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Internet Engineering Task Force (IETF)                         B. ClaiseRequest for Comments: 7119                           Cisco Systems, Inc.Category: Standards Track                                   A. KobayashiISSN: 2070-1721                                                      NTT                                                             B. Trammell                                                              ETH Zurich                                                           February 2014Operation of the IP Flow Information Export (IPFIX) Protocolon IPFIX MediatorsAbstract   This document specifies the operation of the IP Flow Information   Export (IPFIX) protocol specific to IPFIX Mediators, including   Template and Observation Point management, timing considerations, and   other Mediator-specific concerns.Status of This Memo   This is an Internet Standards Track document.   This document is a product of the Internet Engineering Task Force   (IETF).  It represents the consensus of the IETF community.  It has   received public review and has been approved for publication by the   Internet Engineering Steering Group (IESG).  Further information on   Internet Standards is available inSection 2 of RFC 5741.   Information about the current status of this document, any errata,   and how to provide feedback on it may be obtained athttp://www.rfc-editor.org/info/rfc7119.Copyright Notice   Copyright (c) 2014 IETF Trust and the persons identified as the   document authors.  All rights reserved.   This document is subject toBCP 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 Simplified BSD License.Claise, et al.               Standards Track                    [Page 1]

RFC 7119                     IPFIX MED-PROTO               February 2014Table of Contents1. Introduction ....................................................21.1. IPFIX Documents Overview ...................................31.2. IPFIX Mediator Documents Overview ..........................41.3. Relationship with the IPFIX and PSAMP Protocols ............52. Terminology .....................................................53. Handling IPFIX Message Headers ..................................84. Template Management ............................................104.1. Passing Unmodified Templates through an IPFIX Mediator ....114.1.1. Template Mapping and Information Element Ordering ..154.2. Creating New Templates at an IPFIX Mediator ...............174.3. Handling Unknown Information Elements .....................175. Preserving Original Observation Point Information ..............175.1. originalExporterIPv4Address Information Element ...........205.2. originalExporterIPv6Address Information Element ...........206. Managing Observation Domain IDs ................................206.1. originalObservationDomainId Information Element ...........217. Timing Considerations ..........................................218. Transport Considerations .......................................239. Collecting Process Considerations ..............................2310. Specific Reporting Requirements ...............................23      10.1. Intermediate Process Reliability Statistics            Options Template .........................................2410.2. Flow Key Options Template ................................2610.3. intermediateProcessId Information Element ................2610.4. ignoredDataRecordTotalCount Information Element ..........2711. Operations and Management Considerations ......................2712. Security Considerations .......................................2813. IANA Considerations ...........................................2814. Acknowledgments ...............................................2915. References ....................................................2915.1. Normative References .....................................2915.2. Informative References ...................................301.  Introduction   The IPFIX architectural components in [RFC5470] consist of IPFIX   Devices and IPFIX Collectors communicating using the IPFIX protocol   [RFC7011], which specifies how to export IP Flow information.  This   protocol is designed to export information about IP traffic Flows and   related measurement data, where a Flow is defined by a set of key   attributes (e.g., source and destination IP address, source and   destination port, etc.).   However, thanks to its Template mechanism, the IPFIX protocol can   export any type of information, as long as the relevant Information   Element is specified in the IPFIX Information Model [RFC7012],Claise, et al.               Standards Track                    [Page 2]

RFC 7119                     IPFIX MED-PROTO               February 2014   registered with IANA, or specified as an enterprise-specific   Information Element.  The IPFIX protocol [RFC7011] was not originally   written with IPFIX Mediators in mind.  Therefore, the IPFIX protocol   must be adapted for Intermediate Processes, as defined in the IPFIX   Mediation Reference Model as specified in Figure A of [RFC6183],   which is based on the IPFIX Mediation Problem Statement [RFC5982].   This document specifies the IP Flow Information Export (IPFIX)   protocol in the context of the implementation and deployment of IPFIX   Mediators.  The use of the IPFIX protocol within an IPFIX Mediator --   a device that contains both a Collecting Process and an Exporting   Process -- has an impact on the technical details of the usage of the   protocol.  An overview of the technical problem is covered inSection 6 of [RFC5982]: loss of original Exporter information, loss   of base time information, transport sessions management, loss of   Options Template Information, Template Id management, considerations   for network topology, IPFIX mediation interpretation, and   considerations for aggregation.   The specifications in this document are based on the IPFIX protocol   specifications [RFC7011], but they are adapted according to the IPFIX   Mediation Framework [RFC6183].1.1.  IPFIX Documents Overview   The IPFIX protocol [RFC7011] provides network administrators with   access to IP Flow information.   The architecture for the export of measured IP Flow information out   of an IPFIX Exporting Process to a Collecting Process is defined in   the IPFIX Architecture [RFC5470], per the requirements defined in the   IPFIX Requirements document, [RFC3917].   The IPFIX Architecture [RFC5470] specifies how IPFIX Data Records and   Templates are carried via a congestion-aware transport protocol from   IPFIX Exporting Processes to IPFIX Collecting Processes.   IPFIX has a formal description of IPFIX Information Elements, their   names, types, and additional semantic information, as specified in   the IPFIX Information Model [RFC7012].  The IPFIX Information Element   registry [IANA-IPFIX] is maintained by IANA.  New Information Element   definitions can be added to this registry subject to an Expert Review   [RFC5226], with additional process considerations described in   [RFC7013]; that document also provides guidelines for authors and   reviewers of new Information Element definitions.  The inline export   of the Information Element type information is specified in   [RFC5610].Claise, et al.               Standards Track                    [Page 3]

RFC 7119                     IPFIX MED-PROTO               February 2014   The IPFIX Applicability Statement [RFC5472] describes what type of   applications can use the IPFIX protocol and how they can use the   information provided.  It furthermore shows how the IPFIX framework   relates to other architectures and frameworks.1.2.  IPFIX Mediator Documents Overview   "IP Flow Information Export (IPFIX) Mediation: Problem Statement"   [RFC5982] provides an overview of the applicability of IPFIX   Mediators and defines requirements for IPFIX Mediators in general   terms.  This document is of use largely to define the problems to be   solved through the deployment of IPFIX Mediators and to provide scope   to the role of IPFIX Mediators within an IPFIX collection   infrastructure.   "IP Flow Information Export (IPFIX) Mediation: Framework" [RFC6183],   which details the IPFIX Mediation reference model and the components   of an IPFIX Mediator, provides more architectural details of the   arrangement of Intermediate Processes within an IPFIX Mediator.   Documents specifying the operations of specific Intermediate   Processes cover the operation of these Processes within the IPFIX   Mediator framework and comply with the specifications given in this   document; additionally, they may specify the operation of the process   independently, outside the context of an IPFIX Mediator, when this is   appropriate.  The details of specific Intermediate Processes, when   they have additional export specifications (e.g., metadata about the   intermediate processing conveyed through IPFIX Options Templates),   are each addressed in their own document.  As of today, these   documents are:   1.  "IP Flow Anonymization Support", [RFC6235], which describes       anonymization techniques for IP flow data and the export of       anonymized data using the IPFIX protocol.   2.  "Flow Selection Techniques" [RFC7014], which describes the       process of selecting a subset of Flows from all Flows observed at       an Observation Point, the flow selection motivations, and some       specific flow selection techniques.   3.  "Flow Aggregation for the IP Flow Information Export (IPFIX)       Protocol" [RFC7015], which describes Aggregated Flow export       within the framework of IPFIX Mediators and defines an       interoperable, implementation-independent method for Aggregated       Flow export.Claise, et al.               Standards Track                    [Page 4]

RFC 7119                     IPFIX MED-PROTO               February 2014   This document specifies the IP Flow Information Export (IPFIX)   protocol specific to Mediation, to which all Intermediate Processes   must comply.  Some extra specifications might be required per   Intermediate Process type (in which case, the document specific to   the Intermediate Process would apply).1.3.  Relationship with the IPFIX and PSAMP Protocols   The specification in this document is based on the IPFIX protocol   specification [RFC7011].  All specifications from [RFC7011] apply   unless specified otherwise in this document.   As the Packet Sampling (PSAMP) protocol specifications [RFC5476] are   based on the IPFIX protocol specifications, the specifications in   this document are also valid for the PSAMP protocol.  Therefore, the   method specified by this document also applies to PSAMP.2.  Terminology   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and   "OPTIONAL" in this document are to be interpreted as described in   [RFC2119].   IPFIX-specific terms, such as Observation Domain, Flow, Flow Key,   Metering Process, Exporting Process, Exporter, IPFIX Device,   Collecting Process, Collector, Template, IPFIX Message, Message   Header, Template Record, Data Record, Options Template Record, Set,   Data Set, Information Element, Scope and Transport Session, used in   this document are defined in [RFC7011].  The PSAMP-specific terms   used in this document, such as Filtering and Sampling, are defined in   [RFC5476].   IPFIX Mediation terms related to aggregation, such as the Interval,   Aggregated Flow and Aggregated Function, are defined in [RFC7015].   The terminology specific to IPFIX Mediation that is used in this   document is defined in "IP Flow Information Export (IPFIX) Mediation:   Problem Statement" [RFC5982] and reused in "IP Flow Information   Export (IPFIX) Mediation: Framework" [RFC6183].  However, since both   of those documents are Informational RFCs, the definitions have been   reproduced and elaborated on here.   Similarly, since [RFC6235] is an Experimental RFC, the Anonymization   Record, Anonymized Data Record, and Intermediate Anonymization   Process terms, specified in [RFC6235], are also reproduced here.Claise, et al.               Standards Track                    [Page 5]

RFC 7119                     IPFIX MED-PROTO               February 2014   In this document, as in [RFC7011], [RFC5476], [RFC7015], and   [RFC6235], the first letter of each IPFIX-specific and PSAMP-specific   term is capitalized along with the IPFIX Mediation-specific term   defined here.   In this document, we call a stream of records carrying flow- or   packet-based information a "record stream".  The records may be   encoded as IPFIX Data Records or any other format.   Transport Session:   The Transport Session is specified in [RFC7011].      In Stream Control Transmission Protocol (SCTP), the Transport      Session information is the SCTP association.  In TCP and UDP, the      Transport Session information corresponds to a 5-tuple {Exporter      IP address, Collector IP address, Exporter transport port,      Collector transport port, transport protocol}.   Original Exporter:   An Original Exporter is the source from which a      Mediator receives its record stream.  For simple IPFIX mediation      without protocol conversion, this is an IPFIX Device that hosts      the Observation Points where the metered IP packets are observed.   Original Observation Point:   An Observation Point on a Metering      Process associated with the Original Exporter.  In the case of the      Intermediate Aggregation Process on an IPFIX Mediator, the      Original Observation Point can be composed of, but not limited to,      a (set of) specific Exporter(s), a (set of) specific interface(s)      on an Exporter, a (set of) line card(s) on an Exporter, or any      combinations of these.   IPFIX Mediation:   IPFIX Mediation is the manipulation and conversion      of a record stream for subsequent export using the IPFIX protocol.   Template Mapping:   A mapping from Template Records and/or Options      Template Records received by an IPFIX Mediator to Template Records      and/or Options Template Records sent by that IPFIX Mediator.  Each      entry in a Template Mapping is scoped by incoming or outgoing      Transport Session and Observation Domain, as with Templates and      Options Templates in the IPFIX Protocol.   Anonymization Record:   A record that defines the properties of the      anonymization applied to a single Information Element within a      single Template or Options Template, as in [RFC6235].   Anonymized Data Record:   A Data Record within a Data Set containing      at least one Information Element with anonymized values.  The      Information Element(s) within the Template or Options Template      describing this Data Record SHOULD have a corresponding      Anonymization Record, as in [RFC6235].Claise, et al.               Standards Track                    [Page 6]

RFC 7119                     IPFIX MED-PROTO               February 2014   The following terms are used in this document to describe the   architectural entities used by IPFIX Mediation.   Intermediate Process:   An Intermediate Process takes a record stream      as its input from Collecting Processes, Metering Processes, IPFIX      File Readers, other Intermediate Processes, or other record      sources; performs some transformations on this stream, based upon      the content of each record, states maintained across multiple      records, or other data sources; and passes the transformed record      stream as its output to Exporting Processes, IPFIX File Writers,      or other Intermediate Processes, in order to perform IPFIX      Mediation.  Typically, an Intermediate Process is hosted by an      IPFIX Mediator.  Alternatively, an Intermediate Process may be      hosted by an Original Exporter.   IPFIX Mediator:   An IPFIX Mediator is an IPFIX Device that provides      IPFIX Mediation by receiving a record stream from some data      sources, hosting one or more Intermediate Processes to transform      that stream, and exporting the transformed record stream into      IPFIX Messages via an Exporting Process.  In the common case, an      IPFIX Mediator receives a record stream from a Collecting Process,      but it could also receive a record stream from data sources not      encoded using IPFIX, e.g., in the case of conversion from the      NetFlow V9 protocol [RFC3954] to IPFIX protocol.   Specific Intermediate Processes are described below.   Intermediate Conversion Process  (as in [RFC6183]): An Intermediate      Conversion Process is an Intermediate Process that transforms non-      IPFIX into IPFIX or manages the relation among Templates and      states of incoming/outgoing Transport Sessions in the case of      transport protocol conversion (e.g., from UDP to SCTP).   Intermediate Aggregation Process  (as in [RFC7015]): an Intermediate      Process (IAP), as in [RFC6183], that aggregates records, based      upon a set of Flow Keys or functions applied to fields from the      record.   Intermediate Correlation Process  (as in [RFC6183]): An Intermediate      Correlation Process is an Intermediate Process that adds      information to records, noting correlations among them, or      generates new records with correlated data from multiple records      (e.g., the production of bidirectional flow records from      unidirectional flow records).   Intermediate Anonymization Process  (as in [RFC6235]): An      intermediate process that takes Data Records and transforms them      into Anonymized Data Records.Claise, et al.               Standards Track                    [Page 7]

RFC 7119                     IPFIX MED-PROTO               February 2014   Intermediate Selection Process  (as in [RFC6183]): An Intermediate      Selection Process is an Intermediate Process that selects records      from a sequence based upon criteria-evaluated record values and      passes only those records that match the criteria (e.g., Filtering      only records from a given network to a given Collector).   Intermediate Flow Selection Process  (as in [RFC7014]: An      Intermediate Flow Selection Process is an Intermediate Process, as      in [RFC6183] that takes Flow Records as its input and selects a      subset of this set as its output.  The Intermediate Flow Selection      Process is a more general concept than the Intermediate Selection      Process as defined in [RFC6183].  While an Intermediate Selection      Process selects Flow Records from a sequence based upon criteria-      evaluated Flow record values and only passes on those Flow Records      that match the criteria, an Intermediate Flow Selection Process      selects Flow Records using selection criteria applicable to a      larger set of Flow characteristics and information.      Note: for more information on the difference between Intermediate      Flow Selection Process and Intermediate Selection Process, seeSection 4 in [RFC7014].3.  Handling IPFIX Message Headers   The format of the IPFIX Message Header as exported by an IPFIX   Mediator is shown in Figure 1.  This is identical to the format   defined for IPFIX in [RFC7011], though Export Time and Observation   Domain ID may be handled differently at certain Mediators, as noted   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           |            Length             |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |                           Export Time                         |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |                       Sequence Number                         |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+   |                    Observation Domain ID                      |   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                   Figure 1: IPFIX Message Header formatClaise, et al.               Standards Track                    [Page 8]

RFC 7119                     IPFIX MED-PROTO               February 2014   The header fields as exported by an IPFIX Mediator are described   below.   Version:      Version of IPFIX to which this Message conforms.  The value of      this field is 0x000a for the current version, incrementing by one      the version used in the NetFlow services export version 9      [RFC3954].   Length:      Total length of the IPFIX Message, measured in octets, including      Message Header and Set(s).   Export Time:      Time at which the IPFIX Message Header leaves the IPFIX Mediator,      expressed in seconds since the UNIX epoch of 1 January 1970 at      00:00 UTC, encoded as an unsigned 32-bit integer.      However, in the specific case of an IPFIX Mediator containing an      Intermediate Conversion Process, the IPFIX Mediator MAY use the      export time received from the incoming Transport Session.   Sequence Number:      Incremental sequence counter modulo 2^32 of all IPFIX Data Records      sent in the current stream from the current Observation Domain by      the Exporting Process.  Each SCTP Stream counts sequence numbers      separately, while all messages in a TCP connection or UDP      Transport Session are considered to be part of the same stream.      This value can be used by the Collecting Process to identify      whether any IPFIX Data Records have been missed.  Template and      Options Template Records do not increase the Sequence Number.   Observation Domain ID:      A 32-bit identifier of the Observation Domain that is locally      unique to the Exporting Process.  The Exporting Process uses the      Observation Domain ID to uniquely identify to the Collecting      Process the Observation Domain that metered the Flows.  It is      RECOMMENDED that this identifier also be unique per IPFIX Device.      Collecting Processes can use the Transport Session and the      Observation Domain ID field to separate different export streams      originating from the same Exporter.  The Observation Domain ID is      set to 0 when no specific Observation Domain ID is relevant forClaise, et al.               Standards Track                    [Page 9]

RFC 7119                     IPFIX MED-PROTO               February 2014      the entire IPFIX Message, for example, when exporting the      Exporting Process Statistics, or in case of a hierarchy of      Collectors when aggregated Data Records are exported.      SeeSection 4.1 for special considerations for Observation Domain      management while passing unmodified templates through an IPFIX      Mediator, andSection 5 for guidelines for preservation of      original Observation Domain information at an IPFIX Mediator.   The following specifications, copied over from [RFC7011] have some   implications in this document:      Template Withdrawals MAY appear interleaved with Template Sets,      Options Template Sets, and Data Sets within an IPFIX Message.  In      this case, the Templates and Template Withdrawals shall be      interpreted as taking effect in the order in which they appear in      the IPFIX Message.   If an IPFIX Mediator receives an IPFIX Message composed of Template   Withdrawals and Template Sets, and if the IPFIX Mediator forwards   this IPFIX Message, it MUST NOT modify the Set order.  If an IPFIX   Mediator receives IPFIX Messages composed of Template Withdrawals and   Template Sets, and if the IPFIX Mediator forwards these IPFIX   Messages, it MUST NOT modify the IPFIX Message order.  Note that the   Template Mapping (seeSection 4.1) is the authoritative source of   information on the IPFIX Mediator to decide whether the entire IPFIX   Messages can be forwarded as such.4.  Template Management   How an IPFIX Mediator handles the Templates it receives from the   Original Exporter depends entirely on the nature of the Intermediate   Process running on that IPFIX Mediator.  There are two cases here:   1.  IPFIX Mediators that pass substantially the same Data Records       from the Original Exporter downstream (e.g., an Intermediate       Selection Process), pass unmodified Templates as described inSection 4.1; this section describes a Template Mapping required       to make this work in the general case, and the correlation       between the received and generated IPFIX Message Withdrawals.   2.  IPFIX Mediators that export Data Records that are substantially       changed from the Data Records received from the Original Exporter       follow the guidelines inSection 4.2 instead: in this case, the       IPFIX Mediator generates new (Options) Template Records as a       result of the Intermediate Process, and no Template Mapping is       required.Claise, et al.               Standards Track                   [Page 10]

RFC 7119                     IPFIX MED-PROTO               February 2014   Subsequent subsections deal with specific issues in Template   management that may occur at IPFIX Mediators.4.1.  Passing Unmodified Templates through an IPFIX Mediator   For some Intermediate Processes, the IPFIX Mediator doesn't modify   the (Options) Template Record(s) content.  A typical example is an   Intermediate Flow Selection Process acting as distributor, which   collects Flow Records from one or more Exporters, and based on the   content of the Information Elements, redirects the Flow Records to   the appropriate Collector.  This example is a typical case of a   single network operation center managing multiple universities: a   unique IPFIX Collector collects all Flow Records for the common   infrastructure, but might be re-exporting specific university Flow   Records to the responsible system administrator.   As specified in [RFC7011], the Template IDs are unique per Exporter,   per Transport Session, and per Observation Domain.  As there is no   guarantee that, for similar Template Records, the Template IDs   received on the incoming Transport Session and exported to the   outgoing Transport Session would be same, the IPFIX Mediator MUST   maintain a Template Mapping composed of related received and exported   (Options) Template Records:   o  for each received (Options) Template Record: Template Record      Information Elements, Template ID, Observation Domain ID, and      Transport Session information, metadata scoped to the Template (*)   o  for each exported (Options) Template Record: Template Record      Information Elements, Template ID, Collector, Observation Domain      ID, and Transport Session information metadata scoped to the      Template (*)   (*) The "metadata scoped to the Template" encompasses the metadata,   that are scoped to the Template, and that help to determine the   semantics of the Template Record.  Note that these metadata are   typically sent in Data Records described by an Options Template.  An   example is the flowKeyIndicator.  An IPFIX Mediator could potentially   receive two different Template IDs, from the same Exporter, with the   same Information Elements, but with a different set of Flow Keys   (indicated by the flowKeyIndicator in an Options Template Record).   Another example is the combination of anonymizationFlags and   anonymizationTechnique [RFC6235]).  This metadata information must be   present in the Template Mapping, to stress that the two Template   Record semantics are different.Claise, et al.               Standards Track                   [Page 11]

RFC 7119                     IPFIX MED-PROTO               February 2014   If an IPFIX Mediator receives an IPFIX Withdrawal Message for a   (Options) Template Record that is not used anymore in any other   Template Mappings, the IPFIX Mediator SHOULD export the appropriate   IPFIX Withdrawal Message(s) on the outgoing Transport Session and   remove the corresponding entry in the Template Mapping.   If a (Options) Template Record is not used anymore in an outgoing   Transport Session, it MUST be withdrawn with an IPFIX Template   Withdrawal Message on that specific outgoing Transport Session, and   its entry, MUST be removed from the Template Mapping.   If an incoming or outgoing Transport Session is gracefully shut down   or reset, the (Options) Template Records corresponding to that   Transport Session MUST be removed from the Template Mapping.   For example, Figure 2 displays an example of an Intermediate Flow   Selection Process, redistributing Data Records to Collectors on the   basis of customer networks, i.e., the Route Distinguisher (RD).  In   this example, the Template Record received from the Exporter #1 is   reused towards Collector #1, Collector #2, and Collector #3, for the   customer #1, customer #2, and customer #3, respectively.  In this   example, the outgoing Template Records exported to the different   Collectors are identical.  As a reminder that the Template ID   uniqueness is local to the Transport Session and Observation Domain   that generated the Template ID, a mix of Template ID 256 and 257 has   been used.Claise, et al.               Standards Track                   [Page 12]

RFC 7119                     IPFIX MED-PROTO               February 2014                                               .---------.                                   Tmpl.       |         |                                   ID    .---->|Collector|<==>Customer 1                                   256   |     |   #1    |                                         |     |         |                                      RD=100:1 '---------'         .--------.        .--------.    |         |        | Tmpl.  |        |----'         |        | Id     |        |          .---------.         |        | 258    |        | RD=100:2 |         |         | IPFIX  |------->| IPFIX  |--------->|Collector|<==>Customer 2         |Exporter|        |Mediator| Tmpl.    |   #2    |         |   #1   |        |        | ID 257   |         |         |        |        |        |          '---------'         |        |        |        |----.         '--------'        '--------'    |                                      RD=100:3                                         |     .---------.                                   Tmpl. |     |         |                                   ID    '---->|Collector|<==>Customer 3                                   257         |   #3    |                                               |         |                                               '---------'           Figure 2: Intermediate Flow Selection Process Example   Figure 3 shows the Template Mapping for the system shown in Figure 2.Claise, et al.               Standards Track                   [Page 13]

RFC 7119                     IPFIX MED-PROTO               February 2014   +-----------------------------------------------------------------+   | Template Entry A:                                               |   | Incoming Transport Session information (from Exporter#1):       |   |   Source IP: <Exporter#1 export IP address>                     |   |   Destination IP: <IPFIX Mediator IP address>                   |   |   Protocol: SCTP                                                |   |   Source Port: <source port>                                    |   |   Destination Port: 4739 (IPFIX)                                |   | Observation Domain ID: <Observation Domain ID>                  |   | Template ID: 258                                                |   | Metadata scoped to the Template : <not applicable in this case> |   |                                                                 |   | Template Entry B:                                               |   | Outgoing Transport Session information (to Collector#1):        |   |   Source IP: <IPFIX Mediator IP address>                        |   |   Destination IP: <IPFIX Collector#1 IP address>                |   |   Protocol: SCTP                                                |   |   Source Port: <source port>                                    |   |   Destination Port: 4739 (IPFIX)                                |   | Observation Domain ID: <Observation Domain ID>                  |   | Template ID: 256                                                |   | Metadata scoped to the Template : <not applicable in this case> |   |                                                                 |   | Template Entry C:                                               |   | Outgoing Transport Session information (to Collector#2):        |   |   Source IP: <IPFIX Mediator IP address>                        |   |   Destination IP: <IPFIX Collector#2 IP address>                |   |   Protocol: SCTP                                                |   |   Source Port: <source port>                                    |   |   Destination Port: 4739 (IPFIX)                                |   | Observation Domain ID: <Observation Domain ID>                  |   | Template ID: 257                                                |   | Metadata scoped to the Template : <not applicable in this case> |   |                                                                 |   | Template Entry D:                                               |   | Outgoing Transport Session information (to Collector#3):        |   |   Source IP: <IPFIX Mediator IP address>                        |   |   Destination IP: <IPFIX Collector#3 IP address>                |   |   Protocol: SCTP                                                |   |   Source Port: <source port>                                    |   |   Destination Port: 4739 (IPFIX)                                |   | Observation Domain ID: <Observation Domain ID>                  |   | Template ID: 257                                                |   | Metadata scoped to the Template : <not applicable in this case> |   +-----------------------------------------------------------------+               Figure 3: Template Mapping Example: TemplatesClaise, et al.               Standards Track                   [Page 14]

RFC 7119                     IPFIX MED-PROTO               February 2014   The Template Mapping corresponding to Figure 3 is displayed in   Figure 4:   Template Entry A   <----> Template Entry B   Template Entry A   <----> Template Entry C   Template Entry A   <----> Template Entry D               Figure 4: Template Mapping Example: Mappings   Alternatively, the Template Mapping may be optimized as in Figure 5:                         +--> Template Entry B                         |   Template Entry A   <--+--> Template Entry C                         |                         +--> Template Entry D              Figure 5: Template Mapping Example 2: Mappings   Note that all examples use Transport Sessions based on the SCTP, as   simplified use cases.  However, the transport protocol would be   important in situations such as an Intermediate Conversion Process   doing transport protocol conversion.4.1.1.  Template Mapping and Information Element Ordering   In the situation where Original Exporters each export an (Options)   Template Record to a single IPFIX Mediator, and the (Options)   Template Record contains the same Information Elements, but in   different order, should the IPFIX Mediator maintain a Template   Mapping with a single Export Template Record (see Figure 6) or should   the IPFIX Mediator maintain multiple independent Template Records   (see Figure 7) before re-exporting to the Collector?           Template Entry A   <--+                                 |           Template Entry B   <--+--> Template Entry D                                 |           Template Entry C   <--+                 Figure 6: Template Mapping and Ordering:                      A single Export Template RecordClaise, et al.               Standards Track                   [Page 15]

RFC 7119                     IPFIX MED-PROTO               February 2014           Template Entry A   <--+--> Template Entry D           Template Entry B   <--+--> Template Entry E           Template Entry C   <--+--> Template Entry F                 Figure 7: Template Mapping and Ordering:                     Multiple Export Template Records   The answer depends on whether the order of the Information Elements   implies some specific semantic.  One of the guiding principles in   IPFIX protocol specifications is that the semantic meaning of one   Information Element doesn't depend on the value of any other   Information Element.  However, there is one noticeable exception, as   mentioned in [RFC7011]:      Multiple Scope Fields MAY be present in the Options Template      Record, in which case the composite scope is the combination of      the scopes.  For example, if the two scopes are meteringProcessId      and templateId, the combined scope is this Template for this      Metering Process.  If a different order of Scope Fields would      result in a Record having a different semantic meaning, then the      order of Scope Fields MUST be preserved by the Exporting Process.      For example, in the context of PSAMP [RFC5476], if the first scope      defines the filtering function, while the second scope defines the      sampling function, the order of the scope is important.  Applying      the sampling function first, followed by the filtering function,      would lead to potentially different Data Records than applying the      filtering function first, followed by the sampling function.   If an IPFIX Mediator receives, from multiple Exporters, Template   Records with identical Information Elements, but ordered differently,   it SHOULD consider those Template Records as identical, subject to   metadata information in the associated Options Template (for example,   the Flow Key Options Template, seeSection 10.2).   If an IPFIX Mediator receives, from multiple Exporters, Options   Template Records with identical and ordered Information Elements in   the Scope fields, and with identical Information Elements, but   ordered differently, in the non-Scope fields, it SHOULD consider   those Template Records as identical.   If an IPFIX Mediator receives, from multiple Exporters, Options   Template Records with identical Information Elements in the Scope   field, but ones that are ordered differently, it MUST consider those   Template Records as semantically different.Claise, et al.               Standards Track                   [Page 16]

RFC 7119                     IPFIX MED-PROTO               February 20144.2.  Creating New Templates at an IPFIX Mediator   For other Intermediate Processes, the IPFIX Mediator generates new   (Options) Template Records as a result of the Intermediate Process.   In these cases, the IPFIX Mediator doesn't need to maintain a   Template Mapping, as it generates its own series of (Options)   Template Records.  However, some special cases might still require a   Template Mapping.  Consider a situation where the IPFIX Mediator   generates new (Options) Template Records based on what it receives   from the Exporter(s) based on the Intermediate Process function: for   example, an Intermediate Anonymization process that performs black-   marker anonymization [RFC6235] on certain Information Elements.  In   such cases, it's important to keep the correlation between the   received (Options) Template Records and derived (Options) Template   Records in the Template Mapping.  These Template Mappings would be   kept as inSection 4.1, except that the exported Template would not   be identical to the received Template.   Similar to Exporting Processes in any Exporter, an IPFIX Mediator may   use the technique for reducing redundancy in IPFIX described in   [RFC5473].4.3.  Handling Unknown Information Elements   Depending on application requirements, Mediators that do not generate   new Records SHOULD re-export values for unknown Information Elements,   for which the Mediator does not have information about Information   Element data type and semantics.  However, as there may be presence   or ordering dependencies among the unknown Information Elements, the   Mediator MUST NOT omit fields from such re-exported Records or   reorder any fields within the Records.   Mediators that generate new Records, as inSection 4.2, MUST ignore   values of Information Elements they do not understand.  If a Mediator   passes values of Information Elements it does not understand (for   example, when re-exporting Flow Records), it MUST pass them in the   order in which they were originally received.   In any case, Mediators handling unknown Information Elements SHOULD   log this fact, as it is likely that mediation of records containing   unknown values will have unintended consequences.5.  Preserving Original Observation Point Information   Depending on the use case, the Collector in an Exporter/IPFIX   Mediator/Collector structure (for example, tiered Mediators) may need   to receive information about the Original Observation Point(s);Claise, et al.               Standards Track                   [Page 17]

RFC 7119                     IPFIX MED-PROTO               February 2014   otherwise, it may wrongly conclude that the IPFIX Device exporting   the Flow Records, i.e., the IPFIX Mediator, directly observed the   packets that generated the Flow Records.  Two new Information   Elements are introduced to address this use case:   originalExporterIPv4Address and originalExporterIPv6Address.   Practically, the Original Exporters will not be exporting these   Information Elements.  Therefore, the Intermediate Process will   report the Original Observation Point(s) to the best of its   knowledge.  Note that the Configuration Data Model for IPFIX and   PSAMP [RFC6728] may report the Original Exporter information out of   band.   In the IPFIX Mediator, the Observation Point(s) may be represented   by:   o  A single Original Exporter (represented by the      originalExporterIPv4Address or originalExporterIPv6Address      Information Elements).   o  A list of Original Exporters (represented by a list of      originalExporterIPv4Address or originalExporterIPv6Address      Information Elements).   o  Any combination or list of Information Elements representing      Observation Points.  For example:      *  A list of Original Exporter interfaces (represented by the         originalExporterIPv4Address or originalExporterIPv6Address, the         ingressInterface, and/or egressInterface Information Elements,         respectively).      *  A list of Original Exporter line card (represented by the         originalExporterIPv4Address, originalExporterIPv6Address, or         lineCardId Information Elements, respectively).   Some Information Elements characterizing the Observation Point may be   added.  For example, the flowDirection Information Element specifies   the direction of the observation, and, as such, characterizes the   Observation Point.   Any combination of the above representations is possible.  An example   of an Original Observation Point for an Intermediate Aggregation   Process is displayed in Figure 8.Claise, et al.               Standards Track                   [Page 18]

RFC 7119                     IPFIX MED-PROTO               February 2014   exporterIPv4Address 192.0.2.1   exporterIPv4Address 192.0.2.2,     interface ethernet 0, direction ingress     interface ethernet 1, direction ingress     interface serial 1, direction egress     interface serial 2, direction egress   exporterIPv4Address 192.0.2.3,     lineCardId 1, direction ingress          Figure 8: Complex Observation Point Definition Example   A Mediator MAY export such complex Original Observation Point   information, depending on application requirements.  If such   information is exported, the Mediator MUST use [RFC6313] to do so, as   described below.   The most generic way to export the Original Observation Point is to   use a subTemplateMultiList, with the semantic "exactlyOneOf".  Taking   the previous example, the encoding in Figure 9 can be used.   Template Record 257: exporterIPv4Address   Template Record 258: exporterIPv4Address,                        basicList of ingressInterface, flowDirection   Template Record 259: exporterIPv4Address, lineCardId, flowDirection     Figure 9: Complex Observation Point Definition Example: Templates   The Original Observation Point is modeled with the Data Records   corresponding to either Template Record 1, Template Record 2, or   Template Record 3 but not more than one of these ("exactlyOneOf"   semantic).  This implies that the Flow was observed at exactly one of   the Observation Points reported.   When an IPFIX Mediator receives Flow Records containing the Original   Observation Point Information Element, i.e.,   originalExporterIPv4Address or originalExporterIPv6Address, the IPFIX   Mediator SHOULD NOT modify its value(s) when composing new Flow   Records in the general case.  Known exceptions include anonymization   perSection 7.2.4 of [RFC6235] and an Intermediate Correlation   Process rewriting addresses across NAT.  In other words, the Original   Observation Point should not be replaced with the IPFIX Mediator   Observation Point.  The daisy chain of (Exporter, Observation Point)   representing the path the Flow Records took from the Exporter to the   top Collector in the Exporter/IPFIX Mediator(s)/Collector structure   model is out of the scope of this specification.Claise, et al.               Standards Track                   [Page 19]

RFC 7119                     IPFIX MED-PROTO               February 2014   The following subsections describe Information Elements for reporting   Original Exporter addresses as seen by the Collecting Process; note   they may be subject to network address translation upstream; see   [NAT-LOGGING] for more on logging in this situation.5.1.  originalExporterIPv4Address Information Element   Name:   originalExporterIPv4Address   Description:   The IPv4 address used by the Exporting Process on an      Original Exporter, as seen by the Collecting Process on an IPFIX      Mediator.  Used to provide information about the Original      Observation Points to a downstream Collector.   Data Type:   ipv4Address   ElementId:   4035.2.  originalExporterIPv6Address Information Element   Name:   originalExporterIPv6Address   Description:   The IPv6 address used by the Exporting Process on an      Original Exporter, as seen by the Collecting Process on an IPFIX      Mediator.  Used to provide information about the Original      Observation Points to a downstream Collector.   Data Type:   ipv6Address   ElementId:   4046.  Managing Observation Domain IDs   The Observation Domain ID of any IPFIX Message containing Flow   Records relevant to no particular Observation Domain, or to multiple   Observation Domains, MUST have an Observation Domain ID of 0.   IPFIX Mediators that do not change (Options) Template Records MUST   maintain a Template Mapping, as detailed inSection 4.1, to ensure   that the combination of Observation Domain IDs and Template IDs do   not collide on export.   For IPFIX Mediators that export New (Options) Template Records, as inSection 4.2, there are two options for Observation Domain ID   management.  The first and simplest of these is to completely   decouple exported Observation Domain IDs from received ObservationClaise, et al.               Standards Track                   [Page 20]

RFC 7119                     IPFIX MED-PROTO               February 2014   Domain IDs; the IPFIX Mediator, in this case, comprises its own set   of Observation Domain(s) independent of the Observation Domain(s) of   the Original Exporters.   The second option is to provide or maintain a Template Mapping for   received (Options) Template Records and exported inferred (Options)   Template Records, along with the appropriate Observation Domain IDs   per Transport Session, which ensures that the combination of   Observation Domain IDs and Template IDs do not collide on export.   In some cases where the IPFIX Message Header can't contain a   consistent Observation Domain for the entire IPFIX Message, but the   Flow Records exported from the IPFIX Mediator should contain the   Observation Domain of the Original Exporter anyway, the (Options)   Template Record must contain the originalObservationDomainId   Information Element, specified inSection 6.1.  When an IPFIX   Mediator receives Flow Records containing the   originalObservationDomainId Information Element, the IPFIX Mediator   MUST NOT modify its value(s) when composing new Flow Records with the   originalObservationDomainId Information Element.6.1.  originalObservationDomainId Information Element   Name:   originalObservationDomainId   Description:   The Observation Domain ID reported by the Exporting      Process on an Original Exporter, as seen by the Collecting Process      on an IPFIX Mediator.  Used to provide information about the      Original Observation Domain to a downstream Collector.  When      cascading through multiple Mediators, this identifies the initial      Observation Domain in the cascade.   Data Type:   unsigned32   Data Type Semantics:   identifier   ElementId:   4057.  Timing Considerations   The IPFIX Message Header "Export Time" field is the time in seconds   since 0000 UTC Jan 1, 1970, at which the IPFIX Message leaves the   IPFIX Mediator.  However, in the specific case of an IPFIX Mediator   containing an Intermediate Conversion Process, the IPFIX Mediator MAY   use the export time received from the incoming Transport Session.Claise, et al.               Standards Track                   [Page 21]

RFC 7119                     IPFIX MED-PROTO               February 2014   It is RECOMMENDED that IPFIX Mediators handle time using absolute   timestamps (e.g., flowStartSeconds, flowStartMilliseconds, or   flowStartNanoseconds), which are specified relative to the UNIX epoch   (00:00 UTC 1 Jan 1970) [POSIX.1], where possible rather than relative   timestamps (e.g., flowStartSysUpTime or flowStartDeltaMicroseconds),   which are specified relative to protocol structures such as system   initialization or message export time.   The latter are difficult to manage for two reasons.  First, they   require constant translation, as the system initialization time of an   intermediate system and the export time of an intermediate message   will change across mediation operations.  Further, relative   timestamps introduce range problems.  For example, when using the   flowStartDeltaMicroseconds and flowEndDeltaMicroseconds Information   Elements [IANA-IPFIX], the Data Record must be exported within a   maximum of 71 minutes after its creation.  Otherwise, the 32-bit   counter would not be sufficient to contain the flow start time   offset.  Those time constraints might be incompatible with some of   the application requirements of some Intermediate Processes.   Intermediate Processes MUST NOT assume that received records appear   in flowStartTime, flowEndTime, or observationTime order.  An   Intermediate Process processing timing information (e.g., an   Intermediate Aggregation Process) MAY ignore records that are   significantly out of order, in order to meet application-specific   state and latency requirements, but SHOULD report that records were   dropped.   When an Intermediate Process aggregates information from different   Flow Records, the timestamps on exported records SHOULD be the   minimum of the start times and the maximum of the end times in the   general case.  However, if the Flow Records do not overlap, i.e., if   there is a time gap between the times in the Flow Records, then the   report may be inaccurate.  The IPFIX Mediator is only reporting what   it knows, on the basis of the information made available to it, and   there may not have been any data to observe during the gap.  Then   again, if there is an overlap in timestamps, there's the potential of   double-accounting: different Observation Points may have observed the   same traffic simultaneously.  The specification of the precise rules   for applying Flow Record timestamps at IPFIX Mediators for all the   different situations is out of the scope of this document.   Note that [RFC7015] provides additional specifications for handling   of timestamps at an Intermediate Aggregation Process.Claise, et al.               Standards Track                   [Page 22]

RFC 7119                     IPFIX MED-PROTO               February 20148.  Transport Considerations   SCTP [RFC4960] using the Partially Reliable SCTP (PR-SCTP) extension   specified in [RFC3758] MUST be implemented by all compliant IPFIX   Mediator implementations.  TCP [RFC0793] MAY also be implemented by   implementations compliant with the IPFIX Mediator.  UDP [RFC0768] MAY   also be implemented by compliant IPFIX Mediator implementations.   Transport-specific considerations for IPFIX Exporters as specified in   Sections8.3,8.4,9.1,9.2, and10 of [RFC7011] apply to IPFIX   Mediators as well.   SCTP SHOULD be used in deployments where IPFIX Mediators and   Collectors are communicating over links that are susceptible to   congestion.  SCTP is capable of providing any required degree of   reliability.  TCP MAY be used in deployments where IPFIX Mediators   and Collectors communicate over links that are susceptible to   congestion, but SCTP is preferred due to its ability to limit back   pressure on Exporters and its message versus stream orientation.  UDP   MAY be used, although it is not a congestion-aware protocol.   However, in this case, the IPFIX traffic between IPFIX Mediator and   Collector MUST run in an environment where IPFIX traffic has been   provisioned for and/or separated from non-IPFIX traffic, whether   physically or virtually.9.  Collecting Process Considerations   Any Collecting Process compliant with [RFC7011] can receive IPFIX   Messages from an IPFIX Mediator.  If the IPFIX Mediator uses IPFIX   Structured Data [RFC6313] to export Original Exporter Information, as   inSection 5, the Collecting Process MUST support [RFC6313].10.  Specific Reporting Requirements   IPFIX provides Options Templates for the reporting the reliability of   processes within the IPFIX Architecture.  As each Mediator includes   at least one IPFIX Exporting Process, they MAY use the Exporting   Process Reliability Statistics Options Template, as specified in   [RFC7011].   Analogous to the Metering Process Reliability Statistics Options   Template, also specified in [RFC7011], Mediators MAY implement the   Intermediate Process Reliability Statistics Options Template,   specified in Sections10.1,10.3, and10.4 define Information   Elements used by this Options Template.   The Flow Keys Options Template, as specified in [RFC7011], may   require special handling at an IPFIX Mediator, as described inSection 10.2.Claise, et al.               Standards Track                   [Page 23]

RFC 7119                     IPFIX MED-PROTO               February 2014   In addition, each Intermediate Process may have its own specific   reporting requirements (e.g., Anonymization Records as in [RFC6235],   or the Aggregation Counter Distribution Options Template as in   [RFC7015]); these SHOULD be implemented as necessary, as described in   the specification for each Intermediate Process.10.1.  Intermediate Process Reliability Statistics Options Template   The Intermediate Process Statistics Options Template specifies the   structure of a Data Record for reporting Intermediate Process   statistics.  It SHOULD contain the following Information Elements;   the intermediateProcessId Information Element is defined inSection 10.3 and the ignoredDataRecordTotalCount Information Element   is defined inSection 10.4:Claise, et al.               Standards Track                   [Page 24]

RFC 7119                     IPFIX MED-PROTO               February 2014   +-----------------------------+-------------------------------------+   | IE                          | Description                         |   +-----------------------------+-------------------------------------+   | observationDomainId [scope] | An identifier of the Observation    |   |                             | Domain (of messages exported by     |   |                             | this Mediator), locally unique to   |   |                             | the Intermediate Process, to which  |   |                             | this statistics record applies.     |   |                             | ----------------------------------  |   | intermediateProcessId       | An identifier for the Intermediate  |   | [scope]                     | Process to which this statistics    |   |                             | record applies.                     |   |                             | ----------------------------------  |   | ignoredDataRecordTotalCount | The total number of Data Records    |   |                             | received but not processed by the   |   |                             | Intermediate Process.               |   |                             | ----------------------------------  |   | time first record ignored   | The timestamp of the first record   |   |                             | that was ignored by the             |   |                             | Intermediate Process.  For Data     |   |                             | Records containing timestamp        |   |                             | ranges, this SHOULD be taken from   |   |                             | the start timestamp of the range;   |   |                             | for data records containing no      |   |                             | timing information, this SHOULD be  |   |                             | taken from the Export Time in the   |   |                             | message header of the IPFIX Message |   |                             | that contains it.  For this         |   |                             | timestamp, any of the following     |   |                             | timestamp can be used:              |   |                             | observationTimeSeconds,             |   |                             | observationTimeMilliseconds,        |   |                             | observationTimeMicroseconds, or     |   |                             | observationTimeNanoseconds.         |   +-----------------------------+-------------------------------------+Claise, et al.               Standards Track                   [Page 25]

RFC 7119                     IPFIX MED-PROTO               February 2014   +-----------------------------+-------------------------------------+   | IE                          | Description                         |   +-----------------------------+-------------------------------------+   | time last record ignored    | The timestamp of the last record    |   |                             | that was ignored by the             |   |                             | Intermediate Process.  For Data     |   |                             | Records containing timestamp        |   |                             | ranges, this SHOULD be taken from   |   |                             | the end timestamp of the range; for |   |                             | data records containing no timing   |   |                             | information, this SHOULD be taken   |   |                             | from the Export Time in the message |   |                             | header of the containing IPFIX      |   |                             | Message.  For this timestamp, any   |   |                             | of the following timestamp can be   |   |                             | used: observationTimeSeconds,       |   |                             | observationTimeMilliseconds,        |   |                             | observationTimeMicroseconds, or     |   |                             | observationTimeNanoseconds.         |   +-----------------------------+-------------------------------------+10.2.  Flow Key Options Template   The Flow Keys Options Template specifies the structure of a Data   Record for reporting the Flow Keys of reported Flows.  A Flow Keys   Data Record extends a particular Template Record that is referenced   by its templateId identifier.  The Template Record is extended by   specifying which of the Information Elements contained in the   corresponding Data Records describe Flow properties that serve as   Flow Keys of the reported Flow.  This Options Template is defined inSection 4.4 of [RFC7011] and SHOULD be used by Mediators for export   as defined there.   When an Intermediate Process exports Data Records containing   different Flow Keys from those received from the Original Exporter,   and the Original Exporter sent a Flow Keys Options record to the   IPFIX Mediator, the IPFIX Mediator MUST export a Flow Keys Options   record defining the new set of Flow Keys.10.3.  intermediateProcessId Information Element   Name:   intermediateProcessId   Description:   An identifier of an Intermediate Process that is      unique per IPFIX Device.  Typically, this Information Element is      used for limiting the scope of other Information Elements.  Note      that process identifiers may be assigned dynamically; that is, an      Intermediate Process may be restarted with a different ID.Claise, et al.               Standards Track                   [Page 26]

RFC 7119                     IPFIX MED-PROTO               February 2014   Data Type:   unsigned32   Data Type Semantics:   identifier   ElementId:   40610.4.  ignoredDataRecordTotalCount Information Element   Name:   ignoredDataRecordTotalCount   Description:   The total number of received Data Records that the      Intermediate Process did not process since the (re-)initialization      of the Intermediate Process; includes only Data Records not      examined or otherwise handled by the Intermediate Process due to      resource constraints, not Data Records that were examined or      otherwise handled by the Intermediate Process but those that      merely do not contribute to any exported Data Record due to the      operations performed by the Intermediate Process.   Data Type:   unsigned64   Data Type Semantics:   totalCounter   ElementId:   40711.  Operations and Management Considerations   In general, using IPFIX Mediators to combine information from   multiple Original Exporters requires a consistent configuration of   the Metering Processes behind these Original Exporters.  The details   of this consistency are specific to each Intermediate Process.   Consistency of configuration should be verified out of band, with the   MIB modules ([RFC6615] and [RFC6727]) or with the Configuration Data   Model for IPFIX and PSAMP [RFC6728].   From an operational perspective, this specification provides all the   information required to set up IPFIX Mediators and Collectors behind   IPFIX Mediators.  While configuring the IPFIX Mediators, care must be   taken to include all the relevant information so that the Collectors   deduce the Data Records precise semantic.  This is covered by the   Template Mapping specifications inSection 4.1.  Also, caution must   be taken that if something is not carefully configured in the   processing chain, this can lead to the wrong interpretation of   collected IPFIX data, and the associated applications can produce   results that are not operationally meaningful.Claise, et al.               Standards Track                   [Page 27]

RFC 7119                     IPFIX MED-PROTO               February 201412.  Security Considerations   As they act as both IPFIX Collecting Processes and Exporting   Processes, the Security Considerations for the IPFIX Protocol   [RFC7011] also apply to IPFIX Mediators.  The Security Considerations   for IPFIX Files [RFC5655] also apply to IPFIX Mediators that write   IPFIX Files or use them for internal storage.  However, there are a   few specific considerations that IPFIX Mediator implementations must   also take into account.   By design, IPFIX Mediators are "men in the middle": they intercede in   the communication between an Original Exporter (or another upstream   IPFIX Mediator) and a downstream Collecting Process.  This has two   important implications for the level of confidentiality provided   across an IPFIX Mediator and the ability to protect data integrity   and Original Exporter authenticity across an IPFIX Mediator.  These   are addressed in more detail in the Security Considerations for IPFIX   Mediators in [RFC6183].   Note that while IPFIX Mediators can use the exporterCertificate and   collectorCertificate Information Elements defined in [RFC5655] as   described inSection 9.3 of [RFC6183] to export information about   X.509 identities in upstream TLS-protected Transport Sessions, this   mechanism cannot be used to provide true end-to-end assertions about   a chain of IPFIX Mediators: any IPFIX Mediator in the chain can   simply falsify the information about upstream Transport Sessions.  In   situations where information about the chain of mediation is   important, it must be determined out of band.  Note as well that an   Exporting Process has no in-band way to determine whether or not a   given Collecting Process will act as a Mediator.  Trust placed in   Collecting Processes is absolute, so care should be taken when   exporting IPFIX Messages between Exporting Processes and Collecting   Processes controlled by different entities.13.  IANA Considerations   This document specifies new IPFIX Information Elements,   originalExporterIPv4Address inSection 5.1,   originalExporterIPv6Address inSection 5.2,   originalObservationDomainId inSection 6.1, intermediateProcessId inSection 10.3, and ignoredDataRecordTotalCount inSection 10.4, which   have been added to the IPFIX Information Element registry   [IANA-IPFIX].Claise, et al.               Standards Track                   [Page 28]

RFC 7119                     IPFIX MED-PROTO               February 201414.  Acknowledgments   We would like to thank the IPFIX contributors, specifically Paul   Aitken (THE ultimate IPFIX document reviewer) and Andrew Feren for   their thorough reviews; Nevil Brownlee and Juergen Quittek for   shepherding this document and chairing the IPFIX Working Group; and   to Rahul Patel, Meral Shirazipour, and Juergen Schoenwaelder for   their feedback and comments.  This work is materially supported by   the European Union Seventh Framework Programme under grant agreements   257315 (DEMONS) and 318627 (mPlane).15.  References15.1.  Normative References   [RFC0768]  Postel, J., "User Datagram Protocol", STD 6,RFC 768,              August 1980.   [RFC0793]  Postel, J., "Transmission Control Protocol", STD 7,RFC793, September 1981.   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate              Requirement Levels",BCP 14,RFC 2119, March 1997.   [RFC3758]  Stewart, R., Ramalho, M., Xie, Q., Tuexen, M., and P.              Conrad, "Stream Control Transmission Protocol (SCTP)              Partial Reliability Extension",RFC 3758, May 2004.   [RFC4960]  Stewart, R., "Stream Control Transmission Protocol",RFC4960, September 2007.   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an              IANA Considerations Section in RFCs",BCP 26,RFC 5226,              May 2008.   [RFC5655]  Trammell, B., Boschi, E., Mark, L., Zseby, T., and A.              Wagner, "Specification of the IP Flow Information Export              (IPFIX) File Format",RFC 5655, October 2009.   [RFC6313]  Claise, B., Dhandapani, G., Aitken, P., and S. Yates,              "Export of Structured Data in IP Flow Information Export              (IPFIX)",RFC 6313, July 2011.   [RFC6615]  Dietz, T., Kobayashi, A., Claise, B., and G. Muenz,              "Definitions of Managed Objects for IP Flow Information              Export",RFC 6615, June 2012.Claise, et al.               Standards Track                   [Page 29]

RFC 7119                     IPFIX MED-PROTO               February 2014   [RFC6727]  Dietz, T., Claise, B., and J. Quittek, "Definitions of              Managed Objects for Packet Sampling",RFC 6727, October              2012.   [RFC6728]  Muenz, G., Claise, B., and P. Aitken, "Configuration Data              Model for the IP Flow Information Export (IPFIX) and              Packet Sampling (PSAMP) Protocols",RFC 6728, October              2012.   [RFC7011]  Claise, B., Trammell, B., and P. Aitken, "Specification of              the IP Flow Information Export (IPFIX) Protocol for the              Exchange of Flow Information", STD 77,RFC 7011, September              2013.   [RFC7012]  Claise, B. and B. Trammell, "Information Model for IP Flow              Information Export (IPFIX)",RFC 7012, September 2013.   [RFC7013]  Trammell, B. and B. Claise, "Guidelines for Authors and              Reviewers of IP Flow Information Export (IPFIX)              Information Elements",BCP 184,RFC 7013, September 2013.   [RFC7014]  D'Antonio, S., Zseby, T., Henke, C., and L. Peluso, "Flow              Selection Techniques",RFC 7014, September 2013.   [RFC7015]  Trammell, B., Wagner, A., and B. Claise, "Flow Aggregation              for the IP Flow Information Export (IPFIX) Protocol",RFC7015, September 2013.15.2.  Informative References   [RFC3917]  Quittek, J., Zseby, T., Claise, B., and S. Zander,              "Requirements for IP Flow Information Export (IPFIX)",RFC3917, October 2004.   [RFC3954]  Claise, B., "Cisco Systems NetFlow Services Export Version              9",RFC 3954, October 2004.   [RFC5470]  Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,              "Architecture for IP Flow Information Export",RFC 5470,              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.Claise, et al.               Standards Track                   [Page 30]

RFC 7119                     IPFIX MED-PROTO               February 2014   [RFC5476]  Claise, B., Johnson, A., and J. Quittek, "Packet Sampling              (PSAMP) Protocol Specifications",RFC 5476, March 2009.   [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.   [RFC5982]  Kobayashi, A. and B. Claise, "IP Flow Information Export              (IPFIX) Mediation: Problem Statement",RFC 5982, August              2010.   [RFC6183]  Kobayashi, A., Claise, B., Muenz, G., and K. Ishibashi,              "IP Flow Information Export (IPFIX) Mediation: Framework",RFC 6183, April 2011.   [RFC6235]  Boschi, E. and B. Trammell, "IP Flow Anonymization              Support",RFC 6235, May 2011.   [NAT-LOGGING]              Sivakumar, S. and R. Penno, "IPFIX Information Elements              for logging NAT Events", Work in Progress, November 2013.   [IANA-IPFIX]              IANA, "IP Flow Information Export (IPFIX) Entities",              <http://www.iana.org/assignments/ipfix>.   [POSIX.1]  IEEE, "IEEE Standard for Information Technology - Portable              Operating System Interface", IEEE 1003.1-2008, 2008.Claise, et al.               Standards Track                   [Page 31]

RFC 7119                     IPFIX MED-PROTO               February 2014Authors' Addresses   Benoit Claise   Cisco Systems, Inc.   De Kleetlaan 6a b1   1831 Diegem   Belgium   Phone: +32 2 704 5622   EMail: bclaise@cisco.com   Atsushi Kobayashi   NTT Information Sharing Platform Laboratories   3-9-11 Midori-cho   Musashino-shi, Tokyo 180-8585   Japan   Phone: +81 422 59 3978   EMail: akoba@nttv6.net   Brian Trammell   Swiss Federal Institute of Technology Zurich   Gloriastrasse 35   8092 Zurich   Switzerland   Phone: +41 44 632 70 13   EMail: trammell@tik.ee.ethz.chClaise, et al.               Standards Track                   [Page 32]

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