Subject: [ippm] Genart last call review of draft-ietf-ippm-stamp-07

From: Dale Worley via Datatracker <[email-masked]>
Date: Tue, 03 Sep 2019 18:01:00 -0700

Reviewer: Dale Worley
Review result: Ready with Issues

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

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

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

   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
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   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 February 13, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (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

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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   3
     2.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     2.2.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   3.  Softwarization of Performance Measurement . . . . . . . . . .   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.  Interoperability with TWAMP Light . . . . . . . . . . . .  11
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  12
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

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
   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 inherit separation of control (vendor-specific configuration or
   orchestration) and test functions.  One of such is Performance
   Measurement from IP Edge to Customer Equipment using TWAMP Light from
   Broadband Forum [BBF.TR-390] used as the reference TWAMP Light that,
   according to [RFC8545], includes sub-set of TWAMP-Test functions in
   combination with 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

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   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 of Performance Measurement

   Figure 1 presents the Simple Two-way Active Measurement Protocol
   (STAMP) Session-Sender, and Session-Reflector with a measurement
   session.  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)

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   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.

   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 packet formats.

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   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, 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.

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].

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   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 - 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 value of the Z field in accordance with the timestamp
      format in use.  This optional field is to enhance operations, but
      local configuration or defaults could be used in its place.

   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:

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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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                      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 the received sequence number without
      modification.  As a result, only round-trip packet loss can be
      calculated while the reflector is operating in stateless mode.

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   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;

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      *  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)                         |
      |                                                               |

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      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                 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].

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   HMAC MUST be verified as early as possible to avoid using or
   propagating corrupted data.

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

4.4.  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.  IANA Considerations

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

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6.  Security Considerations

   In general, all the security considerations related to TWAMP-Test,
   discussed in [RFC5357] apply to STAMP.  Since STAMP uses the well-
   known UDP port number allocated for the OWAMP-Test/TWAMP-Test
   Receiver port, 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.  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.  References

8.1.  Normative References

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

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   [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>.

Mirsky, et al.          Expires February 13, 2020              [Page 13]

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8.2.  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 (work in progress), March 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: [email-masked]

Mirsky, et al.          Expires February 13, 2020              [Page 14]

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   Guo Jun
   ZTE Corporation
   68# Zijinghua Road
   Nanjing, Jiangsu  210012
   P.R.China

   Phone: +86 18105183663
   Email: [email-masked]

   Henrik Nydell
   Accedian Networks

   Email: [email-masked]

   Richard Foote
   Nokia

   Email: [email-masked]

Mirsky, et al.          Expires February 13, 2020              [Page 15]

---

From: Greg Mirsky <[email-masked]>
Date: Mon, 30 Sep 2019 17:17:08 -0700

Hi Dale,
thank you for your review, comments, and suggestions. Please find answers
and notes in-line under the GIM>> tag.
Attached, please find the diff between -07 and the current working version,
as well as, the working version of the draft.

Regards,
Greg

On Tue, Sep 3, 2019 at 6:01 PM Dale Worley via Datatracker <[email-masked]>
wrote:

>   ----------------------------------------------------------------------
> I am the assigned Gen-ART reviewer for this draft. The General Area
> Review Team (Gen-ART) reviews all IETF documents being processed
> by the IESG for the IETF Chair.  Please treat these comments just
> like any other last call comments.
>
> For more information, please see the FAQ at
>
> <https://trac.ietf.org/trac/gen/wiki/GenArtfaq>.
>
> Document:  draft-ietf-ippm-stamp-07
> Reviewer:  Dale R. Worley
> Review Date:  2019-09-03
> IETF LC End Date:  2019-09-03
> IESG Telechat date:  2019-09-19
>
> Summary:
>
>        This draft is on the right track but has open issues, described
>        in the review.
>
> Minor technical issue:
>
> The consequences of using a TWAMP Session-Sender with a STAMP
> Session-Reflector aren't adequately described.  I suspect that the WG
> understands the technical solution, but the text does not make that
> clear.
>
>    If the Server Octets field is present in the TWAMP
> The final phrase appears to not be true.  In both unauthenticated and
> authenticated mode, the size of the reflected packet is fixed, and so
> in this case, it will not have equal size with the incoming packet.
> Also, there is no requirement that a STAMP Session-Reflector even
> accept incoming packets that are not of the standard length.
>
GIM>> Thank you for catching this issue. When the work on STAMP
specification started, this draft also included extensions, such as Extra
Padding TLV. Over the course of our work, all extensions were moved to the
separate draft. Would the following update (including the previous
paragraph in the section) address your concern:
OLD TEXT:
   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.

NEW TEXT:
   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 would
   transmit the base packet (Figure 5) regardless of the size of the
   Padding field in the packet received from TWAMP Session-Sender.
   Also, 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 and will transmit the
   reflected packet, as displayed in Figure 5.

> It seems that there is an unwritten requirement that a STAMP
> Session-Reflector accept longer packets than are expected for its
> configured operation mode and simply ignore the trailing excess
> octets.
>
> There are also some interactions with how the HMAC is verified for
> over-length incoming authenticated packets -- how does a STAMP
> Session-Reflector authenticate an incoming packet that is longer than
> the STAMP format?
>
GIM>> Authentication in TWAMP and STAMP use different algorithms
(HMAC-SHA-256 in STAMP vs. HMAC-SHA-1 in TWAMP as inherited from OWAMP
[RFC4656]), we don't have the requirement to provide interoperability in
Authenticated mode. Will update the first paragraph of the interoperability
section to explicitly state the scope:
OLD TEXT:
   One of the essential requirements to STAMP is the ability to
   interwork with a TWAMP Light device.
NEW TEXT:
   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 vs. HMAC-
   SHA-1), interoperability is only considered for Unauthenticated mode.

> Editorial issues:
>    orchestration) and test functions.
>
> Is "inherit" intended to be "inherent"?
>
GIM>> Thank you. That was the intention. Done.

>
>    One of such is Performance
>    control and security.
> This sentence is awkward because of the length of the title in the
> middle of the sentence.  Perhaps
>
>    One of such is [BBF.TR-390] (Performance Measurement from IP Edge
>    to Customer Equipment using TWAMP Light from the Broadband Forum),
>    a the reference TWAMP Light, that includes a sub-set of TWAMP-Test
>    functions along with control and security functions.
>
GIM>> Thank you for the proposed text. While addressing other comments the
text has been transformed to the following:
CURRENT TEXT:
   Recent work on IP Edge to Customer Equipment using TWAMP Light from
   Broadband Forum [BBF.TR-390] demonstrated that interoperability among
   implementations of TWAMP Light is challenged because the composition
   and operation of TWAMP Light were not sufficiently specified in
   [RFC5357].  According to [RFC8545], TWAMP Light includes sub-set of
   TWAMP-Test functions to provide comprehensive solution requires
   support by other applications that provide, for example, control and
   security.
Hope the current version is clearer and more readable.

>
> --
>
>    This document defines an active performance measurement test protocol
>
> This sentence doesn't explicitly say that STAMP is connected to TWAMP,
> despite that the preceding sentence does explicitly say that
> BBF.TR-390 is connected to TWAMP.  Perhaps, "This document defines
> another such mechanism ..."  Perhaps also precede with a paragraph
> break for clarity.
>
GIM>> Introduction section now has three paragraphs and the last refers to
common extensions. Do you feel that the current version made the
relationship between TWAMP-Test and STAMP clearer:
CURRENT TEXT:
   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].

> These four terms are not used in the document.
>
GIM>> Thank you, removed.

>    The configuration and management of the STAMP Session-
>    be achieved through various means.
>
> You should probably revise to add "... sessions are outside the scope
> of this document and can be ...".
>
GIM>> Thank you for the suggested text. Agreed and added.

>
>    Command Line Interface, OSS/BSS
> This sentence is long and awkward in a number of ways.  One version
> that I think is clearer is:
>
>     A few examples are:  Command Line Interface, telecommunication
>     services' OSS/BSS systems, SNMP, and Netconf/YANG-based SDN
>     controllers.
>
GIM>> Many thanks for the proposal. The text is denser and informative.

>
> 4.  Theory of Operation
>
> About half of the text in section 4 is about port assignments, but
> that isn't really part of the "Theory of Operation".  I think the
> exposition would be easier to read if the text about port assignments
> was extracted and put into a separate subsection (probably placed
> between 4 and 4.1).
>
GIM>> I've re-arranged Section 4. Please let me know if the flow of
information is clear and makes sense.

> There is no definition of what a STAMP session is in this document.
>
The idea is more or less obvious, but it would be useful to call out
> its primary properties in section 4 "Theory of Operation".  It seems
> like the primary properties are that a session is between one
> Session-Sender and one Session-Reflector and a session contains a
> potentially unlimited number of packets sent between the two.
>
GIM>> Magnus had similar comment and in course of our discussion we've
agreed on the following definition of a STAMP session, now part of Section
3:
   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 specification of how the time format for a particular packet is
> chosen is weak.  I think you want to add to the above paragraph that
> the choice of format is determined either by configuration or the Z
> bit in the Error Estimate field.
>
GIM>> In regard to the format of a timestamp, STAMP specification follows
the idea of RFC 8186 where extension to negotiate timestamp format for
TWAMP-Control and the new interpretation of Z flag were defined. For STAMP,
as defined for TWAMP, the value of the Z flag in the Error Estimate field
is only to reflect the format used by the node.

>    Also, MBZ fields are used to align the packet on 16 octets
>    boundary.
>
> You can't align the packet itself using a field within the packet.
> You want to say "are used to align the fields within the packet on 16
> octets boundaries."  Or perhaps "to make the packet length a multiple
> of 16 octets."  Similarly in 4.2.1 and 4.2.2.
>
GIM>> Thank you for the suggested text. I've used the second option.

> This seems important enough -- the mode determines what data STAMP
> can measure -- to be promoted to part of section 4, "Theory of
> Operation".
>
GIM>> I agree. Moved the text to Section 4 and re-named this section to
Session-Reflector Packet Format

> Of course, this is only regarding authenticated mode.  So you want to
> phrase this "Authenticated mode provides integrity protection to each
> STAMP message by adding ...".
>
GIM>> Again, thank you for the suggestion.

>    For example, a TWAMP Light
>    defined in Section 4.
> The connection between these two sentences is unclear.  I think it
> means:
>
>    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.
>
GIM>> Great, thank you!

> --
>    The
>    NTP.  And it MAY use PTPv2 timestamp format
>
> The first sentence could be made more specific.  But the second
> sentence seems to be redundant -- SHOULD is never mandatory, so you
> don't have to add a MAY.  So perhaps,
>
>    When interoperating with a TWAMP Light Session-Reflector, the
>    NTP.
GIM>> We've reviewed these requirements and had agreed that they are not
needed. The STAMP Session-Sender is required to be able to interpret both
formats, NTP and PTP2, and the selection is local decision that has no
impact on the ability to interwork with TWAMP Light Session-Reflector.
Hence, these two sentences were removed.

> --
>    Section 4.
> The phrase "to use UDP port number as defined in Section 4" isn't
> clear, since second 4 doesn't define what UDP port number should be
> used in this situation.  I think the meaning is "the test management
> system MUST set STAMP Session-Reflector to use an acceptable UDP port
> number, as permitted by Section 4".
>
GIM>> Thank you, accepted the text you've proposed.

>    already or will be assigned by IANA.
>
> This sentence seems to be more part of the port-number discussion (see
> comments on section 4) than security considerations -- unless the
> usage of port numbers is a topic in security.
>
> Additionally, it appears that section 4 requires that a STAMP service
> can be configured to sent packets to any port within the User Ports
> range, regardless of whether IANA assigns a User Port specifically to
> STAMP.  With this consideration, the phrase "that is already or will
> be assigned by IANA" seems to be either redundant or too narrow.
>
GIM>> This text has been moved to the Operational Considerations section.
In the process of re-arraging we've removed the characterization "already
or will be assigned by IANA". Please let me know if the current version of
the text is acceptable.