One document matched: draft-ietf-ipfix-exporting-type-05.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE rfc SYSTEM "rfc2629.dtd" [
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<rfc ipr="trust200902" category="std" docName="draft-ietf-ipfix-exporting-type-05.txt">
<?rfc compact="yes"?>
<?rfc subcompact="no"?>
<?rfc toc="yes"?>
<?rfc symrefs="yes"?>
<front>
<title abbrev="IPFIX Type Information">
Exporting Type Information for IPFIX Information Elements
</title>
<author initials="E." surname="Boschi" fullname="Elisa Boschi">
<organization abbrev="Hitachi Europe">
Hitachi Europe
</organization>
<address>
<postal>
<street>c/o ETH Zurich</street>
<street>Gloriastrasse 35</street>
<city>8092 Zurich</city>
<country>Switzerland</country>
</postal>
<phone>+41 44 632 70 57</phone>
<email>elisa.boschi@hitachi-eu.com</email>
</address>
</author>
<author initials="B." surname="Trammell" fullname="Brian Trammell">
<organization abbrev="Hitachi Europe">
Hitachi Europe
</organization>
<address>
<postal>
<street>c/o ETH Zurich</street>
<street>Gloriastrasse 35</street>
<city>8092 Zurich</city>
<country>Switzerland</country>
</postal>
<phone>+41 44 632 70 13</phone>
<email>brian.trammell@hitachi-eu.com</email>
</address>
</author>
<author initials="L." surname="Mark" fullname="Lutz Mark">
<organization abbrev="Fraunhofer IFAM">
Fraunhofer IFAM
</organization>
<address>
<postal>
<street>Wiener Str. 12</street>
<city>28359 Bremen</city>
<country>Germany</country>
</postal>
<phone>+49 421 2246206</phone>
<email>lutz.mark@ifam.fraunhofer.de</email>
</address>
</author>
<author initials="T." surname="Zseby" fullname="Tanja Zseby">
<organization abbrev="Fraunhofer FOKUS">
Fraunhofer Institute for Open Communication Systems
</organization>
<address>
<postal>
<street>Kaiserin-Augusta-Allee 31</street>
<city>10589 Berlin</city>
<country>Germany</country>
</postal>
<phone>+49 30 3463 7153</phone>
<email>tanja.zseby@fokus.fraunhofer.de</email>
</address>
</author>
<date month="June" day="9" year="2009"></date>
<area>Operations</area>
<workgroup>IPFIX Working Group</workgroup>
<abstract>
<t>This document describes an extension to the IP Flow Information Export
(IPFIX) protocol, which is used to represent and transmit data from IP flow
measurement devices for collection, storage and analysis, to allow the
encoding of IPFIX Information Model properties within an IPFIX Message
stream. This enables the export of extended type information for
enterprise-specific Information Elements, and the storage of such
information within IPFIX Files, facilitating interoperability and
reusability among a wide variety of applications and tools.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>IP Flow Information Export (IPFIX) provides a template mechanism for the
flexible description of Data Records, by defining a record as a collection
of Information Elements defined in an IANA registry, However, these
Templates provide limited information about the type of described data;
indeed, they encode only the size of the fields defined by these
Information Elements. There presently exists no mechanism to provide full
type information for these Information Elements, as is defined for the
Information Elements in the IPFIX Information Model.</t>
<t>This especially limits the interoperability of enterprise-specific
Information Elements. It is not possible to use analysis tools on IPFIX
records containing these partially defined Information Elements that have
not been developed with a priori knowledge of their types, since such tools
will not be able to decode them; these tools can only treat and store them
as opaque octet arrays. However, if richer information is available,
additional operations such as efficient storage, display, and limited
analysis of records containing enterprise-specific Information Elements
become possible, even for Collecting Processes that had not been
specifically developed to understand them.</t>
<t>This document defines a general mechanism to encode the full set of
properties available for the definition of Information Elements within the
IPFIX Information Model inline within an IPFIX Message stream using IPFIX
Options. This mechanism may be used to fully define type information for
Information Elements used within a message stream, without resort to an
external reference or reliance on out-of-band configuration, thereby
improving the interoperability of enterprise-specific Information
Elements.</t>
<t>Note that the solution described in this draft is not intended as a
replacement for registration with IANA of generally useful Information
Elements. It introduces overhead and does not lead to real interoperability
as provided by standardization. Therefore we highly recommend to
standardize all new generally useful Information Elements by registering
them with IANA. Standardization is straightforward, and the type
information that needs to be specified in order to support the proposed
solution provides a perfect basis for the description required for
standardizing the Information Element.</t>
<t>It might happen that an Information Element previously described by the
mechanism in this document later becomes an IANA-registered, standard
Information Element. In such environments old and new versions of the
Information Element can coexist. A translation between Information Elements
expressed by the described solution and standardized Information Elements
is therefore not necessary, and is out of scope for this document.</t>
<section title="IPFIX Documents Overview" anchor="intro-docs">
<t><xref target="RFC5101">"Specification of the IPFIX
Protocol for the Exchange of IP Traffic Flow Information"</xref>
(informally, the IPFIX Protocol document) and its associated documents
define the IPFIX Protocol, which provides network engineers and
administrators with access to IP traffic flow information.</t>
<t><xref target="RFC5470">"Architecture for IP Flow
Information Export"</xref> (the IPFIX Architecture document) defines
the architecture for the export of measured IP flow information out of
an IPFIX Exporting Process to an IPFIX Collecting Process, and the
basic terminology used to describe the elements of this architecture,
per the requirements defined in <xref target="RFC3917">"Requirements
for IP Flow Information Export"</xref>. The IPFIX Protocol document
<xref target="RFC5101"></xref> then covers the details of the method for
transporting IPFIX Data Records and Templates via a congestion-aware
transport protocol from an IPFIX Exporting Process to an IPFIX
Collecting Process.</t>
<t><xref target="RFC5102">"Information Model for IP Flow
Information Export"</xref> (informally, the IPFIX Information Model
document) describes the Information Elements used by IPFIX, including
details on Information Element naming, numbering, and data type
encoding.</t>
<t>This document references the Protocol and Architecture documents for
terminology and extends the IPFIX Information Model to provide new
Information Elements for the representation of Information Element
properties. It draws data type definitions and data type semantics
definitions from the Information Model; the encodings of these data types
are defined in <xref target="RFC5101"/>. </t>
</section>
</section>
<section title="Terminology">
<t>Terms used in this document that are defined in the Terminology section
of the <xref target="RFC5101">IPFIX Protocol</xref>
document are to be interpreted as defined there.</t>
<t>The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in <xref target="RFC2119">RFC
2119</xref>.</t>
</section>
<section title="Type Information Export" anchor="self-description-IEs">
<t>This section describes the mechanism used to encode Information
Element type information within an IPFIX Message stream. This mechanism
consists of an Options Template Record used to define Information Element
type records, and a set of Information Elements required by these type
records. We first specify the necessary Information Elements, followed by
the structure of the Options Template describing the type records.</t>
<t>Note that Information Element type records require one Information
Element, informationElementId, that is defined in the <xref
target="RFC5477">PSAMP Information Model</xref>. This Information Element
supports references only to IANA-defined Information Elements; the
privateEnterpriseNumber Information Element is required alongside
informationElementId to describe enterprise-specific Information
Elements.</t>
<section title="informationElementDataType">
<list style="hanging">
<t hangText="Description: ">
A description of the abstract data type of an IPFIX information element.
These are taken from the abstract data types defined in section 3.1 of
the <xref target="RFC5102">IPFIX Information Model</xref>; see that
section for more information on the types described below. This field
may take the values defined in <xref target="ie-DataType-table"/> below.
<texttable title="IE Data Type values"anchor="ie-DataType-table">
<ttcol align="left">Value</ttcol>
<ttcol align="left">Description</ttcol>
<c>0x00</c><c>octetArray</c>
<c>0x01</c><c>unsigned8</c>
<c>0x02</c><c>unsigned16</c>
<c>0x03</c><c>unsigned32</c>
<c>0x04</c><c>unsigned64</c>
<c>0x05</c><c>signed8</c>
<c>0x06</c><c>signed16</c>
<c>0x07</c><c>signed32</c>
<c>0x08</c><c>signed64</c>
<c>0x09</c><c>float32</c>
<c>0x0A</c><c>float64</c>
<c>0x0B</c><c>boolean</c>
<c>0x0C</c><c>macAddress</c>
<c>0x0D</c><c>string</c>
<c>0x0E</c><c>dateTimeSeconds</c>
<c>0x0F</c><c>dateTimeMilliseconds</c>
<c>0x10</c><c>dateTimeMicroseconds</c>
<c>0x11</c><c>dateTimeNanoseconds</c>
<c>0x12</c><c>ipv4Address</c>
<c>0x13</c><c>ipv6Address</c>
</texttable>
These types are registered in the IANA IPFIX Information Element Data
Type subregistry. This subregistry is intended to assign numbers for type names,
not to provide a mechanism for adding data types to the IPFIX Protocol,
and as such requires a <xref target="RFC5226">Standards Action</xref> to modify.
</t>
<t hangText="Abstract Data Type: ">unsigned8</t>
<t hangText="ElementId: ">TBD1</t>
<t hangText="Status: ">current</t>
<t hangText="Reference: ">
Section 3.1 of the <xref target="RFC5102">IPFIX Information Model</xref>
</t>
</list>
</section>
<section title="informationElementDescription">
<list style="hanging">
<t hangText="Description: ">
A <xref target="RFC3629">UTF-8</xref> encoded Unicode string containing a
human-readable description of an Information Element. The content of the
informationElementDescription MAY be annotated with one or more <xref
target="RFC4646">language tags</xref>, encoded <xref
target="RFC2482">in-line</xref> within the UTF-8 string, in order to
specify the language in which the description is written. Description
text in multiple languages MAY tag each section with its own language
tag; in this case, the description information in each language SHOULD
have equivalent meaning. In the absence of any language tag, the <xref
target="RFC2277">"i-default"</xref> language SHOULD be assumed. See the
Security Considerations section for notes on string handling for
Information Element type records.
</t>
<t hangText="Abstract Data Type: ">string</t>
<t hangText="ElementId: ">TBD2</t>
<t hangText="Status: ">current</t>
</list>
</section>
<section title="informationElementName">
<list style="hanging">
<t hangText="Description: ">
A <xref target="RFC3629">UTF-8</xref> encoded Unicode string containing the name of an Information Element, intended as a simple identifier. See the Security Considerations section for notes on string handling for Information Element type records.
</t>
<t hangText="Abstract Data Type: ">string</t>
<t hangText="ElementId: ">TBD3</t>
<t hangText="Status: ">current</t>
</list>
</section>
<section title="informationElementRangeBegin">
<list style="hanging">
<t hangText="Description: ">
Contains the inclusive low end of the range of acceptable values for an
Information Element.
</t>
<t hangText="Abstract Data Type: ">unsigned64</t>
<t hangText="Data Type Semantics: ">quantity</t>
<t hangText="ElementId: ">TBD4</t>
<t hangText="Status: ">current</t>
</list>
</section>
<section title="informationElementRangeEnd">
<list style="hanging">
<t hangText="Description: ">
Contains the inclusive high end of the range of acceptable values for an
Information Element.
</t>
<t hangText="Abstract Data Type: ">unsigned64</t>
<t hangText="Data Type Semantics: ">quantity</t>
<t hangText="ElementId: ">TBD5</t>
<t hangText="Status: ">current</t>
</list>
</section>
<section title="informationElementSemantics">
<list style="hanging">
<t hangText="Description: ">
A description of the semantics of an IPFIX Information Element. These are
taken from the data type semantics defined in section 3.2 of the <xref
target="RFC5102">IPFIX Information Model</xref>; see that section for more
information on the types described below. This field may take the values
in <xref target="ie-Semantics-table"/> below; the special value 0x00
(default) is used to note that no semantics apply to the field; it cannot
be manipulated by a Collecting Process or File Reader that does not
understand it a priori.
<texttable title="IE Semantics values" anchor="ie-Semantics-table">
<ttcol align="left">Value</ttcol>
<ttcol align="left">Description</ttcol>
<c>0x00</c><c>default</c>
<c>0x01</c><c>quantity</c>
<c>0x02</c><c>totalCounter</c>
<c>0x03</c><c>deltaCounter</c>
<c>0x04</c><c>identifier</c>
<c>0x05</c><c>flags</c>
</texttable>
These semantics are registered in the IANA IPFIX Information Element
Semantics subregistry. This subregistry is intended to assign numbers for
semantics names, not to provide a mechanism for adding semantics to the
IPFIX Protocol, and as such requires a <xref target="RFC5226">Standards Action</xref> to modify.
</t>
<t hangText="Abstract Data Type: ">unsigned8</t>
<t hangText="ElementId: ">TBD6</t>
<t hangText="Status: ">current</t>
<t hangText="Reference: ">
Section 3.2 of the <xref target="RFC5102">IPFIX Information Model</xref>
</t>
</list>
</section>
<section title="informationElementUnits">
<list style="hanging">
<t hangText="Description: ">
A description of the units of an IPFIX Information Element. These
correspond to the units implicitly defined in the Information Element
definitions in section 5 of the <xref target="RFC5102">IPFIX
Information Model</xref>; see that section for more information on the
types described below. This field may take the values in <xref target="ie-Units-table"/> below; the
special value 0x00 (none) is used to note that the field is unitless.
<texttable title="IE Units values" anchor="ie-Units-table">
<ttcol align="left">Value</ttcol>
<ttcol align="left">Name</ttcol>
<ttcol align="left">Notes</ttcol>
<c>0x0000</c><c>none</c><c></c>
<c>0x0001</c><c>bits</c><c></c>
<c>0x0002</c><c>octets</c><c></c>
<c>0x0003</c><c>packets</c><c></c>
<c>0x0004</c><c>flows</c><c></c>
<c>0x0005</c><c>seconds</c><c></c>
<c>0x0006</c><c>milliseconds</c><c></c>
<c>0x0007</c><c>microseconds</c><c></c>
<c>0x0008</c><c>nanoseconds</c><c></c>
<c>0x0009</c><c>4-octet words</c><c>for IPv4 header length</c>
<c>0x000A</c><c>messages</c><c>for reliability reporting</c>
<c>0x000B</c><c>hops</c><c>for TTL</c>
<c>0x000C</c><c>entries</c><c>for MPLS label stack</c>
</texttable>
These types are registered in the IANA IPFIX Information Element Units
subregistry; new types may be added on a <xref target="RFC5226">First
Come First Served</xref> basis.
</t>
<t hangText="Abstract Data Type: ">unsigned16</t>
<t hangText="ElementId: ">TBD7</t>
<t hangText="Status: ">current</t>
<t hangText="Reference: ">
Section 5 of the <xref target="RFC5102">IPFIX Information Model</xref>
</t>
</list>
</section>
<section title="privateEnterpriseNumber">
<list style="hanging">
<t hangText="Description: ">
A private enterprise number, as assigned by IANA. Within the context of
an Information Element Type record, this element can be used along with
the informationElementId element to scope properties to a specific
Information Element. To export type information about an IANA-assigned
Information Element, set the privateEnterpriseNumber to 0, or do not
export the privateEnterpriseNumber in the type record. To export type
information about an enterprise-specific Information Element, export the
enterprise number in privateEnterpriseNumber, and export the Information
Element number with the Enterprise bit cleared in informationElementId.
The Enterprise bit in the associated informationElementId Information
Element MUST be ignored by the Collecting Process.
</t>
<t hangText="Abstract Data Type: ">unsigned32</t>
<t hangText="Data Type Semantics: ">identifier</t>
<t hangText="ElementId: ">TBD8</t>
<t hangText="Status: ">current</t>
<t hangText="Reference: ">
Sections 3.2 and 3.4.1 of the <xref target="RFC5101">IPFIX Protocol</xref>;
section 8.2.3 of the <xref target="RFC5477">PSAMP Information
Model</xref>.
</t>
</list>
</section>
<section title="Information Element Type Options Template">
<t>The Information Element Type Options Template attaches type information
to Information Elements used within Template Records, as scoped to an
Observation Domain within a Transport Session. This provides a mechanism for
representing an IPFIX Information Model inline within an IPFIX Message
stream. Data Records described by this template are referred to as
Information Element type records.</t>
<t>In deployments in which interoperability across vendor implementations of
IPFIX is important, an Exporting Process exporting data using Templates
containing enterprise-specific Information Elements SHOULD export an
Information Element type record for each enterprise-specific Information
Element it exports. Collecting Processes MAY use these type records to
improve handling of unknown enterprise-specific Information Elements.
Exporting Processes using enterprise-specific Information Elements to
implement proprietary features MAY omit type records for those Information
Elements.</t>
<t>Information Element type records MUST be handled by Collecting Processes
as scoped to the Transport Session in which they are sent; this facility is
not intended to provide a method for the permanent definition of Information
Elements.</t>
<t>Similarly, for security reasons, type information for a given Information
Element MUST NOT be re-defined by Information Element type records, and a
Collecting Process MUST NOT allow an Information Element type record to
replace its own internal definition of an Information Element. Information
Element type records SHOULD NOT be duplicated in a given Observation Domain
within a Transport Session. Once an Information Element type record has
been exported for a given Information Element within a given Transport
Session, all subsequent type records for that Information Element MUST be
identical. Information Elements for which a Collecting Process receives
conflicting semantic or type information MUST be ignored.</t>
<t>Note that while this template MAY be used to export information about any
Information Element, including those registered with IANA, Exporting
Processes SHOULD NOT export any type records that could be reasonably
assumed to duplicate type information available at the Collecting Process.
This mechanism is not intended as a replacement for Exporting and Collecting
Processes keeping up to date with changes to the IANA registry; such an
update mechanism is out of scope for this document.</t>
<t>The template SHOULD contain the Information Elements in <xref target="tmpl-TypeOptions-table"/>, below, as defined
in the <xref target="RFC5477">PSAMP Information Model</xref> and
in this document, above.
<texttable title="IE Type Options" anchor="tmpl-TypeOptions-table">
<ttcol align="left">IE</ttcol>
<ttcol align="left">Description</ttcol>
<c>informationElementId [scope]</c>
<c>
The Information Element identifier of the Information Element described
by this type record. This Information Element MUST be defined as a
Scope Field. See the <xref target="RFC5477">PSAMP
Information Model</xref> for a definition of this field.
</c>
<c>privateEnterpriseNumber [scope]</c>
<c>
The Private Enterprise number of the Information Element described by
this type record. This Information Element MUST be defined as a Scope
Field.
</c>
<c>informationElementDataType</c>
<c>
The storage type of the specified Information Element.
</c>
<c>informationElementSemantics</c>
<c>
The semantic type of the specified Information Element.
</c>
<c>informationElementUnits</c>
<c>
The units of the specified Information Element. This element SHOULD
be omitted if the Information Element is a unitless quantity, or a
not a quantity or counter.
</c>
<c>informationElementRangeBegin</c>
<c>
The low end of the range of acceptable values for the specified
Information Element. This element SHOULD be omitted if the beginning
of the Information Element's acceptable range is defined by its data
type.
</c>
<c>informationElementRangeEnd</c>
<c>
The high end of the range of acceptable values for the specified
Information Element. This element SHOULD be omitted if the end
Information Element's acceptable range is defined by its data type.
</c>
<c>informationElementName</c>
<c>
The name of the specified Information Element.
</c>
<c>informationElementDescription</c>
<c>
A human readable description of the specified Information Element.
This element MAY be omitted in the interest of export efficiency.
</c>
</texttable>
</t>
</section>
<section title="Data Type and Semantics Restrictions">
<t>Note that the informationElementSemantics values defined in section 3.2
of <xref target="RFC5102" /> are primarily intended to differentiate
semantic interpretation of numeric values, and that not all combinations
of the informationElementDataType and informationElementSemantics
Information Elements are valid; e.g., a counter cannot be encoded as an
IPv4 address. The following are acceptable values of informationElementSemantics:</t>
<list style="symbols">
<t>Any value is valid for unsigned informationElementDataType values
("unsigned8", "unsigned16", "unsigned32", or "unsigned64").</t>
<t>Any value except "flags" is valid for signed
informationElementDataType values ("signed8", "signed16", "signed32", or
"signed64").</t>
<t>Any value except "identifier" or "flags" is valid for floating-point
informationElementDataType values ("float32" or "float64").</t>
<t>Only "default" is valid for all other other
informationElementDataType values ("octetArray", "boolean",
"macAddress", "string", "dateTimeSeconds", "dateTimeMilliseconds",
"dateTimeMicroseconds", "dateTimeNanoseconds", "ipv4Address", or
"ipv6Address").</t>
</list>
<t>Information Element type records containing invalid combinations of
informationElementSemantics and informationElementDataType MUST NOT be
sent by Exporting Processes, and MUST be ignored by Collecting
Processes.</t>
<t>Future standards actions that modify the Information Element Data Type
subregistry or the Information Element Semantics subregistry should
contain a Data Type and Semantics Restrictions sections such as this one
to define allowable combinations of type and semantics information.</t>
</section>
</section>
<section title="Security Considerations">
<t>The same security considerations as for the <xref target="RFC5101">IPFIX
Protocol</xref> apply.</t>
<t>Attention must be paid to the handling of Information Element type
records at the Collecting Process. Type information precedence rules
defined above (a Collecting Process' current knowledge overrides type
records; types are not redefinable during a session) are designed to
minimize the opportunity for an attacker to maliciously redefine the data
model.</t>
<t>Note that Information Element type records may contain two strings
describing Information Elements: informationElementName and
informationElementDescription. IPFIX strings on the wire are
length-prefixed and <xref target="RFC3629">UTF-8</xref> encoded, most often
within an IPFIX variable-length Information Element, which mitigates the
risk of unterminated-string attacks against IPFIX Collecting Processes.
However, care should still be taken when handling strings within the type
system of the Collecting Process.</t>
<t>First, Collecting Processes should pay particular attention to buffer
sizes converting between length-prefixed and null-terminated strings.
Exporting Processes MUST NOT export, and Collecting Processes MUST ignore,
any informationElementName or informationElementDescription content which
contains null characters (U+0000) in order to ensure buffer and string
lengths are consistent.</t>
<t>Also, note that there is no limit to IPFIX string length beyond that
inherent in the protocol. The maximum IPFIX string length is 65512 octets
(maximum message length (65535), minus message header (16), minus set
header (4), minus long variable length field (3)). Specifically, although
the informationElementName of all IANA Information Elements at the time of
this writing is less than about 40 octets, and the
informationElementDescription is less than 4096 octets, either of these
Information Elements may contain strings up to 65512 octets long.</t>
</section>
<section title="IANA Considerations">
<t>This document specifies the creation of several new IPFIX Information
Elements in the IPFIX Information Element registry as defined in section 3 above. IANA
has assigned the following Information Element numbers for their
respective Information Elements as specified below:</t>
<list style="symbols">
<t>Information Element Number TBD1 for the informationElementDataType
Information Element</t>
<t>Information Element Number TBD2 for the
informationElementDescription Information Element</t>
<t>Information Element Number TBD3 for the informationElementName
Information Element</t>
<t>Information Element Number TBD4 for the
informationElementRangeBegin Information Element</t>
<t>Information Element Number TBD5 for the informationElementRangeEnd
Information Element</t>
<t>Information Element Number TBD6 for the informationElementSemantics
Information Element</t>
<t>Information Element Number TBD7 for the informationElementUnits
Information Element</t>
<t>Information Element Number TBD8 for the privateEnterpriseNumber
Information Element</t>
<t>[NOTE for IANA: The text TBD1, TBD2, TBD3, TBD4, TBD5, TBD6, TBD7,
and TBD8 should be replaced with the respective assigned Information
Element numbers where they appear in this document.]</t>
</list>
<t>IANA has created an Information Element Data Type subregistry for the values
defined for the informationElementSemantics Information Element. Entries may
be added to this subregistry subject to a <xref target="RFC5226">Standards Action</xref>.</t>
<t>[NOTE for IANA: Please create a new Information Element
Data Type subregistry as specified in the paragraph above,
with values taken from section 3.1 of this document.]</t>
<t>IANA has created an Information Element Semantics subregistry for the
values defined for the informationElementSemantics Information Element.
Entries may be added to this subregistry subject to a <xref target="RFC5226">Standards Action</xref>.</t>
<t>[NOTE for IANA: Please create a new Information Element
Semantics subregistry as specified in the paragraph above,
with values taken from section 3.6 of this document.]</t>
<t>IANA has created an Information Element Units subregistry for the
values defined for the informationElementUnits Information Element.
Entries may be added to this subregistry on an <xref target="RFC5226">Expert Review</xref> basis.</t>
<t>[NOTE for IANA: Please create a new Information Element
Units subregistry as specified in the paragraph above,
with values taken from section 3.7 of this document.]</t>
</section>
<section title="Acknowledgements">
<t>Thanks to Paul Aitken and Gerhard Muenz for the detailed reviews, and to
David Moore for first raising this issue to the IPFIX mailing list.</t>
</section>
</middle>
<back>
<references title="Normative References">
&rfc5101;
&rfc5102;
&rfc5477;
&rfc3629;
&rfc2277;
&rfc2482;
&rfc4646;
&rfc5226;
&rfc2119;
</references>
<references title="Informative References">
&rfc3917;
&rfc5470;
</references>
<section title="Examples">
<t>The following example illustrates how the type information
extension mechanism defined in this document may be used to
describe the semantics of enterprise-specific Information
Elements. The Information Elements used in this example are as
follows:</t>
<list style="symbols">
<t>initialTCPFlags, an example private IE 14, 1 octet, the
TCP flags on the first TCP packet in the flow.</t>
<t>unionTCPFlags, an example private IE 15, 1 octet, the
union of the TCP flags on all packets after the first TCP packet
in the flow.</t>
</list>
<t>An Exporting Process exporting flows containing these
Information Elements might use a Template like the following:</t>
<figure title="Template with Enterprise-Specific IEs" anchor="esie-template">
<artwork><![CDATA[
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Set ID = 2 | Length = 52 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 256 | Field Count = 9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| flowStartSeconds 150 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceIPv4Address 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationIPv4Address 12 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceTransportPort 7 | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationTransportPort 11 | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| octetTotalCount 85 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1| (initialTCPFlags) 14 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Private Enterprise Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1| (unionTCPFlags) 15 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Private Enterprise Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| protocolIdentifier 4 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>However, a Collecting Process receiving Data Sets described by this Template can only treat the enterprise-specific Information Elements as opaque octets; specifically, there is no hint to the collector that they contain flag information. To use the type information extension mechanism to address this problem, the Exporting Process would first export the Information Element Type Options Template described in section 3.9 above:</t>
<figure title="Example Information Element Type Options Template" anchor="ieso-template">
<artwork><![CDATA[
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Set ID = 3 | Length = 26 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 257 | Field Count = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scope Field Count = 2 |0| priv.EnterpriseNumber TBD8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 4 |0| informationElementId 303 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 2 |0| inf.El.DataType TBD1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 1 |0| inf.El.Semantics TBD6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 1 |0| inf.El.Name TBD3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 65536 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>Then, the Exporting Process would then export two records described by the Example Information Element Type Options Template to describe the enterprise-specific Information Elements:</t>
<figure title="Type Record Example" anchor="ieso-data">
<artwork><![CDATA[
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Set ID = 257 | Length = 50 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Private Enterprise Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|X| IE 14 |0x01 unsigned8 |0x05 flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 15 length | |
+-+-+-+-+-+-+-+-+ |
| "initialTCPFlags" |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Private Enterprise Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|X| IE 15 |0x01 unsigned8 |0x05 flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 13 length | |
+-+-+-+-+-+-+-+-+ "unionTCPFlags" |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
</section>
</back>
</rfc>
| PAFTECH AB 2003-2026 | 2026-04-23 08:24:20 |