMP (STAMP) Extensions for Segment Routing Networks
draft-gandhi-ippm-stamp-srpm-02

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This is an older version of an Internet-Draft whose latest revision state is "Replaced".
Authors Rakesh Gandhi , Clarence Filsfils , Daniel Voyer , Mach Chen , Bart Janssens
Last updated 2021-02-10 (Latest revision 2021-01-12)
Replaces draft-gandhi-ippm-twamp-srpm
Replaced by draft-ietf-ippm-stamp-srpm, RFC 9503
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draft-gandhi-ippm-stamp-srpm-02
IPPM Working Group                                        R. Gandhi, Ed.
Internet-Draft                                               C. Filsfils
Intended status: Standards Track                     Cisco Systems, Inc.
Expires: August 14, 2021                                        D. Voyer
                                                             Bell Canada
                                                                 M. Chen
                                                                  Huawei
                                                             B. Janssens
                                                                    Colt
                                                       February 10, 2021

      Simple TWAMP (STAMP) Extensions for Segment Routing Networks
                    draft-gandhi-ippm-stamp-srpm-02

Abstract

   Segment Routing (SR) leverages the source routing paradigm.  SR is
   applicable to both Multiprotocol Label Switching (SR-MPLS) and IPv6
   (SRv6) data planes.  This document specifies RFC 8762 (Simple Two-Way
   Active Measurement Protocol (STAMP)) extensions for SR networks, for
   both SR-MPLS and SRv6 data planes.

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 August 14, 2021.

Copyright Notice

   Copyright (c) 2021 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

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   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 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 Used in This Document . . . . . . . . . . . . . .   3
     2.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
     2.2.  Abbreviations . . . . . . . . . . . . . . . . . . . . . .   3
     2.3.  Reference Topology  . . . . . . . . . . . . . . . . . . .   4
   3.  Destination Node Address TLV  . . . . . . . . . . . . . . . .   4
   4.  Return Path TLV . . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Return Path Sub-TLVs  . . . . . . . . . . . . . . . . . .   6
       4.1.1.  Return Path Control Code Sub-TLV  . . . . . . . . . .   6
       4.1.2.  Return Address Sub-TLV  . . . . . . . . . . . . . . .   7
       4.1.3.  Return Segment List Sub-TLVs  . . . . . . . . . . . .   8
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  10
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  10
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  11
   Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  11
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Introduction

   Segment Routing (SR) leverages the source routing paradigm and
   greatly simplifies network operations for Software Defined Networks
   (SDNs).  SR is applicable to both Multiprotocol Label Switching (SR-
   MPLS) and IPv6 (SRv6) data planes [RFC8402].  SR Policies as defined
   in [I-D.ietf-spring-segment-routing-policy] are used to steer traffic
   through a specific, user-defined paths using a stack of Segments.
   Built-in SR Performance Measurement (PM) is one of the essential
   requirements to provide Service Level Agreements (SLAs).

   The Simple Two-way Active Measurement Protocol (STAMP) provides
   capabilities for the measurement of various performance metrics in IP
   networks [RFC8762].  It eliminates the need for control protocol by
   using configuration and management model to provision and manage test
   sessions.  [RFC8972] defines optional extensions for STAMP.

   The STAMP supports two modes of STAMP Session-Reflector: Stateless
   and Stateful as described in Section 4 of [RFC8762].  In Stateless
   mode, maintenance of each STAMP test session on Session-Reflector is

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   avoided.  In SR networks, as the state is in the packet, the
   signaling of the parameters and creating extra states in the network
   are undesired.  Hence, Stateless mode of Session-Reflector is
   preferred in SR networks.

   For performance delay and packet loss measurement, STAMP Session-
   Sender test packets are transmitted in-band on the same path as the
   data traffic flow under measurement to measure the delay and packet
   loss experienced by the data traffic flow.  It is also desired in SR
   networks that the Session-Reflector reply test packets are
   transmitted in-band on the same path in the reverse direction.  This
   is achieved by using the STAMP extensions defined in this document.

   This document specifies RFC 8762 (Simple Two-Way Active Measurement
   Protocol (STAMP)) extensions for SR networks, for both SR-MPLS and
   SRv6 data planes.

2.  Conventions Used in This Document

2.1.  Requirements 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] [RFC8174]
   when, and only when, they appear in all capitals, as shown here.

2.2.  Abbreviations

   MPLS: Multiprotocol Label Switching.

   PM: Performance Measurement.

   SID: Segment ID.

   SL: Segment List.

   SR: Segment Routing.

   SR-MPLS: Segment Routing with MPLS data plane.

   SRv6: Segment Routing with IPv6 data plane.

   SSID: STAMP Session Identifier.

   STAMP: Simple Two-way Active Measurement Protocol.

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2.3.  Reference Topology

   In the reference topology shown below, the STAMP Session-Sender R1
   initiates a STAMP test packet and the STAMP Session-Reflector R3
   transmits a reply test packet.  The reply test packet is transmitted
   back to the STAMP Session-Sender R1 on the same path or a different
   path in the reverse direction.

   The nodes R1 and R3 may be connected via a link or there exists an SR
   path [RFC8402].  The link may be a physical interface, virtual link,
   or Link Aggregation Group (LAG) [IEEE802.1AX], or LAG member link.
   The SR path may be an SR Policy
   [I-D.ietf-spring-segment-routing-policy] on node R1 (called head-end)
   with destination to node R3 (called tail-end).

                          T1                T2
                         /                   \
                +-------+     Test Packet     +-------+
                |       | - - - - - - - - - ->|       |
                |   R1  |=====================|   R3  |
                |       |<- - - - - - - - - - |       |
                +-------+  Reply Test Packet  +-------+
                         \                   /
                          T4                T3

            STAMP Session-Sender        STAMP Session-Reflector

                          Reference Topology

3.  Destination Node Address TLV

   The STAMP Session-Sender may need to transmit test packets to the
   STAMP Session-Reflector with a different destination address (for
   example IPv4 address from 127/8 range).  In an error condition, the
   STAMP test packet may not reach the intended STAMP Session-Reflector,
   an un-intended node may transmit reply test packets resulting in
   reporting of invalid measurement metrics.

   [RFC8972] defines STAMP test packets that can include one or more
   optional TLVs.  In this document, Destination Node Address TLV (Type
   TBA1) is defined for STAMP test packet [RFC8972] and has the
   following format shown in Figure 1:

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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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |STAMP TLV Flags| Type=TBA1     |         Length                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | Reserved                      | Address Family                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    .                           Address                             .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

               Figure 1: Destination Node Address TLV Format

   The Address Family field indicates the type of the address, and it
   SHALL be set to one of the assigned values in the "IANA Address
   Family Numbers" registry.

   The STAMP TLV Flags are set using the procedures described in
   [RFC8972].

   The Destination Node Address TLV is optional.  The Destination Node
   Address TLV indicates the address of the intended destination node of
   the test packet.  The STAMP Session-Reflector that supports this TLV,
   MUST NOT transmit reply test packet if it is not the intended
   destination node of the received test packet.

4.  Return Path TLV

   For end-to-end SR paths, the STAMP Session-Reflector may need to
   transmit the reply test packet on a specific return path.  The STAMP
   Session-Sender can request this in the test packet to the STAMP
   Session-Reflector using a Return Path TLV.  With this TLV carried in
   the STAMP Session-Sender test packet, the STAMP Session-Reflector
   (Stateless mode) does not require signaling and maintaining any
   additional dynamic state for the STAMP sessions for the end-to-end SR
   paths.

   For links, the STAMP Session-Reflector may need to transmit the reply
   test packet on the same incoming link in the reverse direction.  The
   STAMP Session-Sender can request this in the test packet to the STAMP
   Session-Reflector using a Return Path TLV.  With this TLV carried in
   the STAMP Session-Sender test packet, the STAMP Session-Reflector
   (Stateless mode) does not require maintenance of any additional state
   for the STAMP sessions for the links.

   [RFC8972] defines STAMP test packets that can include one or more
   optional TLVs.  In this document, the TLV Type (value TBA2) is
   defined for the Return Path TLV that carries the return path for the

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   STAMP Session-Sender test packet.  The format of the Return Path TLV
   is shown in Figure 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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |STAMP TLV Flags|   Type=TBA2   |         Length                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                   Return Path Sub-TLVs                        |
    .                                                               .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                         Figure 2: Return Path TLV

   The STAMP TLV Flags are set using the procedures described in
   [RFC8972].

   The Return Path TLV is optional.  The STAMP Session-Sender MUST only
   insert one Return Path TLV in the STAMP test packet.  The STAMP
   Session-Reflector that supports this TLV, MUST only process the first
   Return Path TLV in the test packet and ignore other Return Path TLVs
   if present, and it MUST NOT add Return Path TLV in the reply test
   packet.

4.1.  Return Path Sub-TLVs

   The Return Path TLV contains one or more Sub-TLVs to carry the
   information for the requested return path.  A Return Path Sub-TLV can
   either carry Return Path Control Code, Return Path IP Address or
   Return Path Segment List.

   The STAMP Sub-TLV Flags are set using the procedures described in
   [RFC8972].

   When Return Path Sub-TLV is present in the Session-Sender test
   packet, the STAMP Session-Reflector that supports this TLV, MUST
   transmit reply test packet using the return path information
   specified in the Return Path Sub-TLV.

4.1.1.  Return Path Control Code Sub-TLV

   The format of the Return Path Control Code Sub-TLV is shown in
   Figure 3.  The Type of the Return Path Control Code Sub-TLV is
   defined as following:

   o  Type (value 1): Return Path Control Code.  The STAMP Session-
      Sender can request the STAMP Session-Reflector to transmit the

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      reply test packet based on the flags defined in the Control Code
      field.

    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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |STAMP TLV Flags|   Type        |         Length                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                   Control Code                                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 3: Control Code Sub-TLV in Return Path TLV

   Control Code Flags (32-bit): Defined as follows.

       0x0: No Reply Requested.

       0x1: In-band Reply Requested.

   When Control Code flag is set to 0x0 in the STAMP Session-Sender test
   packet, the Session-Reflector does not transmit reply test packet to
   the Session-Sender and terminates the STAMP test packet.  Optionally,
   the Session-Reflector may locally stream performance metrics via
   telemetry using the information from the received test packet.  All
   other Return Path Sub-TLVs are ignored in this case.

   When Control Code flag is set to 0x1 in the STAMP Session-Sender test
   packet, the Session-Reflector transmits the reply test packet in-band
   over the same incoming link where the test packet is received in the
   reverse direction.

4.1.2.  Return Address Sub-TLV

   The STAMP reply test packet may be transmitted to a different node
   than the Session-Sender (e.g. to a controller for telemetry use-
   cases).  For this, the Session-Sender can specify in the test packet
   the receiving destination node address for the Session-Reflector
   reply test packet.

   The format of the Return Address Sub-TLV is shown in Figure 4.  The
   Address Family field indicates the type of the address, and it SHALL
   be set to one of the assigned values in the "IANA Address Family
   Numbers" registry.  The Type of the Return Address Sub-TLV is defined
   as following:

   o  Type (value 2): Return Address.  Destination node address of the
      STAMP Session-Reflector reply test packet different than the
      Source Address in the Session-Sender test packet.

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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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |STAMP TLV Flags|     Type      |         Length                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | Reserved                      | Address Family                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    .                           Address                             .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

            Figure 4: Return Address Sub-TLV in Return Path TLV

4.1.3.  Return Segment List Sub-TLVs

   The format of the Segment List Sub-TLVs in the Return Path TLV is
   shown in Figure 5.  The segment entries MUST be in network order.
   The Segment List Sub-TLV can be one of the following Types:

   o  Type (value 3): SR-MPLS Label Stack of the Return Path

   o  Type (value 4): SR-MPLS Binding SID
      [I-D.ietf-pce-binding-label-sid] of the Return SR Policy

   o  Type (value 5): SRv6 Segment List of the Return Path

   o  Type (value 6): SRv6 Binding SID [I-D.ietf-pce-binding-label-sid]
      of the Return SR Policy

    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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |STAMP TLV Flags|     Type      |         Length                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                    Segment(1)                                 |
    .                                                               .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    .                                                               .
    .                                                               .
    .                                                               .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                    Segment(n) (bottom of stack)               |
    .                                                               .
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 5: Segment List Sub-TLV in Return Path TLV

   The STAMP Session-Sender MUST only insert one Segment List Return
   Path Sub-TLV in the test packet.  The STAMP Session-Reflector MUST

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   only process the first Segment List Return Path Sub-TLV in the test
   packet and ignore other Segment List Return Path Sub-TLVs if present.

5.  Security Considerations

   The performance measurement is intended for deployment in well-
   managed private and service provider networks.  As such, it assumes
   that a node involved in a measurement operation has previously
   verified the integrity of the path and the identity of the STAMP
   Session-Reflector.

   If desired, attacks can be mitigated by performing basic validation
   and sanity checks, at the STAMP Session-Sender, of the timestamp
   fields in received measurement reply packets.  The minimal state
   associated with these protocols also limits the extent of measurement
   disruption that can be caused by a corrupt or invalid packet to a
   single test cycle.

   The security considerations specified in [RFC8762] and [RFC8972] also
   apply to the extensions defined in this document.

6.  IANA Considerations

   IANA will create a "STAMP TLV Type" registry for [RFC8972].  IANA is
   requested to allocate a value for the following Destination Address
   TLV Type from the IETF Review TLV range of this registry.  This TLV
   is to be carried in the STAMP test packets.

   o  Type TBA1: Destination Node Address TLV

   IANA is also requested to allocate a value for the following Return
   Path TLV Type from the IETF Review TLV range of the same registry.
   This TLV is to be carried in the STAMP test packets.

   o  Type TBA2: Return Path TLV

   IANA is requested to create a sub-registry for "Return Path Sub-TLV
   Type".  All code points in the range 1 through 175 in this registry
   shall be allocated according to the "IETF Review" procedure as
   specified in [RFC8126].  Code points in the range 176 through 239 in
   this registry shall be allocated according to the "First Come First
   Served" procedure as specified in [RFC8126].  Remaining code points
   are allocated according to Table 1:

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               +-----------+--------------+---------------+
               | Value     | Description  | Reference     |
               +-----------+--------------+---------------+
               | 0         |   Reserved   | This document |
               | 1 - 175   |  Unassigned  | This document |
               | 176 - 239 |  Unassigned  | This document |
               | 240 - 251 | Experimental | This document |
               | 252 - 254 | Private Use  | This document |
               | 255       |   Reserved   | This document |
               +-----------+--------------+---------------+

                Table 1: Return Path Sub-TLV Type Registry

   IANA is requested to allocate the values for the following Sub-TLV
   Types from this registry.

   o  Type (value 1): Return Path Control Code

   o  Type (value 2): Return Address

   o  Type (value 3): SR-MPLS Label Stack of the Return Path

   o  Type (value 4): SR-MPLS Binding SID of the Return SR Policy

   o  Type (value 5): SRv6 Segment List of the Return Path

   o  Type (value 6): SRv6 Binding SID of the Return SR Policy

7.  References

7.1.  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>.

   [RFC8762]  Mirsky, G., Jun, G., Nydell, H., and R. Foote, "Simple
              Two-Way Active Measurement Protocol", RFC 8762,
              DOI 10.17487/RFC8762, March 2020,
              <https://www.rfc-editor.org/info/rfc8762>.

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   [RFC8972]  Mirsky, G., Min, X., Nydell, H., Foote, R., Masputra, A.,
              and E. Ruffini, "Simple Two-Way Active Measurement
              Protocol Optional Extensions", RFC 8972,
              DOI 10.17487/RFC8972, January 2021,
              <https://www.rfc-editor.org/info/rfc8972>.

7.2.  Informative References

   [RFC8402]  Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
              Decraene, B., Litkowski, S., and R. Shakir, "Segment
              Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
              July 2018, <https://www.rfc-editor.org/info/rfc8402>.

   [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>.

   [I-D.ietf-spring-segment-routing-policy]
              Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and
              P. Mattes, "Segment Routing Policy Architecture", draft-
              ietf-spring-segment-routing-policy-09 (work in progress),
              November 2020.

   [I-D.ietf-pce-binding-label-sid]
              Sivabalan, S., Filsfils, C., Tantsura, J., Hardwick, J.,
              Previdi, S., and C. Li, "Carrying Binding Label/Segment-ID
              in PCE-based Networks.", draft-ietf-pce-binding-label-
              sid-05 (work in progress), October 2020.

Acknowledgments

   The authors would like to thank Thierry Couture for the discussions
   on the use-cases for Performance Measurement in Segment Routing.  The
   authors would also like to thank Greg Mirsky, Mike Koldychev, Gyan
   Mishra, Tianran Zhou, and Cheng Li for providing comments and
   suggestions.

Authors' Addresses

   Rakesh Gandhi (editor)
   Cisco Systems, Inc.
   Canada

   Email: rgandhi@cisco.com

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   Clarence Filsfils
   Cisco Systems, Inc.

   Email: cfilsfil@cisco.com

   Daniel Voyer
   Bell Canada

   Email: daniel.voyer@bell.ca

   Mach(Guoyi) Chen
   Huawei

   Email: mach.chen@huawei.com

   Bart Janssens
   Colt

   Email: Bart.Janssens@colt.net

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