IPFIX working group
   Internet Draft                               EDITORS:      B. Claise
   draft-ietf-ipfix-protocol-01.txt                       Cisco Systems
   Expires: April 2004                                     Mark Fullmer
                                                                 OARnet
                                                            Paul Calato
                                                    Riverstone Networks
                                                         Reinaldo Penno
                                                        Nortel Networks
                                                           October 2003


                       IPFIX Protocol Specifications



 Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026.

   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 obsolete 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.

 Abstract

   This document discusses the IPFIX protocol that provides network
   administrators with access to IP flows information. This document
   focuses on how IPFIX flow record data, options record data and
   control information is carried (via a congestion-aware transport
   protocol) from IPFIX exporting process to IPFIX collecting process.


 Conventions used in this document





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   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.

 Table of Contents

     1. Points of Discussion........................................3
      1.1 Open Issues................................................3
      1.2 Action Items...............................................4
     2. Introduction................................................4
      2.1 Overview...................................................4
     3. Terminology.................................................4
      3.1 Terminology Summary Table..................................9
     4. The Metering Process........................................9
      4.1 Flow Expiration............................................9
     5. Transport Protocol.........................................10
      5.1 TCP.......................................................10
      5.2 STCP......................................................10
     5.2.1  Congestion Avoidance..................................11
     5.2.2  Reliability...........................................11
     5.2.3  Exporting Process.....................................11
     5.2.3.1 MTU size.............................................11
     5.2.3.2 Source ID............................................11
     5.2.3.3 Association..........................................12
     5.2.3.4 Template.............................................12
     5.2.3.5 Template.............................................12
     5.2.4  Collecting Process....................................13
     5.2.5  SCTP Partially Reliable...............................13
     6. Failover...................................................14
      6.1 Simple Failover based on the transport protocol...........14
      6.2 Something else?...........................................14
     7. Packet Layout..............................................14
     8. Export Packet Format.......................................16
      8.1 Header Format.............................................16
      8.2 Template FlowSet Format...................................17
      8.3 Data FlowSet Format.......................................19
     9. Options....................................................20
      9.1 Options Template FlowSet Format...........................20
      9.2 Options Data Record Format................................22
     10. Variable Length Data Type.................................24
     11. Template Management.......................................25
     12. The Collecting Process's Side.............................26
     13. Examples..................................................27
      13.1 Packet Header Example....................................28
      13.2 Template FlowSet Example.................................28
      13.3 Data FlowSet Example.....................................29
      13.4 Options Template FlowSet Example.........................30
      13.5 Data FlowSet with Options Data Records Example...........31
     14. References................................................31


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     15. Acknowledgments...........................................32


 1. Points of Discussion

 1.1 Open Issues

   This section covers the open issues, still to be resolved/updated in
   this draft:

   - The proposal on the table is to send a IPFIX Sync (this would be
   an Options Data Records) message periodically (periodicity is
   configurable), with the following information (aside the standard
   IPFix header)
           * Number of flow records sent (for each template?)
           * Packets and bytes sent (for each template?)
     Question: Per observation domain?
     Question: Do we need a specific FlowSet ID?
   - Template don't need lifetimes with connection oriented protocol.
   We guess this is the consensus from the Working Group.
   - No periodic retransmission of templates is needed, with a reliable
   transport protocol.
   Remark: the template management will vary with TCP, SCTP, etcà
   Must have both sections updated: transport updated and template
   management sections (BTW, this is the same for the failover
   section).
   - There seems to be a consensus that having a length field in the
   Export Packet header.
   Related question: what about the count field then in the NetFlow
   version 9 header? But no consensus yet. So no consensus whether the
   current count should simply be replaced by the length or the length
   field be added.
   - Sub-second timestamps
   - Export ID (ie IP address of exporter) sent to the collector. This
   can be done once with an options template.
   - Metering process stats: for example packets / flows dropped at the
   metering process due to resource exhaustion, etcà This can be done
   with an options template.
   - Error recovery, for example what to do if a collector receives a
   message it can't decode. Per protocol issue, ie TCP reset the
   session because it's a stream protocol and can't recover.
   - If we tackle reliablilty a state diagram is needed.
   - Talk a little bit about extensibility, for example make some



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   decisions now about the reserved template ID's 2-254 for future
   work.

 1.2 Action Items

   This section covers the action items for this draft
   - change the abstract: done, to be reviewed
    -> Reinaldo
   - introduction to be completed: introduction + references to other
   drafts + applications for the protocol.
    -> Reinaldo
   - ôtransport protocolö section to be updated.
      -> TCP, Reinaldo
     Note: each transport protocol (TCP/SCTP) should have at least the
   following subsections: Reliability, Failover, Template Management
   - Review the requirements draft to see what we miss!
     -> Benoit
   - variable length data types
      -> Text and packet format to be worked on. Benoit
   - field types information -> should we have basic type in the
   protocol draft, like Jeff suggested.
      -> Mark: will send an abstract
   - add references to the IPFIX drafts, when published


 2. Introduction

 2.1 Overview

   Will be completed.
   It will cover an introduction, pointers/explanation towards/of the
   other drafts, and the applications for the IPFIX protocol

 3. Terminology

   The definitions of IP Traffic Flow, Metering Process, Exporting
   Process and Collecting Process are the definitions as found in the
   IPFIX requirement document [IPFIX-REQ]. Note nevertheless that,
   even if the Observation Point definition has been also been
   completely copied over from the IPFIX requirement document [IPFIX-
   REQ], this definition has been expanded.

   The terminology summary table in Section 3.1 gives a quick overview
   of the relationships between some of the different terms defined.


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Observation Point

   The Observation Point is a location in the network where IP packets
   can be observed. Examples are a line to which a probe is attached,
   a shared medium such as an Ethernet-based LAN, a single port of a
   router, or a set of interfaces (physical or logical) of a router.
   An Observation Domain is associated with every Observation Point.

   Note that one Observation Point may be a superset of several
   other Observation Points. For example one Observation Point can be
   an entire line card. This would be the superset of the
   individual Observation Points at the line card's interfaces.

Observation Domain

   The set of Observation Points, which is the largest aggregatable set
   of Flow information at the Metering Process is termed an Observation
   Domain. Each Observation Domain presents itself as a unique ID to
   the Collecting Process for identifying the Export Packets it
   generates.
   For example, a router line card composed of several interfaces with
   each interface being an Observation Point.

IP Traffic Flow or Flow

   There are several definitions of the term 'flow' being used by the
   Internet community. Within this document we use the following one:

   A Flow is defined as a set of IP packets passing an Observation
   Point in the network during a certain time interval. All packets
   belonging to a particular Flow have a set of common properties. Each
   property is defined as the result of applying a function to the
   values of:

        1. one or more packet header field (e.g. destination IP
        address), transport header field (e.g. destination port
        number), or application header field (e.g. RTP header fields
        [RFC1889])
        2. one or more characteristics of the packet itself (e.g.
        number of MPLS labels, etc...)
        3. one or more of fields derived from packet treatment (e.g.
        next hop IP address, the output interface, etc...)


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   A packet is defined to belong to a Flow if it completely satisfies
   all the defined properties of the Flow.

   This definition covers the range from a Flow containing all packets
   observed at a network interface to a Flow consisting of just a
   single packet between two applications with a specific sequence
   number. Please note that the Flow definition does not necessarily
   match a general application-level end-to-end stream. However, an
   application may derive properties of application-level streams by
   processing measured Flow data. Also, please note that although
   packet properties may depend on application headers, there is no
   requirement defined in this document related to application headers.

 Flow Record

   A Flow Record provides information about an IP Traffic Flow observed
   at an Observation Point.

Metering Process

   The Metering Process generates Flow Records. Input to the process
   are packet headers observed at an Observation Point and packet
   treatment at the Observation Point, for example the selected output
   interface.
   The Metering Process consists of a set of functions that includes
   packet header capturing, timestamping, sampling, classifying, and
   maintaining Flow Records.

   The maintenance of Flow Records may include creating new records,
   updating existing ones, computing Flow statistics, deriving further
   Flow properties, detecting Flow expiration, passing Flow Records to
   the Exporting Process, and deleting Flow Records.

   The sampling function and the classifying function may be applied
   more than once with different parameters. Figure 1 shows the
   sequence in which the functions are applied. Sampling is not
   illustrated in the figure, it may be applied before any other
   function.

                              packet header capturing
                                        |
                                   timestamping


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                                        |
                                        v
                                 +----->+
                                 |      |
                                 | classifying
                                 |      |
                                 +------+
                                        |
                             maintaining Flow Records
                                        |
                                        v


                    Figure 1: Functions of the Metering Process

Exporting Process

   The Exporting Process sends Flow Records to one or more Collecting
   Processes. The Flow Records are generated by one or more Metering
   Processes.

Collecting Process

   The Collecting Process receives Flow Records from one or more
   Exporting Processes. The Collecting Process might store received
   Flow Records or further process them, but these actions are out of
   the scope of this document.

Export Packet

   An Export Packet is a packet originating at the Exporting Process
   that carries the Flow Records of this Exporting Process and whose
   destination is the Collecting Process.

Packet Header

   The Packet Header is the first part of an Export Packet, which
   provides basic information about the packet such as the IPFIX
   version, number of records contained within the packet, sequence
   numbering, etc.

Template Record



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   A Template Record defines the structure and interpretation of fields
   in a Flow Data Record.

Flow Data Record

   A Flow Data Record is a data record that contains values of the Flow
   parameters corresponding to a Template Record. In this document, the
   Flow Data Record is also referred to as Flow Record.

Options Template Record

   An Options Template Record defines the structure and interpretation
   of fields in an Options Data Record, including defining how to scope
   the applicability of the Options Data Record.

Options Data Record

   The Options Data Record is a data record that contains values and
   scope information of the Flow measurement parameters, corresponding
   to an Options Template Record.

FlowSet

   FlowSet is a generic term for a collection of records that have a
   similar structure. In an Export Packet, one or more FlowSets follow
   the Packet Header.
   There are three different types of FlowSets: Template FlowSet,
   Options Template FlowSet, and Data FlowSet.

Template FlowSet

   A Template FlowSet is a collection of one or more Template Records
   that have been grouped together in an Export Packet.

Options Template FlowSet

   An Options Template FlowSet is a collection of one or more Options
   Template Records that have been grouped together in an Export
   Packet.

Data FlowSet





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   A Data FlowSet is one or more records, of the same type, that are
   grouped together in an Export Packet. Each record is either a Flow
   Data Record or an Options Data Record previously defined by a
   Template Record or an Options Template Record.

 3.1 Terminology Summary Table

         FlowSet        Template  Record        Data Record
   +----------------------------------------------------------------+
   |                  |                    |  Flow Data Record(s)   |
   | Data FlowSet     |          /         |          or            |
   |                  |                    | Options Data Record(s) |
   +----------------------------------------------------------------+
   | Template FlowSet | Template Record(s) |           /            |
   +----------------------------------------------------------------+
   | Options Template | Options Template   |           /            |
   | FlowSet          | Record(s)          |                        |
   +----------------------------------------------------------------+

   A Data FlowSet is composed of an Options Data Record(s) or Flow Data
   Record(s). No Template Record is included. A Template Record defines
   the Flow Data Record, and an Options Template Record defines the
   Options Data Record.

   A Template FlowSet is composed of Template Record(s). No Flow or
   Options Data Record is included.

   An Options Template FlowSet is composed of Options Template
   Record(s). No Flow or Options Data Record is included.

 4. The Metering Process

   The description of the Metering Process (for example, sampled or
   not, aggregation or not), which is the way in which Flows are
   created from the observed IP packets, is beyond the scope of this
   document. Nevertheless, some aspects of the Metering Process have
   some influences on the IPFIX protocol

 4.1 Flow Expiration

   A Flow is considered to be inactive if no packets belonging to the
   Flow have been observed at the Observation Point for a given




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   timeout. If any packet is seen within the timeout, the flow is
   considered an active Flow.
   A Flow can be exported under the following conditions:

      1. If the Metering Process can detect the end of a Flow. For
      example, if the FIN or RST bit is detected in a TCP [3]
      connection, the Flow Record is exported.

      2. If the Flow has been inactive for a certain period of time.
      This inactivity timeout SHOULD be configurable at the Metering
      Process, with a minimum value of 0 for an immediate expiration.

      3. For long-lasting Flows, the Exporting Process SHOULD export
      the Flow Records on a regular basis. This timeout SHOULD be
      configurable at the Metering Process.

      4. If the Metering Process experiences internal constraints, a
      Flow MAY be forced to expire prematurely; for example, counters
      wrapping or low memory.

 5. Transport Protocol

   The IPFIX Protocol Specifications have been designed to be transport
   protocol independent. It can operate over congestion-aware protocols
   such as TCP [3] or SCTP [RFC2960].

   Note that the Exporter can export to multiple Collecting Processes,
   using independent transport protocols.

 5.1 TCP

   To be completed.
   TCP [3]

 5.2 STCP

   This section describes how IPFIX can be transported over SCTP
   [RFC2960] using traditional reliable mode.

   IPFIX can also be transported over the partial reliable or
   unreliable mode [PR-SCTP]. These last 2 modes will be briefly
   discussed, while waiting for [PR-SCTP] to become a standard.




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 5.2.1   Congestion Avoidance

   The SCTP transport protocol provides the required level of
   congestion avoidance by design.

 5.2.2    Reliability

   The SCTP transport protocol is by default reliable, but has the
   capability to operate in unreliable and partially reliable modes
   [PR-SCTP].

   Using reliable SCTP streams for the IPFIX export is not in itself a
   guarantee that all records are delivered. If there is congestion on
   the link from the exporter to the collector, or if a significant
   amount of retransmissions are needed, the send queues on the
   Exporting Process may fill up. In that case it's up to the Exporting
   Process to decide what to do. It may either halt export (buffer the
   data until there is space in the send queues again) or just throw
   Export Packets away instead of inserting them into the send queue.
   If any data is not inserted into the send queues, the sequence
   numbers used for export must reflect the loss of data.

 5.2.3    Exporting Process

 5.2.3.1 MTU size

   Each IPFIX Export Packet should be equal to or less than the local
   MTU in size. When an IPFIX Export Packet is transmitted over a
   network with an MTU smaller than the local MTU, IP fragmentation may
   be used.

 5.2.3.2 Source ID

   The Export Packet must contain a Packet Header, which includes a
   source id (SID). The SID indicates from which Observation Domain the
   data is being exported, and should be kept unique for each such
   domain.

   If a Metering Process consists of a single Observation Domain, a
   single SID value must be used for all Export Packets. The Exporting
   Process will typically open one association to the collector, but
   more are possible, in which one or more streams can be used. The



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   Exporting Process has the choice of transmitting parts of the export
   data in separate streams or all data in one stream.

   If a Metering Process consists of multiple Observation Domains, one
   SID value for each Observation Domain must be used. The Exporting
   Process will typically open one association, but more are possible,
   in which at least one stream per Observation Domain is used.

   The Exporting Process has the choice of using more than one stream
   per Observation Domain, but data from multiple Observation Domains
   should not be transmitted over the same stream.

 5.2.3.3 Association

   The Exporting Process may create one or more associations
   (connection "bundle" in SCTP terminology) to the Collecting Process.
   The Collecting Process may not initiate the connection. Inside each
   association one or more streams may be requested by the Exporting
   Process. If the Collecting Process can not support the requested
   number of streams, it may choose to refuse the connection and the
   Exporting Process should try to reduce, if possible, the number of
   streams needed to perform the export.

 5.2.3.4 Template

   An Observation Domain must use at least one stream, but may use
   multiple streams, to export data records. The Observation Domain
   must use the same SID value for all streams used.

   An Exporting Process must not transmit packets with different SID
   values in one stream, the Collecting Process should however verify
   that the SID values are the expected values.

 5.2.3.5 Template

   Since the SCTP association is connection oriented the available
   Template Records must be transmitted from each Observation Domain to
   the Collecting Process immediately after the association is
   established.

   As a minimum the Template Records must be transmitted immediately
   after they start to exist on the Metering Process and should



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   preferably be transmitted before any data, using the new Template
   Record, have been transmitted. The Collecting Process should however
   accept data without a Template Record.

   When using a reliable mode for Template Record export, or if the
   exporter knows that the Export Packet containing the templates was
   positively acknowledged by the SCTP layer, it is not necessary to
   periodically export the Template Records.

 5.2.4    Collecting Process

   The Collecting Process should listen for a new association request
   from the Exporting Process. The Collecting Process will request a
   number of streams to use for export. If the Collecting Process
   doesn't support the number of streams inside the association, the
   Collecting Process must refuse the connection and continue listen
   for a new request.

   When data is received from an association, the Collecting Process
   must correlate data, with the same SID value, from multiple streams
   into one export Flow from an Observation Domain. This allows the
   Observation Domain to use separate streams for different types of
   information.

   The Collecting Process should verify that the received Export
   Packets inside one stream does not have diverting SID values. The
   Exporting Process must not export packets inside one stream with
   multiple SID values. The correlated Flow Records are then treated
   like a normal export Flow.

 5.2.5    SCTP Partially Reliable

   This mode will not be discussed any further until [PR-SCTP] becomes
   a standard, even if this mode offers a few advantages:
   freedom to use SCTP as a reliable, single stream transport, as well
   as multiple streams with different properties, for example in terms
   of reliability, carrying different data types dependant on their
   importance for the system.
   Unreliable or partial reliability may be chosen for one or more
   streams inside an association. Unreliable transport may be preferred
   where large amount of data is to be exported and keeping send queues
   is either an unnecessary overhead or impractical. Partial
   reliability may be chosen where a small amount of queuing is


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   possible.

   Naturally it is better to send templates over a reliable stream and
   send the data on an unreliable (or partial reliable) stream. When an
   exporter handles data with different properties it might even be
   preferable to send them over different streams according to those
   properties.

   Example: an Exporting Process can use two streams per Observation
   Domain. A reliable stream could be used for exporting templates, to
   reduce the likelihood of loss and to remove the need for blind
   retransmissions, and a partial or unreliable stream for data, to
   avoid buffering of large amounts of data.

 6. Failover

   When to fail over?
   How to fail back?
   How to ensure stability of the failover mechanism (prevent
   oscillations)?
   Does the exporter open connections to all the potential collectors
   and keep them primed with template info?

 6.1 Simple Failover based on the transport protocol

   In case the transport protocol is connection oriented.
   So in case of TCP [3] or SCTP [RFC2960].
   To be completed.

 6.2 Something else?

   Potentially based on some application level ACK from the exporter?

 7. Packet Layout

   An Export Packet consists of a Packet Header followed by one or more
   FlowSets. The FlowSets can be any of the possible three types:
   Template, Data, or Options Template.

   Export Packet:
   +--------+-------------------------------------------+
   |        | +----------+ +---------+ +----------+     |
   | Packet | | Template | | Data    | | Options  |     |



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   | Header | | FlowSet  | | FlowSet | | Template | ... |
   |        | |          | |         | | FlowSet  |     |
   |        | +----------+ +---------+ +----------+     |
   +--------+-------------------------------------------+

   A FlowSet ID is used to distinguish the different types of FlowSets.
   FlowSet IDs lower than 256 are reserved for special FlowSets, such
   as the Template FlowSet (ID 0) and the Options Template FlowSet (ID
   1). The Data FlowSets have a FlowSet ID greater than 255.

   The format of the Template, Data, and Options Template FlowSets will
   be discussed later in this document. The Exporter MUST code all
   fields of the different FlowSets in network byte order (big-endian).

   Following are some examples of export packets:

   1. An Export Packet consisting of interleaved Template, Data, and
   Options Template FlowSets-A newly created Template is exported as
   soon as possible. So if there is already an Export Packet with a
   Data FlowSet that is being prepared for export, the Template and
   Option FlowSets are also interleaved with this information, subject
   to availability of space.

   Export Packet:
   +--------+--------------------------------------------------------+
   |        | +----------+ +---------+     +-----------+ +---------+ |
   | Packet | | Template | | Data    |     | Options   | | Data    | |
   | Header | | FlowSet  | | FlowSet | ... | Template  | | FlowSet | |
   |        | |          | |         |     | FlowSet   | |         | |
   |        | +----------+ +---------+     +-----------+ +---------+ |
   +--------+--------------------------------------------------------+

   2. An Export Packet consisting entirely of Data FlowSets-After the
   appropriate Template Records have been defined and transmitted to
   the NetFlow Collector device, the majority of Export Packets
   consists solely of Data FlowSets.

   Export Packet:
   +--------+----------------------------------------------+
   |        | +---------+     +---------+      +---------+ |
   | Packet | | Data    | ... | Data    | ...  | Data    | |
   | Header | | FlowSet | ... | FlowSet | ...  | FlowSet | |
   |        | +---------+     +---------+      +---------+ |


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   +--------+----------------------------------------------+

   3. An Export Packet consisting entirely of Template and Options
   Template FlowSets-The Exporter MAY transmit a packet containing
   Template and Options Template FlowSets periodically to help ensure
   that the NetFlow Collector has the correct Template Records and
   Options Template Records when the corresponding Flow Data records
   are received.

   Export Packet:
   +--------+-------------------------------------------------+
   |        | +----------+     +----------+      +----------+ |
   | Packet | | Template |     | Template |      | Options  | |
   | Header | | FlowSet  | ... | FlowSet  | ...  | Template | |
   |        | |          |     |          |      | FlowSet  | |
   |        | +----------+     +----------+      +----------+ |
   +--------+-------------------------------------------------+

 8. Export Packet Format

 8.1 Header Format

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Version Number          |            Count              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           sysUpTime                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           UNIX Secs                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Sequence Number                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Source ID                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Packet Header Field Descriptions

   Version
           Version of Flow Record format exported in this packet. The
           value of this field is 0x0009 for the current version.

   Count



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           The total number of records in the Export Packet, which is
           the sum of Options FlowSet records, Template FlowSet
           records, and Data FlowSet records.

   SysUpTime
           Time in milliseconds since this device was first booted.
           Refer to [1].

   UNIX Secs
           Seconds since 0000 UTC 1970.

   Sequence Number
           Incremental sequence counter of all Export Packets sent from
           the current Observation Domain by the Exporting Process.
           This value MUST be cumulative, and SHOULD be used by the
           Collector to identify whether any Export Packets have been
           missed.

   Source ID
           A 32-bit value that identifies the Exporter Process
           Observation Domain. Collecting Process SHOULD use the
           combination of the source IP address and the Source ID field
           to separate different export streams originating from the
           same Exporting Process.

 8.2 Template FlowSet Format

   One of the essential elements in the IPFIX format is the Template
   FlowSet. Templates greatly enhance the flexibility of the Flow
   Record format because they allow the Collecting Process to process
   Flow Records without necessarily knowing the interpretation of all
   the data in the Flow Record.

   The format of the Template FlowSet is as follows:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       FlowSet ID = 0          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Template ID 1           |         Field Count           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Field Type 1           |         Field Length 1        |


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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Field Type 2           |         Field Length 2        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             ...               |              ...              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Field Type N           |         Field Length N        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Template ID 2           |         Field Count           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Field Type 1           |         Field Length 1        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Field Type 2           |         Field Length 2        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             ...               |              ...              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Field Type M           |         Field Length M        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             ...               |              ...              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Template ID K          |         Field Count           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             ...               |              ...              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Template FlowSet Field Descriptions

   FlowSet ID
           FlowSet ID value of 0 is reserved for the Template FlowSet.

   Length
           Total length of this FlowSet. Because an individual Template
           FlowSet MAY contain multiple Template Records, the Length
           value MUST be used to determine the position of the next
           FlowSet record, which could be any type of FlowSet. Length
           is the sum of the lengths of the FlowSet ID, the Length
           itself, and all Template Records within this FlowSet.

   Template ID
           Each of the newly generated Template Records is given a
           unique Template ID. This uniqueness is local to the
           Observation Domain that generated the Template ID.
           Template IDs 0-255 are reserved for Template FlowSets,
           Options FlowSets, and other reserved FlowSets yet to be


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           created. Template IDs of Data FlowSets are numbered from 256
           to 65535.

   Field Count
           Number of fields in this Template Record. Because a Template
           FlowSet usually contains multiple Template Records, this
           field allows the Collecting Process to determine the end of
           the current Template Record and the start of the next.

   Field Type
           A numeric value that represents the type of the field. Refer
           to the "Field Type Definitions" section.

   Field Length
           The length of the corresponding Field Type, in bytes. Refer
           to the "Field Type Definitions" section.

 8.3 Data FlowSet Format

   The format of the Data FlowSet is as follows:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    FlowSet ID = Template ID   |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Record 1 - Field Value 1    |   Record 1 - Field Value 2    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Record 1 - Field Value 3    |             ...               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Record 2 - Field Value 1    |   Record 2 - Field Value 2    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Record 2 - Field Value 3    |             ...               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Record 3 - Field Value 1    |             ...               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              ...              |            Padding            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Data FlowSet Field Descriptions

   FlowSet ID = Template ID



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           Each Data FlowSet is associated with a FlowSet ID. The
           FlowSet ID maps to a (previously generated) Template ID. The
           Collecting Process MUST use the FlowSet ID to find the
           corresponding Template Record and decode the Flow Records
           from the FlowSet.

   Length
           The length of this FlowSet.
           Length is the sum total of lengths of FlowSet ID, Length
           itself, all Flow Records within this FlowSet, and the
           padding bytes, if any.

   Record N - Field Value M
           The remainder of the Data FlowSet is a collection of Flow
           Data Record(s), each containing a set of field types and
           values. The Type and Length of the fields have been
           previously defined in the Template Record referenced by the
           FlowSet ID or Template ID.

   Padding
           The Exporting Process SHOULD insert some padding bytes so
           that the subsequent FlowSet starts at a 4-byte aligned
           boundary. It is important to note that the Length field
           includes the padding bits.

   Interpretation of the Data FlowSet format can be done only if the
   Template FlowSet corresponding to the Template ID is available at
   the Collecting Process.

 9. Options

 9.1 Options Template FlowSet Format

   The Options Template Record (and its corresponding Options Data
   Record) is used to supply information about the Metering Process
   configuration or Metering Process specific data, rather than
   supplying information about IP Flows.
   For example, the Options Template FlowSet can report the sample rate
   of a specific interface, if sampling is supported, along with the
   sampling method used.

   The format of the Options Template FlowSet follows.




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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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       FlowSet ID = 1          |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Template ID           |      Option Scope Length      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Option Length          |       Scope 1 Field Type      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Scope 1 Field Length      |               ...             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Scope N Field Length      |      Option 1 Field Type      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Option 1 Field Length     |             ...               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Option M Field Length     |           Padding             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Options Template FlowSet Field Definitions

   FlowSet ID = 1
           A FlowSet ID value of 1 is reserved for the Options
           Template.

   Length
           Total length of this FlowSet. Each Options Template FlowSet
           MAY contain multiple Options Template Records. Thus, the
           Length value MUST be used to determine the position of the
           next FlowSet record, which could be either a Template
           FlowSet or Data FlowSet.
           Length is the sum total of lengths of FlowSet ID, the Length
           itself, and all Options Template Records within this FlowSet
           Template ID.

   Template ID
           Template ID of this Options Template. This value is greater
           than 255.

   Option Scope Length
           The length in bytes of any Scope fields definition contained
           in the Options Template Record (The use of "Scope" is
           described below).



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   Option Length
           The length (in bytes) of any options field definitions
           contained in this Options Template Record.

   Scope 1 Field Type
           The relevant portion of the Exporting Process/Metering
           Process to which the Options Template Record refers.
           Currently defined values are:
               1 System
               2 Interface
               3 Line Card
               4 Cache
               5 Template
           For example, the Metering Process can be implemented on a
           per-interface basis, so if the Options Template Record were
           reporting on how the NetFlow process is configured, the
           Scope for the report would be 2 (interface). The associated
           interface ID would then be carried in the associated Options
           Data FlowSet. The Scope can be limited further by listing
           multiple scopes that all must match at the same time. Note
           that the Scope fields always precede the Option fields.


   Scope 1 Field Length
           The length (in bytes) of the Scope field, as it would appear
           in an Options Data Record.

   Option 1 Field Type
           A numeric value that represents the type of field that would
           appear in the Options Template Record. Refer to the Field
           Type Definitions section.

   Option 1 Field Length
           The length (in bytes) of the Option Field.

   Padding
           The Exporting Process SHOULD insert some padding bytes so
           that the subsequent FlowSet starts at a 4-byte aligned
           boundary. It is important to note that the Length field
           includes the padding bits.

 9.2 Options Data Record Format



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   The Options Data Records are sent in Data FlowSets, on a regular
   basis, but not with every Flow Data Record. How frequently these
   Options Data Records are exported is configurable. See the Templates
   Management" section for more details.

   The format of the Data FlowSet containing Options Data Records
   follows.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    FlowSet ID = Template ID   |          Length               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Record 1 - Scope 1 Value    |Record 1 - Option Field 1 Value|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Record 1 - Option Field 2 Value|             ...               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Record 2 - Scope 1 Value    |Record 2 - Option Field 1 Value|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Record 2 - Option Field 2 Value|             ...               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Record 3 - Scope 1 Value    |Record 3 - Option Field 1 Value|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |Record 3 - Option Field 2 Value|             ...               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              ...              |            Padding            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Options Data Records of the Data FlowSet Field Descriptions

   FlowSet ID = Template ID
           A FlowSet ID precedes each group of Options Data Records
           within a Data FlowSet. The FlowSet ID maps to a previously
           generated Template ID corresponding to this Options Template
           Record. The Collecting Process MUST use the FlowSet ID to
           map the appropriate type and length to any field values that
           follow.

   Length
           The length of this FlowSet.
           Length is the sum of the lengths of the FlowSet ID, Length
           itself, all the Options Data Records within this FlowSet,
           and the padding bytes, if any.


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   Record N - Option Field M Value
           The remainder of the Data FlowSet is a collection of Flow
           Records, each containing a set of scope and field values.
           The type and length of the fields were previously defined in
           the Options Template Record referenced by the FlowSet ID or
           Template ID.

   Padding
           The Exporting Process SHOULD insert some padding bytes so
           that the subsequent FlowSet starts at a 4-byte aligned
           boundary. It is important to note that the Length field
           includes the padding bits.

   The Data FlowSet format can be interpreted only if the Options
   Template FlowSet corresponding to the Template ID is available at
   the Collecting Process.

 10. Variable Length Data Type

   Note: this section reflects the mailing list ideas but the wording
   should be worked on.

   In the Template Flowset (template definition), let's put FFFF for
   the length of the variable length data types.  Then, the actual
   length is encoded in data Flowset (Flow Records) as follows:
   - if length is < 255 bytes, the length is stored in 1 byte
   - if length is >=255 bytes, 255 is stored in the first byte, and the
   actual 16 bits length is stored in the next 2 bytes.

   The cases of length of >= 255 will be very rear. And even in these
   cases, one extra byte will represent <= 1/255-th part of data
   record.

   Why FFFF and not 0?
   The reason for this is that FFFF is a truly invalid value which
   should be caught in collectors, by good implementations, today. For
   0 this isn't necessary the case as it's meaning is "just" pointless,
   but not a course of concern for the collectors.
   Basically FFFF should make the Collecting Process (current
   implementations) discard the template as being invalid.
   Note also that some option templates data types could potentially
   have a length of 0.


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   So the advantages of this proposal are:
   - code the length on 1 byte for most of the cases;  in that case, we
   use the 8 bits to code the length, so with a max of 254 bytes
    (because 255 is reserved)
   - if the length is above 254, we use 3 bytes, the last 2 bytes could
   transport a length of max 64 k - 7 bytes (in the Data FlowSet, 2 for
   the FlowSet ID + 2 for the FlowSet Length + 1 byte for "0xff" + 2
   for the variable length)

 11. Template Management

   Flow Data records that correspond to a Template Record MAY appear in
   the same and/or subsequent Export Packets. The Template Record is
   not necessarily carried in every Export Packet. As such, the
   Collecting Process MUST store the Template Record to interpret the
   corresponding Flow Data Records that are received in subsequent data
   packets.

   A Collecting Process that receives Export Packets from several
   Observation Domains from the same Exporter MUST be aware that the
   uniqueness of the Template ID is not guaranteed across Observation
   Domains.

   The Template IDs must remain constant for the life of the Metering
   Process and the Exporting Process. If the Exporting Process or the
   Metering Process restarts for any reason, all information about
   Templates will be lost and new Template IDs will be created.
   Template IDs are thus not guaranteed to be consistent across an
   Exporting Process or Metering Process restart.

   A newly created Template record is assigned an unused Template ID
   from the Exporter. If the template configuration is changed, the
   current Template ID is abandoned and SHOULD NOT be reused until the
   Metering Process. If a Collecting Process should receive a new
   definition for an already existing Template ID, it MUST discard the
   previous template definition and use the new one.

   If a configured Template Record on the Exporting Process is deleted,
   and re-configured with exactly the same parameters, the same
   Template ID COULD be reused.




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   The Exporting Process sends the Template FlowSet and Options
   Template FlowSet under the following conditions:

    1. After a NetFlow process restarts, the Exporting Process MUST NOT
       send any Data FlowSet without sending the corresponding Template
       FlowSet and the required Options Template FlowSet in a previous
       packet or including it in the same Export Packet. It MAY
       transmit the Template FlowSet and Options Template FlowSet,
       without any Data FlowSets, in advance to help ensure that the
       Collector will have the correct Template Record before receiving
       the first Flow or Options Data Record.

    2. In the event of configuration changes, the Exporting Process
       SHOULD send the new template definitions at an accelerated rate.
       In such a case, it MAY transmit the changed Template Record(s)
       and Options Template Record(s), without any data, in advance to
       help ensure that the Collector will have the correct template
       information before receiving the first data.

    3. On a regular basis, the Exporting Process MUST send all the
       Template Records and Options Template Records to refresh the
       Collecting Process. Template IDs have a limited lifetime at the
       Collecting Process and MUST be periodically refreshed.
       Two approaches are taken to make sure that Templates get
       refreshed at the Collecting Process:
          * Every N number of Export Packets.
          * On a time basis, so every N number of minutes.
       Both options MUST be configurable by the user on the Exporting
       Porcess.
       When one of these expiry conditions is met, the Exporting
       Process MUST send the Template FlowSet and Options Template.

 12. The Collecting Process's Side

   The Collecting Process receives Template Records from the Exporting
   Process, normally before receiving Flow Data Records (or Options
   Data Records). The Flow Data Records (or Options Data Records) can
   then be decoded and stored locally on the devices. If the Template
   Records have not been received at the time Flow Data Records (or
   Options Data Records) are received, the Collecting Process SHOULD
   store the Flow Data Records (or Options Data Records) and decode
   them after the Template Records are received. A Collecting Process
   device MUST NOT assume that the Data FlowSet and the associated


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   Template FlowSet (or Options Template FlowSet) are exported in the
   same Export Packet.

   The Collecting Process MUST NOT assume that one and only one
   Template FlowSet is present in an Export Packet.

   The life of a template at the Collecting Process is limited to a
   fixed refresh timeout. Templates not refreshed from the Exporting
   Process within the timeout are expired at the Collecting Process.
   The Collecting Process MUST NOT attempt to decode the Flow or
   Options Data Records with an expired Template. At any given time the
   Collecting Process SHOULD maintain the following for all the current
   Template Records and Options Template Records: <Exporting Process,
   Observation Domain, Template ID, Template Definition, Last Received>
   Note that the Observation Domain is identified by the Source ID
   field from the Export Packet.

   Template IDs are unique per Exporting Process and per Observation
   Domain.

   If the Collecting Process receives a new Template Record (for
   example, in the case of an Exporter restart) it MUST immediately
   override the existing Template Record.

   Finally, note that the Collector MUST accept padding in the Data
   FlowSet and Options Template FlowSet, which means for the Flow Data
   Records, the Options Data Records and the Template Records.
   Refer to the terminology summary table in Section 3.1.

 13. Examples

   Let's consider the example of an Export Packet composed of a
   Template FlowSet, a Data FlowSet (which contains three Flow Data
   Records), an Options Template FlowSet and a Data FlowSet (which
   contains 2 Options Data Records).

   Export Packet:
   +--------+---------------------------------------------. . .
   |        | +--------------+ +-----------------------+
   | Packet | | Template     | | Data                  |
   | Header | | FlowSet      | | FlowSet               |   . . .
   |        | | (1 Template) | | (3 Flow Data Records) |
   |        | +--------------+ +-----------------------+


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   +--------+---------------------------------------------. . .

       . . .+-------------------------------------------------+
            +------------------+ +--------------------------+ |
            | Options          | | Data                     | |
       . . .| Template FlowSet | | FlowSet                  | |
            | (1 Template)     | | (2 Options Data Records) | |
            +------------------+ +--------------------------+ |
       . . .--------------------------------------------------+

 13.1 Packet Header Example

   The Packet Header is composed of:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Version = 0x0009          |          Count = 7            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           sysUpTime                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           UNIX Secs                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Sequence Number                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Source ID                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 13.2 Template FlowSet Example

   We want to report the following Field Types:
   - The source IP address (IPv4), so the length is 4
   - The destination IP address (IPv4), so the length is 4
   - The next-hop IP address (IPv4), so the length is 4
   - The number of bytes of the Flow
   - The number of packets of the Flow

   Therefore, the Template FlowSet will be composed of the following:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       FlowSet ID = 0          |      Length = 28 bytes        |



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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Template ID 256         |       Field Count = 5         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     IP_SRC_ADDR = 0x0008      |       Field Length = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     IP_DST_ADDR = 0x000C      |       Field Length = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     IP_NEXT_HOP = 0x000F      |       Field Length = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       IN_PKTS = 0x0002        |       Field Length = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       IN_BYTES = 0x0001       |       Field Length = 4        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 13.3 Data FlowSet Example

   In this example, we report the following three Flow records:

   Src IP addr. | Dst IP addr. | Next Hop addr. | Packet | Bytes
                |              |                | Number | Number
   ---------------------------------------------------------------
   198.168.1.12 | 10.5.12.254  | 192.168.1.1    | 5009   | 5344385
   192.168.1.27 | 10.5.12.23   | 192.168.1.1    | 748    | 388934
   192.168.1.56 | 10.5.12.65   | 192.168.1.1    | 5      | 6534

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       FlowSet ID = 256        |          Length = 64          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          198.168.1.12                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          10.5.12.254                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          192.168.1.1                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             5009                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            5344385                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          192.168.1.27                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           10.5.12.23                          |


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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          192.168.1.1                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              748                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             388934                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          192.168.1.56                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           10.5.12.65                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           192.168.1.1                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                               5                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              6534                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Note that padding was not necessary in this example.

 13.4 Options Template FlowSet Example

   Per line card (the router being composed of two line cards), we want
   to report the following Field Types:
   - Total number of Export Packets
   - Total number of exported Flows

   The format of the Options Template FlowSet is as follows:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       FlowSet ID = 1          |          Length = 24          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Template ID 257         |    Option Scope Length = 4    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Option Length = 8       |  Scope 1 Field Type = 0x0003  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Scope 1 Field Length = 2    |   TOTAL_EXP_PKTS_SENT = 41    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Field Length = 4        |     TOTAL_FLOWS_EXP = 42      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Field Length = 4        |           Padding             |


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   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 13.5 Data FlowSet with Options Data Records Example

   In this example, we report the following two records:

   Line Card ID | Export Packet| Export Flow
   ------------------------------------------
   Line Card 1  | 345          | 10201
   Line Card 2  | 690          | 20402

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    FlowSet ID = 257           |         Length = 14           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             1                 |             345               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           10201               |              2                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             2                 |             690               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           20402               |           Padding             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

 14. References

   [1]  R. Presuhn et al, "Management Information Base (MIB) for the
   Simple Network Management Protocol (SNMP)" RFC 3418, December 2002

   [2]  J. Postel, "User Datagram Protocol" RFC 768, August 1980

   [3]  "TRANSMISSION CONTROL PROTOCOL DARPA INTERNET PROGRAM PROTOCOL
   SPECIFICATION" RFC 793, September 1981

   [IPFIX-REQ] J. Quittek, T. Zseby, B. Claise, S. Zander,
   "Requirements for IP Flow Information Export" draft-ietf-ipfix-reqs-
   10.txt, June 2003

   [IPFIX-ARCH] Sadasivan, G, Brownlee, N. "Architecture Model for IP
   Flow Information Export" draft-ietf-ipfix-arch-01.txt", June 2003





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   [IPFIX-INFO] Calato, P, Meyer, J, Quittek, J, "Information Model for
   IP Flow Information Export" draft-ietf-ipfix-info-01, August 2003

   [IPFIX-PROTO] Claise, B, Fullmer, M, Calato, P, Penno, R, "IPFIX
   Protocol Specifications", draft-ietf-ipfix-protocol-00.txt, June
   2003

   [RFC2960] Stewart, R. (ed.) "Stream Control Transmission Protocol",
   RFC 2960, October 2000

   [PR-SCTP] Stewart, R, "SCTP Partial Reliability Extension", draft-
   stewart-tsvwg-prsctp-04.txt

   [NETFLOW9] Claise, B, et al "Cisco Systems NetFlow Services Export
   Version 9", draft-claise-netflow-9-06.txt, October 2003

5. Acknowledgments

   To be completed.

uthors Addresses

   Benoit Claise
   Cisco Systems
   De Kleetlaan 6a b1
   1831 Diegem
   Belgium
   Phone: +32 2 704 5622
   E-mail: bclaise@cisco.com

   Mark Fullmer
   OARnet
   2455 North Star Rd.
   Columbus, Ohio 43221
   Phone: +1 (614) 728-8100
   Email: maf@eng.oar.net

   Reinaldo Penno
   Nortel Networks
   2305 Mission College Blvd
   Santa Clara, CA 95054
   Phone: +1 408.565.3023
   Email: rpenno@nortelnetworks.com



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                  IPFIX Protocol Specifications          October 2003



   Paul Calato
   Riverstone Networks, Inc.
   5200 Great America Parkway
   Santa Clara, CA 95054  USA
   Phone:  +1 (603) 557-6913
   Email: calato@riverstonenet.com











































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