RFC 5101
Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information
Network Working Group B. Claise, Ed. Request for Comments: 5101 Cisco Systems, Inc. Category: Standards Track January 2008 Specification of the IP Flow Information Export (IPFIX) Protocol for the Exchange of IP Traffic Flow Information Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.Abstract
This document specifies the IP Flow Information Export (IPFIX) protocol that serves for transmitting IP Traffic Flow information over the network. In order to transmit IP Traffic Flow information from an Exporting Process to an information Collecting Process, a common representation of flow data and a standard means of communicating them is required. This document describes how the IPFIX Data and Template Records are carried over a number of transport protocols from an IPFIX Exporting Process to an IPFIX Collecting Process.Table of Contents
1. Introduction ....................................................3 1.1. IPFIX Documents Overview ...................................4 2. Terminology .....................................................4 2.1. Terminology Summary Table ..................................9 3. IPFIX Message Format ...........................................10 3.1. Message Header Format .....................................11 3.2. Field Specifier Format ....................................13 3.3. Set and Set Header Format .................................14 3.3.1. Set Format .........................................14 3.3.2. Set Header Format ..................................15 3.4. Record Format .............................................16 3.4.1. Template Record Format .............................16 3.4.2. Options Template Record Format .....................18 3.4.2.1. Scope .....................................19 3.4.2.2. Options Template Record Format ............20 3.4.3. Data Record Format .................................22 4. Specific Reporting Requirements ................................23 4.1. The Metering Process Statistics Option Template ...........23
4.2. The Metering Process Reliability Statistics Option
Template ..................................................24
4.3. The Exporting Process Reliability Statistics
Option Template ...........................................25
4.4. The Flow Keys Option Template .............................26
5. IPFIX Message Header "Export Time" and Flow Record Time ........27
6. Linkage with the Information Model .............................28
6.1. Encoding of IPFIX Data Types ..............................28
6.1.1. Integral Data Types ................................28
6.1.2. Address Types ......................................28
6.1.3. float32 ............................................28
6.1.4. float64 ............................................28
6.1.5. boolean ............................................28
6.1.6. string and octetarray ..............................28
6.1.7. dateTimeSeconds ....................................29
6.1.8. dateTimeMilliseconds ...............................29
6.1.9. dateTimeMicroseconds ...............................29
6.1.10. dateTimeNanoseconds ...............................29
6.2. Reduced Size Encoding of Integer and Float Types ..........29
7. Variable-Length Information Element ............................30
8. Template Management ............................................31
9. The Collecting Process's Side ..................................34
10. Transport Protocol ............................................36
10.1. Transport Compliance and Transport Usage .................36
10.2. SCTP .....................................................37
10.2.1. Congestion Avoidance ..............................37
10.2.2. Reliability .......................................37
10.2.3. MTU ...............................................37
10.2.4. Exporting Process .................................38
10.2.4.1. Association Establishment ................38
10.2.4.2. Association Shutdown .....................38
10.2.4.3. Stream ...................................38
10.2.4.4. Template Management ......................39
10.2.5. Collecting Process ................................39
10.2.6. Failover ..........................................39
10.3. UDP ......................................................39
10.3.1. Congestion Avoidance ..............................39
10.3.2. Reliability .......................................40
10.3.3. MTU ...............................................40
10.3.4. Port Numbers ......................................40
10.3.5. Exporting Process .................................40
10.3.6. Template Management ...............................40
10.3.7. Collecting Process ................................41
10.3.8. Failover ..........................................42
10.4. TCP ......................................................42
10.4.1. Connection Management .............................42
10.4.1.1. Connection Establishment .................42
10.4.1.2. Graceful Connection Release ..............43
10.4.1.3. Restarting Interrupted Connections .......43
10.4.1.4. Failover .................................43
10.4.2. Data Transmission .................................43
10.4.2.1. IPFIX Message Encoding ...................43
10.4.2.2. Template Management ......................44
10.4.2.3. Congestion Handling and Reliability ......44
10.4.3. Collecting Process ................................45
11. Security Considerations .......................................46
11.1. Applicability of TLS and DTLS ............................47
11.2. Usage ....................................................48
11.3. Authentication ...........................................48
11.4. Protection against DoS Attacks ...........................48
11.5. When DTLS or TLS Is Not an Option ........................50
11.6. Logging an IPFIX Attack ..................................50
11.7. Securing the Collector ...................................51
12. IANA Considerations ...........................................51
Appendix A. IPFIX Encoding Examples ...............................52
A.1. Message Header Example.....................................52
A.2. Template Set Examples......................................53
A.2.1. Template Set Using IETF-Specified Information
Elements ...........................................53
A.2.2. Template Set Using Enterprise-Specific Information
Elements ...........................................53
A.3. Data Set Example ..........................................55
A.4. Options Template Set Examples .............................56
A.4.1. Options Template Set Using IETF-Specified
Information Elements ...............................56
A.4.2. Options Template Set Using Enterprise-Specific
Information Elements ...............................56
A.4.3. Options Template Set Using an Enterprise-Specific
Scope ..............................................57
A.4.4. Data Set Using an Enterprise-Specific Scope ........58
A.5. Variable-Length Information Element Examples ..............59
A.5.1. Example of Variable-Length Information Element
with Length Inferior to 255 Octets .................59
A.5.2. Example of Variable-Length Information Element
with Length 255 to 65535 Octets ....................59
References ........................................................59
Normative References ...........................................59
Informative References .........................................60
Acknowledgments ...................................................61
1. Introduction
A data network with IP traffic primarily consists of IP flows passing
through the network elements. It is often interesting, useful, or
even required to have access to information about these flows that
pass through the network elements for administrative or other
purposes. The IPFIX Collecting Process should be able to receive the flow information passing through multiple network elements within the data network. This requires uniformity in the method of representing the flow information and the means of communicating the flows from the network elements to the collection point. This document specifies the protocol to achieve these aforementioned requirements. This document specifies in detail the representation of different flows, the additional data required for flow interpretation, packet format, transport mechanisms used, security concerns, etc.1.1. IPFIX Documents Overview
The IPFIX protocol 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 [IPFIX-ARCH], per the requirements defined in [RFC3917]. This document specifies how IPFIX data records and templates are carried via a number of transport protocols from IPFIX Exporting Processes to IPFIX Collecting Processes. IPFIX has a formal description of IPFIX Information Elements, their name, type and additional semantic information, as specified in [RFC5102]. Finally, [IPFIX-AS] 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.2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. The definitions of the basic terms like IP Traffic Flow, Exporting Process, Collecting Process, Observation Points, etc. are semantically identical to those found in the IPFIX requirements document [RFC3917]. Some of the terms have been expanded for more clarity when defining the protocol. Additional terms required for the protocol have also been defined. Definitions in this document and in [IPFIX-ARCH] are equivalent, except that definitions that are only relevant to the IPFIX protocol only appear here. The terminology summary table in Section 2.1 gives a quick overview of the relationships between some of the different terms defined.
Observation Point
An Observation Point is a location in the network where IP packets
can be observed. Examples include: a line to which a probe is
attached, a shared medium, such as an Ethernet-based LAN, a single
port of a router, or a set of interfaces (physical or logical) of
a router.
Note that every Observation Point is associated with an
Observation Domain (defined below), and that one Observation Point
may be a superset of several other Observation Points. For
example, one Observation Point can be an entire line card. That
would be the superset of the individual Observation Points at the
line card's interfaces.
Observation Domain
An Observation Domain is the largest set of Observation Points for
which Flow information can be aggregated by a Metering Process.
For example, a router line card may be an Observation Domain if it
is composed of several interfaces, each of which is an Observation
Point. In the IPFIX Message it generates, the Observation Domain
includes its Observation Domain ID, which is unique per Exporting
Process. That way, the Collecting Process can identify the
specific Observation Domain from the Exporter that sends the IPFIX
Messages. Every Observation Point is associated with an
Observation Domain. It is RECOMMENDED that Observation Domain IDs
also be unique per IPFIX Device.
IP Traffic Flow or Flow
There are several definitions of the term 'flow' being used by the
Internet community. Within the context of IPFIX we use the
following definition:
A Flow is defined as a set of IP packets passing an Observation
Point in the network during a certain time interval. All packets
belonging to a particular Flow have a set of common properties.
Each property is defined as the result of applying a function to
the values of:
1. one or more packet header fields (e.g., destination IP
address), transport header fields (e.g., destination port
number), or application header fields (e.g., RTP header
fields [RFC3550]).
2. one or more characteristics of the packet itself (e.g.,
number of MPLS labels, etc...).
3. one or more of fields derived from packet treatment (e.g.,
next hop IP address, the output interface, etc...).
A packet is defined as belonging to a Flow if it completely
satisfies all the defined properties of the Flow.
This definition covers the range from a Flow containing all
packets observed at a network interface to a Flow consisting of
just a single packet between two applications. It includes
packets selected by a sampling mechanism.
Flow Key
Each of the fields that:
1. belong to the packet header (e.g., destination IP address),
2. are a property of the packet itself (e.g., packet length),
3. are derived from packet treatment (e.g., Autonomous System
(AS) number),
and that are used to define a Flow are termed Flow Keys.
Flow Record
A Flow Record contains information about a specific Flow that was
observed at an Observation Point. A Flow Record contains measured
properties of the Flow (e.g., the total number of bytes for all
the Flow's packets) and usually characteristic properties of the
Flow (e.g., source IP address).
Metering Process
The Metering Process generates Flow Records. Inputs to the
process are packet headers and characteristics observed at an
Observation Point, and packet treatment at the Observation Point
(for example, the selected output interface).
The Metering Process consists of a set of functions that includes
packet header capturing, timestamping, sampling, classifying, and
maintaining Flow Records.
The maintenance of Flow Records may include creating new records,
updating existing ones, computing Flow statistics, deriving
further Flow properties, detecting Flow expiration, passing Flow
Records to the Exporting Process, and deleting Flow Records.
Exporting Process
The Exporting Process sends Flow Records to one or more Collecting
Processes. The Flow Records are generated by one or more Metering
Processes.
Exporter
A device that hosts one or more Exporting Processes is termed an
Exporter.
IPFIX Device
An IPFIX Device hosts at least one Exporting Process. It may host
further Exporting Processes and arbitrary numbers of Observation
Points and Metering Processes.
Collecting Process
A Collecting Process receives Flow Records from one or more
Exporting Processes. The Collecting Process might process or
store received Flow Records, but such actions are out of scope for
this document.
Collector
A device that hosts one or more Collecting Processes is termed a
Collector.
Template
A Template is an ordered sequence of <type, length> pairs used to
completely specify the structure and semantics of a particular set
of information that needs to be communicated from an IPFIX Device
to a Collector. Each Template is uniquely identifiable by means
of a Template ID.
IPFIX Message
An IPFIX Message is a message originating at the Exporting Process
that carries the IPFIX records of this Exporting Process and whose
destination is a Collecting Process. An IPFIX Message is
encapsulated at the transport layer.
Message Header
The Message Header is the first part of an IPFIX Message, which
provides basic information about the message, such as the IPFIX
version, length of the message, message sequence number, etc.
Template Record
A Template Record defines the structure and interpretation of
fields in a Data Record.
Data Record
A Data Record is a record that contains values of the parameters
corresponding to a Template Record.
Options Template Record
An Options Template Record is a Template Record that defines the
structure and interpretation of fields in a Data Record, including
defining how to scope the applicability of the Data Record.
Set
Set is a generic term for a collection of records that have a
similar structure. In an IPFIX Message, one or more Sets follow
the Message Header.
There are three different types of Sets: Template Set, Options
Template Set, and Data Set.
Template Set
A Template Set is a collection of one or more Template Records
that have been grouped together in an IPFIX Message.
Options Template Set
An Options Template Set is a collection of one or more Options
Template Records that have been grouped together in an IPFIX
Message.
Data Set
A Data Set is one or more Data Records, of the same type, that are
grouped together in an IPFIX Message. Each Data Record is
previously defined by a Template Record or an Options Template
Record.
Information Element
An Information Element is a protocol and encoding-independent
description of an attribute that may appear in an IPFIX Record.
The IPFIX information model [RFC5102] defines the base set of
Information Elements for IPFIX. The type associated with an
Information Element indicates constraints on what it may contain
and also determines the valid encoding mechanisms for use in
IPFIX.
Transport Session
In Stream Control Transmission Protocol (SCTP), the transport
session is known as the SCTP association, which is uniquely
identified by the SCTP endpoints [RFC4960]; in TCP, the transport
session is known as the TCP connection, which is uniquely
identified by the combination of IP addresses and TCP ports used.
In UDP, the transport session is known as the UDP session, which
is uniquely identified by the combination of IP addresses and UDP
ports used.
2.1. Terminology Summary Table
+------------------+---------------------------------------------+
| | contents |
| +--------------------+------------------------+
| Set | Template | record |
+------------------+--------------------+------------------------+
| Data Set | / | Data Record(s) |
+------------------+--------------------+------------------------+
| Template Set | Template Record(s) | / |
+------------------+--------------------+------------------------+
| Options Template | Options Template | / |
| Set | Record(s) | |
+------------------+--------------------+------------------------+
Figure A: Terminology Summary Table
A Data Set is composed of Data Record(s). No Template Record is
included. A Template Record or an Options Template Record defines
the Data Record.
A Template Set contains only Template Record(s).
An Options Template Set contains only Options Template Record(s).
3. IPFIX Message Format
An IPFIX Message consists of a Message Header, followed by one or more Sets. The Sets can be any of the possible three types: Data Set, Template Set, or Options Template Set. The format of the IPFIX Message is shown in Figure B. +----------------------------------------------------+ | Message Header | +----------------------------------------------------+ | Set | +----------------------------------------------------+ | Set | +----------------------------------------------------+ ... +----------------------------------------------------+ | Set | +----------------------------------------------------+ Figure B: IPFIX Message Format The Exporter MUST code all binary integers of the Message Header and the different Sets in network-byte order (also known as the big-endian byte ordering). Following are some examples of IPFIX Messages: 1. An IPFIX Message consisting of interleaved Template, Data, and Options Template Sets -- A newly created Template is exported as soon as possible. So, if there is already an IPFIX Message with a Data Set that is being prepared for export, the Template and Option Template Sets are interleaved with this information, subject to availability of space. +--------+--------------------------------------------------------+ | | +----------+ +---------+ +-----------+ +---------+ | |Message | | Template | | Data | | Options | | Data | | | Header | | Set | | Set | ... | Template | | Set | | | | | | | | | Set | | | | | | +----------+ +---------+ +-----------+ +---------+ | +--------+--------------------------------------------------------+ Figure C: IPFIX Message, Example 1
2. An IPFIX Message consisting entirely of Data Sets -- After the
appropriate Template Records have been defined and transmitted to
the Collecting Process, the majority of IPFIX Messages consist
solely of Data Sets.
+--------+----------------------------------------------+
| | +---------+ +---------+ +---------+ |
|Message | | Data | | Data | | Data | |
| Header | | Set | ... | Set | ... | Set | |
| | +---------+ +---------+ +---------+ |
+--------+----------------------------------------------+
Figure D: IPFIX Message, Example 2
3. An IPFIX Message consisting entirely of Template and Options
Template Sets.
+--------+-------------------------------------------------+
| | +----------+ +----------+ +----------+ |
|Message | | Template | | Template | | Options | |
| Header | | Set | ... | Set | ... | Template | |
| | | | | | | Set | |
| | +----------+ +----------+ +----------+ |
+--------+-------------------------------------------------+
Figure E: IPFIX Message, Example 3
3.1. Message Header Format
The format of the IPFIX Message Header is shown in Figure F.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version Number | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Export Time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Observation Domain ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure F: IPFIX Message Header Format
Message Header Field Descriptions:
Version
Version of Flow Record format exported in this message. 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, in seconds, since 0000 UTC Jan 1, 1970, at which the IPFIX
Message Header leaves the Exporter.
Sequence Number
Incremental sequence counter modulo 2^32 of all IPFIX Data Records
sent on this PR-SCTP stream from the current Observation Domain by
the Exporting Process. Check the specific meaning of this field
in the subsections of Section 10 when UDP or TCP is selected as
the transport protocol. This value SHOULD 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 SHOULD use the Transport Session and the
Observation Domain ID field to separate different export streams
originating from the same Exporting Process. The Observation
Domain ID SHOULD be 0 when no specific Observation Domain ID is
relevant for 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.
3.2. Field Specifier Format
Vendors need the ability to define proprietary Information Elements, because, for example, they are delivering a pre-standards product, or the Information Element is, in some way, commercially sensitive. This section describes the Field Specifier format for both IETF-specified Information Elements [RFC5102] and enterprise-specific Information Elements. The Information Elements are identified by the Information Element identifier. When the Enterprise bit is set to 0, the corresponding Information Element identifier will report an IETF-specified Information Element, and the Enterprise Number MUST NOT be present. When the Enterprise bit is set to 1, the corresponding Information Element identifier will report an enterprise-specific Information Element; the Enterprise Number MUST be present. An example of this is shown in Section A.4.2. The Field Specifier format is shown in Figure G. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |E| Information Element ident. | Field Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure G: Field Specifier Format Where: E Enterprise bit. This is the first bit of the Field Specifier. If this bit is zero, the Information Element Identifier identifies an IETF-specified Information Element, and the four-octet Enterprise Number field MUST NOT be present. If this bit is one, the Information Element identifier identifies an enterprise-specific Information Element, and the Enterprise Number filed MUST be present. Information Element identifier A numeric value that represents the type of Information Element. Refer to [RFC5102].
Field Length
The length of the corresponding encoded Information Element, in
octets. Refer to [RFC5102]. The field length may be smaller than
the definition in [RFC5102] if the reduced size encoding is used
(see Section 6.2). The value 65535 is reserved for variable-
length Information Elements (see Section 7).
Enterprise Number
IANA enterprise number [PEN] of the authority defining the
Information Element identifier in this Template Record.
3.3. Set and Set Header Format
A Set is a generic term for a collection of records that have a
similar structure. There are three different types of Sets: Template
Sets, Options Template Sets, and Data Sets. Each of these Sets
consists of a Set Header and one or more records. The Set Format and
the Set Header Format are defined in the following sections.
3.3.1. Set Format
A Set has the format shown in Figure H. The record types can be
either Template Records, Options Template Records, or Data Records.
The record types MUST NOT be mixed within a Set.
+--------------------------------------------------+
| Set Header |
+--------------------------------------------------+
| record |
+--------------------------------------------------+
| record |
+--------------------------------------------------+
...
+--------------------------------------------------+
| record |
+--------------------------------------------------+
| Padding (opt.) |
+--------------------------------------------------+
Figure H: Set Format
The Set Field Definitions are as follows:
Set Header
The Set Header Format is defined in Section 3.3.2.
Record
One of the record Formats: Template Record, Options Template
Record, or Data Record Format.
Padding
The Exporting Process MAY insert some padding octets, so that the
subsequent Set starts at an aligned boundary. For security
reasons, the padding octet(s) MUST be composed of zero (0) valued
octets. The padding length MUST be shorter than any allowable
record in this Set. If padding of the IPFIX Message is desired in
combination with very short records, then the padding Information
Element 'paddingOctets' [RFC5102] can be used for padding records
such that their length is increased to a multiple of 4 or 8
octets. Because Template Sets are always 4-octet aligned by
definition, padding is only needed in case of other alignments
e.g., on 8-octet boundaries.
3.3.2. Set Header Format
Every Set contains a common header. This header is defined in Figure
I.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Set ID | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure I: Set Header Format
The Set Header Field Definitions are as follows:
Set ID
Set ID value identifies the Set. A value of 2 is reserved for the
Template Set. A value of 3 is reserved for the Option Template
Set. All other values from 4 to 255 are reserved for future use.
Values above 255 are used for Data Sets. The Set ID values of 0
and 1 are not used for historical reasons [RFC3954].
Length
Total length of the Set, in octets, including the Set Header, all
records, and the optional padding. Because an individual Set MAY
contain multiple records, the Length value MUST be used to
determine the position of the next Set.
3.4. Record Format
IPFIX defines three record formats, defined in the next sections: the Template Record Format, the Options Template Record Format, and the Data Record Format.3.4.1. Template Record Format
One of the essential elements in the IPFIX record format is the Template Record. Templates greatly enhance the flexibility of the record format because they allow the Collecting Process to process IPFIX Messages without necessarily knowing the interpretation of all Data Records. A Template Record contains any combination of IANA-assigned and/or enterprise-specific Information Elements identifiers. The format of the Template Record is shown in Figure J. It consists of a Template Record Header and one or more Field Specifiers. The definition of the Field Specifiers is given in Figure G above. +--------------------------------------------------+ | Template Record Header | +--------------------------------------------------+ | Field Specifier | +--------------------------------------------------+ | Field Specifier | +--------------------------------------------------+ ... +--------------------------------------------------+ | Field Specifier | +--------------------------------------------------+ Figure J: Template Record Format The format of the Template Record Header is shown in Figure K. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID (> 255) | Field Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure K: Template Record Header Format
The Template Record Header Field Definitions are as follows:
Template ID
Each of the newly generated Template Records is given a unique
Template ID. This uniqueness is local to the Transport Session
and Observation Domain that generated the Template ID. Template
IDs 0-255 are reserved for Template Sets, Options Template Sets,
and other reserved Sets yet to be created. Template IDs of Data
Sets are numbered from 256 to 65535. There are no constraints
regarding the order of the Template ID allocation.
Field Count
Number of fields in this Template Record.
The example in Figure L shows a Template Set with mixed standard and
enterprise-specific Information Elements. It consists of a Set
Header, a Template Header, and several Field Specifiers.
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 2 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 256 | Field Count = N | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Information Element id. 1.1 | Field Length 1.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number 1.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| Information Element id. 1.2 | Field Length 1.2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Information Element id. 1.N | Field Length 1.N | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number 1.N | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 257 | Field Count = M | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| Information Element id. 2.1 | Field Length 2.1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Information Element id. 2.2 | Field Length 2.2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number 2.2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| Information Element id. 2.M | Field Length 2.M | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Enterprise Number 2.M | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Padding (opt) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure L: Template Set Example Information Element Identifiers 1.2 and 2.1 are defined by the IETF (Enterprise bit = 0) and, therefore, do not need an Enterprise Number to identify them.3.4.2. Options Template Record Format
Thanks to the notion of scope, The Options Template Record gives the Exporter the ability to provide additional information to the Collector that would not be possible with Flow Records alone.
One Options Template Record example is the "Flow Keys", which reports the Flow Keys for a Template, which is defined as the scope. Another example is the "Template configuration", which reports the configuration sampling parameter(s) for the Template, which is defined as the scope.3.4.2.1. Scope
The scope, which is only available in the Options Template Set, gives the context of the reported Information Elements in the Data Records. Note that the IPFIX Message Header already contains the Observation Domain ID (the identifier of the Observation Domain). If not zero, this Observation Domain ID can be considered as an implicit scope for the Data Records in the IPFIX Message. The Observation Domain ID MUST be zero when the IPFIX Message contains Data Records with different Observation Domain ID values defined as scopes. 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 defined as "metering process" and "template", the combined scope is this Template for this Metering Process. The order of the Scope Fields, as defined in the Options Template Record, is irrelevant in this case. However, if the order of the Scope Fields in the Options Template Record is relevant, the order of the Scope Fields MUST be used. For example, 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. In this case, the Collector deduces the function order by looking at the order of the scope in the Options Template Record. The scope is an Information Element specified in the IPFIX Information Model [RFC5102]. An IPFIX-compliant implementation of the Collecting Process SHOULD support this minimum set of Information Elements as scope: LineCardId, TemplateId, exporterIPv4Address, exporterIPv6Address, and ingressInterface. Note that other Information Elements, such as meteringProcessId, exportingProcessId, observationDomainId, etc. are also valid scopes. The IPFIX protocol doesn't prevent the use of any Information Elements for scope. However, some Information Element types don't make sense if specified as scope; for example, the counter Information Elements. Finally, note that the Scope Field Count MUST NOT be zero.
3.4.2.2. Options Template Record Format
An Options Template Record contains any combination of IANA-assigned and/or enterprise-specific Information Elements identifiers. The format of the Options Template Record is shown in Figure M. It consists of an Options Template Record Header and one or more Field Specifiers. The definition of the Field Specifiers is given in Figure G above. +--------------------------------------------------+ | Options Template Record Header | +--------------------------------------------------+ | Field Specifier | +--------------------------------------------------+ | Field Specifier | +--------------------------------------------------+ ... +--------------------------------------------------+ | Field Specifier | +--------------------------------------------------+ Figure M: Options Template Record Format The format of the Options Template Record Header is shown in Figure N. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID (> 255) | Field Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope Field Count | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure N: Options Template Record Header Format The Options Template Record Header Field Definitions are as follows: Template ID Template ID of this Options Template Record. This value is greater than 255.
Field Count Number of all fields in this Options Template Record, including the Scope Fields. Scope Field Count Number of scope fields in this Options Template Record. The Scope Fields are normal Fields except that they are interpreted as scope at the Collector. The Scope Field Count MUST NOT be zero. The example in Figure O shows an Option Template Set with mixed IETF and enterprise-specific Information Elements. It consists of a Set Header, an Option Template Header, and several Field Specifiers. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = 3 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Template ID = 258 | Field Count = N + M | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope Field Count = N |0| Scope 1 Infor. Element Id. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 1 Field Length |0| Scope 2 Infor. Element Id. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope 2 Field Length | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... |1| Scope N Infor. Element Id. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Scope N Field Length | Scope N Enterprise Number ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... Scope N Enterprise Number |1| Option 1 Infor. Element Id. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option 1 Field Length | Option 1 Enterprise Number ... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ... Option 1 Enterprise Number | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... |0| Option M Infor. Element Id. | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option M Field Length | Padding (optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure O: Option Template Set Example
3.4.3. Data Record Format
The Data Records are sent in Data Sets. The format of the Data Record is shown in Figure P. It consists only of one or more Field Values. The Template ID to which the Field Values belong is encoded in the Set Header field "Set ID", i.e., "Set ID" = "Template ID". +--------------------------------------------------+ | Field Value | +--------------------------------------------------+ | Field Value | +--------------------------------------------------+ ... +--------------------------------------------------+ | Field Value | +--------------------------------------------------+ Figure P: Data Record Format Note that Field Values do not necessarily have a length of 16 bits. Field Values are encoded according to their data type specified in [RFC5102]. Interpretation of the Data Record format can be done only if the Template Record corresponding to the Template ID is available at the Collecting Process. The example in Figure Q shows a Data Set. It consists of a Set Header and several Field Values.
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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Set ID = Template ID | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 1 - Field Value 1 | Record 1 - Field Value 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 1 - Field Value 3 | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 2 - Field Value 1 | Record 2 - Field Value 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 2 - Field Value 3 | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 3 - Field Value 1 | Record 3 - Field Value 2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Record 3 - Field Value 3 | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ... | Padding (optional) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure Q: Data Set, Containing Data Records
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