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rfc:rfc5655

Network Working Group B. Trammell Request for Comments: 5655 E. Boschi Category: Standards Track Hitachi Europe

                                                               L. Mark
                                                       Fraunhofer IFAM
                                                              T. Zseby
                                                      Fraunhofer FOKUS
                                                             A. Wagner
                                                            ETH Zurich
                                                          October 2009
Specification of the IP Flow Information Export (IPFIX) File Format

Abstract

 This document describes a file format for the storage of flow data
 based upon the IP Flow Information Export (IPFIX) protocol.  It
 proposes a set of requirements for flat-file, binary flow data file
 formats, then specifies the IPFIX File format to meet these
 requirements based upon IPFIX Messages.  This IPFIX File format is
 designed to facilitate interoperability and reusability among a wide
 variety of flow storage, processing, and analysis tools.

Status of This Memo

 This document specifies an Internet standards track protocol for the
 Internet community, and requests discussion and suggestions for
 improvements.  Please refer to the current edition of the "Internet
 Official Protocol Standards" (STD 1) for the standardization state
 and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

 Copyright (c) 2009 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (http://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the BSD License.

Trammell, et al. Standards Track [Page 1] RFC 5655 IPFIX Files October 2009

Table of Contents

 1. Introduction ....................................................4
    1.1. IPFIX Documents Overview ...................................4
 2. Terminology .....................................................5
 3. Design Overview .................................................6
 4. Motivation ......................................................7
 5. Requirements ...................................................10
    5.1. Record Format Flexibility .................................10
    5.2. Self-Description ..........................................10
    5.3. Data Compression ..........................................11
    5.4. Indexing and Searching ....................................11
    5.5. Error Recovery ............................................12
    5.6. Authentication, Confidentiality, and Integrity ............12
    5.7. Anonymization and Obfuscation .............................13
    5.8. Session Auditability and Replayability ....................13
    5.9. Performance Characteristics ...............................14
 6. Applicability ..................................................14
    6.1. Storage of IPFIX-Collected Flow Data ......................14
    6.2. Storage of NetFlow-V9-Collected Flow Data .................15
    6.3. Testing IPFIX Collecting Processes ........................15
    6.4. IPFIX Device Diagnostics ..................................16
 7. Detailed File Format Specification .............................16
    7.1. File Reader Specification .................................16
    7.2. File Writer Specification .................................17
    7.3. Specific File Writer Use Cases ............................18
         7.3.1. Collocating a File Writer with a Collecting
                Process ............................................18
         7.3.2. Collocating a File Writer with a Metering Process ..19
         7.3.3. Using IPFIX Files for Archival Storage .............20
         7.3.4. Using IPFIX Files as Documents .....................20
         7.3.5. Using IPFIX Files for Testing ......................21
         7.3.6. Writing IPFIX Files for Device Diagnostics .........22
         7.3.7. IPFIX File Manipulation ............................22
    7.4. Media Type of IPFIX Files .................................22
 8. File Format Metadata Specification .............................22
    8.1. Recommended Options Templates for IPFIX Files .............22
         8.1.1. Message Checksum Options Template ..................23
         8.1.2. File Time Window Options Template ..................23
         8.1.3. Export Session Details Options Template ............24
         8.1.4. Message Details Options Template ...................26
    8.2. Recommended Information Elements for IPFIX Files ..........29
         8.2.1. collectionTimeMilliseconds .........................29
         8.2.2. collectorCertificate ...............................29
         8.2.3. exporterCertificate ................................29
         8.2.4. exportSctpStreamId .................................30
         8.2.5. maxExportSeconds ...................................30
         8.2.6. maxFlowEndMicroseconds .............................30

Trammell, et al. Standards Track [Page 2] RFC 5655 IPFIX Files October 2009

         8.2.7. maxFlowEndMilliseconds .............................31
         8.2.8. maxFlowEndNanoseconds ..............................31
         8.2.9. maxFlowEndSeconds ..................................32
         8.2.10. messageMD5Checksum ................................32
         8.2.11. messageScope ......................................32
         8.2.12. minExportSeconds ..................................33
         8.2.13. minFlowStartMicroseconds ..........................33
         8.2.14. minFlowStartMilliseconds ..........................34
         8.2.15. minFlowStartNanoseconds ...........................34
         8.2.16. minFlowStartSeconds ...............................34
         8.2.17. opaqueOctets ......................................35
         8.2.18. sessionScope ......................................35
 9. Signing and Encryption of IPFIX Files ..........................36
    9.1. CMS Detached Signatures ...................................36
         9.1.1. ContentInfo ........................................37
         9.1.2. SignedData .........................................38
         9.1.3. SignerInfo .........................................38
         9.1.4. EncapsulatedContentInfo ............................39
    9.2. Encryption Error Resilience ...............................39
 10. Compression of IPFIX Files ....................................39
    10.1. Supported Compression Formats ............................40
    10.2. Compression Recognition at the File Reader ...............40
    10.3. Compression Error Resilience .............................40
 11. Recommended File Integration Strategies .......................41
    11.1. Encapsulation of Non-IPFIX Data in IPFIX Files ...........41
    11.2. Encapsulation of IPFIX Files within Other File Formats ...42
 12. Security Considerations .......................................42
    12.1. Relationship between IPFIX File and Transport
          Encryption ...............................................43
    12.2. End-to-End Assertions for IPFIX Files ....................43
    12.3. Recommendations for Strength of Cryptography for
          IPFIX Files ..............................................44
 13. IANA Considerations ...........................................44
 14. Acknowledgements ..............................................46
 15. References ....................................................47
    15.1. Normative References .....................................47
    15.2. Informative References ...................................48
 Appendix A.  Example IPFIX File ...................................49
   A.1.  Example Options Templates .................................50
   A.2.  Example Supplemental Options Data .........................52
   A.3.  Example Message Checksum ..................................54
   A.4.  File Example Data Set .....................................55
   A.5.  Complete File Example .....................................55
 Appendix B.  Applicability of IPFIX Files to NetFlow V9 Flow
              Storage ..............................................57
   B.1.  Comparing NetFlow V9 to IPFIX .............................57
     B.1.1.  Message Header Format .................................57
     B.1.2.  Set Header Format .....................................58

Trammell, et al. Standards Track [Page 3] RFC 5655 IPFIX Files October 2009

     B.1.3.  Template Format .......................................59
     B.1.4.  Information Model .....................................59
     B.1.5.  Template Management ...................................59
     B.1.6.  Transport .............................................59
   B.2.  A Method for Transforming NetFlow V9 Messages to IPFIX ....60
   B.3.  NetFlow V9 Transformation Example .........................61

1. Introduction

 This document specifies a file format based upon IPFIX, designed to
 facilitate interoperability and reusability among a wide variety of
 flow storage, processing, and analysis tools.  It begins with an
 overview of the IPFIX File format, and a quick summary of how IPFIX
 Files work in Section 3.  The detailed specification of the IPFIX
 File format appears in Section 7; this section includes general
 specifications for IPFIX File Readers and IPFIX File Writers and
 specific recommendations for common situations in which they are
 used.  The format makes use of the IPFIX Options mechanism for
 additional file metadata, in order to avoid requiring any protocol
 extensions, and to minimize the effort required to adapt IPFIX
 implementations to use the file format; a detailed definition of the
 Options Templates used for storage metadata appears in Section 8.
 Appendix A contains a detailed example IPFIX File.
 An advantage of file-based storage is that files can be readily
 encapsulated within each other and other data storage and
 transmission formats.  The IPFIX File format leverages this to
 provide encryption, described in Section 9 and compression, described
 in Section 10.  Section 11 provides specific recommendations for
 integration of IPFIX File data with other formats.
 The IPFIX File format was designed to be applicable to a wide variety
 of flow storage situations; the motivation behind its creation is
 described in Section 4.  The document outlines of the set of
 requirements the format is designed to meet in Section 5, and
 explores the applicability of such a format to various specific
 application areas in Section 6.  These sections are intended to give
 background on the development of IPFIX Files.

1.1. IPFIX Documents Overview

 "Specification of the IP Flow Information Export (IPFIX) Protocol for
 the Exchange of IP Traffic Flow Information" [RFC5101] and its
 associated documents define the IPFIX protocol, which provides
 network engineers and administrators with access to IP traffic flow
 information.

Trammell, et al. Standards Track [Page 4] RFC 5655 IPFIX Files October 2009

 "Architecture for IP Flow Information Export" [RFC5470] defines the
 architecture for the export of measured IP flow information out of an
 IPFIX Exporting Process to an IPFIX Collecting Process, and the basic
 terminology used to describe the elements of this architecture, per
 the requirements defined in "Requirements for IP Flow Information
 Export" [RFC3917].  [RFC5101] then covers the details of the method
 for transporting IPFIX Data Records and Templates via a congestion-
 aware transport protocol from an IPFIX Exporting Process to an IPFIX
 Collecting Process.
 "Information Model for IP Flow Information Export" [RFC5102]
 describes the Information Elements used by IPFIX, including details
 on Information Element naming, numbering, and data type encoding.
 "IP Flow Information Export (IPFIX) Applicability" [RFC5472]
 describes the various applications of the IPFIX protocol and their
 use of information exported via IPFIX, and it relates the IPFIX
 architecture to other measurement architectures and frameworks.
 In addition, "Exporting Type Information for IP Flow Information
 Export (IPFIX) Information Elements" [RFC5610] specifies a method for
 encoding Information Model properties within an IPFIX Message stream.
 This document references [RFC5101] and [RFC5470] for terminology,
 defines IPFIX File Writer and IPFIX File Reader in terms of the IPFIX
 Exporting Process and IPFIX Collecting Process definitions from
 [RFC5101], and extends the IPFIX Information Model defined in
 [RFC5102] to provide new Information Elements for IPFIX File
 metadata.  It uses the method described in [RFC5610] to support the
 self-description of IPFIX Files containing enterprise-specific
 Information Elements.

2. Terminology

 This section defines terminology related to the IPFIX File format.
 In addition, terms used in this document that are defined in the
 "Terminology" section of [RFC5101] are to be interpreted as defined
 there.
 IPFIX File:   An IPFIX File is a serialized stream of IPFIX Messages;
    this stream may be stored on a filesystem or transported using any
    technique customarily used for files.  Any IPFIX Message stream
    that would be considered valid when transported over one or more
    of the specified IPFIX transports (Stream Control Transmission
    Protocol (SCTP), TCP, or UDP) as defined in [RFC5101] is

Trammell, et al. Standards Track [Page 5] RFC 5655 IPFIX Files October 2009

    considered an IPFIX File.  However, this document extends that
    definition with recommendations on the construction of IPFIX Files
    that meet the requirements identified in Section 5.
 IPFIX File Reader:   An IPFIX File Reader is a process that reads
    IPFIX Files from a filesystem.  An IPFIX File Reader operates as
    an IPFIX Collecting Process as specified in [RFC5101], except as
    modified by this document.
 IPFIX File Writer:   An IPFIX File Writer is a process that writes
    IPFIX Files to a filesystem.  An IPFIX File Writer operates as an
    IPFIX Exporting Process as specified in [RFC5101], except as
    modified by this document.
 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 [RFC2119].

3. Design Overview

 An IPFIX File is simply a data stream containing one or more IPFIX
 Messages serialized to some filesystem.  Though any set of valid
 IPFIX Messages can be serialized into an IPFIX File, the
 specification includes guidelines designed to ease storage and
 retrieval of flow data using the IPFIX File format.
 IPFIX Files contain only IPFIX Messages; any file metadata such as
 checksums or export session details are stored using Options within
 the IPFIX Message.  This design is completely compatible with the
 IPFIX protocol on the wire.  A schematic of a typical IPFIX File is
 shown below:

Trammell, et al. Standards Track [Page 6] RFC 5655 IPFIX Files October 2009

           +=======================================+
           | IPFIX File                            |
           | +===================================+ |
           | | IPFIX Message                     | |
           | | +-------------------------------+ | |
           | | | IPFIX Message Header          | | |
           | | +-------------------------------+ | |
           | | +-------------------------------+ | |
           | | | Options Template Set          | | |
           | | |   Options Template Record     | | |
           | | |           . . .               | | |
           | | +-------------------------------+ | |
           | | +-------------------------------+ | |
           | | | Template Set                  | | |
           | | |   Template Record             | | |
           | | |            . . .              | | |
           | | +-------------------------------+ | |
           | +===================================+ |
           | | IPFIX Message                     | |
           | | +-------------------------------+ | |
           | | | IPFIX Message Header          | | |
           | | +-------------------------------+ | |
           | | +-------------------------------+ | |
           | | | Data Set                      | | |
           | | |   Data Record                 | | |
           | | |            . . .              | | |
           | | +-------------------------------+ | |
           | | +-------------------------------+ | |
           | | | Data Set                      | | |
           | | |   Data Record                 | | |
           | | |            . . .              | | |
           | | +-------------------------------+ | |
           | |              . . .                | |
           | +===================================+ |
           |                . . .                  |
           +=======================================+
                   Figure 1: Typical File Structure

4. Motivation

 There is a wide variety of applications for the file-based storage of
 IP flow data, across a continuum of time scales.  Tools used in the
 analysis of flow data and creation of analysis products often use
 files as a convenient unit of work, with an ephemeral lifetime.  A
 set of flows relevant to a security investigation may be stored in a
 file for the duration of that investigation, and further exchanged
 among incident handlers via email or within an external incident

Trammell, et al. Standards Track [Page 7] RFC 5655 IPFIX Files October 2009

 handling workflow application.  Sets of flow data relevant to
 Internet measurement research may be published as files, much as
 libpcap [pcap] packet trace files are, to provide common datasets for
 the repeatability of research efforts; these files would have
 lifetimes measured in months or years.  Operational flow measurement
 systems also have a need for long-term, archival storage of flow
 data, either as a primary flow data repository, or as a backing tier
 for online storage in a relational database management system
 (RDBMS).
 The variety of applications of flow data, and the variety of
 presently deployed storage approaches, indicates the need for a
 standard approach to flow storage with applicability across the
 continuum of time scales over which flow data is stored.  A storage
 format based around flat files would best address the variety of
 storage requirements.  While much work has been done on structured
 storage via RDBMS, relational database systems are not a good basis
 for format standardization owing to the fact that their internal data
 structures are generally private to a single implementation and
 subject to change for internal reasons.  Also, there are a wide
 variety of operations available on flat files, and external tools and
 standards can be leveraged to meet file-based flow storage
 requirements.  Further, flow data is often not very semantically
 complicated, and is managed in very high volume; therefore, an RDBMS-
 based flow storage system would not benefit much from the advantages
 of relational database technology.
 The simplest way to create a new file format is simply to serialize
 some internal data model to disk, with either textual or binary
 representation of data elements, and some framing strategy for
 delimiting fields and records.  "Ad hoc" file formats such as this
 have several important disadvantages.  They impose the semantics of
 the data model from which they are derived on the file format, and as
 such, they are difficult to extend, describe, and standardize.
 Indeed, one de facto standard for the storage of flow data is one of
 these ad hoc formats.  A common method of storing data collected via
 Cisco NetFlow is to serialize a stream of raw NetFlow datagrams into
 files.  These NetFlow PDU files consist of a collection of header-
 prefixed blocks (corresponding to the datagrams as received on the
 wire) containing fixed-length binary flow records.  NetFlow V5, V7,
 and V8 data may be mixed within a given file, as the header on each
 datagram defines the NetFlow version of the records following.  While
 this NetFlow PDU file format has all the disadvantages of an ad hoc
 format, and is not extensible to data models other than that defined
 by Cisco NetFlow, it is at least reasonably well understood due to
 its ubiquity.

Trammell, et al. Standards Track [Page 8] RFC 5655 IPFIX Files October 2009

 Over the past decade, XML has emerged as a new "universal"
 representation format for structured data.  It is intended to be
 human readable; indeed, that is one reason for its rapid adoption.
 However, XML has limited usefulness for representing network flow
 data.  Network flow data has a simple, repetitive, non-hierarchical
 structure that does not benefit much from XML.  An XML representation
 of flow data would be an essentially flat list of the attributes and
 their values for each flow record.
 The XML approach to data encoding is very heavyweight when compared
 to binary flow encoding.  XML's use of start- and end-tags, and
 plaintext encoding of the actual values, leads to significant
 inefficiency in encoding size.  Typical network traffic datasets can
 contain millions or billions of flows per hour of traffic
 represented.  Any increase in storage size per record can have
 dramatic impact on flow data storage and transfer sizes.  While data
 compression algorithms can partially remove the redundancy introduced
 by XML encoding, they introduce additional overhead of their own.
 A further problem is that XML processing tools require a full XML
 parser.  XML parsers are fully general and therefore complex,
 resource-intensive, and relatively slow, introducing significant
 processing time overhead for large network-flow datasets.  In
 contrast, parsers for typical binary flow data encodings are simply
 structured, since they only need to parse a very small header and
 then have complete knowledge of all following fields for the
 particular flow.  These can then be read in a very efficient linear
 fashion.
 This leads us to propose the IPFIX Message format as the basis for a
 new flow data file format.  The IPFIX Working Group, in defining the
 IPFIX protocol, has already defined an information model and data
 formatting rules for representation of flow data.  Especially at
 shorter time scales, when a file is a unit of data interchange, the
 filesystem may be viewed as simply another IPFIX Message transport
 between processes.  This format is especially well suited to
 representing flow data, as it was designed specifically for flow data
 export; it is easily extensible, unlike ad hoc serialization, and
 compact, unlike XML.  In addition, IPFIX is an IETF Standards-Track
 protocol for the export and collection of flow data; using a common
 format for storage and analysis at the collection side allows
 implementors to use substantially the same information model and data
 formatting implementation for transport as well as storage.

Trammell, et al. Standards Track [Page 9] RFC 5655 IPFIX Files October 2009

5. Requirements

 In this section, we outline a proposed set of requirements
 [SAINT2007] for any persistent storage format for flow data.  First
 and foremost, a flow data file format should support storage across
 the continuum of time scales important to flow storage applications.
 Each of the requirements enumerated in the sections below is broadly
 applicable to flow storage applications, though each may be more
 important at certain time scales.  For each, we first identify the
 requirement, then explain how the IPFIX Message format addresses it,
 or briefly outline the changes that must be made in order for an
 IPFIX-based file format to meet the requirement.

5.1. Record Format Flexibility

 Due to the wide variety of flow attributes collected by different
 network flow attribute measurement systems, the ideal flow storage
 format will not impose a single data model or a specific record type
 on the flows it stores.  The file format must be flexible and
 extensible; that is, it must support the definition of multiple
 record types within the file itself, and must be able to support new
 field types for data within the records in a graceful way.
 IPFIX provides record format flexibility through the use of Templates
 to describe each Data Record, through the use of an IANA Registry to
 define its Information Elements, and through the use of enterprise-
 specific Information Elements.

5.2. Self-Description

 Archived data may be read at a time in the future when any external
 reference to the meaning of the data may be lost.  The ideal flow
 storage format should be self-describing; that is, a process reading
 flow data from storage should be able to properly interpret the
 stored flows without reference to anything other than standard
 sources (e.g., the standards document describing the file format) and
 the stored flow data itself.
 The IPFIX Message format is partially self-describing; that is, IPFIX
 Templates containing only IANA-assigned Information Elements can be
 completely interpreted according to the IPFIX Information Model
 without additional external data.
 However, Templates containing private information elements lack
 detailed type and semantic information; a Collecting Process
 receiving Data Records described by a Template containing enterprise-
 specific Information Elements it does not understand can only treat
 the data contained within those Information Elements as octet arrays.

Trammell, et al. Standards Track [Page 10] RFC 5655 IPFIX Files October 2009

 To be fully self-describing, enterprise-specific Information Elements
 must be additionally described via IPFIX Options according to the
 Information Element Type Options Template defined in [RFC5610].

5.3. Data Compression

 Regardless of the representation format, flow data describing traffic
 on real networks tends to be highly compressible.  Compression tends
 to improve the scalability of flow collection systems, by reducing
 the disk storage and I/O bandwidth requirement for a given workload.
 The ideal flow storage format should support applications that wish
 to leverage this fact by supporting compression of stored data.
 The IPFIX Message format has no support for data compression, as the
 IPFIX protocol was designed for speed and simplicity of export.  Of
 course, any flat file is readily compressible using a wide variety of
 external data compression tools, formats, and algorithms; therefore,
 this requirement can be met via encapsulation in one of these
 formats.  Section 10 specifies an encapsulation based on bzip2 or
 gzip, to maximize interoperability.
 A few simple optimizations can be made by File Writers to increase
 the integrity and usability of compressed IPFIX data; these are
 outlined in Section 10.3.

5.4. Indexing and Searching

 Binary, record-stream-oriented file formats natively support only one
 form of searching: sequential scan in file order.  By choosing the
 order of records in a file carefully (e.g., by flow end time), a file
 can be indexed by a single key.
 Beyond this, properly addressing indexing is an application-specific
 problem, as it inherently involves trade-offs between storage
 complexity and retrieval speed, and requirements vary widely based on
 time scales and the types of queries used from site to site.
 However, a generic standard flow storage format may provide limited
 direct support for indexing and searching.
 The ideal flow storage format will support a limited table of
 contents facility noting that the records in a file contain data
 relating only to certain keys or values of keys, in order to keep
 multi-file search implementations from having to scan a file for data
 it does not contain.
 The IPFIX Message format has no direct support for indexing.
 However, the technique described in "Reducing Redundancy in IP Flow
 Information Export (IPFIX) and Packet Sampling (PSAMP) Reports"

Trammell, et al. Standards Track [Page 11] RFC 5655 IPFIX Files October 2009

 [RFC5473] can be used to describe the contents of a file in a limited
 way.  Additionally, as flow data is often sorted and divided by time,
 the start and end time of the flows in a file may be declared using
 the File Time Window Options Template defined in Section 8.1.2.

5.5. Error Recovery

 When storing flow data for archival purposes, it is important to
 ensure that hardware or software faults do not introduce errors into
 the data over time.  The ideal flow storage format will support the
 detection and correction of encoding-level errors in the data.
 Note that more advanced error correction is best handled at a layer
 below that addressed by this document.  Error correction is a topic
 well addressed by the storage industry in general (e.g., by Redundant
 Array of Independent Disks (RAID) and other technologies).  By
 specifying a flow storage format based upon files, we can leverage
 these features to meet this requirement.
 However, the ideal flow storage format will be resilient against
 errors, providing an internal facility for the detection of errors
 and the ability to isolate errors to as few data records as possible.
 Note that this requirement interacts with the choice of data
 compression or encryption algorithm.  For example, the use of block
 compression algorithms can serve to isolate errors to a single
 compression block, unlike stream compressors, which may fail to
 resynchronize after a single bit error, invalidating the entire
 message stream.
 The IPFIX Message format does not support data integrity assurance.
 It is assumed that advanced error correction will be provided
 externally.  Compression and encryption, if used, provide some
 allowance for detection, if not correction, of errors.  For simple
 error detection support in the absence of compression or encryption,
 checksums may be attached to messages via IPFIX Options according to
 the Message Checksum Options Template defined in Section 8.1.1.

5.6. Authentication, Confidentiality, and Integrity

 Archival storage of flow data may also require assurance that no
 unauthorized entity can read or modify the stored data.  Cryptography
 can be applied to this problem to ensure integrity and
 confidentiality by signing and encryption.

Trammell, et al. Standards Track [Page 12] RFC 5655 IPFIX Files October 2009

 As with error correction, this problem has been addressed well at a
 layer below that addressed by this document.  We can leverage the
 fact that existing cryptographic technologies work quite well on data
 stored in files to meet this requirement.
 Beyond support for the use of Transport Layer Security (TLS) for
 transport over TCP or Datagram Transport Layer Security (DTLS) for
 transport over SCTP or UDP, both of which provide transient
 authentication and confidentiality, the IPFIX protocol does not
 support this requirement directly.  The IETF has specified the
 Cryptographic Message Syntax (CMS) [RFC3852] for creating detached
 signatures for integrity and authentication; Section 9 specifies a
 CMS-based method for signing IPFIX Files.  Confidentiality protection
 is assumed to be met by methods external to this specification,
 leveraging one of the many such technologies for encrypting files to
 meet specific application and process requirements; however, notes on
 improving archival integrity of encrypted IPFIX Files are given in
 Section 9.2.

5.7. Anonymization and Obfuscation

 To ensure the privacy of individuals and organizations at the
 endpoints of communications represented by flow records, it is often
 necessary to obfuscate or anonymize stored and exported flow data.
 The ideal flow storage format will provide for a notation that a
 given information element on a given record type represents
 anonymized, rather than real, data.
 The IPFIX protocol presently has no support for anonymization
 notation.  It should be noted that anonymization is one of the
 requirements given for IPFIX in [RFC3917].  The decision to qualify
 this requirement with 'MAY' and not 'MUST' in the requirements
 document, and its subsequent lack of specification in the current
 version of the IPFIX protocol, is due to the fact that anonymization
 algorithms are still an open area of research, and that there
 currently exist no standardized methods for anonymization.
 No support is presently defined in [RFC5101] or this IPFIX-based File
 format for anonymization, as anonymization notation is an area of
 open work for the IPFIX Working Group.

5.8. Session Auditability and Replayability

 Certain use cases for archival flow storage require the storage of
 collection infrastructure details alongside the data itself.  These
 details include information about how and when data was received, and
 where it was received from.  They are useful for auditing as well as
 for the replaying received data for testing purposes.

Trammell, et al. Standards Track [Page 13] RFC 5655 IPFIX Files October 2009

 The IPFIX protocol contains no direct support for auditability and
 replayability, though the IPFIX Information Model does define various
 Information Elements required to represent collection infrastructure
 details.  These details may be stored in IPFIX Files using the Export
 Session Details Options Template defined in Section 8.1.3, and the
 Message Details Options Template defined in Section 8.1.4.

5.9. Performance Characteristics

 The ideal standard flow storage format will not have a significant
 negative impact on the performance of the application generating or
 processing flow data stored in the format.  This is a non-functional
 requirement, but it is important to note that a standard that implies
 a significant performance penalty is unlikely to be widely
 implemented and adopted.
 An examination of the IPFIX protocol would seem to suggest that
 implementations of it are not particularly prone to slowness; indeed,
 a template-based data representation is more easily subject to
 optimization for common cases than representations that embed
 structural information directly in the data stream (e.g., XML).
 However, a full analysis of the impact of using IPFIX Messages as a
 basis for flow data storage on read/write performance will require
 more implementation experience and performance measurement.

6. Applicability

 This section describes the specific applicability of IPFIX Files to
 various use cases.  IPFIX Files are particularly useful in a flow
 collection and processing infrastructure using IPFIX for flow export.
 We explore the applicability and provide guidelines for using IPFIX
 Files for the storage of flow data collected by IPFIX Collecting
 Processes and NetFlow V9 collectors, the testing of IPFIX Collecting
 Processes, and diagnostics of IPFIX Devices.

6.1. Storage of IPFIX-Collected Flow Data

 IPFIX Files can naturally be used to store flow data collected by an
 IPFIX Collecting Process; indeed, this was one of the primary initial
 motivations behind the file format described within this document.
 Using IPFIX Files as such provides a single, standard, well-
 understood encoding to be used for flow data on disk and on the wire,
 and allows IPFIX implementations to leverage substantially the same
 code for flow export and flow storage.  In addition, the storage of
 single Transport Sessions in IPFIX Files is particularly important
 for network measurement research, allowing repeatability of

Trammell, et al. Standards Track [Page 14] RFC 5655 IPFIX Files October 2009

 experiments by providing a format for the storage and exchange of
 IPFIX flow trace data much as the libpcap [pcap] format is used for
 experiments on packet trace data.

6.2. Storage of NetFlow-V9-Collected Flow Data

 Although the IPFIX protocol is based on the Cisco NetFlow Services,
 Version 9 (NetFlow V9) protocol [RFC3954], the two have diverged
 since work began on IPFIX.  However, since the NetFlow V9 information
 model is a compatible subset of the IPFIX Information Model, it is
 possible to use IPFIX Files to store collected NetFlow V9 flow data.
 This approach may be particularly useful in multi-vendor, multi-
 protocol collection infrastructures using both NetFlow V9 and IPFIX
 to export flow data.
 The applicability of IPFIX Files to this use case is outlined in
 Appendix B.

6.3. Testing IPFIX Collecting Processes

 IPFIX Files can be used to store IPFIX Messages for the testing of
 IPFIX Collecting Processes.  A variety of test cases may be stored in
 IPFIX Files.  First, IPFIX data collected in real network
 environments and stored in an IPFIX File can be used as input to
 check the behavior of new or extended implementations of IPFIX
 Collectors.  Furthermore, IPFIX Files can be used to validate the
 operation of a given IPFIX Collecting Process in a new environment,
 i.e., to test with recorded IPFIX data from the target network before
 installing the Collecting Process in the network.
 The IPFIX File format can also be used to store artificial, non-
 compliant reference messages for specific Collecting Process test
 cases.  Examples for such test cases are sets of IPFIX records with
 undefined Information Elements, Data Records described by missing
 Templates, or incorrectly framed Messages or Data Sets.
 Representative error handling test cases are defined in [RFC5471].
 Furthermore, fast replay of IPFIX Messages stored in a file can be
 used for stress/load tests (e.g., high rate of incoming Data Records,
 large Templates with high Information Element counts), as described
 in [RFC5471].  The provisioning and use of a set of reference files
 for testing simplifies the performance of tests and increases the
 comparability of test results.

Trammell, et al. Standards Track [Page 15] RFC 5655 IPFIX Files October 2009

6.4. IPFIX Device Diagnostics

 As an IPFIX File can be used to store any collection of flows, the
 format may also be used for dumping and storing various types of flow
 data for IPFIX Device diagnostics (e.g., the open flow cache of a
 Metering Process or the flow backlog of an Exporting or Collecting
 Process at the time of a process reset or crash).  File-based storage
 is preferable to remote transmission in such error-recovery
 situations.

7. Detailed File Format Specification

 Any valid serialized IPFIX Message stream MUST be accepted by a File
 Reader as a valid IPFIX File.  In this way, the filesystem is simply
 treated as another IPFIX transport alongside SCTP, TCP, and UDP,
 albeit a potentially high-latency transport, as the File Reader and
 File Writer do not necessarily run at the same time.
 This section specifies the detailed actions of File Readers and File
 Writers in handling IPFIX Files, and further specifies actions of
 File Writers in specific use cases.  Unless otherwise specified
 herein, IPFIX File Writers MUST behave as IPFIX Exporting Processes,
 and IPFIX File Readers MUST behave as IPFIX Collecting Processes,
 where appropriate.

7.1. File Reader Specification

 An IPFIX File Reader MUST act as an IPFIX Collecting Process as
 specified in [RFC5101], except as modified by this document.
 An IPFIX File Reader MUST accept as valid any serialized IPFIX
 Message stream that would be considered valid by one or more of the
 other defined IPFIX transport layers.  Practically, this means that
 the union of IPFIX Template management features supported by SCTP,
 TCP, and UDP MUST be supported in IPFIX Files.  File Readers MUST:
 o  accept IPFIX Messages containing Template Sets, Options Template
    Sets, and Data Sets within the same message, as with IPFIX over
    TCP or UDP;
 o  accept Template Sets that define Templates already defined within
    the File, as may occur with retransmission of Templates when using
    IPFIX over UDP as described in Section 10.3.6 of [RFC5101];
 o  resolve any conflict between a resent definition and a previous
    definition by assuming that the new Template replaces the old, as
    consistent with Template expiration and ID reuse when using UDP at
    the IPFIX transport protocol; and

Trammell, et al. Standards Track [Page 16] RFC 5655 IPFIX Files October 2009

 o  accept Template Withdrawals as described in Section 8 of
    [RFC5101], provided that the Template to be withdrawn is defined,
    as is the case with IPFIX over TCP and SCTP.
 Considering the filesystem-as-transport view, in the general case, an
 IPFIX File SHOULD be treated as containing a single Transport Session
 as defined by [RFC5101].  However, some applications may benefit from
 the ability to treat a collection of IPFIX Files as a single
 Transport Session; see especially Section 7.3.3 below.  A File Reader
 MAY be configurable to treat a collection of Files as a single
 Transport Session.  However, a File Reader MUST NOT treat a single
 IPFIX File as containing multiple Transport Sessions.
 If an IPFIX File uses the technique described in [RFC5473] AND all of
 the non-Options Templates in the File contain the commonPropertiesId
 Information Element, a File Reader MAY assume the set of
 commonPropertiesId definitions provides a complete table of contents
 for the File for searching purposes.

7.2. File Writer Specification

 An IPFIX File Writer MUST act as an IPFIX Exporting Process as
 specified in [RFC5101], except as modified by this document.  This
 section contains specifications for IPFIX File Writers in all
 situations; specifications and recommendations for specific File
 Writer use cases are found in Section 7.3 below.
 File Writers SHOULD store the Templates and Options required to
 decode the data within the File itself, unless modified by the
 requirements of a specific use case in a subsection of Section 7.3.
 In this way, a single IPFIX File generally contains a single notional
 Transport Session as defined by [RFC5101].
 File Writers SHOULD emit each Template Set or Options Template Set to
 appear in the File before any Data Set described by the Templates
 within that Set, to ensure the File Reader can decode every Data Set
 without waiting to process subsequent Templates or Options Templates.
 File Writers SHOULD emit Data Records described by Options Templates
 to appear in the File before any Data Records that depend on the
 scopes defined by those options.
 File Writers SHOULD use Template Withdrawals to withdraw Templates if
 Template IDs need to be reused.  Template Withdrawals SHOULD NOT be
 used unless it is necessary to reuse Template IDs.
 File Writers SHOULD write IPFIX Messages within an IPFIX File in
 ascending Export Time order.

Trammell, et al. Standards Track [Page 17] RFC 5655 IPFIX Files October 2009

 File Writers MAY write Data Records to an IPFIX File in any order.
 However, File Writers that write flow records to an IPFIX File in
 flowStartTime or flowEndTime order SHOULD be consistent in this
 ordering within each File.

7.3. Specific File Writer Use Cases

 The specifications in this section apply to specific situations.
 Each section below extends or modifies the base File Writer
 specification in Section 7.2.  Considerations for collocation of a
 File Writer with IPFIX Collecting Processes and Metering Processes
 are given, as are specific guidelines for using IPFIX Files for
 archival storage, or as documents.  Also covered are the use of IPFIX
 Files in the testing and diagnostics of IPFIX Devices.

7.3.1. Collocating a File Writer with a Collecting Process

 When collocating a File Writer with an IPFIX Collecting Process for
 archival storage of collected data in IPFIX Files as described in
 Section 6.1, the following recommendations may improve the usefulness
 of the stored data.
 The simplest way for a File Writer to store the data collected in a
 single Transport Session is to simply write the incoming IPFIX
 Messages to an IPFIX File as they are collected.  This approach has
 several drawbacks.  First, if the original Exporting Process did not
 conform to the recommendations in Section 7.2 with respect to
 Template and Data Record ordering, the written file can be difficult
 to use later; in this case, File Writers MAY reorder records as
 received in order to ensure that Templates appear before the Data
 Records they describe.
 A File Writer collocated with a Collecting Process that starts
 writing data from a running Transport Session SHOULD write all the
 Templates currently active within that Transport Session before
 writing any Data Records described by them.
 Also, the resulting IPFIX Files will lack information about the IPFIX
 Transport Session used to export them, such as the network addresses
 of the Exporting and Collecting Processes and the protocols used to
 transport them.  In this case, if information about the Transport
 Session is required, the File Writer SHOULD store a single IPFIX
 Transport Session in an IPFIX File and SHOULD record information
 about the Transport Session using the Export Session Details Options
 Template described in Section 8.1.3.

Trammell, et al. Standards Track [Page 18] RFC 5655 IPFIX Files October 2009

 Additional per-Message information MAY be recorded by the File Writer
 using the Message Details Options Template described in
 Section 8.1.4.  Per-Message information includes the time at which
 each IPFIX Message was received at the Collecting Process, and can be
 used to resend IPFIX Messages while keeping the original measurement
 plane traffic profile.
 When collocating a File Writer with a Collecting Process, the Export
 Time of each Message SHOULD be the Export Time of the Message
 received by the Collecting Process containing the first Data Record
 in the Message.  Note that File Writers storing IPFIX data collected
 from an IPFIX Collecting Process using SCTP as the transport protocol
 SHOULD interleave messages from multiple streams in order to preserve
 Export Time order, and SHOULD reorder the written messages as
 necessary to ensure that each Template Set or Options Template Set
 appears in the File before any Data Set described by the Templates
 within that Set.  Template reordering MUST preserve the sequence of
 Template Sets with Template Withdrawals in order to ensure
 consistency of Templates.
 Note that when adding additional information to IPFIX Messages
 received from Collecting Processes (e.g., Message Checksum Options,
 Message Detail Options), the File Writer SHOULD extend the length of
 the Message for the additional data if possible; otherwise, the
 Message SHOULD be split into two approximately equal-size Messages
 aligned on a Data Set or Template Set boundary from the original
 Message if possible; otherwise, the Message SHOULD be split into two
 approximately equal-size Messages aligned on a Data Record boundary.
 Note that, since the Maximum Segment Size (MSS) or MTU of most
 network links (1500-9000 for common Ethernets) is smaller than the
 maximum IPFIX Message size (65536) within an IPFIX File, it is
 expected that message length extension will suffice in most
 circumstances.
 A File Writer collocated with a Collecting Process SHOULD NOT sign a
 File as specified in Section 9.1 unless the Transport Session over
 which the data was exported was protected via TLS or DTLS, and the
 Collecting Process positively identified the Exporting Process by its
 certificate.  See Section 12.2 for more information on this issue.

7.3.2. Collocating a File Writer with a Metering Process

 Note that File Writers may also be collocated directly with IPFIX
 Metering Processes, for writing measured information directly to disk
 without intermediate IPFIX Exporting or Collecting Processes.  This
 arrangement may be particularly useful when providing data to an

Trammell, et al. Standards Track [Page 19] RFC 5655 IPFIX Files October 2009

 analysis environment with an IPFIX-File-based workflow, when testing
 Metering Processes during development, or when the authentication of
 a Metering Process is important.
 When collocating a File Writer with a Metering Process, note that
 Information Elements associated with Exporting or Collecting
 Processes are meaningless, and SHOULD NOT appear in the Export
 Session Details Options Template described in Section 8.1.3 or the
 Message Details Options Template described in Section 8.1.4.
 When collocating a File Writer with a Metering Process, the Export
 Time of each Message SHOULD be the time at which the first Data
 Record in the Message was received from the Metering Process.
 Note that collocating a File Writer with a Metering Process is the
 only way to provide positive authentication of a Metering Process
 through signatures as in Section 9.1.  See Section 12.2 for more
 information on this issue.

7.3.3. Using IPFIX Files for Archival Storage

 While in the general case File Writers should store one Transport
 Session per IPFIX File, some applications storing large collections
 of data over long periods of time may benefit from the ability to
 treat a collection of IPFIX Files as a single Transport Session.  A
 File Writer MAY be configurable to write data from a single Transport
 Session into multiple IPFIX Files; however, File Writers supporting
 such a configuration option MUST provide a configuration option to
 support one-file-per-session behavior for interoperability purposes.
 File Writers using IPFIX Files for archival storage SHOULD support
 compression as in Section 10.

7.3.4. Using IPFIX Files as Documents

 When IPFIX Files are used as documents, to store a set of flows
 relevant to query, investigation, or other common context, or for the
 publication of traffic datasets relevant to network research, each
 File MUST be readable as a single Transport Session, self-contained
 aside from any detached signature as in Section 9.1, and making no
 reference to metadata stored in separate Files, in order to ensure
 interoperability.
 When writing Files to be used as documents, File Writers MAY emit the
 special Data Records described by Options Templates before any other
 Data Records in the File in the following order to ease the
 inspection and use of documents by File Readers:

Trammell, et al. Standards Track [Page 20] RFC 5655 IPFIX Files October 2009

 o  Time Window records described by the File Time Window Options
    Template as defined in Section 8.1.2 below; followed by:
 o  Information Element Type Records as described in [RFC5610];
    followed by
 o  commonPropertiesId definitions as described in [RFC5473]; followed
    by
 o  Export Session details records described by the Export Session
    Details Options Template as defined in Section 8.1.3 below.
 The Export Time of each Message within a File used as a document
 SHOULD be the time at which the Message was written by the File
 Writer.
 If an IPFIX File used as a document uses the technique described in
 [RFC5473] AND all of the non-Options Templates in the File contain
 the commonPropertiesId Information Element, a File Reader MAY assume
 the set of commonPropertiesId definitions provides a complete table
 of contents for the File for searching purposes.

7.3.5. Using IPFIX Files for Testing

 IPFIX Files can be used for testing IPFIX Collecting Processes in two
 ways.  First, IPFIX Files can be used to store specific flow data for
 regression and stress testing of Collectors; there are no special
 considerations for IPFIX Files used in this way.
 Second, IPFIX Files are useful for storing reference messages that do
 not comply to the IPFIX protocol in order to test the error handling
 and recovery behavior of Collectors.  Of course, IPFIX Files intended
 to be used in this application necessarily MAY violate any of the
 specifications in this document or in [RFC5101], and such Files MUST
 NOT be transmitted to Collecting Processes or given as input to File
 Readers not under test.
 Note that an extremely simple IPFIX Exporting Process may be crafted
 for testing purposes by simply reading an IPFIX File and transmitting
 it directly to a Collecting Process.  Similarly, an extremely simple
 Collecting Process may be crafted for testing purposes by simply
 accepting connections and/or IPFIX Messages from Exporting Processes
 and writing the session's message stream to an IPFIX File.

Trammell, et al. Standards Track [Page 21] RFC 5655 IPFIX Files October 2009

7.3.6. Writing IPFIX Files for Device Diagnostics

 IPFIX Files can be used in the debugging of devices that use flow
 data as internal state, as a common format for the representation of
 flow tables.  In such situations, the opaqueOctets information
 element can be used to store additional non-IPFIX encoded, non-flow
 information (e.g., stack backtraces, process state, etc.) within the
 IPFIX File as in Section 11.1; the IPFIX flow table information could
 also be embedded in a larger proprietary diagnostic format using
 delimiters as in Section 11.2

7.3.7. IPFIX File Manipulation

 For many applications, it may prove useful for implementations to
 provide functionality for the manipulation of IPFIX Files; for
 example, to select data from a File, to change the Templates used
 within a File, or to split or join data in Files.  Any such utility
 should take special care to ensure that its output remains a valid
 IPFIX File, specifically with respect to Templates and Options, which
 are scoped to Transport Sessions.
 Any operation that splits one File into multiple Files SHOULD write
 all necessary Templates and Options to each resulting File, and
 ensure that written Options are valid for each resulting File (e.g.,
 the Time Window Options Template in Section 8.1.2).  Any operation
 that joins multiple Files into a single File should do the same,
 additionally ensuring that Template IDs do not collide, through the
 use of different Observation Domain IDs or Template ID rewriting.
 Combining operations may also want to ensure any desired ordering of
 flow records is maintained.

7.4. Media Type of IPFIX Files

 The media type for IPFIX Files is application/ipfix.  The
 registration information [RFC4288] for this media type is given in
 the IANA Considerations section.

8. File Format Metadata Specification

 This section defines the Options Templates used for IPFIX File
 metadata, and the Information Elements they require.

8.1. Recommended Options Templates for IPFIX Files

 The following Options Templates allow IPFIX Message streams to meet
 the requirements outlined above without extension to the message
 format or protocol.  They are defined in terms of existing
 Information Elements defined in [RFC5102], the Information Elements

Trammell, et al. Standards Track [Page 22] RFC 5655 IPFIX Files October 2009

 defined in [RFC5610], as well as Information Elements defined in
 Section 8.2.  IPFIX File Readers and Writers SHOULD support these
 Options Templates as defined below.
 In addition, IPFIX File Readers and Writers SHOULD support the
 Options Templates defined in [RFC5610] in order to support self-
 description of enterprise-specific Information Elements.

8.1.1. Message Checksum Options Template

 The Message Checksum Options Template specifies the structure of a
 Data Record for attaching an MD5 message checksum to an IPFIX
 Message.  An MD5 message checksum as described MAY be used if data
 integrity is important to the application but file signing is not
 available or desired.  The described Data Record MUST appear only
 once per IPFIX Message, but MAY appear anywhere within the Message.
 This Options Template SHOULD contain the following Information
 Elements:
 +--------------------+----------------------------------------------+
 | IE                 | Description                                  |
 +--------------------+----------------------------------------------+
 | messageScope       | A marker denoting this Option applies to the |
 | [scope]            | whole IPFIX Message; content is ignored.     |
 |                    | This Information Element MUST be defined as  |
 |                    | a Scope Field.                               |
 | messageMD5Checksum | The MD5 checksum of the containing IPFIX     |
 |                    | Message.                                     |
 +--------------------+----------------------------------------------+

8.1.2. File Time Window Options Template

 The File Time Window Options Template specifies the structure of a
 Data Record for attaching a time window to an IPFIX File; this Data
 Record is referred to as a time window record.  A time window record
 defines the earliest flow start time and the latest flow end time of
 the flow records within a File.  One and only one time window record
 MAY appear within an IPFIX File if the time window information is
 available; a File Writer MUST NOT write more than one time window
 record to an IPFIX File.  A File Writer that writes a time window
 record to a File MUST NOT write any Flow with a start time before the
 beginning of the window or an end time after the end of the window to
 that File.
 This Options Template SHOULD contain the following Information
 Elements:

Trammell, et al. Standards Track [Page 23] RFC 5655 IPFIX Files October 2009

 +---------------+---------------------------------------------------+
 | IE            | Description                                       |
 +---------------+---------------------------------------------------+
 | sessionScope  | A marker denoting this Option applies to the      |
 | [scope]       | whole IPFIX Transport Session (i.e., the IPFIX    |
 |               | File in the common case); content is ignored.     |
 |               | This Information Element MUST be defined as a     |
 |               | Scope Field.                                      |
 | minFlowStart* | Exactly one of minFlowStartSeconds,               |
 |               | minFlowStartMilliseconds,                         |
 |               | minFlowStartMicroseconds, or                      |
 |               | minFlowStartNanoseconds SHOULD match the          |
 |               | precision of the accompanying maxFlowEnd*         |
 |               | Information Element.  The start time of the       |
 |               | earliest flow in the Transport Session (i.e.,     |
 |               | File).                                            |
 | maxFlowEnd*   | Exactly one of maxFlowEndSeconds,                 |
 |               | maxFlowEndMilliseconds, maxFlowEndMicroseconds,   |
 |               | or maxFlowEndNanoseconds SHOULD match the         |
 |               | precision of the accompanying minFlowStart*       |
 |               | Information Element.  The end time of the latest  |
 |               | flow in the Transport Session (i.e., File).       |
 +---------------+---------------------------------------------------+

8.1.3. Export Session Details Options Template

 The Export Session Details Options Template specifies the structure
 of a Data Record for recording the details of an IPFIX Transport
 Session in an IPFIX File.  It is intended for use in storing a single
 complete IPFIX Transport Session in a single IPFIX File.  The
 described Data Record SHOULD appear only once in a given IPFIX File.
 This Options Template SHOULD contain at least the following
 Information Elements, subject to applicability as noted on each
 Information Element:

Trammell, et al. Standards Track [Page 24] RFC 5655 IPFIX Files October 2009

 +----------------------------+--------------------------------------+
 | IE                         | Description                          |
 +----------------------------+--------------------------------------+
 | sessionScope [scope]       | A marker denoting this Option        |
 |                            | applies to the whole IPFIX Transport |
 |                            | Session (i.e., the IPFIX File in the |
 |                            | common case); content is ignored.    |
 |                            | This Information Element MUST be     |
 |                            | defined as a Scope Field.            |
 | exporterIPv4Address        | IPv4 address of the IPFIX Exporting  |
 |                            | Process from which the Messages in   |
 |                            | this Transport Session were          |
 |                            | received.  Present only for          |
 |                            | Exporting Processes with an IPv4     |
 |                            | interface.  For multi-homed SCTP     |
 |                            | associations, this SHOULD be the     |
 |                            | primary path endpoint address of the |
 |                            | Exporting Process.                   |
 | exporterIPv6Address        | IPv6 address of the IPFIX Exporting  |
 |                            | Process from which the Messages in   |
 |                            | this Transport Session were          |
 |                            | received.  Present only for          |
 |                            | Exporting Processes with an IPv6     |
 |                            | interface.  For multi-homed SCTP     |
 |                            | associations, this SHOULD be the     |
 |                            | primary path endpoint address of the |
 |                            | Exporting Process.                   |
 | exporterTransportPort      | The source port from which the       |
 |                            | Messages in this Transport Session   |
 |                            | were received.                       |
 | exporterCertificate        | The certificate used by the IPFIX    |
 |                            | Exporting Process from which the     |
 |                            | Messages in this Transport Session   |
 |                            | were received.  Present only for     |
 |                            | Transport Sessions protected by TLS  |
 |                            | or DTLS.                             |
 | collectorIPv4Address       | IPv4 address of the IPFIX Collecting |
 |                            | Process that received the Messages   |
 |                            | in this Transport Session.  Present  |
 |                            | only for Collecting Processes with   |
 |                            | an IPv4 interface.  For multi-homed  |
 |                            | SCTP associations, this SHOULD be    |
 |                            | the primary path endpoint address of |
 |                            | the Collecting Process.              |
 | collectorIPv6Address       | IPv6 address of the IPFIX Collecting |
 |                            | Process that received the Messages   |
 |                            | in this Transport Session.  Present  |
 |                            | only for Collecting Processes with   |

Trammell, et al. Standards Track [Page 25] RFC 5655 IPFIX Files October 2009

 |                            | an IPv6 interface.  For multi-homed  |
 |                            | SCTP associations, this SHOULD be    |
 |                            | the primary path endpoint address of |
 |                            | the Collecting Process.              |
 | collectorTransportPort     | The destination port on which the    |
 |                            | Messages in this Transport Session   |
 |                            | were received.                       |
 | collectorTransportProtocol | The IP Protocol Identifier of the    |
 |                            | transport protocol used to transport |
 |                            | Messages within this Transport       |
 |                            | Session.                             |
 | collectorProtocolVersion   | The version of the export protocol   |
 |                            | used to transport Messages within    |
 |                            | this Transport Session.  Applicable  |
 |                            | only in mixed NetFlow V9-IPFIX       |
 |                            | collection environments when storing |
 |                            | NetFlow V9 data in IPFIX Messages,   |
 |                            | as in Appendix B.                    |
 | collectorCertificate       | The certificate used by the IPFIX    |
 |                            | Collecting Process that received the |
 |                            | Messages in this Transport Session.  |
 |                            | Present only for Transport Sessions  |
 |                            | protected by TLS or DTLS.            |
 | minExportSeconds           | The Export Time of the first Message |
 |                            | in the Transport Session.            |
 | maxExportSeconds           | The Export Time of the last Message  |
 |                            | in the Transport Session.            |
 +----------------------------+--------------------------------------+

8.1.4. Message Details Options Template

 The Message Details Options Template specifies the structure of a
 Data Record for attaching additional export details to an IPFIX
 Message.  These details include the time at which a message was
 received and information about the export and collection
 infrastructure used to transport the Message.  This Options Template
 also allows the storage of the export session metadata provided the
 Export Session Details Options Template, for storing information from
 multiple Transport Sessions in the same IPFIX File.
 This Options Template SHOULD contain at least the following
 Information Elements, subject to applicability as noted for each
 Information Element.  Note that when used in conjunction with the
 Export Session Details Options Template, when storing a single
 complete IPFIX Transport Session in an IPFIX File, this Options
 Template SHOULD contain only the messageScope and

Trammell, et al. Standards Track [Page 26] RFC 5655 IPFIX Files October 2009

 collectionTimeMilliseconds Information Elements, and the
 exportSctpStreamId Information Element for Messages transported via
 SCTP.
 +----------------------------+--------------------------------------+
 | IE                         | Description                          |
 +----------------------------+--------------------------------------+
 | messageScope [scope]       | A marker denoting this Option        |
 |                            | applies to the whole IPFIX message;  |
 |                            | content is ignored.  This            |
 |                            | Information Element MUST be defined  |
 |                            | as a Scope Field.                    |
 | collectionTimeMilliseconds | The absolute time at which this      |
 |                            | Message was received by the IPFIX    |
 |                            | Collecting Process.                  |
 | exporterIPv4Address        | IPv4 address of the IPFIX Exporting  |
 |                            | Process from which this Message was  |
 |                            | received.  Present only for          |
 |                            | Exporting Processes with an IPv4     |
 |                            | interface, and if this information   |
 |                            | is not available via the Export      |
 |                            | Session Details Options Template.    |
 |                            | For multi-homed SCTP associations,   |
 |                            | this SHOULD be the primary path      |
 |                            | endpoint address of the Exporting    |
 |                            | Process.                             |
 | exporterIPv6Address        | IPv6 address of the IPFIX Exporting  |
 |                            | Process from which this Message was  |
 |                            | received.  Present only for          |
 |                            | Exporting Processes with an IPv6     |
 |                            | interface and if this information is |
 |                            | not available via the Export Session |
 |                            | Details Options Template.  For       |
 |                            | multi-homed SCTP associations, this  |
 |                            | SHOULD be the primary path endpoint  |
 |                            | address of the Exporting Process.    |
 | exporterTransportPort      | The source port from which this      |
 |                            | Message was received.  Present only  |
 |                            | if this information is not available |
 |                            | via the Export Session Details       |
 |                            | Options Template.                    |
 | exporterCertificate        | The certificate used by the IPFIX    |
 |                            | Exporting Process from which this    |
 |                            | Message was received.  Present only  |
 |                            | for Transport Sessions protected by  |
 |                            | TLS or DTLS.                         |
 | collectorIPv4Address       | IPv4 address of the IPFIX Collecting |
 |                            | Process that received this Message.  |

Trammell, et al. Standards Track [Page 27] RFC 5655 IPFIX Files October 2009

 |                            | Present only for Collecting          |
 |                            | Processes with an IPv4 interface,    |
 |                            | and if this information is not       |
 |                            | available via the Export Session     |
 |                            | Details Options Template.  For       |
 |                            | multi-homed SCTP associations, this  |
 |                            | SHOULD be the primary path endpoint  |
 |                            | address of the Collecting Process.   |
 | collectorIPv6Address       | IPv6 address of the IPFIX Collecting |
 |                            | Process that received this Message.  |
 |                            | Present only for Collecting          |
 |                            | Processes with an IPv6 interface,    |
 |                            | and if this information is not       |
 |                            | available via the Export Session     |
 |                            | Details Options Template.  For       |
 |                            | multi-homed SCTP associations, this  |
 |                            | SHOULD be the primary path endpoint  |
 |                            | address of the Collecting Process.   |
 | collectorTransportPort     | The destination port on which this   |
 |                            | Message was received.  Present only  |
 |                            | if this information is not available |
 |                            | via the Export Session Details       |
 |                            | Options Template.                    |
 | collectorTransportProtocol | The IP Protocol Identifier of the    |
 |                            | transport protocol used to transport |
 |                            | this Message.  Present only if this  |
 |                            | information is not available via the |
 |                            | Export Session Details Options       |
 |                            | Template.                            |
 | collectorProtocolVersion   | The version of the export protocol   |
 |                            | used to transport this Message.      |
 |                            | Present only if necessary and if     |
 |                            | this information is not available    |
 |                            | via the Export Session Details       |
 |                            | Options Template.                    |
 | collectorCertificate       | The certificate used by the IPFIX    |
 |                            | Collecting Process that received     |
 |                            | this Message.  Present only for      |
 |                            | Transport Sessions protected by TLS  |
 |                            | or DTLS.                             |
 | exportSctpStreamId         | The SCTP stream used to transport    |
 |                            | this Message.  Present only if the   |
 |                            | Message was transported via SCTP.    |
 +----------------------------+--------------------------------------+

Trammell, et al. Standards Track [Page 28] RFC 5655 IPFIX Files October 2009

8.2. Recommended Information Elements for IPFIX Files

 The following Information Elements are used by the Options Templates
 in Section 8.1 to allow IPFIX Message streams to meet the
 requirements outlined above without extension of the protocol.  IPFIX
 File Readers and Writers SHOULD support these Information Elements as
 defined below.
 In addition, IPFIX File Readers and Writers SHOULD support the
 Information Elements defined in [RFC5610] in order to support full
 self-description of Information Elements.

8.2.1. collectionTimeMilliseconds

 Description:   The absolute timestamp at which the data within the
    scope containing this Information Element was received by a
    Collecting Process.  This Information Element SHOULD be bound to
    its containing IPFIX Message via IPFIX Options and the
    messageScope Information Element, as defined below.
 Abstract Data Type:   dateTimeMilliseconds
 ElementId:   258
 Status:   current

8.2.2. collectorCertificate

 Description:   The full X.509 certificate, encoded in ASN.1 DER
    format, used by the Collector when IPFIX Messages were transmitted
    using TLS or DTLS.  This Information Element SHOULD be bound to
    its containing IPFIX Transport Session via an options record and
    the sessionScope Information Element, or to its containing IPFIX
    Message via an options record and the messageScope Information
    Element.
 Abstract Data Type:   octetArray
 ElementId:   274
 Status:   current

8.2.3. exporterCertificate

 Description:   The full X.509 certificate, encoded in ASN.1 DER
    format, used by the Collector when IPFIX Messages were transmitted
    using TLS or DTLS.  This Information Element SHOULD be bound to
    its containing IPFIX Transport Session via an options record and

Trammell, et al. Standards Track [Page 29] RFC 5655 IPFIX Files October 2009

    the sessionScope Information Element, or to its containing IPFIX
    Message via an options record and the messageScope Information
    Element.
 Abstract Data Type:   octetArray
 ElementId:   275
 Status:   current

8.2.4. exportSctpStreamId

 Description:   The value of the SCTP Stream Identifier used by the
    Exporting Process for exporting IPFIX Message data.  This is
    carried in the Stream Identifier field of the header of the SCTP
    DATA chunk containing the IPFIX Message(s).
 Abstract Data Type:   unsigned16
 Data Type Semantics:   identifier
 ElementId:   259
 Status:   current

8.2.5. maxExportSeconds

 Description:   The absolute Export Time of the latest IPFIX Message
    within the scope containing this Information Element.  This
    Information Element SHOULD be bound to its containing IPFIX
    Transport Session via IPFIX Options and the sessionScope
    Information Element.
 Abstract Data Type:   dateTimeSeconds
 ElementId:   260
 Status:   current
 Units:   seconds

8.2.6. maxFlowEndMicroseconds

 Description:   The latest absolute timestamp of the last packet
    within any Flow within the scope containing this Information
    Element, rounded up to the microsecond if necessary.  This
    Information Element SHOULD be bound to its containing IPFIX
    Transport Session via IPFIX Options and the sessionScope

Trammell, et al. Standards Track [Page 30] RFC 5655 IPFIX Files October 2009

    Information Element.  This Information Element SHOULD be used only
    in Transport Sessions containing Flow Records with microsecond-
    precision (or better) timestamp Information Elements.
 Abstract Data Type:   dateTimeMicroseconds
 ElementId:   268
 Status:   current
 Units:   microseconds

8.2.7. maxFlowEndMilliseconds

 Description:   The latest absolute timestamp of the last packet
    within any Flow within the scope containing this Information
    Element, rounded up to the millisecond if necessary.  This
    Information Element SHOULD be bound to its containing IPFIX
    Transport Session via IPFIX Options and the sessionScope
    Information Element.  This Information Element SHOULD be used only
    in Transport Sessions containing Flow Records with millisecond-
    precision (or better) timestamp Information Elements.
 Abstract Data Type:   dateTimeMilliseconds
 ElementId:   269
 Status:   current
 Units:   milliseconds

8.2.8. maxFlowEndNanoseconds

 Description:   The latest absolute timestamp of the last packet
    within any Flow within the scope containing this Information
    Element.  This Information Element SHOULD be bound to its
    containing IPFIX Transport Session via IPFIX Options and the
    sessionScope Information Element.  This Information Element SHOULD
    be used only in Transport Sessions containing Flow Records with
    nanosecond-precision timestamp Information Elements.
 Abstract Data Type:   dateTimeNanoseconds
 ElementId:   270
 Status:   current
 Units:   nanoseconds

Trammell, et al. Standards Track [Page 31] RFC 5655 IPFIX Files October 2009

8.2.9. maxFlowEndSeconds

 Description:   The latest absolute timestamp of the last packet
    within any Flow within the scope containing this Information
    Element, rounded up to the second if necessary.  This Information
    Element SHOULD be bound to its containing IPFIX Transport Session
    via IPFIX Options and the sessionScope Information Element.
 Abstract Data Type:   dateTimeSeconds
 ElementId:   261
 Status:   current
 Units:   seconds

8.2.10. messageMD5Checksum

 Description:   The MD5 checksum of the IPFIX Message containing this
    record.  This Information Element SHOULD be bound to its
    containing IPFIX Message via an options record and the
    messageScope Information Element, as defined below, and SHOULD
    appear only once in a given IPFIX Message.  To calculate the value
    of this Information Element, first buffer the containing IPFIX
    Message, setting the value of this Information Element to all
    zeroes.  Then calculate the MD5 checksum of the resulting buffer
    as defined in [RFC1321], place the resulting value in this
    Information Element, and export the buffered message.  This
    Information Element is intended as a simple checksum only;
    therefore collision resistance and algorithm agility are not
    required, and MD5 is an appropriate message digest.
 Abstract Data Type:   octetArray (16 bytes)
 ElementId:   262
 Status:   current
 Reference:   RFC 1321, The MD5 Message-Digest Algorithm [RFC1321]

8.2.11. messageScope

 Description:   The presence of this Information Element as scope in
    an Options Template signifies that the options described by the
    Template apply to the IPFIX Message that contains them.  It is
    defined for general purpose message scoping of options, and
    proposed specifically to allow the attachment of checksum and
    collection information to a message via IPFIX Options.  The value

Trammell, et al. Standards Track [Page 32] RFC 5655 IPFIX Files October 2009

    of this Information Element MUST be written as 0 by the File
    Writer or Exporting Process.  The value of this Information
    Element MUST be ignored by the File Reader or the Collecting
    Process.
 Abstract Data Type:   unsigned8
 ElementId:   263
 Status:   current

8.2.12. minExportSeconds

 Description:   The absolute Export Time of the earliest IPFIX Message
    within the scope containing this Information Element.  This
    Information Element SHOULD be bound to its containing IPFIX
    Transport Session via an options record and the sessionScope
    Information Element.
 Abstract Data Type:   dateTimeSeconds
 ElementId:   264
 Status:   current
 Units:   seconds

8.2.13. minFlowStartMicroseconds

 Description:   The earliest absolute timestamp of the first packet
    within any Flow within the scope containing this Information
    Element, rounded down to the microsecond if necessary.  This
    Information Element SHOULD be bound to its containing IPFIX
    Transport Session via an options record and the sessionScope
    Information Element.  This Information Element SHOULD be used only
    in Transport Sessions containing Flow Records with microsecond-
    precision (or better) timestamp Information Elements.
 Abstract Data Type:   dateTimeMicroseconds
 ElementId:   271
 Status:   current
 Units:   microseconds

Trammell, et al. Standards Track [Page 33] RFC 5655 IPFIX Files October 2009

8.2.14. minFlowStartMilliseconds

 Description:   The earliest absolute timestamp of the first packet
    within any Flow within the scope containing this Information
    Element, rounded down to the millisecond if necessary.  This
    Information Element SHOULD be bound to its containing IPFIX
    Transport Session via an options record and the sessionScope
    Information Element.  This Information Element SHOULD be used only
    in Transport Sessions containing Flow Records with millisecond-
    precision (or better) timestamp Information Elements.
 Abstract Data Type:   dateTimeMilliseconds
 ElementId:   272
 Status:   current
 Units:   milliseconds

8.2.15. minFlowStartNanoseconds

 Description:   The earliest absolute timestamp of the first packet
    within any Flow within the scope containing this Information
    Element.  This Information Element SHOULD be bound to its
    containing IPFIX Transport Session via an options record and the
    sessionScope Information Element.  This Information Element SHOULD
    be used only in Transport Sessions containing Flow Records with
    nanosecond-precision timestamp Information Elements.
 Abstract Data Type:   dateTimeNanoseconds
 ElementId:   273
 Status:   current
 Units:   nanoseconds

8.2.16. minFlowStartSeconds

 Description:   The earliest absolute timestamp of the first packet
    within any Flow within the scope containing this Information
    Element, rounded down to the second if necessary.  This
    Information Element SHOULD be bound to its containing IPFIX
    Transport Session via an options record and the sessionScope
    Information Element.
 Abstract Data Type:   dateTimeSeconds

Trammell, et al. Standards Track [Page 34] RFC 5655 IPFIX Files October 2009

 ElementId:   265
 Status:   current
 Units:   seconds

8.2.17. opaqueOctets

 Description:   This Information Element is used to encapsulate non-
    IPFIX data into an IPFIX Message stream, for the purpose of
    allowing a non-IPFIX data processor to store a data stream inline
    within an IPFIX File.  A Collecting Process or File Writer MUST
    NOT try to interpret this binary data.  This Information Element
    differs from paddingOctets as its contents are meaningful in some
    non-IPFIX context, while the contents of paddingOctets MUST be
    0x00 and are intended only for Information Element alignment.
 Abstract Data Type:   octetArray
 ElementId:   266
 Status:   current

8.2.18. sessionScope

 Description:   The presence of this Information Element as scope in
    an Options Template signifies that the options described by the
    Template apply to the IPFIX Transport Session that contains them.
    Note that as all options are implicitly scoped to Transport
    Session and Observation Domain, this Information Element is
    equivalent to a "null" scope.  It is defined for general purpose
    session scoping of options, and proposed specifically to allow the
    attachment of time window and collection information to an IPFIX
    File via IPFIX Options.  The value of this Information Element
    MUST be written as 0 by the File Writer or Exporting Process.  The
    value of this Information Element MUST be ignored by the File
    Reader or the Collecting Process.
 Abstract Data Type:   unsigned8
 ElementId:   267
 Status:   current

Trammell, et al. Standards Track [Page 35] RFC 5655 IPFIX Files October 2009

9. Signing and Encryption of IPFIX Files

 In order to ensure the integrity of IPFIX Files and the identity of
 IPFIX File Writers, File Writers and File Readers SHOULD provide for
 an interoperable and easily implemented method for signing IPFIX
 Files, and verifying those signatures.  This section specifies method
 via CMS detached signatures.
 Note that while CMS specifies an encapsulation format that can be
 used for encryption as well as signing, no method is specified for
 encapsulation for confidentiality protection.  It is assumed that
 application-specific or process-specific requirements outweigh the
 need for interoperability for encrypted files.

9.1. CMS Detached Signatures

 The Cryptographic Message Syntax (CMS) [RFC3852] defines an
 encapsulation syntax for data protection, used to digitally sign,
 authenticate, or encrypt arbitrary message content.  CMS can also be
 used to create detached signatures, in which the signature is stored
 in a separate file.  This arrangement maximizes interoperability, as
 File Readers that are not aware of CMS detached signatures and have
 no requirement for them can simply ignore them; the content of the
 IPFIX File itself is unchanged by the signature.
 The detached signature file for an IPFIX File SHOULD be stored,
 transported, or otherwise made available (e.g., by FTP or HTTP)
 alongside the signed IPFIX File, with the same filename as the IPFIX
 File, except that the file extension ".p7s" is added to the end,
 conforming to the naming convention in [RFC3851].
 Within the detached signature, the CMS ContentInfo type MUST always
 be present, and it MUST encapsulate the CMS SignedData content type,
 which in turn MUST NOT encapsulate the signed IPFIX File content.
 The CMS detached signature is summarized as follows:

Trammell, et al. Standards Track [Page 36] RFC 5655 IPFIX Files October 2009

 ContentInfo {
   contentType          id-signedData, -- (1.2.840.113549.1.7.2)
   content              SignedData
 }
 SignedData {
   version              CMSVersion, -- Always set to 3
   digestAlgorithms     DigestAlgorithmIdentifiers,
   encapContentInfo     EncapsulatedContentInfo,
   certificates         CertificateSet, -- File Writer certificate(s)
   crls                 CertificateRevocationLists, -- Optional
   signerInfos          SET OF SignerInfo -- Only one signer
 }
 SignerInfo {
   version              CMSVersion, -- Always set to 3
   sid                  SignerIdentifier,
   digestAlgorithm      DigestAlgorithmIdentifier,
   signedAttrs          SignedAttributes,
   signatureAlgorithm   SignatureAlgorithmIdentifier,
   signature            SignatureValue,
   unsignedAttrs        UnsignedAttributes
 }
 EncapsulatedContentInfo {
   eContentType         id-data, -- (1.2.840.113549.1.7.1)
   eContent             OCTET STRING  -- Always absent
 }
 The details of the contents of each CMS encapsulation are detailed in
 the subsections below.

9.1.1. ContentInfo

 [RFC3852] requires the outer-most encapsulation to be ContentInfo;
 the fields of ContentInfo are as follows:
 contentType:  the type of the associated content.  For the detached
    signature file, the encapsulated type is always SignedData, so the
    id-signedData (1.2.840.113549.1.7.2) object identifier MUST be
    present in this field.
 content:  a SignedData content, detailed in Section 9.1.2.

Trammell, et al. Standards Track [Page 37] RFC 5655 IPFIX Files October 2009

9.1.2. SignedData

 The SignedData content type contains the signature of the IPFIX File
 and information to aid in validation; the fields of SignedData are as
 follows:
 version:  MUST be 3.
 digestAlgorithms:  a collection of one-way hash function identifiers.
    It MUST contain the identifier used by the File Writer to generate
    the digital signature.
 encapContentInfo:  the signed content, including a content type
    identifier.  Since a detached signature is being created, it does
    not encapsulate the IPFIX File.  The EncapsulatedContentInfo is
    detailed in Section 9.1.4.
 certificates:  a collection of certificates.  It SHOULD include the
    X.509 certificate needed to validate the digital signature file.
    Certification Authority (CA) and File Writer certificates MUST
    conform to the certificate profile specified in [RFC5280].
 crls:  an optional collection of certificate revocation lists (CRLs).
    It SHOULD NOT contain any CRLs; any CRLs that are present MUST
    conform to the certificate profile specified in [RFC5280].
 signerInfos:  a collection of per-signer information; this identifies
    the File Writer.  More than one SignerInfo MAY appear to
    facilitate transitions between keys or algorithms.  The SignerInfo
    type is detailed in Section 9.1.3.

9.1.3. SignerInfo

 The SignerInfo type identifies the File Writer; the fields of
 SignerInfo are as follows:
 version:  MUST be 3.
 sid:  identifies the File Writer's public key.  This identifier MUST
    match the value included in the subjectKeyIdentifier certificate
    extension on the File Writer's X.509 certificate.
 digestAlgorithm:  identifies the one-way hash function and associated
    parameters used to generate the signature.

Trammell, et al. Standards Track [Page 38] RFC 5655 IPFIX Files October 2009

 signedAttrs:  an optional set of attributes that are signed along
    with the content.
 digestAlgorithm:  identifies the digital signature algorithm and
    associated parameters used to generate the signature.
 signature:  the digital signature of the associated file.
 unsignedAttrs:  an optional set of attributes that are not signed.

9.1.4. EncapsulatedContentInfo

 The EncapsulatedContentInfo structure contains a content type
 identifier.  Since a detached signature is being created, it does not
 encapsulate the IPFIX File.  The fields of EncapsulatedContentInfo
 are as follows:
 eContentType:  an object identifier that uniquely specifies the
    content type.  The content type associated with IPFIX File MUST be
    id-data (1.2.840.113549.1.7.1).
 eContent:  an optional field containing the signed content.  Since
    this is a detached signature, eContent MUST be absent.

9.2. Encryption Error Resilience

 Note that single bit errors in the encrypted data stream can result
 in larger errors in the decrypted stream, depending on the encryption
 scheme used.
 In applications (e.g., archival storage) in which error resilience is
 very important, File Writers SHOULD use an encryption scheme that can
 resynchronize after bit errors.  A common example is a block cipher
 in CBC (Cipher Block Chaining) mode.  In this case, File Writers MAY
 also use the Message Checksum Options Template to attach a checksum
 to each IPFIX Message in the IPFIX File, in order to support the
 recognition of errors in the decrypted data.

10. Compression of IPFIX Files

 Network traffic measurement data is generally highly compressible.
 IPFIX Templates tend to increase the information content per record
 by not requiring the export of irrelevant or non-present fields in
 records, and the technique described in [RFC5473] also reduces the
 export of redundant information.  However, even with these
 techniques, generalized compression can decrease storage requirements
 significantly; therefore, IPFIX File Writers and File Readers SHOULD
 support compression as described in this section.

Trammell, et al. Standards Track [Page 39] RFC 5655 IPFIX Files October 2009

10.1. Supported Compression Formats

 IPFIX Files support two compression encapsulation formats: bzip2
 [bzip2] and gzip [RFC1952]. bzip2 provides better compression than
 gzip and, as a block compression algorithm, better error recovery
 characteristics, at the expense of slower compression. gzip is
 potentially a better choice when compression time is an issue.  These
 two algorithms and encapsulation formats were chosen for ubiquity and
 ease of implementation.
 IPFIX File Readers and Writers supporting compression MUST support
 bzip2, and SHOULD support gzip.

10.2. Compression Recognition at the File Reader

 bzip2, gzip, and uncompressed IPFIX Files have distinct magic
 numbers.  IPFIX File Readers SHOULD use these magic numbers to
 determine what compression, if any, is in use for an IPFIX File, and
 invoke the proper decompression. bzip2 files are identified by the
 initial three-octet string 0x42, 0x5A, 0x68 ("BZh"). gzip files are
 identified by the initial two-octet string 0x1F, 0x8B.  IPFIX Files
 are identified by the initial two-octet string 0x00, 0x0A; these are
 the version bytes of the first IPFIX Message header in the File.

10.3. Compression Error Resilience

 Compression at the file level, like encryption, is not particularly
 resilient to errors; in the worst case, a single bit error in a
 stream-compressed file could result in the loss of the entire file.
 Since block compression algorithms that support the identification
 and isolation of blocks containing errors limit the impact of errors
 on the recoverability of compressed data, the use of bzip2 in
 applications where error resilience is important is RECOMMENDED.
 Since the block boundary of a block-compressed IPFIX File may fall in
 the middle of an IPFIX Message, resynchronization of an IPFIX Message
 stream by a File Reader after a compression error requires some care.
 The beginning of an IPFIX Message may be identified by its header
 signature (the Version field of the Message Header, 0x00 0x0A,
 followed by a 16-bit Message Length), but simply searching for the
 first occurrence of the Version field is insufficient, since these
 two bytes may occur in valid IPFIX Template or Data Sets.
 Therefore, we specify the following algorithm for File Readers to
 resynchronize an IPFIX Message Stream after skipping a compressed
 block containing errors:

Trammell, et al. Standards Track [Page 40] RFC 5655 IPFIX Files October 2009

 1.  Search after the error for the first occurrence of the octet
     string 0x00, 0x0A (the IPFIX Message Header Version field).
 2.  Treat this field as the beginning of a candidate IPFIX Message.
     Read the two bytes following the Version field as a Message
     Length, and seek to that offset from the beginning of the
     candidate IPFIX Message.
 3.  If the first two octets after the candidate IPFIX Message are
     0x00, 0x0A (i.e., the IPFIX Message Header Version field of the
     next message in the stream), or if the end-of-file is reached
     precisely at the end of the candidate IPFIX Message, presume that
     the candidate IPFIX Message is valid, and begin reading the IPFIX
     File from the start of the candidate IPFIX Message.
 4.  If not, or if the seek reaches end-of-file or another block
     containing errors before finding the end of the candidate
     message, go back to step 1, starting the search two bytes from
     the start of the candidate IPFIX Message.
 The algorithm above will improperly identify a non-message as a
 message approximately 1 in 2^32 times, assuming random IPFIX data.
 It may be expanded to consider multiple candidate IPFIX Messages in
 order to increase reliability.
 In applications (e.g., archival storage) in which error resilience is
 very important, File Writers SHOULD use block compression algorithms,
 and MAY attempt to align IPFIX Messages within compression blocks to
 ease resynchronization after errors.  File Readers SHOULD use the
 resynchronization algorithm above to minimize data loss due to
 compression errors.

11. Recommended File Integration Strategies

 This section describes methods for integrating IPFIX File data with
 other file formats.

11.1. Encapsulation of Non-IPFIX Data in IPFIX Files

 At times, it may be useful to export or store non-IPFIX data inline
 in an IPFIX File or Message stream.  To do this cleanly, this data
 must be encapsulated into IPFIX Messages so that an IPFIX File Reader
 or Collecting Process can handle it without any need to interpret it.
 At the same time, this data must not be changed during transmission
 or storage.  The opaqueOctets Information Element, as defined in
 Section 8.2.17, is provided for this encapsulation.

Trammell, et al. Standards Track [Page 41] RFC 5655 IPFIX Files October 2009

 Processing the encapsulated non-IPFIX data is left to a separate
 processing mechanisms that can identify encapsulated non-IPFIX data
 in an IPFIX Message Stream, but need not have any other IPFIX
 handling capability, except the ability to skip over all IPFIX
 Messages that do not encapsulate non-IPFIX data.
 The Message Checksum Options Template, described in Section 8.1.1,
 may be used as a uniform mechanism to identify errors within
 encapsulated data.
 Note that this mechanism can only encapsulate data objects up to
 65,515 octets in length.  If the space available in one IPFIX Message
 is not enough for the amount of data to be encapsulated, then the
 data must be broken into smaller segments that are encapsulated into
 consecutive IPFIX Messages.  Any additional structuring or semantics
 of the raw data is outside the scope of IPFIX and must be implemented
 within the encapsulated binary data itself.  Furthermore, the raw
 encapsulated data cannot be assumed by an IPFIX File Reader to have
 any specific format.

11.2. Encapsulation of IPFIX Files within Other File Formats

 Consequently, it may also be useful to reverse the encapsulation,
 that is, to export or store IPFIX data inline within a non-IPFIX File
 or data stream.  This makes sense when the other file format is not
 compatible with the encapsulation described above in Section 11.1.
 Generally speaking, the encapsulation here will be specific to the
 format of the containing file.  For example, IPFIX Files may be
 embedded in XML elements using hex or Base64 encoding, or in raw
 binary files using start and end delimiters or some form of run-
 length encoding.  As there are as many potential encapsulations here
 as there are potential file formats, the specifics of each are out of
 scope for this specification.

12. Security Considerations

 The Security Considerations section of [RFC5101], on which the IPFIX
 File format is based, is largely concerned with the proper
 application of TLS and DTLS to ensure confidentiality and integrity
 when exporting IPFIX Messages.  By analogy, this document specifies
 the use of CMS [RFC3852] detached signatures to provide equivalent
 integrity protection to TLS and DTLS in Section 9.1.  However, aside
 from merely applying CMS for signatures, there are several security
 issues which much be considered in certain circumstances; these are
 covered in the subsections below.

Trammell, et al. Standards Track [Page 42] RFC 5655 IPFIX Files October 2009

12.1. Relationship between IPFIX File and Transport Encryption

 The underlying protocol used to exchange the information that will be
 stored using the format proposed in this document must as well apply
 appropriate procedures to guarantee the integrity and confidentiality
 of the exported information.  Such issues are addressed in [RFC5101].
 Specifically, IPFIX Files that store data taken from an IPFIX
 Collecting Process using TLS or DTLS for transport security SHOULD be
 signed as in Section 9.1 and SHOULD be encrypted out of band; storage
 of such flow data without encryption may present a potential breach
 of confidentiality.  Conversely, flow data considered sensitive
 enough to require encryption in storage that is later transmitted
 using IPFIX SHOULD be transmitted using TLS or DTLS for transport
 security.

12.2. End-to-End Assertions for IPFIX Files

 Note that while both TLS and CMS provide the ability to sign an IPFIX
 Transport Session or an IPFIX File, there exists no method for
 protecting data integrity end-to-end in the case in which a
 Collecting Process is collocated with a File Writer.  The channel
 between the Exporting Process to Collecting Process using IPFIX is
 signed by the Exporting Process key and protected via TLS and DTLS,
 while the File is signed by the File Writer key and protected via
 CMS.  The identity of the Exporting Process is not asserted in the
 file, and the records may be modified between the Collecting Process
 and the File Writer.
 There are two potential ways to address this issue.  The first is by
 fiat, and is appropriate only when the application allows the
 Collecting-Process-to-File-Writer channel to be trusted.  In this
 case, the File Writer's signature is an implicit assertion that the
 channel to the Exporting Process was protected, that the Exporting
 Process's signature was verified, and that the data was not changed
 after collection.  For this to work, a File Writer collocated with a
 Collecting Process SHOULD NOT sign a File as specified in Section 9.1
 unless the Transport Session over which the data was exported was
 protected via TLS or DTLS, and the Collecting Process positively
 identified the Exporting Process by its certificate.  The File Writer
 SHOULD include the Exporting Process and Collecting Process
 certificates within the File using the Export Session Detail Options
 Template in Section 8.1.3 or the Message Detail Options Template in
 Section 8.1.4 to allow for later verification.
 In situations in which the Collecting Process and/or File Writer
 cannot be trusted, end-to-end integrity can then be approximated by
 collocating the File Writer with the Metering Process, and removing
 the IPFIX protocol completely from the chain.  In this case, the File

Trammell, et al. Standards Track [Page 43] RFC 5655 IPFIX Files October 2009

 Writer's signature is an implicit assertion that the Metering Process
 is identified and is not tampering with the information as observed
 on the wire.
 Verification of these trust relationships is out of scope for this
 document, and should be considered on a per-implementation basis.

12.3. Recommendations for Strength of Cryptography for IPFIX Files

 Note that when encrypting files for archival storage, the
 cryptographic strength is dependent on the length of time over which
 archival data is expected to be kept.  Long-term storage may require
 re-application of cryptographic protection, periodically resigning
 and reencrypting files with stronger keys.  In this case, it is
 recommended that the existing signed and/or encypted data be
 encapsulated within newer, stronger protection.  See [RFC4810] for a
 discussion of this issue.

13. IANA Considerations

 This document specifies the creation of several new IPFIX Information
 Elements in the IPFIX Information Element registry located at
 http://www.iana.org, as defined in Section 8.2 above.  IANA has
 assigned the following Information Element numbers for their
 respective Information Elements as specified below:
 o  Information Element number 258 for the collectionTimeMilliseconds
    Information Element.
 o  Information Element number 274 for the collectorCertificate
    Information Element.
 o  Information Element number 275 for the exporterCertificate
    Information Element.
 o  Information Element number 259 for the exportSctpStreamId
    Information Element.
 o  Information Element number 260 for the maxExportSeconds
    Information Element.
 o  Information Element number 268 for the maxFlowEndMicroseconds
    Information Element.
 o  Information Element number 269 for the maxFlowEndMilliseconds
    Information Element.

Trammell, et al. Standards Track [Page 44] RFC 5655 IPFIX Files October 2009

 o  Information Element number 270 for the maxFlowEndNanoseconds
    Information Element.
 o  Information Element number 261 for the maxFlowEndSeconds
    Information Element.
 o  Information Element number 262 for the messageMD5Checksum
    Information Element.
 o  Information Element number 263 for the messageScope Information
    Element.
 o  Information Element number 264 for the minExportSeconds
    Information Element.
 o  Information Element number 271 for the minFlowStartMicroseconds
    Information Element.
 o  Information Element number 272 for the minFlowStartMilliseconds
    Information Element.
 o  Information Element number 273 for the minFlowStartNanoseconds
    Information Element.
 o  Information Element number 265 for the minFlowStartSeconds
    Information Element.
 o  Information Element number 266 for the opaqueOctets Information
    Element.
 o  Information Element number 267 for the sessionScope Information
    Element.
 IANA has created the media type application/ipfix for IPFIX data, as
 described by the following registration information:
 Type name:   application
 Subtype name:   ipfix
 Required parameters:   none
 Optional parameters:   none
 Encoding considerations:   IPFIX Files are binary, and therefore must
    be encoded in non-binary contexts.

Trammell, et al. Standards Track [Page 45] RFC 5655 IPFIX Files October 2009

 Security considerations:   See the Security Considerations
    (Section 12) of RFC 5655, and the Security Considerations of
    [RFC5101].
 Interoperability considerations:   See the "Detailed Specification"
    (Section 7) of RFC 5655.  The format is designed to be broadly
    interoperable, as any valid stream of IPFIX Messages over any
    transport specified in [RFC5101] MUST be recognizable as a valid
    IPFIX File.
 Published specification:   RFC 5655, especially Section 7, and
    [RFC5101].
 Applications that use this media type:   Various IPFIX
    implementations (see [RFC5153]) support the construction of IPFIX
    File Readers and Writers.
 Additional information:
    Magic number(s):   None, although the first two bytes of any IPFIX
       File are the first two bytes of a message header, the Version
       field, which as of [RFC5101] are always 10 in network byte
       order: 0x00, 0x0A.
    File extension(s):   .ipfix
    Macintosh file type code(s):   none
 Person & email address to contact for further information:   Brian
    Trammell <brian.trammell@hitachi-eu.com> for the authors of RFC
    5655; Nevil Brownlee <n.brownlee@auckland.ac.nz> for the IPFIX
    Working Group.
 Intended usage:   LIMITED USE
 Restrictions on usage:   none
 Change controller:   Brian Trammell <brian.trammell@hitachi-eu.com>
    for the authors of RFC 5655; Nevil Brownlee
    <n.brownlee@auckland.ac.nz> for the IPFIX Working Group.

14. Acknowledgements

 Thanks to Maurizio Molina, Tom Kosnar, and Andreas Kind for technical
 assistance with the requirements for a standard flow storage format.
 Thanks to Benoit Claise, Paul Aitken, Andrew Johnson, Gerhard Muenz,
 and Nevil Brownlee for their reviews and feedback.  Thanks to Pasi
 Eronen for pointing out [RFC5485], and Russ Housley for writing it;

Trammell, et al. Standards Track [Page 46] RFC 5655 IPFIX Files October 2009

 it specifies a detached signature format, from which Section 9.1 is
 largely drawn.  Thanks to the PRISM project for its support of this
 work.

15. References

15.1. Normative References

 [RFC5101]    Claise, B., "Specification of the IP Flow Information
              Export (IPFIX) Protocol for the Exchange of IP Traffic
              Flow Information", RFC 5101, January 2008.
 [RFC5102]    Quittek, J., Bryant, S., Claise, B., Aitken, P., and J.
              Meyer, "Information Model for IP Flow Information
              Export", RFC 5102, January 2008.
 [RFC5610]    Boschi, E., Trammell, B., Mark, L., and T. Zseby,
              "Exporting Type Information for IP Flow Information
              Export (IPFIX) Information Elements", RFC 5610,
              July 2009.
 [RFC1321]    Rivest, R., "The MD5 Message-Digest Algorithm",
              RFC 1321, April 1992.
 [RFC1952]    Deutsch, P., Gailly, J-L., Adler, M., Deutsch, L., and
              G. Randers-Pehrson, "GZIP file format specification
              version 4.3", RFC 1952, May 1996.
 [RFC2119]    Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.
 [RFC3852]    Housley, R., "Cryptographic Message Syntax (CMS)",
              RFC 3852, July 2004.
 [RFC4810]    Wallace, C., Pordesch, U., and R. Brandner, "Long-Term
              Archive Service Requirements", RFC 4810, March 2007.
 [RFC5280]    Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation
              List (CRL) Profile", RFC 5280, May 2008.
 [bzip2]      Seward, J., "bzip2 (http://www.bzip.org/)", March 2008.

Trammell, et al. Standards Track [Page 47] RFC 5655 IPFIX Files October 2009

15.2. Informative References

 [RFC3917]    Quittek, J., Zseby, T., Claise, B., and S. Zander,
              "Requirements for IP Flow Information Export (IPFIX)",
              RFC 3917, October 2004.
 [RFC3954]    Claise, B., "Cisco Systems NetFlow Services Export
              Version 9", RFC 3954, October 2004.
 [RFC5153]    Boschi, E., Mark, L., Quittek, J., Stiemerling, M., and
              P. Aitken, "IP Flow Information Export (IPFIX)
              Implementation Guidelines", RFC 5153, April 2008.
 [RFC5470]    Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,
              "Architecture for IP Flow Information Export", RFC 5470,
              March 2009.
 [RFC5471]    Schmoll, C., Aitken, P., and B. Claise, "Guidelines for
              IP Flow Information Export (IPFIX) Testing", RFC 5471,
              March 2009.
 [RFC5472]    Zseby, T., Boschi, E., Brownlee, N., and B. Claise, "IP
              Flow Information Export (IPFIX) Applicability",
              RFC 5472, March 2009.
 [RFC5473]    Boschi, E., Mark, L., and B. Claise, "Reducing
              Redundancy in IP Flow Information Export (IPFIX) and
              Packet Sampling (PSAMP) Reports", RFC 5473, March 2009.
 [SAINT2007]  Trammell, B., Boschi, E., Mark, L., and T. Zseby,
              "Requirements for a standardized flow storage solution",
               in Proceedings of the SAINT 2007 workshop on Internet
              Measurement Technology, Hiroshima, Japan, January 2007.
 [RFC3851]    Ramsdell, B., "Secure/Multipurpose Internet Mail
              Extensions (S/MIME) Version 3.1 Message Specification",
              RFC 3851, July 2004.
 [RFC4288]    Freed, N. and J. Klensin, "Media Type Specifications and
              Registration Procedures", BCP 13, RFC 4288,
              December 2005.
 [RFC5485]    Housley, R., "Digital Signatures on Internet-Draft
              Documents", RFC 5485, March 2009.
 [pcap]       "libpcap (http://www.tcpdump.org/)", October 2008.

Trammell, et al. Standards Track [Page 48] RFC 5655 IPFIX Files October 2009

Appendix A. Example IPFIX File

 In this section we will explore an example IPFIX File that
 demonstrates the various features of the IPFIX File format.  This
 File contains flow records described by a single Template.  This File
 also contains a File Time Window record to note the start and end
 time of the data, and an Export Session Details record to record
 collection infrastructure information.  Each Message within this File
 also contains a Message Checksum record, as this File may be
 externally encrypted and/or stored as an archive.  The structure of
 this File is shown in Figure 2.
           +=================================================+
           | IPFIX Message                       seq. 0      |
           | +---------------------------------------------+ |
           | | Template Set (ID 2)                  1 rec  | |
           | |   Data Tmpl. ID 256                         | |
           | +---------------------------------------------+ |
           | | Options Template Set (ID 3)          3 recs | |
           | |   File Time Window Opt. Tmpl. ID 257        | |
           | |   Message Checksum Opt. Tmpl. ID 259        | |
           | |   Export Session Details Opt. Tmpl. ID 258  | |
           | +---------------------------------------------+ |
           | | Data Set (ID 259) [Message Checksum] 1 rec  | |
           | +---------------------------------------------+ |
           +=================================================+
           | IPFIX Message                       seq. 1      |
           | +---------------------------------------------+ |
           | | Data Set (ID 257) [File Time Window] 1 rec  | |
           | +---------------------------------------------+ |
           | | Data Set (ID 258) [Export Session]   1 rec  | |
           | +---------------------------------------------+ |
           | | Data Set (ID 259) [Message Checksum] 1 rec  | |
           | +---------------------------------------------+ |
           +=================================================+
           | IPFIX Message                       seq. 4      |
           | +---------------------------------------------+ |
           | | Data Set (ID 256)                   50 recs | |
           | |  contains flow data                         | |
           | +---------------------------------------------+ |
           | | Data Set (ID 259) [Message Checksum] 1 rec  | |
           | +---------------------------------------------+ |
           +=================================================+
           | IPFIX Message                       seq. 55     |
           |                    . . .                        |
                   Figure 2: File Example Structure

Trammell, et al. Standards Track [Page 49] RFC 5655 IPFIX Files October 2009

 The Template describing the data records contains a flow start
 timestamp, an IPv4 5-tuple, and packet and octet total counts.  The
 Template Set defining this is as shown in Figure 3 below:
                      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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Set ID = 2           |          Length =  40         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |      Template ID = 256        |        Field Count = 8        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| flowStartSeconds      = 150 |       Field Length =  4       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| sourceIPv4Address     =   8 |       Field Length =  4       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| dest.IPv4Address      =  12 |       Field Length =  4       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| sourceTransportPort   =   7 |       Field Length =  2       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| dest.TransportPort    =  11 |       Field Length =  2       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| protocolIdentifier    =   4 |       Field Length =  1       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| octetTotalCount       =  85 |       Field Length =  4       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| packetTotalCount      =  86 |       Field Length =  4       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 Figure 3: File Example Data Template

A.1. Example Options Templates

 This is followed by an Options Template Set containing the Options
 Templates required to read the File: the File Time Window Options
 Template (defined in Section 8.1.2 above), the Export Session Details
 Options Template (defined in Section 8.1.3 above), and the Message
 Checksum Options Template (defined in Section 8.1.1 above).  This
 Options Template Set is shown in Figure 4 and Figure 5 below:

Trammell, et al. Standards Track [Page 50] RFC 5655 IPFIX Files October 2009

                      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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Set ID = 3           |          Length =  80         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |      Template ID = 257        |        Field Count = 3        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Scope Field Count = 1      |0| sessionScope          = 267 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length = 1        |0| minFlowStartSeconds   = 265 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length = 4        |0| maxFlowEndSeconds     = 261 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length = 4        |      Template ID = 259        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Count = 2         |    Scope Field Count = 1      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| messageScope          = 263 |       Field Length =  1       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| messageMD5Checksum    = 262 |       Field Length = 16       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  Figure 4: File Example Options Templates (Time Window and Checksum)

Trammell, et al. Standards Track [Page 51] RFC 5655 IPFIX Files October 2009

                      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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Template ID = 258       |         Field Count = 9       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |    Scope Field Count = 1      |0| sessionScope          = 267 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  1       |0| exporterIPv4Address   = 130 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  4       |0| collectorIPv4Address  = 211 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  4       |0| exporterTransportPort = 217 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  2       |0| col.TransportPort     = 216 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  2       |0| col.TransportProtocol = 215 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  1       |0| col.ProtocolVersion   = 214 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  1       |0| minExportSeconds      = 264 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  4       |0| maxExportSeconds      = 260 |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Field Length =  4       |     set padding (2 octets)    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 Figure 5: File Example Options Templates, Continued (Session Details)

A.2. Example Supplemental Options Data

 Following the Templates required to decode the File is the
 supplemental IPFIX Options information used to describe the File's
 contents and type information.  First comes the File Time Window
 record; it notes that the File contains data from 9 October 2007
 between 00:01:13 and 23:56:27 UTC, and appears as in Figure 6:

Trammell, et al. Standards Track [Page 52] RFC 5655 IPFIX Files October 2009

                      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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Set ID = 257         |          Length =  13         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | sessionScope  |           minFlowStartSeconds
 |       0       |         2007-10-09 00:01:13 UTC           . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |            maxFlowEndSeconds
 . . .           |         2007-10-09 23:56:27 UTC           . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |
 . . .           |
 +-+-+-+-+-+-+-+-+
                  Figure 6: File Example Time Window
 This is followed by information about how the data in the File was
 collected, in the Export Session Details record.  This record notes
 that the session stored in this File was sent via SCTP from an
 Exporter at 192.0.2.30 port 32769 to a Collector at 192.0.2.40 port
 4739, and contains messages exported between 00:01:57 and 23:57:12
 UTC on 9 October 2007; it is represented in its Data Set as in
 Figure 7:

Trammell, et al. Standards Track [Page 53] RFC 5655 IPFIX Files October 2009

                     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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Set ID = 258         |          Length =  27         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | sessionScope  |           exporterIPv4Address
 |       0       |               192.0.2.30                  . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |           collectorIPv4Address
 . . .           |               192.0.2.31                  . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |     exporterTransportPort     |   cTPort
 . . .           |             32769             |    4739   . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |   cTProtocol  |  cPVersion    |
 . . .           |      132      |     10        |           . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              minExportSeconds                   |
 . . .     2007-10-09 00:01:57 UTC               |           . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              maxExportSeconds                   |
 . . .     2007-10-09 23:57:12 UTC               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             Figure 7: File Example Export Session Details

A.3. Example Message Checksum

 Each IPFIX Message within the File is completed with a Message
 Checksum record; the structure of this record within its Data Set is
 as in Figure 8:
  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
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Set ID = 259         |          Length =  24         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | messageScope  |                                               |
 |       0       |                                               |
 +-+-+-+-+-+-+-+-+                                               |
 |                       messageMD5Checksum                      |
 |           (16-byte MD5 checksum of options message)           |
 |                                                               |
 |                                                               |
 |               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |               |              set padding (3 octets)           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                Figure 8: File Example Message Checksum

Trammell, et al. Standards Track [Page 54] RFC 5655 IPFIX Files October 2009

A.4. File Example Data Set

 After the Templates and supplemental Options information comes the
 data itself.  The first record of an example Data Set is shown with
 its message and set headers in Figure 9:
                      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 = 10              |         Length = 1296         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Export Time = 2007-10-09 00:01:57 UTC                |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      Sequence Number = 4                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                   Observation Domain ID = 1                   |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Set ID = 256           |          Length = 1254         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      flowStartSeconds                         |
 |                    2007-10-09 00:01:13 UTC                    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                      sourceIPv4Address                        |
 |                          192.0.2.2                            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    destinationIPv4Address                     |
 |                          192.0.2.3                            |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |      sourceTransportPort      |   destinationTransportPort    |
 |             32770             |               80              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |  protocolId   |             totalOctetCount
 |       6       |                  18000                    . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             totalPacketCount
 . . .           |                    65                     . . .
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 |             (49 more records)
 . . .           |
 +-+-+-+-+-+-+-+-+
                    Figure 9: File Example Data Set

A.5. Complete File Example

 Bringing together the examples above and adding message headers as
 appropriate, a hex dump of the first 317 bytes of the example File
 constructed above would appear as in the annotated Figure 10 below.

Trammell, et al. Standards Track [Page 55] RFC 5655 IPFIX Files October 2009

   0:|00 0A 00 A0 47 0A B6 E5 00 00 00 00 00 00 00 01
    [^ first message header (length 160 bytes) -->
  16:|00 02 00 28 01 00 00 08 00 96 00 04 00 08 00 04
    [^ data template set -->
  32: 00 0C 00 04 00 07 00 02 00 0B 00 02 00 04 00 01
  48: 00 55 00 04 00 56 00 04|00 03 00 50 01 01 00 03
                            [^ opt template set -->
  64: 00 01 01 0B 00 01 01 09 00 04 01 05 00 04 01 03
  80: 00 02 00 01 01 07 00 01 01 06 00 10 01 02 00 09
  96: 00 01 01 0B 00 01 00 82 00 04 00 D3 00 04 00 D9
 112: 00 02 00 D8 00 02 00 D7 00 01 00 D0 00 01 01 08
 128: 00 04 01 04 00 04 00 00|01 03 00 18 00 73 F1 12
                            [^ checksum record -->
 144: D6 C7 58 BE 44 E6 60 06 4E 78 74 AE 7D 00 00 00
 176:|00 0A 00 50 47 0A B6 E5 00 00 00 01 00 00 00 01
    [^ second message header (length 80 bytes) -->
 192:|01 01 00 0E 00 47 0A B6 B9 47 0C 07 1B 00|01 02
    [^ time window rec -> [ session detail rec ^ -->
 208: 00 1C 00 C0 00 02 1E 0C 00 02 1F 80 01 12 83 84
 224: 0A 47 0A B6 E5 47 0C 07 48 00|01 03 00 18 00 3E
         [ message checksum record ^ -->
 240: 2B 37 08 CE B2 0E 30 11 32 12 4A 5F E3 AD DB 00
 256:|00 0A 05 10 47 0A B6 E5 00 00 00 06 00 00 00 01
    [^ third message header (length 1296 bytes) -->
 272:|01 00 04 E6|47 0A B6 B9 C0 00 02 02 C0 00 02 03
    [^ set hdr ][^ first data rec -->
 288: 80 02 00 50 06 00 00 46 50 00 00 00 41
                   Figure 10: File Example Hex Dump

Trammell, et al. Standards Track [Page 56] RFC 5655 IPFIX Files October 2009

Appendix B. Applicability of IPFIX Files to NetFlow V9 Flow Storage

 As the IPFIX Message format is nearly a superset of the NetFlow V9
 packet format, IPFIX Files can be used for store NetFlow V9 data
 relatively easily.  This section describes a method for doing so.
 The differences between the two protocols are outlined in
 Appendix B.1 below.  A simple, lightweight, message-for-message
 translation method for transforming V9 Packets into IPFIX Messages
 for storage within IPFIX Files is described in Appendix B.2.  An
 example of this translation method is given in Appendix B.3.

B.1. Comparing NetFlow V9 to IPFIX

 With a few caveats, the IPFIX protocol is a superset of the NetFlow
 V9 protocol, having evolved from it largely through a process of
 feature addition to bring it into compliance with the IPFIX
 Requirements and the needs of stakeholders within the IPFIX Working
 Group.  This appendix outlines the differences between the two
 protocols.  It is informative only, and presented as an exploration
 of the two protocols to motivate the usage of IPFIX Files to store
 V9-collected flow data.

B.1.1. Message Header Format

 Both NetFlow V9 and IPFIX use streams of messages prefixed by a
 message header, though the message header differs significantly
 between the two.  Note that in NetFlow V9 terminology, these messages
 are called packets, and messages must be delimited by datagram
 boundaries.  IPFIX does not have this constraint.  The header formats
 are detailed below:
  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                              |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
              Figure 11: NetFlow V9 Packet Header Format

Trammell, et al. Standards Track [Page 57] RFC 5655 IPFIX Files October 2009

  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          |            Length             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                           Export Time                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       Sequence Number                         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                    Observation Domain ID                      |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                Figure 12: IPFIX Message Header Format
 Version Number:   The IPFIX Version Number MUST be 10, while the
    NetFlow V9 Version Number MUST be 9.
 Length vs. Count:   The Count field in the NetFlow V9 packet header
    counts records in the message (including Data and Template
    Records), while the Length field in the IPFIX Message Header
    counts octets in the message.  Note that this implies that NetFlow
    V9 collectors must rely on datagram boundaries or some other
    external delimiter; otherwise, they must completely consume a
    message before finding its end.
 System Uptime:   System uptime in milliseconds is exported in the
    NetFlow V9 packet header.  This field is not present in the IPFIX
    Message Header, and must be exported using an IPFIX Option if
    required.
 Export Time:   Aside from being called UNIX Secs in the NetFlow V9
    packet header specification, the export time in seconds since 1
    January 1970 at 0000 UTC appears in both NetFlow V9 and IPFIX
    message headers.
 Sequence Number:   The NetFlow V9 Sequence Number counts packets,
    while the IPFIX Sequence Number counts records in Data Sets.  Both
    are scoped to Observation Domain.
 Observation Domain ID:   Similarly, the NetFlow V9 sourceID has
    become the IPFIX Observation Domain ID.

B.1.2. Set Header Format

 Set headers are identical between NetFlow V9 and IPFIX; that is, each
 Set (FlowSet in NetFlow V9 terminology) is prefixed by a 4-byte set
 header containing the Set ID and the length of the set in octets.

Trammell, et al. Standards Track [Page 58] RFC 5655 IPFIX Files October 2009

 Note that the special Set IDs are different between IPFIX and NetFlow
 V9.  IPFIX Template Sets are identified by Set ID 2, while NetFlow V9
 Template FlowSets are identified by Set ID 0.  Similarly, IPFIX
 Options Template Sets are identified by Set ID 3, while NetFlow V9
 Options Template FlowSets are identified by Set ID 1.
 Both protocols reserve Set IDs 0-255, and use Set IDs 256-65535 for
 Data Sets (or FlowSets, in NetFlow V9 terminology).

B.1.3. Template Format

 Template FlowSets in NetFlow V9 support a subset of functionality of
 those in IPFIX.  Specifically, NetFlow V9 does not have any support
 for vendor-specific Information Elements as IPFIX does, so there is
 no enterprise bit or facility for associating a private enterprise
 number with an information element.  NetFlow V9 also does not support
 variable-length fields.
 Options Template FlowSets in NetFlow V9 are similar to Options
 Template Sets in IPFIX subject to the same caveats.

B.1.4. Information Model

 The NetFlow V9 field type definitions are a compatible subset of, and
 have evolved in concert with, the IPFIX Information Model.  IPFIX
 Information Element identifiers in the range 1-127 are defined by the
 IPFIX Information Model [RFC5102] to be compatible with the
 corresponding NetFlow V9 field types.

B.1.5. Template Management

 NetFlow V9 has no concept of a Transport Session as in IPFIX, as
 NetFlow V9 was designed with a connectionless transport in mind.
 Template IDs are therefore scoped to an Exporting Process lifetime
 (i.e., an Exporting Process instance between restarts).  There is no
 facility in NetFlow V9 as in IPFIX for Template withdrawal or
 Template ID reuse.  Template retransmission at the Exporter works as
 in UDP-based IPFIX Exporting Processes.

B.1.6. Transport

 In practice, though NetFlow V9 is designed to be transport-
 independent, it is transported only over UDP.  There is no facility
 as in IPFIX for full connection-oriented transport without datagram
 boundaries, due to the use of a record count field as opposed to a
 message length field in the packet header.  There is no support in
 NetFlow V9 for transport layer security via TLS or DTLS.

Trammell, et al. Standards Track [Page 59] RFC 5655 IPFIX Files October 2009

B.2. A Method for Transforming NetFlow V9 Messages to IPFIX

 This appendix describes a method for transforming NetFlow V9 Packets
 into IPFIX Messages, which can be used to store NetFlow V9 data in
 IPFIX Files.  A process transforming NetFlow V9 Packets into IPFIX
 Messages must handle the fact that NetFlow V9 Packets and IPFIX
 Messages are framed differently, that sequence numbering works
 differently, and that the NetFlow V9 field type definitions are only
 compatible with the IPFIX Information Model below Information Element
 identifier 128.
 For each incoming NetFlow V9 packet, the transformation process must:
 1.  Verify that the Version field of the packet header is 9.
 2.  Verify that the Sequence Number field of the packet header is
     valid.
 3.  Scan the packet to:
     1.  Verify that it contains no Templates with field types outside
         the range 1-127;
     2.  Verify that it contains no FlowSets with Set IDs between 2
         and 255 inclusive;
     3.  Verify that it contains the number of records in FlowSets,
         Template FlowSets, and Options Template FlowSets declared in
         the Count field of the packet header; and
     4.  Count the number of records in Data FlowSets for calculating
         the IPFIX Sequence Number.
 4.  Calculate a Sequence Number for each IPFIX Observation Domain by
     storing the last Sequence Number sent for each Observation Domain
     plus the count of records in Data FlowSets in the previous step
     to be sent as the Sequence Number for the IPFIX Message following
     this one within that Observation Domain.
 5.  Generate a new IPFIX Message Header with:
     1.  a Version field of 10;
     2.  a Length field with the number of octets in the IPFIX
         Message, generally available by subtracting 4 from the length
         of the NetFlow V9 packet as returned from the transport layer
         (accounting for the difference in message header lengths);

Trammell, et al. Standards Track [Page 60] RFC 5655 IPFIX Files October 2009

     3.  the Sequence Number calculated for this message by the
         Sequence Number calculation step; and
     4.  Export Time and Observation Domain ID taken from the UNIX
         secs and Source ID fields of the NetFlow V9 packet header,
         respectively.
 6.  Copy each FlowSet from the Netflow V9 packet to the IPFIX Message
     after the header.  Replace Set ID 0 with Set ID 2 for Template
     Sets, and Set ID 1 with Set ID 3 for Options Template Sets.
 Note that this process loses system uptime information; if such
 information is required, the transformation process will have to
 export that information using IPFIX Options.  This may require a more
 sophisticated transformation process structure.

B.3. NetFlow V9 Transformation Example

 The following two figures show a single NetFlow V9 packet with
 templates and the corresponding IPFIX Message, exporting a single
 flow record representing 60,303 octets sent from 192.0.2.2 to
 192.0.2.3.  This would be the third packet exported in Observation
 Domain 33 from the NetFlow V9 exporter, containing records starting
 with the 12th record (packet and record sequence numbers count from
 0).
 The ** symbol in the IPFIX example shows those fields that required
 modification from the NetFlow V9 packet by the transformation
 process.

Trammell, et al. Standards Track [Page 61] RFC 5655 IPFIX Files October 2009

                      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 = 9          |         Count = 2             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |               Uptime = 3750405 ms (1:02:30.405)               |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |   Export Time = 1171557627 epoch sec (2007-02-15 16:40:27)    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                     Sequence Number = 2                       |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                 Observation Domain ID = 33                    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |           Set ID = 0          |       Set Length = 20         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Template ID = 256       |       Field Count = 3         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | IPV4_SRC_ADDR           =   8 |       Field Length = 4        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | IPV4_DST_ADDR           =  12 |       Field Length = 4        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | IN_BYTES                =   1 |       Field Length = 4        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Set ID = 256         |       Set Length = 16         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                         IPV4_SRC_ADDR                         |
 |                           192.0.2.2                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                         IPV4_DST_ADDR                         |
 |                           192.0.2.3                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                           IN_BYTES                            |
 |                             60303                             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                 Figure 13: Example NetFlow V9 Packet

Trammell, et al. Standards Track [Page 62] RFC 5655 IPFIX Files October 2009

                     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 = 10         | **      Length = 52           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |   Export Time = 1171557627 epoch sec (2007-02-15 16:40:27)    |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | **                   Sequence Number = 11                     |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                   Observation Domain ID = 33                  |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 | **         Set ID = 2         |       Set Length = 20         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |       Template ID = 256       |       Field Count  = 3        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| sourceIPv4Address      =  8 |       Field Length = 4        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| destinationIPv4Address = 12 |       Field Length = 4        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |0| octetDeltaCount        =  1 |       Field Length = 4        |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |          Set ID = 256         |       Set Length = 16         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                       sourceIPv4Address                       |
 |                           192.0.2.2                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                     destinationIPv4Address                    |
 |                           192.0.2.3                           |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                        octetDeltaCount                        |
 |                             60303                             |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
            Figure 14: Corresponding Example IPFIX Message

Trammell, et al. Standards Track [Page 63] RFC 5655 IPFIX Files October 2009

Authors' Addresses

 Brian Trammell
 Hitachi Europe
 c/o ETH Zurich
 Gloriastrasse 35
 8092 Zurich
 Switzerland
 Phone: +41 44 632 70 13
 EMail: brian.trammell@hitachi-eu.com
 Elisa Boschi
 Hitachi Europe
 c/o ETH Zurich
 Gloriastrasse 35
 8092 Zurich
 Switzerland
 Phone: +41 44 632 70 57
 EMail: elisa.boschi@hitachi-eu.com
 Lutz Mark
 Fraunhofer IFAM
 Wiener Str. 12
 28359 Bremen
 Germany
 Phone: +49 421 2246206
 EMail: lutz.mark@ifam.fraunhofer.de
 Tanja Zseby
 Fraunhofer Institute for Open Communication Systems
 Kaiserin-Augusta-Allee 31
 10589 Berlin
 Germany
 Phone: +49 30 3463 7153
 EMail: tanja.zseby@fokus.fraunhofer.de
 Arno Wagner
 ETH Zurich
 Gloriastrasse 35
 8092 Zurich
 Switzerland
 Phone: +41 44 632 70 04
 EMail: arno@wagner.name

Trammell, et al. Standards Track [Page 64]

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