INTERNET-DRAFT                                                   C. Zhou
Intended Status: Informational                                  H. Zheng
Expires: September 14, 2017                                       Huawei
                                                          March 13, 2017


   IP Flow Information Export (IPFIX) Information Elements Extension
                     for Flow Variance Information
                      draft-zhou-ipfix-variance-00


Abstract

   This document proposes several new Information Elements for the IP
   Flow Information Export (IPFIX) protocol, which are used to export
   variance information about the flow, regarding the sizes of the
   packets sampled. This kind of information is helpful to form a
   statistical view of the flow.

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   Internet-Drafts.

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Copyright and License Notice

   Copyright (c) 2017 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



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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents
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Table of Contents

   1  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1  Terminology . . . . . . . . . . . . . . . . . . . . . . . .  3
   2  Information Elements  . . . . . . . . . . . . . . . . . . . . .  3
   3  Security Considerations . . . . . . . . . . . . . . . . . . . .  4
   4  IANA Considerations . . . . . . . . . . . . . . . . . . . . . .  4
   5  References  . . . . . . . . . . . . . . . . . . . . . . . . . .  4
     5.1  Normative References  . . . . . . . . . . . . . . . . . . .  4
     5.2  Informative References  . . . . . . . . . . . . . . . . . .  4
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . .  5






























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  Introduction

   The current set of IP Flow Information Export (IPFIX) Information
   Elements [IANA-IPFIX] is extensive.  However, it contains no means to
   export information about the average size of packets in a flow, as
   well as the variance of the pack sizes.  Having those information not
   only helps gain more insight of the flow from a statistical view, but
   also facilitates the detection of any anomaly traffic.

   Below are the new Information Elements being introduced:

      o  ipTotalLengthSampleMean
      o  ipTotalLengthSampleVariance

   The definitions of the Information Elements are given in Section 2.
   Another reason to add these Information Elements is that it may not
   be practical to export every sampled packet's size and then calculate
   the mean and variance offline.  For the sake of saving the data size
   to export, it is better to calculate mean and variance at the
   Observation Point and export only the calculated values.  Algorithms
   such as [RunningVariance] exist to calculate mean and variance
   online, in a single pass, without having to save sizes of the sampled
   packets.


1.1  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

   This document also makes use of the same terminology and definitions
   as Section 2 of [RFC5470].

  Information Elements

   Following the guidelines provided by [RFC 7013], the definitions of
   the new Information Elements are given below:

   Name: ipTotalLengthSampleMean
   Description:
      The calculated mean of the ipTotalLength values of the sampled
      packets in a flow.
   Abstract Data Type: unsigned64
   ElementId: TBD
   Status: current
   Units: octets
   Reference:



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      See RFC 5102 for the definition of ipTotalLength.

   Name: ipTotalLengthSampleVariance
      The calculated variance of the ipTotalLength values of the sampled
      packets in a flow.

      The result of the calculation should be converted to unsigned64.
      If the result is too large to be contained in an unsigned64, then
      0xFFFFFFFFFFFFFFFF should be set as the value instead.
   Description:
   Abstract Data Type: unsigned64
   ElementId: TBD
   Status: current
   Reference:
      See RFC 5102 for the definition of ipTotalLength.

  Security Considerations

   For this extension to the IPFIX protocol, the same security
   considerations as for the IPFIX protocol apply [RFC7011].


  IANA Considerations

   The Information Elements defined Section 2 are expected to be added
   to the IANA's IPFIX registry [IANA-IPFIX]. The 'TBD' values of the
   ElementIds should be replaced by IANA for assigned numbers.

  References

5.1  Normative References


   [RFC7013]  Trammell, B. and B. Claise, "Guidelines for Authors and
              Reviewers of IP Flow Information Export (IPFIX)
              Information Elements", BCP 184, RFC 7013, September 2013.

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

   [RFC5470]  Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,
              "Architecture for IP Flow Information Export", RFC 5470,
              March 2009.


5.2  Informative References




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   [IANA-IPFIX]
              IANA, "IP Flow Information Export (IPFIX) Entities",
              <http://www.iana.org/assignments/ipfix>.

   [RunningVariance]
              John D. Cook, Accurately computing running variance
              <https://www.johndcook.com/blog/standard_deviation/>.

Authors' Addresses



   Chong Zhou
   Huawei
   156 Beiqing Road, M06 Shichuang Technology Demonstration Park
   Haidian, Beijing  100094
   China

   Email: mr.zhouchong@huawei.com


   Hui Zheng (Marvin)
   Huawei
   101 Ruanjian Avenue, Nanjing, China

   EMail: marvin.zhenghui@huawei.com

























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