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Versions: 00 01 02 03 04 05 06 07 08 09 10 11 RFC 5477

Network Working Group                                           T. Dietz
Internet-Draft                                           NEC Europe Ltd.
Expires: September 7, 2006                                   F. Dressler
                                        University of Erlangen-Nuremberg
                                                                G. Carle
                                                 University of Tuebingen
                                                               B. Claise
                                                               P. Aitken
                                                           Cisco Systems
                                                           March 6, 2006


             Information Model for Packet Sampling Exports
                     <draft-ietf-psamp-info-04.txt>

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
   applicable patent or other IPR claims of which he or she is aware
   have been or will be disclosed, and any of which he or she becomes
   aware will be disclosed, in accordance with Section 6 of BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on September 7, 2006.

Copyright Notice

   Copyright (C) The Internet Society (2006).

Abstract

   This memo defines an information model for the Packet Sampling
   (PSAMP) protocol.  It is used by the PSAMP protocol for encoding



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   sampled packet data and information related to the sampling process.
   As the PSAMP protocol is based on the IPFIX protocol, this
   information model is an extension to the IPFIX information model.

Table of Contents

   1.   Open Issues  . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.1  IPFIX  . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     1.2  PSAMP  . . . . . . . . . . . . . . . . . . . . . . . . . .   4

   2.   Introduction . . . . . . . . . . . . . . . . . . . . . . . .   4

   3.   PSAMP Documents Overview . . . . . . . . . . . . . . . . . .   5

   4.   Relationship between PSAMP and IPFIX . . . . . . . . . . . .   5

   5.   Terminology  . . . . . . . . . . . . . . . . . . . . . . . .   6

   6.   Properties of a PSAMP Information Element  . . . . . . . . .   7

   7.   Type Space . . . . . . . . . . . . . . . . . . . . . . . . .   7

   8.   Overloading Information Elements . . . . . . . . . . . . . .   7

   9.   The PSAMP Information Elements . . . . . . . . . . . . . . .   8
     9.1  PSAMP Usage of IPFIX Attributes  . . . . . . . . . . . . .   8
     9.2  Additional PSAMP Information Elements  . . . . . . . . . .   9
       9.2.1  observationPointId . . . . . . . . . . . . . . . . . .   9
       9.2.2  selectionSequenceId  . . . . . . . . . . . . . . . . .   9
       9.2.3  selectorId . . . . . . . . . . . . . . . . . . . . . .   9
       9.2.4  informationElementId . . . . . . . . . . . . . . . . .   9
       9.2.5  selectorAlgorithm  . . . . . . . . . . . . . . . . . .  10
       9.2.6  samplingPacketInterval . . . . . . . . . . . . . . . .  10
       9.2.7  samplingPacketSpace  . . . . . . . . . . . . . . . . .  11
       9.2.8  samplingTimeInterval . . . . . . . . . . . . . . . . .  11
       9.2.9  samplingTimeSpace  . . . . . . . . . . . . . . . . . .  11
       9.2.10   samplingSize . . . . . . . . . . . . . . . . . . . .  12
       9.2.11   samplingPopulation . . . . . . . . . . . . . . . . .  12
       9.2.12   samplingProbability  . . . . . . . . . . . . . . . .  12
       9.2.13   [unused] . . . . . . . . . . . . . . . . . . . . . .  13
       9.2.14   ipHeaderPacketSection  . . . . . . . . . . . . . . .  13
       9.2.15   ipPayloadPacketSection . . . . . . . . . . . . . . .  13
       9.2.16   dataLinkFrameSection . . . . . . . . . . . . . . . .  13
       9.2.17   mplsLabelStackSection  . . . . . . . . . . . . . . .  14
       9.2.18   mplsPayloadPacketSection . . . . . . . . . . . . . .  14
       9.2.19   packetsObserved  . . . . . . . . . . . . . . . . . .  15
       9.2.20   packetsSelected  . . . . . . . . . . . . . . . . . .  15
       9.2.21   fixedError . . . . . . . . . . . . . . . . . . . . .  15



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       9.2.22   relativeError  . . . . . . . . . . . . . . . . . . .  15
       9.2.23   observationTimeSeconds . . . . . . . . . . . . . . .  16
       9.2.24   observationTimeMilliSeconds  . . . . . . . . . . . .  16
       9.2.25   observationTimeMicroSeconds  . . . . . . . . . . . .  16
       9.2.26   observationTimeNanoSeconds . . . . . . . . . . . . .  16
       9.2.27   digestHashValue  . . . . . . . . . . . . . . . . . .  16
       9.2.28   hashIPPayloadOffset  . . . . . . . . . . . . . . . .  17
       9.2.29   hashIPPayloadSize  . . . . . . . . . . . . . . . . .  17
       9.2.30   hashInitialiserValue . . . . . . . . . . . . . . . .  17
       9.2.31   hashOutputRangeMin . . . . . . . . . . . . . . . . .  17
       9.2.32   hashOutputRangeMax . . . . . . . . . . . . . . . . .  17
       9.2.33   hashSelectedRangeMin . . . . . . . . . . . . . . . .  17
       9.2.34   hashSelectedRangeMax . . . . . . . . . . . . . . . .  18
       9.2.35   hashDigestOutput . . . . . . . . . . . . . . . . . .  18

   10.  Security Considerations  . . . . . . . . . . . . . . . . . .  18

   11.  IANA Considerations  . . . . . . . . . . . . . . . . . . . .  18

   12.  References . . . . . . . . . . . . . . . . . . . . . . . . .  19
     12.1   Normative References . . . . . . . . . . . . . . . . . .  19
     12.2   Informative References . . . . . . . . . . . . . . . . .  20

        Authors' Addresses . . . . . . . . . . . . . . . . . . . . .  21

   A.   Formal Specification of PSAMP Information Elements . . . . .  22

        Intellectual Property and Copyright Statements . . . . . . .  36























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1.  Open Issues

   This section covers some open issues which have to be solved in a
   future version of this draft.

1.1  IPFIX

   o  The export of sampled data may not need all information elements
      defined by the IPFIX information model.  Thus a section within
      this document should give an overview of flow Information Elements
      defined in the IPFIX information model and their usage in the
      PSAMP environment.  PROPOSAL: This is already covered by section
      6.2 and 6.3 of draft-ietf-psamp-framework-10.txt Double check
      whether it's covered by [I-D.ietf-psamp-sample-tech].
   o  Insert or cross reference the following sections from IPFIX-INFO:
      *  2.  Properties of IPFIX Protocol Information Elements
      *  2.1  Information Elements Specification Template
      *  2.2  Scope of Information Elements
      *  2.3  Naming Conventions for Information Elements
      *  3.  Type Space
      *  4.  Information Element Identifiers
   o  Verify consistency with definitions in
      *  draft-ietf-psamp-sample-tech-07.txt
      *  draft-ietf-psamp-framework-10.txt

1.2  PSAMP

   o  Should the ipHeaderPacketSection and mplsLabelStackSection also
      report payload contents if the specified section length is longer
      than the header or stack size, respectively?

2.  Introduction

   Packet sampling techniques are required for various measurement
   scenarios.  The packet sampling (PSAMP) protocol provides mechanisms
   for the packet selection using different filtering and sampling
   techniques.  A standard way for the export and storage of such
   sampled packet data is required.  The definition of the PSAMP
   information and data model is based on the IP Flow Information eXport
   (IPFIX) protocol [I-D.ietf-ipfix-protocol].  The PSAMP protocol
   document [I-D.ietf-psamp-protocol] describes how to use the IPFIX
   protocol in the PSAMP context.

   This document examines the IPFIX information model [I-D.ietf-ipfix-
   info] and extends it to meet the PSAMP requirements.  Therefore, the
   structure of this document is strongly based on the IPFIX document.
   It complements the PSAMP protocol specification by providing an
   appropriate PSAMP information model.  The main part of this document,



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   section 9, defines the list of Information Elements to be transmitted
   by the PSAMP protocol.  Sections 7 and 6 describe the data types and
   Information Element properties used within this document and their
   relationship to the IPFIX information model.

   The main body of section 9 was generated from a XML document.  The
   XML-based specification of the PSAMP Information Elements can be used
   for automatically checking syntactical correctness of the
   specification.  Furthermore it can be used - in combination with the
   IPFIX information model - for an automated code generation.  The
   resulting code can be used in PSAMP protocol implementations to deal
   with processing PSAMP information elements.

   For that reason, the XML document that served as source for section 9
   is attached to this document in Appendix A.

   Note that although partially generated from the attached XML
   documents, the main body of this document is normative while the
   appendices are informational.

3.  PSAMP Documents Overview

   [I-D.ietf-psamp-framework]: "A Framework for Packet Selection and
   Reporting", describes the PSAMP framework for network elements to
   select subsets of packets by statistical and other methods, and to
   export a stream of reports on the selected packets to a collector.

   [I-D.ietf-psamp-sample-tech]: "Sampling and Filtering Techniques for
   IP Packet Selection", describes the set of packet selection
   techniques supported by PSAMP.

   [I-D.ietf-psamp-protocol]: "Packet Sampling (PSAMP) Protocol
   Specifications" specifies the export of packet information from a
   PSAMP Exporting Process to a PSAMP Collecting Process.

   [I-D.ietf-psamp-info]: "Information Model for Packet Sampling
   Exports" (this document), defines an information and data model for
   PSAMP.

   [I-D.ietf-psamp-mib]: "Definitions of Managed Objects for Packet
   Sampling" describes the PSAMP Management Information Base

4.  Relationship between PSAMP and IPFIX

   As described in the PSAMP protocol draft [I-D.ietf-psamp-protocol] a
   PSAMP data record can be seen as a very special IPFIX flow record.
   It represents an IPFIX flow containing only a single packet.
   Therefore, the IPFIX information model can be used as a basis for



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   PSAMP reports.

   Nevertheless, there are properties required in PSAMP reports which
   cannot be modelled using the current IPFIX information model.  This
   document describes extensions to the IPFIX model which allow the
   modelling of information and data required by PSAMP.

   Some of these extensions allow the export of what may be considered
   sensitive information.  Refer to the Security Considerations section
   for a fuller discussion.

5.  Terminology

   As the IPFIX export protocol is used to export the PSAMP information,
   the relevant IPFIX terminology from [I-D.ietf-ipfix-protocol] is
   copied over in this document.

      IETF:  The Internet Engineering Task Force
      http://www.ietf.org

      IPFIX: The IETF IP Flow Information eXport working group
      http://www.ietf.org/html.charters/ipfix-charter.html

      PSAMP: The IETF Packet SAMPling working group
      http://www.ietf.org/html.charters/psamp-charter.html

      IANA:  Internet Assigned Numbers Authority
      http://www.iana.org

      RFC:   Requests for Comments
      http://www.rfc-editor.org

      ISO:   International Organisation for Stadardisation
      http://www.iso.org

      IEC:   International Electrotechnical Commission
      http://www.iec.ch

      Information Element
      An Information Element is a protocol and encoding independent
      description of an attribute which may appear in an IPFIX Record.

      Collecting Process
      A Collecting Process receives Flow Records from one or more
      Exporting Processes.






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      Observation Point
      An Observation Point is a location in the network where IP packets
      can be observed.

      Selector
      Observation Domain
      An Observation Domain is the largest set of Observation Points for
      which Flow information can be aggregated by a Metering Process.

      A Selector defines the action of a Selection Process on a single
      packet of its input.

      Primitive Selector
      A Selector is primitive if it is not a Composite Selector.


   EDITORS NOTE: This section to be completed.

6.  Properties of a PSAMP Information Element

   The PSAMP Information Elements are in accordance with the definitions
   of IPFIX.  Therefore we do not repeat the properties in this draft.
   Nevertheless, we strongly recommend to define the optional "unit"
   element for every information element (if applicable).

7.  Type Space

   The PSAMP Information Elements MUST be constructed from the basic
   data types described in the IPFIX Information Model [I-D.ietf-ipfix-
   info].  To avoid duplicated work and to keep consistency between
   IPFIX and PSAMP the data types are not repeated in this document.

8.  Overloading Information Elements

   Information Elements won't be overloaded with multiple meanings or
   re-used for multiple purposes.  Different Information Elements will
   be allocated for each requirement.

   In particular, special information will be encoded in new Information
   Elements as necessary, and not be encoded in the selection method.

   Although the prescence of certain other Information Elements allows
   the selection method to be inferred, a separate Information Element
   is provided for the selectorAlgorithm, e.g. for including in scope
   info and depicting the contents of composites.






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9.  The PSAMP Information Elements

   This section describes the Information Elements used by the PSAMP
   exporting functions.  Basically, the Information Elements described
   by the IPFIX information model [I-D.ietf-ipfix-info] are used by the
   PSAMP export functions where applicable.  To avoid inconsistencies
   between the IPFIX and the PSAMP information and data models, only
   those Information Elements are defined here that are not already
   described by the IPFIX information model.

9.1  PSAMP Usage of IPFIX Attributes

   Some Information Elements defined by the IPFIX information model are
   not needed by the PSAMP protocol.

   This section lists additional Information Elements that are needed in
   the PSAMP context and introduces their usage.

   List of additional PSAMP Information Elements:

   o  300 - observationPointId
   o  301 - selectionSequenceId
   o  302 - selectorId
   o  303 - informationElementId
   o  304 - selectorAlgorithm
   o  305 - samplingPacketInterval
   o  306 - samplingPacketSpace
   o  307 - samplingTimeInterval
   o  308 - samplingTimeSpace
   o  309 - samplingSize
   o  310 - samplingPopulation
   o  311 - samplingProbability
   o  312 - [unused]
   o  313 - ipHeaderPacketSection
   o  314 - ipPayloadPacketSection
   o  315 - dataLinkFrameSection
   o  316 - mplsLabelStackSection
   o  317 - mplsPayloadPacketSection
   o  318 - packetsObserved
   o  319 - packetsSelected
   o  320 - fixedError
   o  321 - relativeError
   o  322 - timeSeconds
   o  323 - timeMilliSeconds
   o  324 - timeMicroSeconds
   o  325 - timeNanoSeconds





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   o  326 - digestHashValue
   o  327 - hashIPPayloadOffset
   o  328 - hashIPPayloadSize
   o  329 - hashInitialiserValue
   o  330 - hashOutputRangeMin
   o  331 - hashOutputRangeMax
   o  332 - hashSelectedRangeMin
   o  333 - hashSelectedRangeMax
   o  334 - hashDigestOutput

9.2  Additional PSAMP Information Elements

9.2.1  observationPointId

   Description:
      ID of the observation process.  Unique in the observation domain.
   Abstract Data Type: unsigned64
   ElementId: 300
   Status: current

9.2.2  selectionSequenceId

   Description:
      From all the packets observed at an Observation Point, a subset of
      packets is selected by a sequence of one or more Selectors.  The
      selectionSequenceId is a unique value per Observation Domain,
      describing the Observation Point and the sequence of Selectors
      through which the packets are selected.
   Abstract Data Type: unsigned64
   ElementId: 301
   Status: current

9.2.3  selectorId

   Description:
      The Selector ID is the unique ID identifying a Primitive Selector.
      Each Primitive Selector must have a unique ID in the observation
      domain.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 302
   Status: current

9.2.4  informationElementId







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   Description:
      Contains the ID of another Information Element.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 303
   Status: current

9.2.5  selectorAlgorithm

   Description:
      Specifies the selector algorithm (e.g., filter, sampler, hash)
      that was used on a packet.  It is exported in the options data
      flow record to specify how a collector has to interpret a data
      flow record.

      The following selector algorithms are currently defined:

      *  1 Systematic count-based sampling
      *  2 Systematic time-based sampling
      *  3 Random n-out-of-N sampling
      *  4 Uniform probabilistic sampling
      *  5 Property match filtering
      *  6 Hash based filtering using BOB
      *  7 Hash based filtering using IPSX
      *  8 Hash based filtering using CRC

      EDITOR'S NOTE: This list may be extended in the final version.

      The parameters for most of these algorithms are defined in this
      information model.  Some parameters for these algorithms are not
      covered by this information model since they very much depend on
      the underlying hardware.

      In future, this list will be maintained by IANA.  IANA can update
      this information element as long as there's a new RFC specifying
      the algorithm and any new Information Elements which are required.
   Abstract Data Type: unsigned16
   Data Type Semantics: identifier
   ElementId: 304
   Status: current

9.2.6  samplingPacketInterval

   Description:







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      Number of packets that are consecutively sampled.  For example a
      value of 100 means that 100 contiguous packets are sampled.

      This information element is used to describe the configuration of
      a systematic count-based sampling selector.
   Abstract Data Type: unsigned32
   ElementId: 305
   Status: current
   Units: packets

9.2.7  samplingPacketSpace

   Description:
      The number of packets between two "samplingPacketInterval"s.  A
      value of 100 means that the next interval starts after 100 packets
      (which are not sampled) when the current "samplingPacketInterval"
      is over.

      This information element is used to describe the configuration of
      a systematic count-based sampling selector.
   Abstract Data Type: unsigned32
   ElementId: 306
   Status: current
   Units: packets

9.2.8  samplingTimeInterval

   Description:
      Time interval in microseconds in which all arriving packets are
      sampled.

      This information element is used to describe the configuration of
      a systematic time-based sampling selector.
   Abstract Data Type: dateTimeMicroSeconds
   ElementId: 307
   Status: current
   Units: microseconds

9.2.9  samplingTimeSpace

   Description:
      The time interval in microseconds between two
      "samplingTimeInterval"s.  A value of 100 means that the next
      interval starts after 100 microseconds (in which no packets are
      sampled) when the current "samplingTimeInterval" is over.






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      This information element is used to describe the configuration of
      a systematic time-based sampling selector.
   Abstract Data Type: dateTimeMicroSeconds
   ElementId: 308
   Status: current
   Units: microseconds

9.2.10  samplingSize

   Description:
      The number of elements taken from the parent population for random
      sampling algorithms.

      This information element is used to describe the configuration of
      a random n-out-of-N sampling selector.
   Abstract Data Type: unsigned32
   ElementId: 309
   Status: current
   Units: packets

9.2.11  samplingPopulation

   Description:
      The number of elements in the parent population for random
      sampling algorithms.

      This information element is used to describe the configuration of
      a random n-out-of-N sampling selector.
   Abstract Data Type: unsigned32
   ElementId: 310
   Status: current
   Units: packets

9.2.12  samplingProbability

   Description:
      The probability that a packet is sampled, expressed as a value
      between 0 and 1.  The probability is equal for every packet.  A
      value of 0 means no packet was sampled since the probability is 0.

      This information element is used to describe the configuration of
      a uniform probabilistic sampling selector.
   Abstract Data Type: float64







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   ElementId: 311
   Status: current

9.2.13  [unused]

   Description:
      This ID is not currently in use.
   Abstract Data Type:
   ElementId: 312
   Status: unused

9.2.14  ipHeaderPacketSection

   Description:
      This information element carries a series of octets from the start
      of the IP header of a sampled packet.

      The size of the exported section may be constrained due to
      limitations in the IPFIX protocol.
   Abstract Data Type: variable length octetArray
   ElementId: 313
   Status: current

9.2.15  ipPayloadPacketSection

   Description:
      This information element carries a series of octets from the start
      of the IP payload of a sampled packet.

      The IPv4 payload is that part of the packet which follows the IPv4
      header and any options, which [RFC0791] refers to as "data" or
      "data octets". e.g., see the examples in [RFC0791] APPENDIX A.

      The size of the exported section may be constrained due to
      limitations in the IPFIX protocol.

      If insufficient octets are available for the length specified in
      the template, the packet section must be sent with a new template
      using either a fixed length Information Element of the necessary
      size or a variable length Information Element.  It's not
      permissible to pad a short packet section to a longer length.
   Abstract Data Type: variable length octetArray
   ElementId: 314
   Status: current

9.2.16  dataLinkFrameSection





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   Description:
      This information element carries the first n octets from the data
      link frame of a sampled packet.

      The data link layer is defined in [ISO/IEC.7498-1:1994].

      The size of the exported section may be constrained due to
      limitations in the IPFIX protocol.

      If insufficient octets are available for the length specified in
      the template, the packet section must be sent with a new template
      using either a fixed length Information Element of the necessary
      size or a variable length Information Element.  It's not
      permissible to pad a short packet section to a longer length.
   Abstract Data Type: variable length octetArray
   ElementId: 315
   Status: current

9.2.17  mplsLabelStackSection

   Description:
      This information element carries the first n octets from the MPLS
      label stack of a sampled packet.

      See [RFC3031] for the specification of MPLS packets.
      See [RFC3032] for the specification of the MPLS label stack.

      The size of the exported section may be constrained due to
      limitations in the IPFIX protocol.
   Abstract Data Type: variable length octetArray
   ElementId: 316
   Status: current

9.2.18  mplsPayloadPacketSection

   Description:
      This information element carries the first n octets from the MPLS
      payload of a sampled packet, being data that follows immediately
      after the MPLS label stack.

      See [RFC3031] for the specification of MPLS packets.
      See [RFC3032] for the specification of the MPLS label stack.

      The size of the exported section may be constrained due to
      limitations in the IPFIX protocol.






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      If insufficient octets are available for the length specified in
      the template, the packet section must be sent with a new template
      using either a fixed length Information Element of the necessary
      size or a variable length Information Element.  It's not
      permissible to pad a short packet section to a longer length.
   Abstract Data Type: variable length octetArray
   ElementId: 317
   Status: current

9.2.19  packetsObserved

   Description:
      Number of packets observed by a selector.
   Abstract Data Type: unsigned64
   ElementId: 318
   Status: current
   Units: packets

9.2.20  packetsSelected

   Description:
      Number of packets selected by a selector.
   Abstract Data Type: unsigned64
   ElementId: 319
   Status: current
   Units: packets

9.2.21  fixedError

   Description:
      Specifies the maximum possible positive or negative error interval
      of the reported value for a given Information Element.
   Abstract Data Type: float64
   ElementId: 320
   Status: current
   Units: The units of the Information Element for which the error is
      specified.

9.2.22  relativeError

   Description:
      Specifies the maximum possible positive or negative error ratio
      for a given Information Element.







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   Abstract Data Type: float64
   ElementId: 321
   Status: current

9.2.23  observationTimeSeconds

   Description:
      The absolute time of an observation.
   Abstract Data Type: dateTimeSeconds
   ElementId: 322
   Status: current
   Units: seconds

9.2.24  observationTimeMilliSeconds

   Description:
      The absolute time of an observation.
   Abstract Data Type: dateTimeSeconds
   ElementId: 323
   Status: current
   Units: milliseconds

9.2.25  observationTimeMicroSeconds

   Description:
      The absolute time of an observation.
   Abstract Data Type: dateTimeSeconds
   ElementId: 324
   Status: current
   Units: microseconds

9.2.26  observationTimeNanoSeconds

   Description:
      The absolute time of an observation.
   Abstract Data Type: dateTimeSeconds
   ElementId: 325
   Status: current
   Units: nanoseconds

9.2.27  digestHashValue

   Description:
      The value from the digest hash function.







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   Abstract Data Type: unsigned64
   ElementId: 326
   Status: current

9.2.28  hashIPPayloadOffset

   Description:
      The IP payload offset used by a hash based selector.
   Abstract Data Type: unsigned64
   ElementId: 327
   Status: current

9.2.29  hashIPPayloadSize

   Description:
      The IP payload size used by a hash based selector.
   Abstract Data Type: unsigned64
   ElementId: 328
   Status: current

9.2.30  hashInitialiserValue

   Description:
      The initialiser value to the hash function.
   Abstract Data Type: unsigned64
   ElementId: 326
   Status: current

9.2.31  hashOutputRangeMin

   Description:
      A value for the beginning of a hash function's potential output
      range.
   Abstract Data Type: unsigned64
   ElementId: 329
   Status: current

9.2.32  hashOutputRangeMax

   Description:
      A value for the end of a hash function's potential output range.
   Abstract Data Type: unsigned64
   ElementId: 330
   Status: current

9.2.33  hashSelectedRangeMin





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   Description:
      A value for the beginning of a hash function's selected range.
   Abstract Data Type: unsigned64
   ElementId: 331
   Status: current

9.2.34  hashSelectedRangeMax

   Description:
      A value for the end of a hash function's selected range.
   Abstract Data Type: unsigned64
   ElementId: 332
   Status: current

9.2.35  hashDigestOutput

   Description:
      A boolean value, TRUE if the output from this hash selector has
      been configured to be included in the packet report as a packet
      digest, else FALSE.
   Abstract Data Type: boolean
   ElementId: 333
   Status: current

10.  Security Considerations

   The PSAMP information model itself does not directly introduce
   security issues.  Rather it defines a set of attributes which may for
   privacy or business issues be considered sensitive information.

   Specifically, the Information Elements pertaining to packet sections
   MUST target no more than the packet header, some subsequent bytes of
   the packet, and encapsulating headers if present.  Full packet
   capture of arbitrary packet streams is explicitly out of scope, per
   [RFC2804] and the PSAMP WG charter.

   The underlying protocol used to exchange the information described
   here must therefore apply appropriate procedures to guarantee the
   integrity and confidentiality of the exported information.  Such
   protocols are defined in separate documents, specifically the IPFIX
   protocol document [I-D.ietf-ipfix-protocol].

11.  IANA Considerations

   This document defines an initial set of PSAMP Information Elements as
   specified in [I-D.ietf-psamp-sample-tech], as an extension to the
   IPFIX Information Elements [I-D.ietf-ipfix-info].  New assignments
   for PSAMP Information Elements will be administered according to



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   rules explained in the "IANA Consideration" section of the IPFIX
   Information Model document [I-D.ietf-ipfix-info].

   Note that the PSAMP Information Element IDs were initially started at
   the value 300, in order to leave a gap for any ongoing IPFIX work
   requiring new Information Elements.  It is expected that this gap in
   the Information Element numbering will be filled in by IANA with new
   IPFIX Information Elements.

   Appendix B defines an XML schema which may be used to create
   consistent machine readable extensions to the IPFIX information
   model.  This schema introduces a new namespace, which will be
   assigned by IANA according to [RFC3688].

   In future the selectorAlgorithm registry will be maintained by IANA.
   IANA can update this information element as long as there's a new RFC
   specifying the algorithm and any new Information Elements which are
   required.

12.  References

12.1  Normative References

   [I-D.ietf-psamp-sample-tech]
              Zseby, T., Molina, M., Duffield, N., Niccolini, S., and F.
              Raspall, "Sampling and Filtering Techniques for IP Packet
              Selection", draft-ietf-psamp-sample-tech-07 (work in
              progress), July 2005.

   [I-D.ietf-psamp-protocol]
              Claise, B., Quittek, J., and A. Johnson, "Packet Sampling
              (PSAMP) Protocol Specifications",
              draft-ietf-psamp-protocol-03 (work in progress),
              December 2005.

   [I-D.ietf-psamp-mib]
              Dietz, T. and B. Claise, "Definitions of Managed Objects
              for Packet Sampling", draft-ietf-psamp-mib-05 (work in
              progress), October 2005.

   [I-D.ietf-ipfix-info]
              Quittek, J., Bryant, S., Claise, B., and J. Meyer,
              "Information Model for IP Flow Information Export",
              draft-ietf-ipfix-info-11 (work in progress),
              September 2005.

   [I-D.ietf-ipfix-protocol]
              Claise, B., Bryant, S., Sadasivan, G., Leinen, S., and T.



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              Dietz, "IPFIX Protocol Specification",
              draft-ietf-ipfix-protocol-19 (work in progress),
              September 2005.

   [ISO/IEC.7498-1:1994]
              International Organization for Standardization,
              "Information technology -- Open Systems Interconnection --
              Basic Reference Model: The Basic Mode", ISO Standard 7498-
              1:1994, June 1996.

12.2  Informative References

   [RFC3917]  Quittek, J., Zseby, T., Claise, B., and S. Zander,
              "Requirements for IP Flow Information Export", RFC 3917,
              October 2004.

   [I-D.ietf-ipfix-architecture]
              Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,
              "Architecture for IP Flow Information Export",
              draft-ietf-ipfix-architecture-09 (work in progress),
              August 2005.

   [I-D.ietf-psamp-framework]
              Duffield, N., Chiou, D., Claise, B., Greenberg, A.,
              Grossglauser, M., Marimuthu, P., Rexford, J., and G.
              Sadasivan, "A Framework for Packet Selection and
              Reporting", draft-ietf-psamp-framework-10 (work in
              progress), January 2005.

   [RFC2804]  IAB and IESG, "IETF Policy on Wiretapping", RFC 2804,
              May 2000.

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              September 1981.

   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031, January 2001.

   [RFC3032]  Rosen, E., Tappan, D., Rekhter, Y., Fedorkow, G.,
              Farinacci, D., Li, T., and A. Conta, "MPLS Label Stack
              Encoding", RFC 3032, January 2001.

   [RFC3444]  Pras, A. and J. Schoenwaelder, "On the Difference between
              Information Models and Data Models", RFC 3444,
              January 2003.

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



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   [RFC3470]  Hollenbeck, S., Rose, M., and L. Masinter, "Guidelines for
              the Use of Extensible Markup Language (XML) within IETF
              Protocols", BCP 70, RFC 3470, January 2003.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              January 2004.


Authors' Addresses

   Thomas Dietz
   NEC Europe Ltd.
   Network Laboratories
   Kurfuersten-Anlage 36
   Heidelberg  69115
   Germany

   Phone: +49 6221 90511-28
   Email: dietz@netlab.nec.de
   URI:   http://www.netlab.nec.de/


   Falko Dressler
   University of Erlangen-Nuremberg
   Dept. of Computer Sciences
   Martensstr. 3
   Erlangen  91058
   Germany

   Phone: +49 9131 85-27914
   Email: dressler@informatik.uni-erlangen.de
   URI:   http://www7.informatik.uni-erlangen.de/~dressler


   Georg Carle
   University of Tuebingen
   Wilhelm-Schickard-Institute for Computer Science
   Auf der Morgenstelle 10C
   Tuebingen  71076
   Germany

   Phone: +49 7071 29-70505
   Email: carle@informatik.uni-tuebingen.de
   URI:   http://net.informatik.uni-tuebingen.de/~carle/







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   Benoit Claise
   Cisco Systems
   De Kleetlaan 6a b1
   Degem  1813
   Belgium

   Phone: +32 2 704 5622
   Email: bclaise@cisco.com


   Paul Aitken
   Cisco Systems
   96 Commercial Quay
   Edinburgh  EH6 6LX
   Scotland

   Phone: +44 131 561 3616
   Email: paitken@cisco.com
   URI:   http://www.cisco.com/

Appendix A.  Formal Specification of PSAMP Information Elements

   This appendix contains a formal description of the PSAMP information
   model XML document.  Note that this appendix is of informational
   nature, while the text in section Section 9 generated from this
   appendix is normative.

   Using a formal and machine readable syntax for the information model
   enables the creation of PSAMP aware tools which can automatically
   adapt to extensions to the information model, by simply reading
   updated information model specifications.

   The wide availability of XML aware tools and libraries for client
   devices is a primary consideration for this choice.  In particular
   libraries for parsing XML documents are readily available.  Also
   mechanisms such as the Extensible Stylesheet Language (XSL) allow for
   transforming a source XML document into other documents.  This draft
   was authored in XML and transformed according to [RFC2629].

   It should be noted that the use of XML in exporters, collectors or
   other tools is not mandatory for the deployment of PSAMP.  In
   particular, exporting processes do not produce or consume XML as part
   of their operation.  It is expected that PSAMP collectors MAY take
   advantage of the machine readability of the information model vs.
   hardcoding their behavior or inventing proprietary means for
   accommodating extensions.

   Using XML-based specifications does not currently address possible



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   IANA implications associated with XML Namespace URIs.  The use of
   Namespaces as an extension mechanism implies that an IANA registered
   Namespace URI should be available and that directory names below this
   base URI be assigned for relevant IETF specifications.  The authors
   are not aware of this mechanism today.



   <?xml version="1.0" encoding="UTF-8"?>
   <fieldDefinitions><!-- xmlns="http://www.ietf.org/ipfix"-->
     <field name="observationPointId" dataType="unsigned64"
            fieldId="300" status="current" group="common">
       <description>
         <paragraph>
           ID of the observation process.
           Unique in the observation domain.
         </paragraph>
       </description>
     </field>

     <field name="selectionSequenceId" dataType="unsigned64"
            fieldId="301" status="current" group="common">
       <description>
         <paragraph>
           From all the packets observed at an Observation Point, a
           subset of packets is selected by a sequence of one or more
           Selectors.  The selectionSequenceId is a unique value per
           Observation Domain, describing the Observation Point and the
           sequence of Selectors through which the packets are selected.
         </paragraph>
       </description>
     </field>

     <field name="selectorId" dataType="unsigned16"
            dataTypeSemantics="identifier"
            fieldId="302" status="current" group="common">
       <description>
         <paragraph>
             The Selector ID is the unique ID identifying a Primitive
             Selector. Each Primitive Selector must have a unique ID
             in the observation domain.
         </paragraph>
       </description>
     </field>

     <field name="informationElementId" dataType="unsigned16"
            dataTypeSemantics="identifier"
            fieldId="303" status="current" group="common">



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       <description>
         <paragraph>
           Contains the ID of another Information Element.
         </paragraph>
       </description>
     </field>

     <field name="selectorAlgorithm" dataType="unsigned16"
            dataTypeSemantics="identifier"
            fieldId="304" status="current" group="common">
       <description>
         <paragraph>
           Specifies the selector algorithm (e.g., filter, sampler,
           hash) that was used on a packet.
           It is exported in the options data flow record to specify
           how a collector has to interpret a data flow record.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The following selector algorithms are currently defined:
         </paragraph>
         <paragraph>
         </paragraph>

         <itemlist>
           <item>1 Systematic count-based sampling</item>
           <item>2 Systematic time-based sampling</item>
           <item>3 Random n-out-of-N sampling</item>
           <item>4 Uniform probabilistic sampling</item>
           <item>5 Property match filtering</item>
           <item>6 Hash based filtering using BOB</item>
           <item>7 Hash based filtering using IPSX</item>
           <item>8 Hash based filtering using CRC</item>
         </itemlist>

         <paragraph>
         </paragraph>
         <paragraph>
           EDITOR'S NOTE: This list may be extended in the final
           version.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The parameters for most of these algorithms
           are defined in this information model. Some parameters for
           these algorithms are not covered by this information model



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           since they very much depend on the underlying hardware.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           In future, this list will be maintained by IANA.
           IANA can update this information element as long as
           there's a new RFC specifying the algorithm and
           any new Information Elements which are required.
         </paragraph>
       </description>
     </field>

     <field name="samplingPacketInterval" dataType="unsigned32"
            fieldId="305" status="current" group="common">
       <description>
         <paragraph>
           Number of packets that are consecutively sampled.
           For example a value of 100 means that 100 contiguous
           packets are sampled.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           This information element is used to describe the
           configuration of a systematic count-based sampling selector.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="samplingPacketSpace" dataType="unsigned32"
            fieldId="306" status="current" group="common">
       <description>
         <paragraph>
           The number of packets between two
           "samplingPacketInterval"s. A value of 100 means that the
           next interval starts after 100 packets (which are not
           sampled) when the current "samplingPacketInterval" is over.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           This information element is used to describe the
           configuration of a systematic count-based sampling selector.
         </paragraph>
       </description>
       <units>packets</units>



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     </field>

     <field name="samplingTimeInterval" dataType="dateTimeMicroSeconds"
            fieldId="307" status="current" group="common">
       <description>
         <paragraph>
           Time interval in microseconds in which all arriving
           packets are sampled.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           This information element is used to describe the
           configuration of a systematic time-based sampling selector.
         </paragraph>
       </description>
       <units>microseconds</units>
     </field>

     <field name="samplingTimeSpace" dataType="dateTimeMicroSeconds"
            fieldId="308" status="current" group="common">
       <description>
         <paragraph>
           The time interval in microseconds between two
           "samplingTimeInterval"s. A value of 100 means that the
           next interval starts after 100 microseconds (in which no
           packets are sampled) when the current "samplingTimeInterval"
           is over.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           This information element is used to describe the
           configuration of a systematic time-based sampling selector.
         </paragraph>
       </description>
       <units>microseconds</units>
     </field>

     <field name="samplingSize" dataType="unsigned32"
            fieldId="309" status="current" group="common">
       <description>
         <paragraph>
           The number of elements taken from the parent
           population for random sampling algorithms.
         </paragraph>
         <paragraph>
         </paragraph>



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         <paragraph>
           This information element is used to describe the
           configuration of a random n-out-of-N sampling selector.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="samplingPopulation" dataType="unsigned32"
            fieldId="310" status="current" group="common">
       <description>
         <paragraph>
           The number of elements in the parent population
           for random sampling algorithms.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           This information element is used to describe the
           configuration of a random n-out-of-N sampling selector.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="samplingProbability" dataType="float64"
            fieldId="311" status="current" group="common">
       <description>
         <paragraph>
           The probability that a packet is sampled,
           expressed as a value between 0 and 1.
           The probability is equal for every packet.
           A value of 0 means no packet was sampled
           since the probability is 0.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           This information element is used to describe the
           configuration of a uniform probabilistic sampling selector.
         </paragraph>
       </description>
     </field>

     <field name="[unused]" dataType=""
            fieldId="312" status="unused" group="common">
       <description>
         <paragraph>



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           This ID is not currently in use.
         </paragraph>
       </description>
     </field>

     <field name="ipHeaderPacketSection"
            dataType="variable length octetArray"
            fieldId="313" status="current" group="common">
       <description>
         <paragraph>
           This information element carries a series of octets
           from the start of the IP header of a sampled packet.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The size of the exported section may be constrained
           due to limitations in the IPFIX protocol.
         </paragraph>
       </description>
     </field>

     <field name="ipPayloadPacketSection"
            dataType="variable length octetArray"
            fieldId="314" status="current" group="common">
       <description>
         <paragraph>
           This information element carries a series of octets
           from the start of the IP payload of a sampled packet.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The IPv4 payload is that part of the packet which follows the
           IPv4 header and any options, which <xref target="RFC0791"/>
           refers to as "data" or "data octets".
           e.g., see the examples in <xref target="RFC0791"/>
           APPENDIX A.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The size of the exported section may be constrained
           due to limitations in the IPFIX protocol.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>



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           If insufficient octets are available for the length specified
           in the template, the packet section must be sent with a new
           template using either a fixed length Information Element of
           the necessary size or a variable length Information Element.
           It's not permissible to pad a short packet section to a
           longer length.
         </paragraph>
       </description>
     </field>

     <field name="dataLinkFrameSection"
            dataType="variable length octetArray"
            fieldId="315" status="current" group="common">
       <description>
         <paragraph>
           This information element carries the first n octets
           from the data link frame of a sampled packet.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The data link layer is defined in
           <xref target="ISO/IEC.7498-1:1994"/>.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The size of the exported section may be constrained
           due to limitations in the IPFIX protocol.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           If insufficient octets are available for the length specified
           in the template, the packet section must be sent with a new
           template using either a fixed length Information Element of
           the necessary size or a variable length Information Element.
           It's not permissible to pad a short packet section to a
           longer length.
         </paragraph>
       </description>
     </field>

     <field name="mplsLabelStackSection"
            dataType="variable length octetArray"
            fieldId="316" status="current" group="common">
       <description>
         <paragraph>



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           This information element carries the first n octets
           from the MPLS label stack of a sampled packet.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           See <xref target="RFC3031"/>
           for the specification of MPLS packets.
           <vspace blankLines="0" />
           See <xref target="RFC3032"/>
           for the specification of the MPLS label stack.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The size of the exported section may be constrained
           due to limitations in the IPFIX protocol.
         </paragraph>
         <!-- To be decided. See open issues.
         <paragraph>
         </paragraph>
         <paragraph>
           If insufficient octets are available for the length specified
           in the template, the packet section must be sent with a new
           template using either a fixed length Information Element of
           the necessary size or a variable length Information Element.
           It's not permissible to pad a short packet section to a
           longer length.
         </paragraph>
         -->
       </description>
     </field>

     <field name="mplsPayloadPacketSection"
            dataType="variable length octetArray"
            fieldId="317" status="current" group="common">
       <description>
         <paragraph>
           This information element carries the first n octets
           from the MPLS payload of a sampled packet, being data
           that follows immediately after the MPLS label stack.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           See <xref target="RFC3031"/>
           for the specification of MPLS packets.
           <vspace blankLines="0" />



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           See <xref target="RFC3032"/>
           for the specification of the MPLS label stack.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           The size of the exported section may be constrained
           due to limitations in the IPFIX protocol.
         </paragraph>
         <paragraph>
         </paragraph>
         <paragraph>
           If insufficient octets are available for the length specified
           in the template, the packet section must be sent with a new
           template using either a fixed length Information Element of
           the necessary size or a variable length Information Element.
           It's not permissible to pad a short packet section to a
           longer length.
         </paragraph>
       </description>
     </field>

     <field name="packetsObserved" dataType="unsigned64"
            fieldId="318" status="current" group="common">
       <description>
         <paragraph>
           Number of packets observed by a selector.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="packetsSelected" dataType="unsigned64"
            fieldId="319" status="current" group="common">
       <description>
         <paragraph>
           Number of packets selected by a selector.
         </paragraph>
       </description>
       <units>packets</units>
     </field>

     <field name="fixedError" dataType="float64"
            fieldId="320" status="current" group="common">
       <description>
         <paragraph>
            Specifies the maximum possible positive or negative error
            interval of the reported value for a given Information



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            Element.
         </paragraph>
       </description>
       <units>
         The units of the Information Element
         for which the error is specified.
       </units>
     </field>

     <field name="relativeError" dataType="float64"
            fieldId="321" status="current" group="common">
       <description>
         <paragraph>
           Specifies the maximum possible positive or negative
           error ratio for a given Information Element.
         </paragraph>
       </description>
     </field>

     <field name="observationTimeSeconds"
            dataType="dateTimeSeconds"
            fieldId="322" status="current" group="common">
       <description>
         <paragraph>
           The absolute time of an observation.
         </paragraph>
       </description>
       <units>seconds</units>
     </field>

     <field name="observationTimeMilliSeconds"
            dataType="dateTimeSeconds"
            fieldId="323" status="current" group="common">
       <description>
         <paragraph>
           The absolute time of an observation.
         </paragraph>
       </description>
       <units>milliseconds</units>
     </field>

     <field name="observationTimeMicroSeconds"
            dataType="dateTimeSeconds"
            fieldId="324" status="current" group="common">
       <description>
         <paragraph>
           The absolute time of an observation.
         </paragraph>



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       </description>
       <units>microseconds</units>
     </field>

     <field name="observationTimeNanoSeconds"
            dataType="dateTimeSeconds"
            fieldId="325" status="current" group="common">
       <description>
         <paragraph>
           The absolute time of an observation.
         </paragraph>
       </description>
       <units>nanoseconds</units>
     </field>

     <field name="digestHashValue" dataType="unsigned64"
            fieldId="326" status="current" group="common">
       <description>
         <paragraph>
           The value from the digest hash function.
         </paragraph>
       </description>
     </field>

     <field name="hashIPPayloadOffset" dataType="unsigned64"
            fieldId="327" status="current" group="common">
       <description>
         <paragraph>
           The IP payload offset used by a hash based selector.
         </paragraph>
       </description>
     </field>

     <field name="hashIPPayloadSize" dataType="unsigned64"
            fieldId="328" status="current" group="common">
       <description>
         <paragraph>
           The IP payload size used by a hash based selector.
         </paragraph>
       </description>
     </field>

     <field name="hashInitialiserValue" dataType="unsigned64"
            fieldId="326" status="current" group="common">
       <description>
         <paragraph>
           The initialiser value to the hash function.
         </paragraph>



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       </description>
     </field>

     <field name="hashOutputRangeMin" dataType="unsigned64"
            fieldId="329" status="current" group="common">
       <description>
         <paragraph>
           A value for the beginning of a hash function's
           potential output range.
         </paragraph>
       </description>
     </field>

     <field name="hashOutputRangeMax" dataType="unsigned64"
            fieldId="330" status="current" group="common">
       <description>
         <paragraph>
           A value for the end of a hash function's
           potential output range.
         </paragraph>
       </description>
     </field>

     <field name="hashSelectedRangeMin" dataType="unsigned64"
            fieldId="331" status="current" group="common">
       <description>
         <paragraph>
           A value for the beginning of a hash function's
           selected range.
         </paragraph>
       </description>
     </field>

     <field name="hashSelectedRangeMax" dataType="unsigned64"
            fieldId="332" status="current" group="common">
       <description>
         <paragraph>
           A value for the end of a hash function's
           selected range.
         </paragraph>
       </description>
     </field>

     <field name="hashDigestOutput" dataType="boolean"
            fieldId="333" status="current" group="common">
       <description>
         <paragraph>
           A boolean value, TRUE if the output from this hash selector



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           has been configured to be included in the packet report as a
           packet digest, else FALSE.
         </paragraph>
       </description>
     </field>

   </fieldDefinitions>












































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