Network Working Group                                          G. Mirsky
Internet-Draft                                                 ZTE Corp.
Intended status: Standards Track                                  G. Jun
Expires: February 13, March 27, 2020                                  ZTE Corporation
                                                               H. Nydell
                                                       Accedian Networks
                                                                R. Foote
                                                                   Nokia
                                                         August 12,
                                                      September 24, 2019

               Simple Two-way Active Measurement Protocol
                        draft-ietf-ippm-stamp-07
                        draft-ietf-ippm-stamp-08

Abstract

   This document describes a Simple Two-way Active Measurement Protocol
   which enables the measurement of both one-way and round-trip
   performance metrics like delay, delay variation, and packet loss.

Status of This Memo

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   This Internet-Draft will expire on February 13, March 27, 2020.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  Softwarization  Operation and Management of Performance Measurement Based on
       STAMP . . . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Theory of Operation . . . . . . . . . . . . . . . . . . . . .   4
     4.1.  Session-Sender Behavior and Packet Format . . . . . . . .   5
       4.1.1.  Session-Sender Packet Format in Unauthenticated Mode    5
       4.1.2.  Session-Sender Packet Format in Authenticated Mode  .   6
     4.2.  Session-Reflector Behavior and Packet Format  . . . . . .   7
       4.2.1.  Session-Reflector Packet Format in Unauthenticated
               Mode  . . . . . . . . . . . . . . . . . . . . . . . .   8
       4.2.2.  Session-Reflector Packet Format in Authenticated Mode   9
     4.3.  Integrity and Confidentiality Protection in STAMP . . . . . . . . . . . . . .  10
     4.4.  Confidentiality Protection in STAMP . . . . . . . . . . .  11
     4.5.  Interoperability with TWAMP Light . . . . . . . . . . . .  11
   5.  Operational Considerations  . . . . . . . . . . . . . . . . .  12
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   6.  12
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   7.
   8.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   8.  13
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     8.1.  13
     9.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     8.2.  13
     9.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14  15

1.  Introduction

   Development and deployment of Two-Way Active Measurement Protocol
   (TWAMP) [RFC5357] and its extensions, e.g., [RFC6038] that defined
   features such as Reflect Octets and
   Symmetrical Size for TWAMP provided invaluable experience.  Several
   independent implementations of both TWAMP and TWAMP Light exist, have
   been deployed deployed, and provide important operational performance
   measurements.

   At the same time, there has been noticeable interest in using a more
   straightforward mechanism for active performance monitoring that can
   provide deterministic behavior and inherit separation of control
   (vendor-specific configuration or orchestration) and test functions.  One of such is Performance
   Measurement from
   Recent work on IP Edge to Customer Equipment using TWAMP Light from
   Broadband Forum [BBF.TR-390] used as demonstrated that interoperability among
   implementations of TWAMP Light is challenged because the reference composition
   and operation of TWAMP Light that,
   according were not sufficiently specified in
   [RFC5357].  According to [RFC8545], TWAMP Light includes sub-set of
   TWAMP-Test functions in
   combination with to provide comprehensive solution requires
   support by other applications that provide, for example, control and
   security.

   This document defines an active performance measurement test
   protocol, Simple Two-way Active Measurement Protocol (STAMP), that
   enables measurement of both one-way and round-trip performance
   metrics like delay, delay variation, and packet loss.  Some TWAMP
   extensions, e.g., [RFC7750] are supported by the extensions to STAMP
   base specification in [I-D.ietf-ippm-stamp-option-tlv].

2.  Conventions used in this document

2.1.  Terminology

   AES Advanced Encryption Standard

   CBC Cipher Block Chaining

   ECB Electronic Cookbook

   KEK Key-encryption Key

   STAMP - Simple Two-way Active Measurement Protocol

   NTP - Network Time Protocol

   PTP - Precision Time Protocol

   HMAC Hashed Message Authentication Code

   OWAMP One-Way Active Measurement Protocol

   TWAMP Two-Way Active Measurement Protocol

   MBZ May be Zero

2.2.  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.  Softwarization  Operation and Management of Performance Measurement Based on STAMP

   Figure 1 presents the Simple Two-way Active Measurement Protocol
   (STAMP) Session-Sender, and Session-Reflector with a measurement
   session.  In this document, a measurement session also referred to as
   STAMP session, is the bi-directional packet flow between one specific
   Session-Sender and one particular Session-Reflector for a time
   duration.  The configuration and management of the STAMP Session-
   Sender, Session-Reflector, and management of the STAMP sessions can
   be achieved through various means.  Command Line Interface, OSS/BSS
   (operations support system/business support system as a combination
   of two systems used to support a range of telecommunication services)
   using SNMP or controllers in Software-Defined Networking using
   Netconf/YANG are but a few examples.

         o----------------------------------------------------------o
         |                      Configuration and                   |
         |                         Management                       |
         o----------------------------------------------------------o
                ||                                          ||
                ||                                          ||
                ||                                          ||
     +----------------------+                +-------------------------+
     | STAMP Session-Sender | <--- STAMP---> | STAMP Session-Reflector |
     +----------------------+                +-------------------------+

                      Figure 1: STAMP Reference Model

4.  Theory of Operation

   STAMP Session-Sender transmits test packets over UDP transport toward
   STAMP Session-Reflector.  A STAMP Session-Sender MUST use UDP port
   862 (TWAMP-Test Receiver Port) as the default destination UDP port
   number.  A STAMP implementation of Session-Sender MUST be able to use
   UDP port numbers from User, a.k.a.  Registered, Ports and Dynamic,
   a.k.a.  Private or Ephemeral, Ports ranges defined in [RFC6335].
   Before using numbers from the User Ports range, the possible impact
   on the network MUST be carefully studied and agreed by all users of
   the network. network domain where the test has been planned.

   STAMP Session-Reflector receives Session-Sender's packet and acts
   according to the configuration and optional control information
   communicated in the Session-Sender's test packet.  An implementation
   of STAMP Session-Reflector by default MUST use receive STAMP test
   packets on UDP port 862.  An implementation of Session-Reflector that
   supports this specification MUST be able to define the port number to
   receive STAMP test packets from User Ports and Dynamic Ports ranges
   that are defined in [RFC6335].  STAMP defines two different test
   packet formats, one for packets transmitted by the STAMP-Session-
   Sender and one for packets transmitted by the STAMP-Session-
   Reflector.

   STAMP supports two modes: unauthenticated and authenticated.
   Unauthenticated STAMP test packets, defined in Section 4.1.1 and
   Section 4.2.1, ensure interworking between STAMP and TWAMP Light as
   described in Section 4.4 4.5 packet formats.

   By default, STAMP uses symmetrical packets, i.e., size of the packet
   transmitted by Session-Reflector equals the size of the packet
   received by the Session-Reflector.

4.1.  Session-Sender Behavior and Packet Format

   Because

   STAMP supports symmetrical test packets, packets.  The base STAMP Session-Sender Session-
   Sender packet has a minimum size of 44 octets in unauthenticated
   mode, see Figure 2, and 112 octets in the authenticated mode, see
   Figure 4.  The variable length of a test packet in STAMP is supported
   by using Extra Padding TLV defined in
   [I-D.ietf-ippm-stamp-option-tlv].

4.1.1.  Session-Sender Packet Format in Unauthenticated Mode

   STAMP Session-Sender packet format in unauthenticated mode:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Sequence Number                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Timestamp                            |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Error Estimate        |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
      |                                                               |
      |                                                               |
      |                         MBZ (30 octets)                       |
      |                                                               |
      |                                                               |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Figure 2: STAMP Session-Sender test packet format in unauthenticated
                                   mode

   where fields are defined as the following:

   o  Sequence Number is four octets long field.  For each new session
      its value starts at zero and is incremented with each transmitted
      packet.

   o  Timestamp is eight octets long field.  STAMP node MUST support
      Network Time Protocol (NTP) version 4 64-bit timestamp format
      [RFC5905], the format used in [RFC5357].  STAMP node MAY support
      IEEE 1588v2 Precision Time Protocol truncated 64-bit timestamp
      format [IEEE.1588.2008], the format used in [RFC8186].

   o  Error Estimate is two octets long field with format displayed in
      Figure 3

            0                   1
            0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
           |S|Z|   Scale   |   Multiplier  |
           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                      Figure 3: Error Estimate Format

      where S, Scale, and Multiplier fields are interpreted as they have
      been defined in section 4.1.2 [RFC4656]; and Z field flag - as has been
      defined in section 2.3 [RFC8186]:

      *  0 - NTP 64 bit format of a timestamp;

      *  1 - PTPv2 truncated format of a timestamp.

      The STAMP Session-Sender and Session-Reflector MAY use, not use,
      or set MUST use a Z field
      value of 0, (NTP 64 bit format of a timestamp) as the Z field in accordance with default.
      The STAMP Session-Sender and Session-Reflector MAY optionally set
      the timestamp
      format in use.  This optional Z field is to enhance operations, but
      local configuration or defaults could be used in its place. a value of 1 (PTPv2 truncated format of a
      timestamp).

   o  May-be-Zero (MBZ) field in the session-sender unauthenticated
      packet is 30 octets long.  It MAY be all zeroed on the
      transmission and MUST be ignored on receipt.

4.1.2.  Session-Sender Packet Format in Authenticated Mode

   STAMP Session-Sender packet format in authenticated mode:

     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                      Sequence Number                          |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                      MBZ (12 octets)                          |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                        Timestamp                              |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |        Error Estimate         |                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
    ~                                                               ~
    |                         MBZ (70 octets)                       |
    ~                                                               ~
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                               |
    |                       HMAC (16 octets)                        |
    |                                                               |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Figure 4: STAMP Session-Sender test packet format in authenticated
                                   mode

   The field definitions are the same as the unauthenticated mode,
   listed in Section 4.1.1.  Also, MBZ fields are used to align the
   packet on 16 octets boundary.  The value of the field MAY be zeroed
   on transmission and MUST be ignored on receipt.  Also, the packet
   includes a key-hashed message authentication code (HMAC) ([RFC2104])
   hash at the end of the PDU.  The detailed use of the HMAC field is
   described in Section 4.3.

4.2.  Session-Reflector Behavior and Packet Format

   The Session-Reflector receives the STAMP test packet, verifies it,
   prepares and transmits the reflected test packet.

   Two modes of STAMP Session-Reflector characterize the expected
   behavior and, consequently, performance metrics that can be measured:

   o  Stateless - STAMP Session-Reflector does not maintain test state
      and will reflect use the received sequence number without
      modification.  As a result, only round-trip packet loss can be
      calculated while value in the Sequence Number field in the
      recieved packet as the value for the Sequence Number field in the
      reflected packet.  As a result, values in Sequence Number and
      Session-Sender Sequence Number fields are the same, and only
      round-trip packet loss can be calculated while the reflector is
      operating in stateless mode.

   o  Stateful - STAMP Session-Reflector maintains test state thus
      enabling the ability to determine forward loss, gaps recognized in
      the received sequence number.  As a result, both near-end
      (forward) and far-end (backward) packet loss can be computed.
      That implies that the STAMP Session-Reflector MUST keep a state
      for each accepted STAMP-test session, uniquely identifying STAMP-
      test packets to one such session instance, and enabling adding a
      sequence number in the test reply that is individually incremented
      on a per-session basis.

4.2.1.  Session-Reflector Packet Format in Unauthenticated Mode

   For unauthenticated mode:

     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                        Sequence Number                        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                          Timestamp                            |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |         Error Estimate        |           MBZ                 |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                          Receive Timestamp                    |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                 Session-Sender Sequence Number                |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                  Session-Sender Timestamp                     |
    |                                                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | Session-Sender Error Estimate |           MBZ                 |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |Ses-Sender TTL |                    MBZ                        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          Figure 5: STAMP Session-Reflector test packet format in
                           unauthenticated mode

   where fields are defined as the following:

   o  Sequence Number is four octets long field.  The value of the
      Sequence Number field is set according to the mode of the STAMP
      Session-Reflector:

      *  in the stateless mode the Session-Reflector copies the value
         from the received STAMP test packet's Sequence Number field;

      *  in the stateful mode the Session-Reflector counts the received
         STAMP test packets in each test session and uses that counter
         to set the value of the Sequence Number field.

   o  Timestamp and Receiver Timestamp fields are each eight octets
      long.  The format of these fields, NTP or PTPv2, indicated by the
      Z flag of the Error Estimate field as described in Section 4.1.

   o  Error Estimate has the same size and interpretation as described
      in Section 4.1.

   o  Session-Sender Sequence Number, Session-Sender Timestamp, and
      Session-Sender Error Estimate are copies of the corresponding
      fields in the STAMP test packet sent by the Session-Sender.

   o  Session-Sender TTL is one octet long field, and its value is the
      copy of the TTL field in IPv4 (or Hop Limit in IPv6) from the
      received STAMP test packet.

   o  MBZ is used to achieve alignment on a four octets boundary.  The
      value of the field MAY be zeroed on transmission and MUST be
      ignored on receipt.

4.2.2.  Session-Reflector Packet Format in Authenticated Mode

   For the authenticated mode:

      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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Sequence Number                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        MBZ (12 octets)                        |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Timestamp                            |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Error Estimate        |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
      |                        MBZ (6 octets)                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Receive Timestamp                      |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        MBZ (8 octets)                         |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                 Session-Sender Sequence Number                |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        MBZ (12 octets)                        |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                 Session-Sender Timestamp                      |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Session-Sender Error Estimate |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
      |                        MBZ (6 octets)                         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |Ses-Sender TTL |                                               |
      +-+-+-+-+-+-+-+-+                                               +
      |                                                               |
      |                        MBZ (15 octets)                        |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        HMAC (16 octets)                       |
      |                                                               |
      |                                                               |
      |                                                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Figure 6: STAMP Session-Reflector test packet format in authenticated
                                   mode

   The field definitions are the same as the unauthenticated mode,
   listed in Section 4.2.1.  Additionally, the MBZ field is used to
   align the packet on 16 octets boundary.  The value of the field MAY
   be zeroed on transmission and MUST be ignored on receipt.  Also,
   STAMP Session-Reflector test packet format in authenticated mode
   includes a key (HMAC) ([RFC2104]) hash at the end of the PDU.  The
   detailed use of the HMAC field is in Section 4.3.

4.3.  Integrity and Confidentiality Protection in STAMP

   To provide integrity protection, each STAMP message is being
   authenticated by adding Hashed Message Authentication Code (HMAC).
   STAMP uses HMAC-SHA-256 truncated to 128 bits (similarly to the use
   of it in IPSec defined in [RFC4868]); hence the length of the HMAC
   field is 16 octets.  HMAC uses its own key, and the definition of the
   mechanism to distribute the HMAC key is outside the scope of this
   specification.  One example is to use an orchestrator to configure
   HMAC key based on STAMP YANG data model [I-D.ietf-ippm-stamp-yang].
   HMAC MUST be verified as early as possible to avoid using or
   propagating corrupted data.

4.4.  Confidentiality Protection in STAMP

   If confidentiality protection for STAMP is required, encryption at
   the higher level a STAMP test
   session MUST be used. use a secured transport.  For example, STAMP packets
   could be transmitted in the dedicated IPsec tunnel or share the IPsec
   tunnel with the monitored flow.

4.4.  Also, Datagram Transport Layer
   Security protocol would provide the desired confidentiality
   protection.

4.5.  Interoperability with TWAMP Light

   One of the essential requirements to STAMP is the ability to
   interwork with a TWAMP Light device.  There are two possible
   combinations for such use case:

   o  STAMP Session-Sender with TWAMP Light Session-Reflector;

   o  TWAMP Light Session-Sender with STAMP Session-Reflector.

   In the former case, the Session-Sender MAY not be aware that its
   Session-Reflector does not support STAMP.  For example, a TWAMP Light
   Session-Reflector may not support the use of UDP port 862 as defined
   in [RFC8545].  Thus STAMP Session-Sender MAY use port numbers as
   defined in Section 4.  If any of STAMP extensions are used, the TWAMP
   Light Session-Reflector will view them as Packet Padding field.  The
   Session-Sender SHOULD use the default format for its timestamps -
   NTP.  And it MAY use PTPv2 timestamp format.

   In the latter scenario, if a TWAMP Light Session-Sender does not
   support the use of UDP port 862, the test management system MUST set
   STAMP Session-Reflector to use UDP port number as defined in
   Section 4.  If the TWAMP Light Session-Sender includes Packet Padding
   field in its transmitted packet, the STAMP Session-Reflector will
   return the reflected packet of the symmetrical size if the size of
   the received test packet is larger than the size of the STAMP base
   packet.  The Session-Reflector MUST be set to use the default format
   for its timestamps, NTP.

   STAMP does not support the Reflect Octets capability defined in
   [RFC6038].  If the Server Octets field is present in the TWAMP
   Session-Sender packet, STAMP Session-Reflector will not copy the
   content starting from the Server Octets field but will transmit the
   reflected packet of equal size.

5.  Operational Considerations

   STAMP is intended to be used on production networks to enable the
   operator to assess service level agreements based on packet delay,
   delay variation, and loss.  When using STAMP over the Internet,
   especially when STAMP test packets are transmitted with the
   destination UDP port number from the User Ports range, the possible
   impact of the STAMP test packets MUST be thoroughly analyzed.  The
   use of STAMP for each case MUST be agreed by users of nodes hosting
   the Session-Sender and Session-Reflector before starting the STAMP
   test session.

   Also, the use of the well-known port number as the destination UDP
   port number in STAMP test packets transmitted by a Session-Sender
   would not impede the ability to measure performance in an Equal Cost
   Multipath environment and analysis in Section 5.3 [RFC8545] fully
   applies to STAMP.

6.  IANA Considerations

   This document doesn't have any IANA action.  This section may be
   removed before the publication.

6.

7.  Security Considerations

   In general, all the

   [RFC5357] does not identify security considerations specific to
   TWAMP-Test but refers to security considerations identified for OWAMP
   in [RFC4656].  Since both OWAMP and TWAMP include control plane and
   data plane components, only security considerations related to TWAMP-Test, OWAMP-
   Test, discussed in [RFC5357] Sections 6.2, 6.3[RFC4656] apply to STAMP.  Since

   STAMP uses the well-
   known well-known UDP port number allocated for the OWAMP-Test/TWAMP-Test OWAMP-
   Test/TWAMP-Test Receiver port, port.  Thus the security considerations and
   measures to mitigate the risk of the attack using the registered port
   number documented in Section 6 [RFC8545] equally apply to STAMP.
   Because of the control and management of a STAMP test being outside
   the scope of this specification only the more general requirement is
   set:

      To mitigate the possible attack vector, the control, and
      management of a STAMP test session MUST use the secured transport.

      Load of STAMP test packets offered to a network MUST be carefully
      estimated, and the possible impact on the existing services MUST
      be thoroughly analyzed before launching the test session.
      [RFC8085] section 3.1.5 provides guidance on handling network load
      for UDP-based protocol.  While the characteristic of test traffic
      depends on the test objective, it is highly recommended to stay in
      the limits as provided in [RFC8085].

   STAMP test packets can be transmitted with the destination UDP port
   number from the User Ports range, as defined in Section 4, that is
   already or will be assigned by IANA.  The possible impact of the
   STAMP test packets on the network MUST be thoroughly analyzed, and
   the use of STAMP for each case MUST be agreed by all users on the
   network before starting the STAMP test session.

   Use of HMAC-SHA-256 in the authenticated mode protects the data
   integrity of the STAMP test packets.

7.

8.  Acknowledgments

   Authors express their appreciation to Jose Ignacio Alvarez-Hamelin
   and Brian Weis for their great insights into the security and
   identity protection, and the most helpful and practical suggestions.
   Also, our sincere thanks to David Ball and Rakesh Gandhi or their
   thorough reviews and helpful comments.

8.

9.  References

8.1.

9.1.  Normative References

   [I-D.ietf-ippm-stamp-option-tlv]
              Mirsky, G., Xiao, M., Jun, G., Nydell, H., Foote, R., and
              A. Masputra, "Simple Two-way Active Measurement Protocol
              Optional Extensions", draft-ietf-ippm-stamp-option-tlv-01
              (work in progress), September 2019.

   [IEEE.1588.2008]
              "Standard for a Precision Clock Synchronization Protocol
              for Networked Measurement and Control Systems",
              IEEE Standard 1588, March 2008.

   [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>.

   [RFC4656]  Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
              Zekauskas, "A One-way Active Measurement Protocol
              (OWAMP)", RFC 4656, DOI 10.17487/RFC4656, September 2006,
              <https://www.rfc-editor.org/info/rfc4656>.

   [RFC5357]  Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
              Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
              RFC 5357, DOI 10.17487/RFC5357, October 2008,
              <https://www.rfc-editor.org/info/rfc5357>.

   [RFC5905]  Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
              "Network Time Protocol Version 4: Protocol and Algorithms
              Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
              <https://www.rfc-editor.org/info/rfc5905>.

   [RFC6038]  Morton, A. and L. Ciavattone, "Two-Way Active Measurement
              Protocol (TWAMP) Reflect Octets and Symmetrical Size
              Features", RFC 6038, DOI 10.17487/RFC6038, October 2010,
              <https://www.rfc-editor.org/info/rfc6038>.

   [RFC6335]  Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S.
              Cheshire, "Internet Assigned Numbers Authority (IANA)
              Procedures for the Management of the Service Name and
              Transport Protocol Port Number Registry", BCP 165,
              RFC 6335, DOI 10.17487/RFC6335, August 2011,
              <https://www.rfc-editor.org/info/rfc6335>.

   [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>.

   [RFC8186]  Mirsky, G. and I. Meilik, "Support of the IEEE 1588
              Timestamp Format in a Two-Way Active Measurement Protocol
              (TWAMP)", RFC 8186, DOI 10.17487/RFC8186, June 2017,
              <https://www.rfc-editor.org/info/rfc8186>.

   [RFC8545]  Morton, A., Ed. and G. Mirsky, Ed., "Well-Known Port
              Assignments for the One-Way Active Measurement Protocol
              (OWAMP) and the Two-Way Active Measurement Protocol
              (TWAMP)", RFC 8545, DOI 10.17487/RFC8545, March 2019,
              <https://www.rfc-editor.org/info/rfc8545>.

8.2.

9.2.  Informative References

   [BBF.TR-390]
              "Performance Measurement from IP Edge to Customer
              Equipment using TWAMP Light", BBF TR-390, May 2017.

   [I-D.ietf-ippm-stamp-option-tlv]
              Mirsky, G., Xiao, M., Jun, G., Nydell, H., and R. Foote,
              "Simple Two-way Active Measurement Protocol Optional
              Extensions", draft-ietf-ippm-stamp-option-tlv-00 (work in
              progress), July 2019.

   [I-D.ietf-ippm-stamp-yang]
              Mirsky, G., Xiao, M., and W. Luo, "Simple Two-way Active
              Measurement Protocol (STAMP) Data Model", draft-ietf-ippm-
              stamp-yang-03
              stamp-yang-04 (work in progress), March September 2019.

   [RFC2104]  Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
              Hashing for Message Authentication", RFC 2104,
              DOI 10.17487/RFC2104, February 1997,
              <https://www.rfc-editor.org/info/rfc2104>.

   [RFC4868]  Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA-
              384, and HMAC-SHA-512 with IPsec", RFC 4868,
              DOI 10.17487/RFC4868, May 2007,
              <https://www.rfc-editor.org/info/rfc4868>.

   [RFC7750]  Hedin, J., Mirsky, G., and S. Baillargeon, "Differentiated
              Service Code Point and Explicit Congestion Notification
              Monitoring in the Two-Way Active Measurement Protocol
              (TWAMP)", RFC 7750, DOI 10.17487/RFC7750, February 2016,
              <https://www.rfc-editor.org/info/rfc7750>.

   [RFC8085]  Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
              Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
              March 2017, <https://www.rfc-editor.org/info/rfc8085>.

Authors' Addresses

   Greg Mirsky
   ZTE Corp.

   Email: gregimirsky@gmail.com

   Guo Jun
   ZTE Corporation
   68# Zijinghua Road
   Nanjing, Jiangsu  210012
   P.R.China

   Phone: +86 18105183663
   Email: guo.jun2@zte.com.cn

   Henrik Nydell
   Accedian Networks

   Email: hnydell@accedian.com

   Richard Foote
   Nokia

   Email: footer.foote@nokia.com