Operation of the IP Flow Information Export (IPFIX) Protocol on IPFIX Mediators
RFC 7119
| Document | Type | RFC - Proposed Standard (February 2014; No errata) | |
|---|---|---|---|
| Authors | Benoît Claise , Atsushi Kobayashi , Brian Trammell | ||
| Last updated | 2015-10-14 | ||
| Replaces | draft-claise-ipfix-mediation-protocol | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Adrian Farrel | ||
| Shepherd write-up | Show (last changed 2013-10-06) | ||
| IESG | IESG state | RFC 7119 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Joel Jaeggli | ||
| Send notices to | (None) | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) B. Claise
Request for Comments: 7119 Cisco Systems, Inc.
Category: Standards Track A. Kobayashi
ISSN: 2070-1721 NTT
B. Trammell
ETH Zurich
February 2014
Operation of the IP Flow Information Export (IPFIX) Protocol
on IPFIX Mediators
Abstract
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 in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://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 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 Simplified BSD License.
Claise, et al. Standards Track [Page 1]
RFC 7119 IPFIX MED-PROTO February 2014
Table of Contents
1. Introduction ....................................................2
1.1. IPFIX Documents Overview ...................................3
1.2. IPFIX Mediator Documents Overview ..........................4
1.3. Relationship with the IPFIX and PSAMP Protocols ............5
2. Terminology .....................................................5
3. Handling IPFIX Message Headers ..................................8
4. Template Management ............................................10
4.1. Passing Unmodified Templates through an IPFIX Mediator ....11
4.1.1. Template Mapping and Information Element Ordering ..15
4.2. Creating New Templates at an IPFIX Mediator ...............17
4.3. Handling Unknown Information Elements .....................17
5. Preserving Original Observation Point Information ..............17
5.1. originalExporterIPv4Address Information Element ...........20
5.2. originalExporterIPv6Address Information Element ...........20
6. Managing Observation Domain IDs ................................20
6.1. originalObservationDomainId Information Element ...........21
7. Timing Considerations ..........................................21
8. Transport Considerations .......................................23
9. Collecting Process Considerations ..............................23
10. Specific Reporting Requirements ...............................23
10.1. Intermediate Process Reliability Statistics
Options Template .........................................24
10.2. Flow Key Options Template ................................26
10.3. intermediateProcessId Information Element ................26
10.4. ignoredDataRecordTotalCount Information Element ..........27
11. Operations and Management Considerations ......................27
12. Security Considerations .......................................28
13. IANA Considerations ...........................................28
14. Acknowledgments ...............................................29
15. References ....................................................29
15.1. Normative References .....................................29
15.2. Informative References ...................................30
1. 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 in
Section 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, see
Section 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 format
Claise, 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 for
Claise, 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.
See Section 4.1 for special considerations for Observation Domain
management while passing unmodified templates through an IPFIX
Mediator, and Section 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 (see Section 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 in
Section 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 in Section 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: Templates
Claise, 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 Record
Claise, 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, see Section 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 2014
4.2. 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 in Section 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 in Section 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
per Section 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: 403
5.2. 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: 404
6. 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 in Section 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 in
Section 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 Observation
Claise, 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 in Section 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: 405
7. 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 2014
8. 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
Sections 8.3, 8.4, 9.1, 9.2, and 10 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
in Section 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 Sections 10.1, 10.3, and 10.4 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 in
Section 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 in
Section 10.3 and the ignoredDataRecordTotalCount Information Element
is defined in Section 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 in
Section 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: 406
10.4. 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: 407
11. 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 in Section 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 2014
12. 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 in Section 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 in Section 5.1,
originalExporterIPv6Address in Section 5.2,
originalObservationDomainId in Section 6.1, intermediateProcessId in
Section 10.3, and ignoredDataRecordTotalCount in Section 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 2014
14. 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. References
15.1. Normative References
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
August 1980.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, RFC
793, 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", RFC
4960, 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", RFC
7015, September 2013.
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.
[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 2014
Authors' 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.ch
Claise, et al. Standards Track [Page 32]