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Versions: 00 01 02

 Internet Draft                                              G. Pohl
 Document: <draft-pohl-perpktinfo-02.txt>           Fraunhofer FOKUS
 Expires: August 2005                                        L. Mark
                                                    Fraunhofer FOKUS
                                                           E. Boschi
                                                    Fraunhofer FOKUS
                                                       February 2005
 
 
 
 
           Use of IPFIX for Export of Per-Packet Information
 
 Status of this Memo
 
    This document is an Internet-Draft and is subject to all
    provisions of section 3 of RFC 3667. 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 become aware
    will be disclosed, in accordance with RFC 3668.
 
    Internet-Drafts are working documents of the Internet
    Engineering Task Force (IETF), its areas, and its working
    groups.  Note that other groups may also distribute working
    documents as Internet-Drafts.
    Internet-Drafts are draft documents valid for a maximum of six
    months and may be updated, replaced, or obsoleted by other
    documents at any time.  It is inappropriate to use
    Internet-Drafts as reference material or to cite them other than
    as "work in progress."
 
    The list of current Internet-Drafts can be accessed at
    http://www.ietf.org/ietf/1id-abstracts.txt.
 
    The list of Internet-Draft Shadow Directories can be accessed at
    http://www.ietf.org/shadow.html.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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           Use of IPFIX for Export of Per-Packet Information
 
 Abstract
 
    This document describes the usage of the IP Flow Information
    Export (IPFIX) protocol for the case of exporting and processing
    per-packet information.
    The main idea is to export two types of records per flow: the
    first one contains the usual flow information plus a unique flow
    identifier while the other one consists of the actual per-packet
    information plus a flow identifier that refers to the flow the
    specific packet belongs to -- that means the flow identifier is
    used to associate the packet data to its corresponding flow.
 
 
 Table of Contents
 
    1.   Introduction¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸2
    2.   Terminology¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸2
    3.   General Problem Statement¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸3
    4.   Export Per-Packet Information¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸3
    5.   Flow ID Management¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸5
    6.   Example of Per-Packet Information Export¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸5
    7.   IPFIX for per-packet information export and PSAMP¸¸¸¸¸¸¸6
    8.   Export and evaluation considerations¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸6
    9.   IANA Consideration¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸7
    10.  Security Considerations¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸7
    11.  References¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸7
    11.1   Normative References¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸7
    11.2   Informative References¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸7
    12.  Author's Addresses¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸8
    13.  Intellectual Property Statement¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸8
    14.  Copyright Statement¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸9
    15.  Disclaimer¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸¸9
 
 1. Introduction
 
    In the scope of passive QoS Measurements, there is often the
    need to exchange and export measurement data in a finer
    granularity then per flows. One typical application is passive
    One-Way-Delay measurement; this draft takes it as example when
    demonstrating the need for information export on a per-packet
    basis.
 
    The IPFIX protocol however, has been designed to export flow
    records. A possible approach to export packet records using
    IPFIX could be exporting flow records containing information
    about single packets. This method has been proposed by the PSAMP
    working group in [Cla204]. Exporting flow related information
    per-packet introduces a high degree of redundancy. This draft
    shows how packet information and flow information can be
    efficiently exported and related using IPFIX.
 
 
 2. Terminology
 
    Collecting Process
         The collecting process receives records of flow or packet
         information. The data is stored for later processing (by
         the calculation process)
 
    Exporting Process
         The exporting processes send flow and packet records to the
         collecting processes. The records are generated by the
         measurement process.
 
    Filtering
 
 
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           Use of IPFIX for Export of Per-Packet Information
 
         Filtering selects a subset of packets by applying
         deterministic functions on parts of the packet content like
         header fields or parts of the payload. A filtering process
         needs to process the packet (look at packet header and/or
         payload) in order to make the selection decision.
 
    Measurement Device
         A measurement device has access to at least one observation
         point. It is hosting at least one measurement process and
         one export process.
 
    Metering/Measurement Process
         The measurement process generates records of packet and
         flow information. Packets passing the observation point are
         captured, time stamped, filtered and classified. The
         measurement process calculates the packet Ids.
 
    Passive One-Way-Delay Measurement
         Abbreviated: POWD Measurement
 
 
 3. General Problem Statement
 
    In [Cla104] the IPFIX working group has defined a protocol to
    transport measurement data containing flow information.
 
    The main purpose of the protocol is to exchange information
    about IP traffic flows. In this scope a flow is defined by a set
    of key attributes (source/destination address,
    source/destination port, Layer3 Protocol Type, TOS/DSCP byte,
    interface of the flow exporting network element). As such, a
    flow is a collection of packets that share a set of common
    attributes.
 
    However, for a number of metrics there is a need to export
    per-packet data.
 
    Undoubtedly a single packet could be considered a special case
    of a flow and thus, per-packet information could be exported
    using flow records. Doing this though would have consequences on
    the efficiency of the exporting procedure, as it would mean
    additional overhead. Packets belonging to the same flow share
    common attributes, i.e. source address, destination address,
    etc. Exporting these attributes on a per-packet basis, each time
    with a different packet ID, would be redundant information.
 
    There are cases however, where it is desirable to keep flow
    information along with the per-packet information, that is, when
    analyzing packet characteristics while observing flows. This
    document proposes a solution that reduces the overhead caused by
    the flow properties while keeping a link to flow information.
 
    The proposed method does not need any changes to the IPFIX
    protocol.
 
 4. Export Per-Packet Information
 
    Figure 2 depicts three packets belonging to flow A and one
    packet that belongs to flow B, respectively. It shows export
    records containing packet information plus flow information
    (source and destination address). Undoubtedly, the flow
    information introduces a huge amount of redundancy, as it is
    repeated for every packet in every record. Minimizing the
    redundancy is a common problem in relational data base design
    and we apply here similar solutions to those proposed in that
    area.
 
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           Use of IPFIX for Export of Per-Packet Information
 
    In Figure 2 we separate flow from packet information. In order
    to maintain the relation between Packet Properties and Flow
    Properties we introduce indices (idxA and idxB) for the Flow
    Properties that are unique for all Flow Property entries. The
    purpose of the indices is to serve as "primary key" that
    identifies rows of the Flow Properties. The rows are then
    referenced by the Packet Properties by using the appropriate
    value for the flow identifier.
 
 
    One-packet flows
    +------+------+------------+---------+
    | srcA | dstA | packet info|   ...   |
    +------+------+------------+---------+
    | srcA | dstA | packet info|   ...   |
    +------+------+------------+---------+
    | srcB | dstB | packet info|   ...   |
    +------+------+------------+---------+
    | srcA | dstA | packet info|   ...   |
    +------+------+------------+---------+
 
    Figure 1: Flow and packet information represented in one-packet
    flows
 
                                  Packet Properties
                                 +-----+------------+---------+
    Flow Properties              >idxA | packet info|   ...   |
    +------+------+-----+        +-----+------------+---------+
    | srcA | dstA |idxA <        >idxA | packet info|   ...   |
    +------+------+-----+        +-----+------------+---------+
    | srcB | dstB |idxB <-------->idxB | packet info|   ...   |
    +------+------+-----+        +-----+------------+---------+
                                 >idxB | packet info|   ...   |
                                 +-----+------------+---------+
 
             here, the linkage of one packet and
             flow B (srcB, dstB, idxB) is explicitly drawn
 
    Figure 2: Flow information and packet information
 
 
    The IPFIX protocol is template based like NetFlow version 9. For
    a complete description of features of IPFIX refer to [Fehler!
    Verweisquelle konnte nicht gefunden werden.].
    Templates define the structure of data to be exported, including
    describing data fields to be exported together with their type
    and meaning.
 
    For Measurement Process Results we define two different template
    records, namely Flow Properties and Packet Properties. The Flow
    Properties templates SHOULD be sent before the Packet Properties
    Templates.
 
    In Figure 3,  the Flow Properties template defines the
    attributes for a flow; e.g. IP source and destination address
    and the flow identifier. The flow identifier is a unique
    identifier for flow definitions; this field allows packet
    records to reference flow attributes. Subsequent data records of
    this template define the actual flows.
 
    The format for the information related to single packets is
    defined in the Packet Properties template. This information is
    packet specific and normally not shared between many packets.
    Otherwise one would rather consider the information as flow
    related and therefore it needs not be exported in every record.
 
 
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           Use of IPFIX for Export of Per-Packet Information
 
 
 
    +------------------+      +-------------------+
    | Template Set     |      | Template Set      |
    |                  |      |                   |  Description of
    | Flow Properties  |      | Packet Properties |  exported data
    +----------+-------+      +----------+--------+
    ...........|.........................|.........................
               |                         |
    +----------v-------+      +----------v--------+
    | Data Set         |      | Data Set          |  exported data
    |                  <------+                   |  with references
    | Flow Properties  |      | Packet Properties |  by means of
    +------------------+      +-------------------+  flow identfier
 
    Figure 3: Template FlowSet and Data FlowSet dependencies
 
 
 
 5. Flow ID Management
 
    Like template IDs the flow IDs have to be unique per observation
    domain (source identifier in the IPFIX header). Using 32 bit
    flow IDs allows the export of 2**32 active flows in parallel.
 
    If it is desired, one can optionally use option templates to
    specify the mapping between two flow and packet properties
    templates. In this case, the flow ID only has to be unique
    within this association.
 
 
 6. Example of Per-Packet Information Export
 
    To demonstrate how to use IPFIX efficiently to export per-packet
    information, this section proposes how to use the IPFIX protocol
    for exporting flow information and per-packet information (in
    this case related to a long-lived flow) for OWD computation.
 
    In order to acquire a One-Way path delay information, two
    measurement points with synchronized clocks must exist, one at
    each end of the path under examination. Both measurement points
    will capture packets, assign them timestamps and generate an
    identifier for a packet passing that point. Each measurement
    point will export its measurement data to a collecting process
    where the data are correlated based on the packet identifiers
    and timestamps and then the delay is calculated as a difference
    of two timestamps of a packet pair.
 
    The templates that would be needed for exporting measurement
    data of this kind are illustrated in Figure 4.
    The upper part of the figure shows the template containing the
    information concerning flows. The lower part displays the
    template with the packet properties.
 
    For passive One-Way-Delay measurement, the Packet Properties
    template consists of at least Timestamp and Packet ID.
    Additionally, this template contains a flow identifier field. In
    packet records, the value of this field will contain one of the
    unique indices of the flow records exported before.
 
 
 
 
 
 
 
 
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           Use of IPFIX for Export of Per-Packet Information
 
 
    +-------------------+-------------------+-----------------------+..
    | flowID            | sourceAddressV4   | destinationAddressV4  |
    |                   |                   |                       |
    | unsigned32/vendor | ipv4Address/ID 8  | ipv4Address/ID 12     |
    +-------------------+-------------------+-----------------------+..
 
    ..+------------------+--------------------+---------------------+..
      | classOfServiceV4 | protocolIdentifier | transportSourcePort |
      |                  |                    |                     |
      | octet/ID 5       | octet/ID 4         | unsigned16/ID 7     |
    ..+------------------+--------------------+---------------------+..
 
    ..+--------------------------+
      | transportDestinationPort |
      |                          |
      | unsigned16/ID 11         |
    ..+--------------------------+
                                                       FlowPropTemplate
    ===================================================================
                                                     PacketPropTemplate
    +-------------------+-------------------+-------------------+..
    | packetTimestamp   | packetID          | packetLength      |
    |                   |                   |                   |
    | unsigned64/vendor | unsigned32/vendor | unsigned32/vendor |
    +-------------------+-------------------+-------------------+..
 
    ..+-------------------+
      | flowID            |
      |                   |
      | unsigned32/vendor |
    ..+-------------------+
 
    Figure 4: Example Templates for Flow and Packet Properties
 
 
    The delay is derived by a calculation step: At the collection
    point packet records of two measurement points are gathered and
    correlated by means of the packet ID. The resulting delay data
    records are exported in a similar manner as the packet data have
    been. Especially, the linkage between delay data and flow
    information is represented with the discussed flow identifier
    fields. The OWD properties contain the Packet Pair ID (which is
    the packet ID matching that of the two contributing packet
    records), a timestamp (which is the timestamp of the packet
    passing the reference monitor point) in order to reconstruct a
    time series, the calculated delay value, and finally a flow
    identifier.
 
 7. IPFIX for per-packet information export and PSAMP
 
    In [Cla204] the PSAMP working group proposes to use IPFIX to
    export packet information from a PSAMP Exporting Process to a
    PSAMP Collecting Process. Even though no new version of the
    draft has been produced the solution seems to be accepted from
    the group.
    While IPFIX is well suited for the purpose due to the good match
    between the IPFIX and PSAMP architectures and to the fact that
    IPFIX satisfies PSAMP requirements, the described approach has a
    high degree of redundancy. It proposes to treat packets as flows
    and export per-packet information using flow records.
    We propose to use the solution described in this draft to
    efficiently export PSAMP packet information.
 
 8. Export and evaluation considerations
 
 
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           Use of IPFIX for Export of Per-Packet Information
 
    The main advantage of this proposed method to export per-packet
    information is the reduced amount of measurement data that has
    to be transferred from the exporter to the collector. In
    addition there is less storage capacity needed at the collector
    side.
 
    On the other hand there is some extra processing power needed on
    the exporter side to manage flow information and to assign
    packets to flows. The collector has to process records of two
    templates instead of just one but has to read and write less
    data. Additional effort is needed when post processing the
    measurement data, because now the correlation of flow and packet
    information is needed.
 
    In the above example (see Figure 4) using IPFIX to export the
    measurement data for each received packet 28 bytes have to be
    transferred (sourceAddressV4=4, destinationAddressV4=4,
    classOfServiceV4=1, protocolIdentifier=1, transportSourcePort=2,
    transportDestionationPort=2, packetTimestamp=8, packetID=4,
    packetLength=2). Disregarding the IPFIX protocol overhead a flow
    of 1000 packets produces 28000 bytes of measurement data. Using
    the proposed optimization each packet produces an export of only
    16 bytes (packetTimestamp=8, packetID=4, packetLength=2,
    flowID=2). The export of the flow information produces 16 bytes
    (sourceAddressV4=4, destinationAddressV4=4, classOfServiceV4=1,
    protocolIdentifier=1, transportSourcePort=2,
    transportDestionationPort=2, flowID =2). For a flow of 1000
    packet this sums up to 16016 bytes. This is a decrease of more
    than 40 percent.
 
 9. IANA Consideration
 
    This document does not imply any IANA action.
 
 10. Security Considerations
 
    For the proposed use of the IPFIX protocol for export of
    per-packet information the security considerations as for the
    IPFIX protocol apply.
 
 11. References
 
 11.1    Normative References
 
    [Cla104]    Benoit Claise: IPFIX Protocol Specification,
                 IETF draft work in progress
                 <draft-ietf-ipfix-protocol-05.txt>, August 2004
 
    [Cla204]    Benoit Claise: PSAMP Protocol Specification,
                 Internet Draft <draft-ietf-psamp-protocol-01.txt>,
                 February 2004
 
 11.2    Informative References
 
    [DuGG03]    Nick Duffield, et Al.: A Framework for Packet
                 Selection and reporting, Internet Draft
                 <draft-ietf-psamp-framework-08.txt>, September 2004
 
    [DuGr00]    Nick Duffield, Matthias Grossglauser: Trajectory
                 Sampling for Direct Traffic Observation,
                 Proceedings of ACM SIGCOMM 2000, Stockholm, Sweden,
                 August 28 - September 1, 2000
 
    [QuZC04]    J. Quittek, et Al.: Requirements for IP Flow
                 Information Export, Internet Draft
                 <draft-ietf-ipfix-reqs-16.txt>, June 2004
 
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           Use of IPFIX for Export of Per-Packet Information
 
 
    [GrDM98]    Ian D. GRAHAM, Stephen F. DONNELLY, Stele MARTIN,
                 Jed MARTENS, John G. CLEARY: Nonintrusive and
                 Accurate Measurement of Unidirectional Delay and
                 Delay Variation on the Internet, INET'98, Geneva,
                 Switzerland, July 21-24, 1998
 
    [TPBC03]    T. Zseby, E. Boschi, R. Penno, N. Brownlee, B.
                 Claise: IPFIX Applicability, Internet Draft
                 <draft-ietf-ipfix-as-02.txt>, July 2004
 
 12. Author's Addresses
 
        Elisa Boschi
        Fraunhofer Institute for Open Communication Systems
        Kaiserin-Augusta-Allee 31
        10589 Berlin
        Germany
        Phone: +49-30-34 63 7366
        Fax:   +49-30-34 53 8366
        Email: boschi@fokus.fraunhofer.de
 
        Lutz Mark
        Fraunhofer Institute for Open Communication Systems
        Kaiserin-Augusta-Allee 31
        10589 Berlin
        Germany
        Phone: +49-30-34 63 7306
        Fax:   +49-30-34 53 8306
        Email: mark@fokus.fraunhofer.de
 
        Guido Pohl
        Fraunhofer Institute for Open Communication Systems
        Kaiserin-Augusta-Allee 31
        10589 Berlin
        Germany
        Phone: +49-30-34 63 7164
        Fax:   +49-30-34 53 8164
        Email: pohl@fokus.fraunhofer.de
 
 13. Intellectual Property Statement
 
    The IETF takes no position regarding the validity or scope of
    any Intellectual Property Rights or other rights that might be
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    technology described in this document or the extent to which any
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    BCP 79.
 
    Copies of IPR disclosures made to the IETF Secretariat and any
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    repository at http://www.ietf.org/ipr.
 
    The IETF invites any interested party to bring to its attention
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    proprietary rights that may cover technology that may be
    required to implement this standard. Please address the
    information to the IETF at ietf-ipr@ietf.org.
 
 
 
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           Use of IPFIX for Export of Per-Packet Information
 
 14. Copyright Statement
 
    Copyright (C) The Internet Society (2005).  This document is
    subject to the rights, licenses and restrictions contained in
    BCP 78, and except as set forth therein, the authors retain all
    their rights.
 
 15. Disclaimer
 
    This document and the information contained herein are provided
    on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE
    REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND
    THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES,
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    FOR A PARTICULAR PURPOSE.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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