Differentiated Service Code Point and Explicit Congestion Notification Monitoring in Two-Way Active Measurement Protocol (TWAMP)
draft-hedin-ippm-type-p-monitor-04

Network Working Group                                           J. Hedin
Internet-Draft                                                 G. Mirsky
Intended status: Standards Track                                Ericsson
Expires: October 17, 2013                                 April 15, 2013


  Type-P Descriptor Monitoring in Two-Way Active Measurement Protocol
                                (TWAMP)
                   draft-hedin-ippm-type-p-monitor-00

Abstract

   This document specifies how optional monitoring of Type-P Descriptor
   can be negotiated and performed by TWAMP [RFC5357] Control and Test
   protocols.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
     1.1.  Conventions used in this document . . . . . . . . . . . . . 3
       1.1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . 3
       1.1.2.  Requirements Language . . . . . . . . . . . . . . . . . 3
   2.  TWAMP Extensions  . . . . . . . . . . . . . . . . . . . . . . . 3
     2.1.  Setting Up Connection to Monitor Type-P Descriptor  . . . . 4
     2.2.  TWAMP-Test Extension  . . . . . . . . . . . . . . . . . . . 4
       2.2.1.  Session-Reflector Packet Format for Type-P
               Descriptor Monitoring . . . . . . . . . . . . . . . . . 4
       2.2.2.  Type-P Descriptor Monitoring with RFC 6038
               extensions  . . . . . . . . . . . . . . . . . . . . . . 6
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
   4.  Security Considerations . . . . . . . . . . . . . . . . . . . . 8
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 8
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 8
     6.1.  Normative References  . . . . . . . . . . . . . . . . . . . 8
     6.2.  Informative References  . . . . . . . . . . . . . . . . . . 9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . . . 9































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1.  Introduction

   Re-marking of Type-P Descriptor, i.e. change in value, might be
   demonstration of intentional or errorneous behavior.  Monitoring of
   Type-P Descriptor can provide valuable information for network
   operators.  One-Way Active Measurement Protocol [RFC4656] and Two-Way
   Active Measurement Protocol [RFC5357] define negotiation of TypeP
   Descriptor value that must be used by Session-Sender and Session-
   Reflector.  But there's not means for Session-Sender to know whether
   Type-P Descriptor was received by Session-Reflector unchanged.
   Opional monitoring of Type-P Descriptor between Session-Sender and
   Session-Reflector requires extensions to TWAMP [RFC5357] that are
   described in this document.

1.1.  Conventions used in this document

1.1.1.  Terminology

   DSCP: Differentiated Service Codepoint

   IPPM: IP Performance Measurement

   TWAMP: Two-Way Active Measuremnt Protocol

   OWAMP: One-Way Active Measurement Protocol

   PHD: Per Hop Behavior

   PHB ID: PHB Identification Code

1.1.2.  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
   [RFC2119].


2.  TWAMP Extensions

   TWAMP connection establishment follows the procedure defined in
   Section 3.1 of [RFC4656] and Section 3.1 of [RFC5357] where the Modes
   field been used to identify and select specific communication
   capabilities.  At the same time the Modes field been recognized and
   used as extension mechanism [RFC6038].  The new feature requires new
   bit position to identify the ability of a Session-Reflector to return
   value of received Type-P Descriptor back to a Session-Sender, and to
   support the new Session-Reflector packet format in the TWAMP-Test



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   protocol.  See the Section 3 for details on the assigned value and
   bit position.

2.1.  Setting Up Connection to Monitor Type-P Descriptor

   The Server sets Type-P Descriptor Monitoring flag in Modes field of
   the Server Greeting message to indicate its capabilities and
   willingness to monitor Type-P.  If the Control-Client agrees to
   monitor Type-P Descriptor on some or all test sessions invoked with
   this control connection, it MUST set the Type-P Descriptor Monitoring
   flag in Modes field in the Setup Response message.

2.2.  TWAMP-Test Extension

   Monitoring of Type-P Descriptor requires support by Session-Reflector
   and changes format of its test packet format both in unauthenticated,
   authenticated and encrypted modes.  Monitoring of Type-P Descriptor
   does not alter Session-Sender test packet format but certain
   considerations must be taken when and if this mode is accepted in
   combination with Symmetrical Size mode[RFC6038].

2.2.1.  Session-Reflector Packet Format for Type-P Descriptor Monitoring

   When Session-Reflector supports Type-P Descriptor Monitoring in MUST
   construct Sender Type-P Descriptor for each test packet it sends to
   Session-Sender according to the following procedure:

      - first two bits MUST be the same as two first bits of Type-P
      Descriptor field Request-Session control packet;

      - remaining bits MUST be copied from received Session-Sender test
      packet according to two first bits:



         - if first two bits are 00, then value of Differentiated
         Services Codepoint (DSCP), as defined in [RFC2474], copied into
         subsequent six bits;

         - if first two bits are 01, then value of PHB Identification
         Code (PHB ID), as defined in [RFC2836], copied into sebsequent
         16 bits.

   For unauthenticated 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                            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                          Timestamp                          |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |       Error Estimate        |             MBZ               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                     Receive Timestamp                       |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                  Sender Sequence Number                     |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                     Sender Timestamp                        |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |    Sender Error Estimate    |             MBZ               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | Sender TTL  |                      MBZ                      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                   Sender Type-P Descriptor                  |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                             |
    .                                                             .
    .                        Packet Padding                       .
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

        Figure 1:  Session-Reflector test packet format with Type-P
               Descriptor monitoring in unauthenticated mode

   For authenticated and encrypted modes:

    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        |                               |



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    +-+-+-+-+-+-+-+-+-+-+-+-+-+                                   +
    |                        MBZ (6 octets)                       |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                      Receive Timestamp                      |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                       MBZ (8 octets)                        |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                   Sender Sequence Number                    |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                             |
    |                      MBZ (12 octets)                        |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                      Sender Timestamp                       |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |  Sender Error Estimate  |                                   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+                                   +
    |                       MBZ (6 octets)                        |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    | Sender TTL |                 MBZ                            |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                  Sender Type-P Descriptor                   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                       MBZ (8 octets)                        |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                             |
    |                      HMAC (16 octets)                       |
    |                                                             |
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                                                             |
    .                                                             .
    .                   Packet Padding                            .
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

        Figure 2:  Session-Reflector test packet format with Type-P
         Descriptor monitoring in authenticated or encrypted modes

2.2.2.  Type-P Descriptor Monitoring with RFC 6038 extensions

   [RFC6038] defined two extensions to TWAMP.  First, to ensure that
   Session-Sender and Session-Reflector exchange TWAMP-Test packets of
   equal size.  Second, to specify number of octets to be reflected by



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   Session-Reflector.  If Type-P Descriptor monitoring and Symmetrical
   Size and/or Reflects Octets modes being negotiated between Server and
   Control-Client in Unauthenticated mode, then because Sender Type-P
   Descriptor increases size of unauthenticated Session-Reflector packet
   by 4 octets the Padding Length value SHOULD be >= 31 octets to allow
   for the truncation process that TWAMP recommends in Section 4.2. 1 of
   [RFC5357].


    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 (31 octets)                       |
    |                                                             |
    +             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |             |                                               |
    +-+-+-+-+-+-+-+                                               +
    |                                                             |
    .                                                             .
    .                        Packet Padding                       .
    |                                                             |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    Figure 3:  Session-Sender test packet format with Type-P Descriptor
      monitoring and Symmetrical Test Packet in unauthenticated mode


3.  IANA Considerations

   The TWAMP-Modes registry defined in [RFC5618].

   IANA is requested to reserve a new Type-P Descriptor Monitoring
   Capability as follows:









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   +-----------+-------------------------+------------------+----------+
   | Value     |       Description       | Semantics        | Referenc |
   |           |                         |                  | e        |
   +-----------+-------------------------+------------------+----------+
   | X (propos | Type-P Descriptor Monit | bit position Y ( | This doc |
   | ed 128)   | o    ring Capability    | proposed 7)      | ument    |
   +-----------+-------------------------+------------------+----------+

           Table 1: New Type-P Descriptor Monitoring Capability


4.  Security Considerations

   Monitoring of Type-P Descriptor does not appear to introduce any
   additional security threat to hosts that communicate with TWAMP as
   defined in [RFC5357], and existing extensions [RFC6038].  The
   security considerations that apply to any active measurement of live
   networks are relevant here as well.  See the Security Considerations
   sections in [RFC4656] and [RFC5357].


5.  Acknowledgements

   TBD


6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC2474]  Nichols, K., Blake, S., Baker, F., and D. Black,
              "Definition of the Differentiated Services Field (DS
              Field) in the IPv4 and IPv6 Headers", RFC 2474,
              December 1998.

   [RFC2836]  Brim, S., Carpenter, B., and F. Le Faucheur, "Per Hop
              Behavior Identification Codes", RFC 2836, May 2000.

   [RFC4656]  Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
              Zekauskas, "A One-way Active Measurement Protocol
              (OWAMP)", RFC 4656, September 2006.

   [RFC5357]  Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
              Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
              RFC 5357, October 2008.



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   [RFC5618]  Morton, A. and K. Hedayat, "Mixed Security Mode for the
              Two-Way Active Measurement Protocol (TWAMP)", RFC 5618,
              August 2009.

   [RFC6038]  Morton, A. and L. Ciavattone, "Two-Way Active Measurement
              Protocol (TWAMP) Reflect Octets and Symmetrical Size
              Features", RFC 6038, October 2010.

6.2.  Informative References

   [RFC2629]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
              June 1999.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008.


Authors' Addresses

   Jonas Hedin
   Ericsson

   Email: jonas.hedin@ericsson.com


   Greg Mirsky
   Ericsson

   Email: gregory.mirsky@ericsson.com





















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