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rfc:rfc8762



Internet Engineering Task Force (IETF) G. Mirsky Request for Comments: 8762 G. Jun Category: Standards Track ZTE Corp. ISSN: 2070-1721 H. Nydell

                                                     Accedian Networks
                                                              R. Foote
                                                                 Nokia
                                                            March 2020
             Simple Two-Way Active Measurement Protocol

Abstract

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

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc8762.

Copyright Notice

 Copyright (c) 2020 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
 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.  Conventions Used in This Document
   2.1.  Terminology
   2.2.  Requirements Language
 3.  Operation and Management of Performance Measurement Based on
         STAMP
 4.  Theory of Operation
   4.1.  UDP Port Numbers in STAMP Testing
   4.2.  Session-Sender Behavior and Packet Format
     4.2.1.  Session-Sender Packet Format in Unauthenticated Mode
     4.2.2.  Session-Sender Packet Format in Authenticated Mode
   4.3.  Session-Reflector Behavior and Packet Format
     4.3.1.  Session-Reflector Packet Format in Unauthenticated Mode
     4.3.2.  Session-Reflector Packet Format in Authenticated Mode
   4.4.  Integrity Protection in STAMP
   4.5.  Confidentiality Protection in STAMP
   4.6.  Interoperability with TWAMP Light
 5.  Operational Considerations
 6.  IANA Considerations
 7.  Security Considerations
 8.  References
   8.1.  Normative References
   8.2.  Informative References
 Acknowledgments
 Authors' Addresses

1. Introduction

 Development and deployment of the Two-Way Active Measurement Protocol
 (TWAMP) [RFC5357] and its extensions (e.g., [RFC6038], which defines
 Symmetrical Size for TWAMP) provided invaluable experience.  Several
 independent implementations of both TWAMP and TWAMP Light exist, have
 been 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 inherent separation of control
 (vendor-specific configuration or orchestration) and test functions.
 Recent work on "Performance Measurement from IP Edge to Customer
 Equipment using TWAMP Light" [BBF.TR-390] by the Broadband Forum
 demonstrates that interoperability among implementations of TWAMP
 Light is difficult because the composition and operation of TWAMP
 Light were not sufficiently specified in [RFC5357].  According to
 [RFC8545], TWAMP Light includes a subset of TWAMP-Test functions.
 Thus, to have a comprehensive tool to measure packet loss and delay
 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.  Support of
 some optional TWAMP extensions, e.g., [RFC7750], is discussed in
 [STAMP-OPTION].

2. Conventions Used in This Document

2.1. Terminology

 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:        Must be Zero
 PDU:        Protocol Data Unit

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. 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 a "STAMP session", is the bidirectional 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 sessions are outside the scope
 of this document and can be achieved through various means.  A few
 examples are Command Line Interface, telecommunication services'
 Operational Support System (OSS) / Business Support System (BSS),
 SNMP, and NETCONF/YANG-based Software-Defined Networking (SDN)
 controllers.
       o----------------------------------------------------------o
       |                      Configuration and                   |
       |                         Management                       |
       o----------------------------------------------------------o
              ||                                          ||
              ||                                          ||
              ||                                          ||
   +----------------------+                +-------------------------+
   | STAMP Session-Sender | <--- STAMP---> | STAMP Session-Reflector |
   +----------------------+                +-------------------------+
                    Figure 1: STAMP Reference Model

4. Theory of Operation

 The STAMP Session-Sender transmits test packets over UDP transport
 toward the STAMP Session-Reflector.  The STAMP Session-Reflector
 receives the Session-Sender's packet and acts according to the
 configuration.  Two modes of the STAMP Session-Reflector characterize
 the expected behavior and, consequently, performance metrics that can
 be measured:
 Stateless:
    The STAMP Session-Reflector does not maintain test state and will
    use the value in the Sequence Number field in the received packet
    as the value for the Sequence Number field in the reflected
    packet.  As a result, values in the 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.
 Stateful:
    STAMP Session-Reflector maintains the test state, thus allowing
    the Session-Sender to determine directionality of loss using the
    combination of gaps recognized in the Session Sender Sequence
    Number and Sequence Number fields, respectively.  As a result,
    both near-end (forward) and far-end (backward) packet loss can be
    computed.  That implies that the STAMP Session-Reflector MUST
    maintain a state for each configured STAMP-Test session, thereby
    uniquely associating STAMP-Test packets with one such session
    instance and, thus, enabling the addition of a sequence number in
    the test reply that is individually incremented by one on a per-
    session basis.
 STAMP supports two authentication modes: unauthenticated and
 authenticated.  Unauthenticated STAMP-Test packets, defined in
 Sections 4.2.1 and 4.3.1, ensure interworking between STAMP and TWAMP
 Light, as described in Section 4.6 regarding packet formats.
 By default, STAMP uses symmetrical packets, i.e., the size of the
 packet transmitted by the Session-Reflector equals the size of the
 packet received by the Session-Reflector.

4.1. UDP Port Numbers in STAMP Testing

 A STAMP Session-Sender MUST use UDP port 862 (TWAMP-Test Receiver
 Port) as the default destination UDP port number.  A STAMP
 implementation of the Session-Sender MUST be able to be used as the
 destination UDP port numbers from the User Ports (aka Registered
 Ports) and Dynamic Ports (aka 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 on by all users of the network domain where the test has
 been planned.
 By default, an implementation of the STAMP Session-Reflector MUST
 receive STAMP-Test packets on UDP port 862.  An implementation of the
 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, which 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.

4.2. Session-Sender Behavior and Packet Format

 A STAMP Session-Reflector supports the symmetrical size of test
 packets, as defined in Section 3 of [RFC6038], as the default
 behavior.  A reflected base test packet includes information from the
 Session-Reflector and, thus, is larger.  To maintain the symmetry
 between base STAMP packets, the base STAMP Session-Sender packet
 includes the Must-Be-Zero (MBZ) field to match to the size of a base
 reflected STAMP test packet.  Hence, the base STAMP 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).
 Generating variable length of a test packet in STAMP is defined in
 [STAMP-OPTION].

4.2.1. 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
 The fields are defined as following:
  • The Sequence Number field is four octets long. For each new

session, its value starts at zero and is incremented by one with

    each transmitted packet.
  • The Timestamp field is eight octets long. The STAMP node MUST

support the Network Time Protocol (NTP) version 4 64-bit timestamp

    format [RFC5905], the format used in [RFC5357].  The STAMP node
    MAY support the IEEE 1588v2 Precision Time Protocol (PTP)
    truncated 64-bit timestamp format [IEEE.1588.2008], the format
    used in [RFC8186].  The use of the specific format, NTP or PTP, is
    part of configuration of the Session-Sender or the particular test
    session.
  • The Error Estimate field is two octets long with the 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
    The S, Scale, and Multiplier fields are interpreted as they are
    defined in Section 4.1.2 of [RFC4656].  The Z field is interpreted
    as it is defined in Section 2.3 of [RFC8186]:
    0:  NTP 64-bit format of a timestamp
    1:  PTPv2 truncated format of a timestamp
    The default behavior of the STAMP Session-Sender and Session-
    Reflector is to use the NTP 64-bit timestamp format (Z field value
    of 0).  An operator using configuration/management function MAY
    configure the STAMP Session-Sender and Session-Reflector to use
    the PTPv2 truncated format of a timestamp (Z field value of 1).
    Note that an implementation of a Session-Sender that supports this
    specification MAY be configured to use the PTPv2 format of a
    timestamp even though the Session-Reflector is configured to use
    NTP format.
  • The MBZ field in the Session-Sender unauthenticated packet is 30

octets long. It MUST be all zeroed on the transmission and MUST

    be ignored on receipt.

4.2.2. 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 4.2.1.  Also, MBZ fields are used to make the
 packet length a multiple of 16 octets.  The value of the field MUST
 be zeroed on transmission and MUST be ignored on receipt.  Note, that
 both MBZ fields are used to calculate a key hashed message
 authentication code (HMAC) [RFC2104] hash.  Also, the packet includes
 an HMAC hash at the end of the PDU.  The detailed use of the HMAC
 field is described in Section 4.4.

4.3. Session-Reflector Behavior and Packet Format

 The Session-Reflector receives the STAMP-Test packet and verifies it.
 If the base STAMP-Test packet is validated, the Session-Reflector
 that supports this specification prepares and transmits the reflected
 test packet symmetric to the packet received from the Session-Sender
 copying the content beyond the size of the base STAMP packet (see
 Section 4.2).

4.3.1. Session-Reflector 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                |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                          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
 Fields are defined as the following:
  • The Sequence Number field is four octets long. The value of the

Sequence Number field is set according to the mode of the STAMP

    Session-Reflector:
  1. In the stateless mode, the Session-Reflector copies the value

from the received STAMP-Test packet's Sequence Number field.

  1. In the stateful mode, the Session-Reflector counts the

transmitted STAMP-Test packets. It starts with zero and is

       incremented by one for each subsequent packet for each test
       session.  The Session-Reflector uses that counter to set the
       value of the Sequence Number field.
  • The Timestamp and Receive Timestamp fields are each eight octets

long. The format of these fields, NTP or PTPv2, is indicated by

    the Z field of the Error Estimate field, as described in
    Section 4.2.1.  Receive Timestamp is the time the test packet was
    received by the Session-Reflector.  Timestamp is the time taken by
    the Session-Reflector at the start of transmitting the test
    packet.
  • The Error Estimate field has the same size and interpretation as

described in Section 4.2.1. It is applicable to both Timestamp

    and Receive Timestamp.
  • The Session-Sender Sequence Number, Session-Sender Timestamp, and

Session-Sender Error Estimate fields are copies of the

    corresponding fields in the STAMP-Test packet sent by the Session-
    Sender.
  • The Session-Sender TTL field is one octet long, and its value is

the copy of the TTL field in IPv4 (or Hop Limit in IPv6) from the

    received STAMP-Test packet.
  • The MBZ fields are used to achieve alignment of fields within the

packet on a four-octet boundary. The value of each MBZ field MUST

    be zeroed on transmission and MUST be ignored on receipt.

4.3.2. Session-Reflector 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 (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 4.3.1.  Additionally, the MBZ field is used to make
 the packet length a multiple of 16 octets.  The value of the field
 MUST be zeroed on transmission and MUST be ignored on receipt.  Note
 that the MBZ field is used to calculate the HMAC hash value.  Also,
 the STAMP Session-Reflector test packet format in authenticated mode
 includes the HMAC [RFC2104] hash at the end of the PDU.  The detailed
 use of the HMAC field is in Section 4.4.

4.4. Integrity Protection in STAMP

 Authenticated mode provides integrity protection to each STAMP
 message 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.  In the authenticated mode, HMAC covers the first six
 blocks (96 octets).  HMAC uses its own key, which may be unique for
 each STAMP-Test session; key management and the mechanisms to
 distribute the HMAC key are outside the scope of this specification.
 One example is to use an orchestrator to configure the HMAC key based
 on the STAMP YANG data model [STAMP-YANG].  HMAC MUST be verified as
 early as possible to avoid using or propagating corrupted data.
 Future specifications may define the use of other, more advanced
 cryptographic algorithms, possibly providing an update to the STAMP
 YANG data model [STAMP-YANG].

4.5. Confidentiality Protection in STAMP

 If confidentiality protection for STAMP is required, a STAMP-Test
 session MUST 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.  Also, the Datagram Transport Layer
 Security protocol would provide the desired confidentiality
 protection.

4.6. Interoperability with TWAMP Light

 One of the essential requirements to STAMP is the ability to
 interwork with a TWAMP Light device.  Because STAMP and TWAMP use
 different algorithms in authenticated mode (HMAC-SHA-256 versus HMAC-
 SHA-1), interoperability is only considered for unauthenticated mode.
 There are two possible combinations for such a use case:
  • STAMP Session-Sender with TWAMP Light Session-Reflector
  • TWAMP Light Session-Sender with STAMP Session-Reflector
 In the former case, the Session-Sender might 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
 specified in [RFC8545].  Thus, Section 4 permits a STAMP Session-
 Sender to use alternative ports.  If any of STAMP extensions are
 used, the TWAMP Light Session-Reflector will view them as the Packet
 Padding field.
 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
 the STAMP Session-Reflector to use UDP port number, as permitted by
 Section 4.  The Session-Reflector MUST be set to use the default
 format for its timestamps, NTP.
 A STAMP Session-Reflector that supports this specification will
 transmit the base packet (Figure 5) if it receives a packet smaller
 than the STAMP base packet.  If the packet received from the TWAMP
 Session-Sender is larger than the STAMP base packet, the STAMP
 Session-Reflector that supports this specification will copy the
 content of the remainder of the received packet to transmit a
 reflected packet of symmetrical 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 of [RFC8545] fully
 applies to STAMP.

6. IANA Considerations

 This document has no IANA actions.

7. Security Considerations

 [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 OWAMP-
 Test discussed in Sections 6.2 and 6.3 of [RFC4656] apply to STAMP.
 STAMP uses the well-known UDP port number allocated for the OWAMP-
 Test/TWAMP-Test Receiver Port.  Thus, the security considerations and
 measures to mitigate the risk of the attack using the registered port
 number documented in Section 6 of [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.
    The load of the 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.  Section 3.1.5 of [RFC8085] 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].
 Use of HMAC-SHA-256 in the authenticated mode protects the data
 integrity of the STAMP-Test packets.

8. References

8.1. Normative References

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

 [BBF.TR-390]
            Broadband Forum, "Performance Measurement from IP Edge to
            Customer Equipment using TWAMP Light", TR-390 Issue 1, May
            2017.
 [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>.
 [STAMP-OPTION]
            Mirsky, G., Xiao, M., Nydell, H., Foote, R., Masputra, A.,
            and E. Ruffini, "Simple Two-way Active Measurement
            Protocol Optional Extensions", Work in Progress, Internet-
            Draft, draft-ietf-ippm-stamp-option-tlv-03, 21 February
            2020, <https://tools.ietf.org/html/draft-ietf-ippm-stamp-
            option-tlv-03>.
 [STAMP-YANG]
            Mirsky, G., Xiao, M., and W. Luo, "Simple Two-way Active
            Measurement Protocol (STAMP) Data Model", Work in
            Progress, Internet-Draft, draft-ietf-ippm-stamp-yang-05,
            25 October 2019, <https://tools.ietf.org/html/draft-ietf-
            ippm-stamp-yang-05>.

Acknowledgments

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

Authors' Addresses

 Greg Mirsky
 ZTE Corp.
 Email: gregimirsky@gmail.com
 Guo Jun
 ZTE Corp.
 68# Zijinghua Road
 Nanjing
 Jiangsu, 210012
 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
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