Internet Engineering Task Force (IETF) B. Claise
Request for Comments: 6313 G. Dhandapani
Updates: 5102 P. Aitken
Category: Standards Track S. Yates
ISSN: 2070-1721 Cisco Systems, Inc.
July 2011
Export of Structured Data in IP Flow Information Export (IPFIX)
Abstract
This document specifies an extension to the IP Flow Information
Export (IPFIX) protocol specification in RFC 5101 and the IPFIX
information model specified in RFC 5102 to support hierarchical
structured data and lists (sequences) of Information Elements in data
records. This extension allows definition of complex data structures
such as variable-length lists and specification of hierarchical
containment relationships between Templates. Finally, the semantics
are provided in order to express the relationship among multiple list
elements in a structured data record.
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/rfc6313.
Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the
document authors. All rights reserved.
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the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Overview ........................................................5
1.1. IPFIX Documents Overview ...................................5
1.2. Relationship between IPFIX and PSAMP .......................6
2. Introduction ....................................................6
2.1. The IPFIX Track ............................................7
2.2. The IPFIX Limitations ......................................8
2.3. Structured Data Use Cases ..................................8
2.4. Specifications Summary ....................................11
3. Terminology ....................................................11
3.1. New Terminology ...........................................12
3.2. Conventions Used in This Document .........................12
4. Linkage with the IPFIX Information Model .......................12
4.1. New Abstract Data Types ...................................12
4.1.1. basicList ..........................................12
4.1.2. subTemplateList ....................................12
4.1.3. subTemplateMultiList ...............................12
4.2. New Data Type Semantic ....................................13
4.2.1. List ...............................................13
4.3. New Information Elements ..................................13
4.3.1. basicList ..........................................13
4.3.2. subTemplateList ....................................13
4.3.3. subTemplateMultiList ...............................13
4.4. New Structured Data Type Semantics ........................13
4.4.1. undefined ..........................................14
4.4.2. noneOf .............................................14
4.4.3. exactlyOneOf .......................................14
4.4.4. oneOrMoreOf ........................................15
4.4.5. allOf ..............................................16
4.4.6. ordered ............................................16
4.5. Encoding of IPFIX Data Types ..............................16
4.5.1. basicList ..........................................17
4.5.2. subTemplateList ....................................19
4.5.3. subTemplateMultiList ...............................21
5. Structured Data Format .........................................25
5.1. Length Encoding Considerations ............................25
5.2. Recursive Structured Data .................................26
5.3. Structured Data Information Elements Applicability
in Options Template Sets ..................................26
5.4. Usage Guidelines for Equivalent Data Representations ......27
5.5. Padding ...................................................29
5.6. Semantic ..................................................29
6. Template Management ............................................33
7. The Collecting Process's Side ..................................33
8. Defining New Information Elements Based on the New
Abstract Data Types ............................................34
9. Structured Data Encoding Examples ..............................34
9.1. Encoding a Multicast Data Record with basicList ...........35
9.2. Encoding a Load-Balanced Data Record with a basicList .....37
9.3. Encoding subTemplateList ..................................38
9.4. Encoding subTemplateMultiList .............................41
9.5. Encoding an Options Template Set Using Structured Data ....46
10. Relationship with the Other IPFIX Documents ...................51
10.1. Relationship with Reducing Redundancy ....................51
10.1.1. Encoding Structured Data Element Using
Common Properties .................................51
10.1.2. Encoding Common Properties Elements with
Structured Data Information Element ...............51
10.2. Relationship with Guidelines for IPFIX Testing ...........53
10.3. Relationship with IPFIX Mediation Function ...............54
11. IANA Considerations ...........................................54
11.1. New Abstract Data Types ..................................54
11.1.1. basicList .........................................54
11.1.2. subTemplateList ...................................54
11.1.3. subTemplateMultiList ..............................55
11.2. New Data Type Semantics ..................................55
11.2.1. list ..............................................55
11.3. New Information Elements .................................55
11.3.1. basicList .........................................55
11.3.2. subTemplateList ...................................56
11.3.3. subTemplateMultiList ..............................56
11.4. New Structured Data Semantics ............................56
11.4.1. undefined .........................................56
11.4.2. noneOf ............................................57
11.4.3. exactlyOneOf ......................................57
11.4.4. oneOrMoreOf .......................................57
11.4.5. allOf .............................................57
11.4.6. ordered ...........................................58
12. Security Considerations .......................................58
13. References ....................................................58
13.1. Normative References .....................................58
13.2. Informative References ...................................58
14. Acknowledgements ..............................................59
Appendix A. Additions to XML Specification of IPFIX
Information Elements and Abstract Data Types ..........60
Appendix B. Encoding IPS Alert Using Structured Data
Information Elements ..................................65
Table of Figures
Figure 1: basicList Encoding ......................................17
Figure 2: basicList Encoding with Enterprise Number ...............18
Figure 3: Variable-Length basicList Encoding (Length < 255 Octets) 18
Figure 4: Variable-Length basicList Encoding (Length 0 to 65535
Octets) .................................................19
Figure 5: subTemplateList Encoding ................................19
Figure 6: Variable-Length subTemplateList Encoding
(Length < 255 Octets) ...................................20
Figure 7: Variable-Length subTemplateList Encoding
(Length 0 to 65535 Octets) ..............................21
Figure 8: subTemplateMultiList Encoding ...........................21
Figure 9: Variable-Length subTemplateMultiList Encoding
(Length < 255 Octets) ...................................23
Figure 10: Variable-Length subTemplateMultiList Encoding
(Length 0 to 65535 Octets) ..............................24
Figure 11: Encoding basicList, Template Record .....................35
Figure 12: Encoding basicList, Data Record, Semantic allOf .........36
Figure 13: Encoding basicList, Data Record with Variable-Length
Elements, Semantic allOf ................................37
Figure 14: Encoding basicList, Data Record, Semantic exactlyOneOf ..38
Figure 15: Encoding subTemplateList, Template for One-Way Delay
Metrics .................................................39
Figure 16: Encoding subTemplateList, Template Record ...............40
Figure 17: Encoding subTemplateList, Data Set ......................40
Figure 18: Encoding subTemplateMultiList, Template for Filtering
Attributes ..............................................44
Figure 19: Encoding subTemplateMultiList, Template for Sampling
Attributes ..............................................44
Figure 20: Encoding subTemplateMultiList, Template for Flow Record .45
Figure 21: Encoding subTemplateMultiList, Data Set .................45
Figure 22: PSAMP SSRI to Be encoded ................................48
Figure 23: Options Template Record for PSAMP SSRI Using
subTemplateMultiList ....................................48
Figure 24: PSAMP SSRI, Template Record for interface ...............49
Figure 25: PSAMP SSRI, Template Record for linecard ................49
Figure 26: PSAMP SSRI, Template Record for linecard and interface ..49
Figure 27: Example of a PSAMP SSRI Data Record, Encoded Using a
subTemplateMultiList ...................................50
Figure 28: Common and Specific Properties Exported Together
[RFC5473] ..............................................51
Figure 29: Common and Specific Properties Exported Separately
According to [RFC5473] .................................52
Figure 30: Common and Specific Properties Exported with Structured
Data Information Element ...............................52
Figure 31: Encoding IPS Alert, Template for Target ................67
Figure 32: Encoding IPS Alert, Template for Attacker ..............68
Figure 33: Encoding IPS Alert, Template for Participant ...........68
Figure 34: Encoding IPS Alert, Template for IPS Alert .............69
Figure 35: Encoding IPS Alert, Data Set ...........................69
1. Overview
1.1. IPFIX Documents Overview
The IPFIX protocol [RFC5101] 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 RFC
3917 [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
name, type, and additional semantic information, as specified in the
IPFIX information model [RFC5102].
In order to gain a level of confidence in the IPFIX implementation,
probe the conformity and robustness, and allow interoperability, the
guidelines for IPFIX testing [RFC5471] present a list of tests for
implementers of compliant Exporting Processes and Collecting
Processes.
The Bidirectional Flow Export [RFC5103] specifies a method for
exporting bidirectional flow (biflow) information using the IP Flow
Information Export (IPFIX) protocol, representing each biflow using a
single Flow Record.
"Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet
Sampling (PSAMP) Reports" [RFC5473] specifies a bandwidth-saving
method for exporting Flow or packet information, by separating
information common to several Flow Records from information specific
to an individual Flow Record: common Flow information is exported
only once.
1.2. Relationship between IPFIX and PSAMP
The specification in this document applies to the IPFIX protocol
specifications [RFC5101]. All specifications from [RFC5101] apply
unless specified otherwise in this document.
The Packet Sampling (PSAMP) protocol [RFC5476] specifies the export
of packet information from a PSAMP Exporting Process to a PSAMP
Collecting Process. Like IPFIX, PSAMP has a formal description of
its information elements, their name, type, and additional semantic
information. The PSAMP information model is defined in [RFC5477].
As the PSAMP protocol specifications [RFC5476] are based on the IPFIX
protocol specifications, the specifications in this document are also
valid for the PSAMP protocol.
Indeed, the major difference between IPFIX and PSAMP is that the
IPFIX protocol exports Flow Records while the PSAMP protocol exports
Packet Reports. From a pure export point of view, IPFIX will not
distinguish a Flow Record composed of several packets aggregated
together from a Flow Record composed of a single packet. So the
PSAMP export can be seen as a special IPFIX Flow Record containing
information about a single packet.
2. Introduction
While collecting the interface counters every five minutes has proven
to be useful in the past, more and more granular information is
required from network elements for a series of applications:
performance assurance, capacity planning, security, billing, or
simply monitoring. However, the amount of information has become so
large that, when dealing with highly granular information such as
Flow information, a push mechanism (as opposed to a pull mechanism,
such as Simple Network Management Protocol (SNMP)) is the only
solution for routers whose primary function is to route packets.
Indeed, polling short-lived Flows via SNMP is not an option: high-end
routers can support hundreds of thousands of Flows simultaneously.
Furthermore, in order to reduce the export bandwidth requirements,
the network elements have to integrate mediation functions to
aggregate the collected information, both in space (typically, from
different linecards or different Exporters) and in time.
Typically, it would be beneficial if access routers could export Flow
Records, composed of the counters before and after an optimization
mechanism on the egress interface, instead of exporting two Flow
Records with identical tuple information.
In terms of aggregation in time, let us imagine that, for performance
assurance, the network management application must receive the
performance metrics associated with a specific Flow, every
millisecond. Since the performance metrics will be constantly
changing, there is a new dimension to the Flow definition: we are not
dealing anymore with a single Flow lasting a few seconds or a few
minutes, but with a multitude of one millisecond sub-flows for which
the performance metrics are reported.
Which current protocol is suitable for these requirements: push
mechanism, highly granular information, and huge number of similar
records? IPFIX, as specified in RFC 5101 would give part of the
solution.
2.1. The IPFIX Track
The IPFIX working group has specified a protocol to export Flow
information [RFC5101]. 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).
The IPFIX protocol specification [RFC5101] specifies that traffic
measurements for Flows are exported using a TLV (type, length, value)
format. The information is exported using a Template Record that is
sent once to export the {type, length} pairs that define the data
format for the Information Elements in a Flow. The Data Records
specify values for each Flow.
Based on the requirements for IP Flow Information Export (IPFIX)
[RFC3917], the IPFIX protocol has been optimized to export Flow-
related information. 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 [RFC5102], registered with IANA [IANA-IPFIX], or specified as
an enterprise-specific Information Element. For each Information
Element, the IPFIX information model [RFC5102] defines a numeric
identifier, an abstract data type, an encoding mechanism for the data
type, and any semantic constraints. Only basic, single-valued data
types, e.g., numbers, strings, and network addresses, are currently
supported.
2.2. The IPFIX Limitations
The IPFIX protocol specification [RFC5101] does not support the
encoding of hierarchical structured data and arbitrary-length lists
(sequences) of Information Elements as fields within a Template
Record. As it is currently specified, a Data Record is a "flat" list
of single-valued attributes. However, it is a common data modeling
requirement to compose complex hierarchies of data types, with
multiple occurrences, e.g., 0..* cardinality allowed for instances of
each Information Element in the hierarchy.
A typical example is the MPLS label stack entries model. An early
NetFlow implementation used two Information Elements to represent the
MPLS label stack entry: a "label stack entry position" followed by a
"label stack value". However, several drawbacks were discovered.
Firstly, the Information Elements in the Template Record had to be
imposed so that the position would always precede the value.
However, some encoding optimizations are based on the permutation of
Information Element order. Secondly, a new semantic intelligence,
not described in the information model, had to be hard-coded in the
Collecting Process: the label value at the position "X" in the stack
is contained in the "label stack value" Information Element following
by a "label stack entry position" Information Element containing the
value "X". Therefore, this model was abandoned.
The selected solution in the IPFIX information model [RFC5102] is a
long series of Information Elements: mplsTopLabelStackSection,
mplsLabelStackSection2, mplsLabelStackSection3,
mplsLabelStackSection4, mplsLabelStackSection5,
mplsLabelStackSection6, mplsLabelStackSection7,
mplsLabelStackSection8, mplsLabelStackSection9,
mplsLabelStackSection10. While this model removes any ambiguity, it
overloads the IPFIX information model with repetitive information.
Furthermore, if mplsLabelStackSection11 is required, IANA
[IANA-IPFIX] will not be able to assign the new Information Element
next to the other ones in the registry, which might cause some
confusion.
2.3. Structured Data Use Cases
Clearly, the MPLS label stack entries issue can best be solved by
using a real structured data type composed of ("label stack entry
position", "label stack value") pairs, potentially repeated multiple
times in Flow Records, since this would be the most efficient from an
information model point of view.
Some more examples enter the same category: how to encode the list of
output interfaces in a multicast Flow, how to encode the list of BGP
Autonomous Systems (AS) in a BGP Flow, how to encode the BGP
communities in a BGP Flow, etc.
The one-way delay passive measurement, which is described in the
IPFIX applicability [RFC5472], is yet another example that would
benefit from a structured data encoding. Assuming synchronized
clocks, the Collector can deduce the one-way delay between two
Observation Points from the following two Information Elements,
collected from two different Observation Points:
- Packet arrival time: observationTimeMicroseconds [RFC5477]
- Packet ID: digestHashValue [RFC5477]
In practice, this implies that many pairs of
(observationTimeMicroseconds, digestHashValue) must be exported for
each Observation Point, even if Hash-Based Filtering [RFC5475] is
used. On top of that information, if the requirement is to
understand the one-way delay per application type, the 5-tuple
(source IP address, destination IP address, protocol, source port,
destination port) would need to be added to every Flow Record.
Instead of exporting this repetitive 5-tuple, as part of every single
Flow Record a Flow Record composed of a structured data type such as
the following would save a lot of bandwidth:
5-tuple
{ observationTimeMicroseconds 1, digestHashValue 1 }
{ observationTimeMicroseconds 2, digestHashValue 2 }
{ observationTimeMicroseconds 3, digestHashValue 3 }
{ ... , ... }
As a last example, here is a more complex case of hierarchical
structured data encoding. Consider the example scenario of an IPS
(Intrusion Prevention System) alert data structure containing
multiple participants, where each participant contains multiple
attackers and multiple targets, with each target potentially composed
of multiple applications, as depicted below:
alert
signatureId
protocolIdentifier
riskRating
participant 1
attacker 1
sourceIPv4Address
applicationId
...
attacker N
sourceIPv4Address
applicationId
target 1
destinationIPv4Address
applicationId 1
...
applicationId n
...
target N
destinationIPv4Address
applicationId 1
...
applicationId n
participant 2
...
To export this information in IPFIX, the data would need to be
flattened (thus, losing the hierarchical relationships) and a new
IPFIX Template created for each alert, according to the number of
applicationId elements in each target, the number of targets and
attackers in each participant, and the number of participants in each
alert. Clearly, each Template will be unique to each alert, and a
large amount of CPU, memory, and export bandwidth will be wasted
creating, exporting, maintaining, and withdrawing the Templates. See
Appendix B for a specific example related to this case study.
2.4. Specifications Summary
This document specifies an IPFIX extension to support hierarchical
structured data and variable-length lists by defining three new
Information Elements and three corresponding new abstract data types
called basicList, subTemplateList, and subTemplateMultiList. These
are defined in Sections 4.1 and 4.3.
The three Structured Data Information Elements carry some semantic
information so that the Collecting Process can understand the
relationship between the different list elements. The semantic in
the Structured Data Information Elements is provided in order to
express the relationship among the multiple top-level list elements.
As an example, if a list is composed of the elements (A,B,C), the
semantic expresses the relationship among A, B, and C, regardless of
whether A, B, and C are individual elements or a list of elements.
It is important to note that whereas the Information Elements and
abstract data types defined in the IPFIX information model [RFC5102]
represent single values, these new abstract data types are structural
in nature and primarily contain references to other Information
Elements and to Templates. By referencing other Information Elements
and Templates from an Information Element's data content, it is
possible to define complex data structures such as variable-length
lists and to specify hierarchical containment relationships between
Templates. Therefore, this document prefers the more generic "Data
Record" term to the "Flow Record" term.
This document specifies three new abstract data types, which are
basic blocks to represent structured data. However, this document
does not comment on all possible combinations of basicList,
subTemplateList, and subTemplateMultiList. Neither does it limit the
possible combinations.
3. Terminology
IPFIX-specific terminology used in this document is defined in
Section 2 of the IPFIX protocol specification [RFC5101] and Section 3
of the PSAMP protocol specification [RFC5476]. As in [RFC5101],
these IPFIX-specific terms have the first letter of a word
capitalized when used in this document.
3.1. New Terminology
Structured Data Information Element
One of the Information Elements supporting structured data, i.e.,
the basicList, subTemplateList, or subTemplateMultiList
Information Elements specified in Section 4.3.
3.2. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
4. Linkage with the IPFIX Information Model
As in the IPFIX protocol specification [RFC5101], the new Information
Elements specified in Section 4.3 MUST be sent in canonical format in
network-byte order (also known as the big-endian byte ordering).
4.1. New Abstract Data Types
This document specifies three new abstract data types, as described
below.
4.1.1. basicList
The type "basicList" represents a list of zero or more instances of
any Information Element, primarily used for single-valued data types.
Examples include a list of port numbers, a list of interface indexes,
a list of AS in a BGP AS-PATH, etc.
4.1.2. subTemplateList
The type "subTemplateList" represents a list of zero or more
instances of a structured data type, where the data type of each list
element is the same and corresponds with a single Template Record.
Examples include a structured data type composed of multiple pairs of
("MPLS label stack entry position", "MPLS label stack value"), a
structured data type composed of performance metrics, and a
structured data type composed of multiple pairs of IP address, etc.
4.1.3. subTemplateMultiList
The type "subTemplateMultiList" represents a list of zero or more
instances of a structured data type, where the data type of each list
element can be different and corresponds with different Template
definitions. Examples include a structured data type composed of
multiple access-list entries, where entries can be composed of
different criteria types.
4.2. New Data Type Semantic
This document specifies a new data type semantic, in addition to the
ones specified in Section 3.2 of the IPFIX information model
[RFC5102], as described below.
4.2.1. List
A list represents an arbitrary-length sequence of zero or more
structured data Information Elements, either composed of regular
Information Elements or composed of data conforming to a Template
Record.
4.3. New Information Elements
This document specifies three new Information Elements, as described
below.
4.3.1. basicList
A basicList specifies a generic Information Element with a basicList
abstract data type as defined in Section 4.1.1 and list semantics as
defined in Section 4.2.1. Examples include a list of port numbers, a
list of interface indexes, etc.
4.3.2. subTemplateList
A subTemplateList specifies a generic Information Element with a
subTemplateList abstract data type as defined in Section 4.1.2 and
list semantics as defined in Section 4.2.1.
4.3.3. subTemplateMultiList
A subTemplateMultiList specifies a generic Information Element with a
subTemplateMultiList abstract data type as defined in Section 4.1.3
and list semantics as defined in Section 4.2.1.
4.4. New Structured Data Type Semantics
Structured data type semantics are provided in order to express the
relationship among multiple list elements in a Structured Data
Information Element. These structured data type semantics require a
new IPFIX subregistry, as specified in the "IANA Considerations"
section. The semantics are specified in the following subsections.
4.4.1. undefined
The "undefined" structured data type semantic specifies that the
semantic of list elements is not specified and that, if a semantic
exists, then it is up to the Collecting Process to draw its own
conclusions. The "undefined" structured data type semantic, which is
the default value, is used when no other structured data type
semantic applies.
For example, a mediator that wants to translate IPFIX [RFC5101] into
the export of structured data according to the specifications in this
document doesn't know what the semantic is; it can only guess, as the
IPFIX specifications [RFC5101] does not contain any semantic.
Therefore, the mediator should use the "undefined" semantic.
4.4.2. noneOf
The "noneOf" structured data type semantic specifies that none of the
elements are actual properties of the Data Record.
For example, a mediator might want to report to a Collector that a
specific Flow is suspicious, but that it checked already that this
Flow does not belong to the attack type 1, attack type 2, or attack
type 3. So this Flow might need some further inspection. In such a
case, the mediator would report the Flow Record with a basicList
composed of (attack type 1, attack type 2, attack type 3) and the
respective structured data type semantic of "noneOf".
Another example is a router that monitors some specific BGP AS-PATHs
and reports if a Flow belongs to any of them. If the router wants to
export that a Flow does not belong to any of the monitored BGP AS-
PATHs, the router reports a Data Record with a basicList composed of
(BGP AS-PATH 1, BGP AS-PATH 2, BGP AS-PATH 3) and the respective
structured data type semantic of "noneOf".
4.4.3. exactlyOneOf
The "exactlyOneOf" structured data type semantic specifies that only
a single element from the structured data is an actual property of
the Data Record. This is equivalent to a logical XOR operation.
For example, if a Flow record contains a basicList of outgoing
interfaces with the "exactlyOneOf" semantic, then it implies that the
reported Flow only egressed from a single interface, although the
Flow Record lists all of the possible outgoing interfaces. This is a
typical example of a per destination load-balancing.
Another example is a mediator that must aggregate Data Records from
different Observation Points and report an aggregated Observation
Point. However, the different Observation Points can be specified by
different Information Element types depending on the Exporter. For
example:
Exporter1 Observation Point is characterized by the
exporterIPv4Address, so a specific Exporter can be represented.
Exporter2 Observation Point is characterized by the
exporterIPv4Address and a basicList of ingressInterface, so the
Exporting Process can express that the observations were made on a
series of input interfaces.
Exporter3 Observation Point is characterized by the
exporterIPv4Address and a specific lineCardId, so the Exporting
Process can express that the observation was made on a specific
linecard.
If the mediator models the three different types of Observation
Points with the three Template Records below:
Template Record 1: exporterIPv4Address
Template Record 2: exporterIPv4Address, basicList of
ingressInterface
Template Record 3: exporterIPv4Address, lineCardId
then it can represent the aggregated Observation Point with a
subTemplateMultiList and the semantic "exactlyOneOf". The aggregated
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. This implies that the Flow was observed
at exactly one of the Observation Points reported.
4.4.4. oneOrMoreOf
The "oneOrMoreOf" structured data type semantic specifies that one or
more elements from the list in the structured data are actual
properties of the Data Record. This is equivalent to a logical OR
operation.
Consider an example where a mediator must report an aggregated Flow
(e.g., by aggregating IP addresses from IP prefixes), with an
aggregated Observation Point. However, the different Observation
Points can be specified by different Information Element types as
described in Section 4.4.2.
If the mediator models the three different types of Observation
Points with the three Template Records below:
Template Record 1: exporterIPv4Address
Template Record 2: exporterIPv4Address, basicList of
ingressInterface
Template Record 3: exporterIPv4Address, lineCardId
then it can represent the aggregated Observation Point with a
subTemplateMultiList and the semantic "oneOrMoreOf". The aggregated
Observation Point is modeled with the Data Records corresponding to
either Template Record 1, Template Record 2, or Template Record 3.
This implies that the Flow was observed on at least one of the
Observation Points reported, and potentially on multiple Observation
Points.
4.4.5. allOf
The "allOf" structured data type semantic specifies that all of the
list elements from the structured data are actual properties of the
Data Record.
For example, if a Record contains a basicList of outgoing interfaces
with the "allOf" semantic, then the observed Flow is typically a
multicast Flow where each packet in the Flow has been replicated to
each outgoing interface in the basicList.
4.4.6. ordered
The "ordered" structured data type semantic specifies that elements
from the list in the structured data are ordered.
For example, an Exporter might want to export the AS10 AS20 AS30 AS40
BGP AS-PATH. In such a case, the Exporter would report a basicList
composed of (AS10, AS20, AS30, AS40) and the respective structured
data type semantic of "ordered".
4.5. Encoding of IPFIX Data Types
The following subsections define the encoding of the abstract data
types defined in Section 4.1. These data types may be encoded using
either fixed- or variable-length Information Elements, as discussed
in Section 5.1. Like in the IPFIX specifications [RFC5101], all
lengths are specified in octets.
4.5.1. basicList
The basicList Information Element defined in Section 4.3.1 represents
a list of zero or more instances of an Information Element and is
encoded as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Semantic |0| Field ID | Element... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...Length | basicList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: basicList Encoding
Semantic
The Semantic field indicates the relationship among the different
Information Element values within this Structured Data Information
Element. Refer to IANA's "IPFIX Structured Data Types Semantics"
registry.
Field ID
Field ID is the Information Element identifier of the Information
Element(s) contained in the list.
Element Length
Per Section 7 of [RFC5101], the Element Length field indicates the
length, in octets, of each list element specified by Field ID, or
contains the value 0xFFFF if the length is encoded as a variable-
length Information Element at the start of the basicList Content.
Effectively, the Element Length field is part of the header, so
even in the case of a zero-element list, it MUST NOT be omitted.
basicList Content
A Collecting Process decodes list elements from the basicList
Content until no further data remains. A field count is not
included but can be derived when the Information Element is
decoded.
Note that in the diagram above, Field ID is shown with the Enterprise
bit (most significant bit) set to 0. Instead, if the Enterprise bit
is set to 1, a four-byte Enterprise Number MUST be encoded
immediately after the Element Length as shown below. See the "Field
Specifier Format" section in the IPFIX protocol [RFC5101] for
additional information.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Semantic |1| Field ID | Element... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...Length | Enterprise Number ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | basicList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: basicList Encoding with Enterprise Number
Also, note that if a basicList has zero elements, the encoded data
contains the Semantic field, Field ID, the Element Length field, and
the four-byte Enterprise Number (if present), while the basicList
Content is empty.
If the basicList is encoded as a variable-length Information Element
in less than 255 octets, it MAY be encoded with the Length field per
Section 7 of [RFC5101] as shown in Figure 3. However, the three-byte
length encoding, as shown in Figure 4, is RECOMMENDED (see Section
5.1).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (< 255)| Semantic |0| Field ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element Length | basicList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Variable-Length basicList Encoding
(Length < 255 Octets)
If the basicList is encoded as a variable-length Information Element
in 255 or more octets, it MUST be encoded with the Length field per
Section 7 of [RFC5101] as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | Length (0 to 65535) | Semantic |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Field ID | Element Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| basicList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Variable-Length basicList Encoding
(Length 0 to 65535 Octets)
4.5.2. subTemplateList
The subTemplateList Information Element represents a list of zero or
more Data Records corresponding to a specific Template. Because the
Template Record referenced by a subTemplateList Information Element
can itself contain other subTemplateList Information Elements, and
because these Template Record references are part of the Information
Elements content in the Data Record, it is possible to represent
complex hierarchical data structures. The following diagram shows
how a subTemplateList Information Element is encoded within a Data
Record:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Semantic | Template ID | ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| subTemplateList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: subTemplateList Encoding
Semantic
The Semantic field indicates the relationship among the different
Data Records within this Structured Data Information Element.
Template ID
The Template ID field contains the ID of the Template used to
encode and decode the subTemplateList Content.
subTemplateList Content
subTemplateList Content consists of zero or more instances of Data
Records corresponding to the Template ID specified in the Template
ID field. A Collecting Process decodes the subTemplateList
Content until no further data remains. A record count is not
included but can be derived when the subTemplateList is decoded.
Encoding and decoding are performed recursively if the specified
Template itself contains Structured Data Information Elements as
described here.
Note that, if a subTemplateList has zero elements, the encoded data
contains only the Semantic field and the Template ID field, while the
subTemplateList Content is empty.
If the subTemplateList is encoded as a variable-length Information
Element in less than 255 octets, it MAY be encoded with the Length
field per Section 7 of [RFC5101] as shown in Figure 6. However, the
three-byte length encoding, as shown in Figure 7, is RECOMMENDED (see
Section 5.1).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (< 255)| Semantic | Template ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| subTemplateList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Variable-Length subTemplateList Encoding
(Length < 255 Octets)
If the subTemplateList is encoded as a variable-length Information
Element in 255 or more octets, it MUST be encoded with the Length
field per Section 7 of [RFC5101] as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | Length (0 to 65535) | Semantic |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID | subTemplateList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Variable-Length subTemplateList Encoding
(Length 0 to 65535 Octets)
4.5.3. subTemplateMultiList
Whereas each element in a subTemplateList Information Element
corresponds to a single Template, it is sometimes useful for a list
to contain elements corresponding to different Templates. To support
this case, each top-level element in a subTemplateMultiList
Information Element carries a Template ID, Length, and zero or more
Data Records corresponding to the Template ID. The following diagram
shows how a subTemplateMultiList Information Element is encoded
within a Data Record. Note that the encoding following the Semantic
field is consistent with the Set Header specified in [RFC5101].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Semantic | Template ID X |Data Records...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Length X | Data Record X.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record X.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record X.L Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Template ID Y |Data Records...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Length Y | Data Record Y.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record Y.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record Y.M Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Template ID Z |Data Records...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Length Z | Data Record Z.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record Z.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record Z.N Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+
Figure 8: subTemplateMultiList Encoding
Semantic
The Semantic field indicates the top-level relationship among the
series of Data Records corresponding to the different Template
Records within this Structured Data Information Element.
Template ID
Unlike the subTemplateList Information Element, each element of
the subTemplateMultiList contains a Template ID that specifies the
encoding of the following Data Records.
Data Records Length
This is the total length of the Data Records encoding for the
Template ID previously specified, including the two bytes for the
Template ID and the two bytes for the Data Records Length field
itself.
Data Record X.M
The Data Record X.M consists of the Mth Data Record of the
Template Record X. A Collecting Process decodes the Data Records
according to Template Record X until no further data remains,
according to the Data Records Length X. Further Template IDs and
Data Records may then be decoded according to the overall
subTemplateMultiList length. A record count is not included but
can be derived when the Element Content is decoded. Encoding and
decoding are performed recursively if the specified Template
itself contains Structured Data Information Elements as described
here.
In the exceptional case of zero instances in the
subTemplateMultiList, no data is encoded, only the Semantic field and
Template ID field(s), and the Data Records Length field is set to
four.
EID 3232 (Verified) is as follows:Section: 4.5.3
Original Text:
In the exceptional case of zero instances in the
subTemplateMultiList, no data is encoded, only the Semantic field and
Template ID field(s), and the Data Record Length field is set to
zero.
Corrected Text:
In the exceptional case of zero instances in the
subTemplateMultiList, no data is encoded, only the Semantic field and
Template ID field(s), and the Data Records Length field is set to
four.
Notes:
s/zero/four/ && s/Record/Records/
- because the Data Record Length field includes two bytes for the Template ID and two bytes for the Data Records Length field itself, as specified on page 23:
Data Records Length
This is the total length of the Data Records encoding for the Template ID previously specified, including the two bytes for the Template ID and the two bytes for the Data Records Length field itself.
Therefore, a Data Records Length < 4 bytes is invalid. This should be noted in the "Data Records Length" definition.
Also note the pluralisation of "Records" in the definition.
Kudos to Manish Patil, manish.patil@guavus.com
If the subTemplateMultiList is encoded as a variable-length
Information Element in less than 255 octets, it MAY be encoded with
the Length field per Section 7 of [RFC5101] as shown in Figure 9.
However, the three-byte length encoding, as shown in Figure 10, is
RECOMMENDED (see Section 5.1).
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (< 255)| Semantic | Template ID X |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Records Length X | Data Record X.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record X.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record X.L Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Template ID Y |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Records Length Y | Data Record Y.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record Y.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record Y.M Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Template ID Z |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Records Length Z | Data Record Z.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record Z.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | Data Record Z.N Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: Variable-Length subTemplateMultiList Encoding
(Length < 255 Octets)
If the subTemplateMultiList is encoded as a variable-length
Information Element in 255 or more octets, it MUST be encoded with
the Length field per Section 7 of [RFC5101] as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | Length (0 to 65535) | Semantic |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID X | Data Records Length X |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record X.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record X.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record X.L Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID Y | Data Records Length Y |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record Y.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record Y.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record Y.M Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID Z | Data Records Length Z |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record Z.1 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record Z.2 Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Data Record Z.N Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Variable-Length subTemplateMultiList Encoding
(Length 0 to 65535 Octets)
5. Structured Data Format
5.1. Length Encoding Considerations
The new Structured Data Information Elements represent a list that
potentially carries complex hierarchical and repeated data.
When the encoding of a Structured Data Information Element has a
fixed length (because, for example, it contains the same number of
fixed-length elements, or if the permutations of elements in the list
always produces the same total length), the element length can be
encoded in the corresponding Template Record.
However, when representing variable-length data, hierarchical data,
and repeated data with variable element counts, where the number and
length of elements can vary from record to record, we RECOMMEND that
the Information Elements are encoded using the variable-length
encoding described in Section 7 of [RFC5101], with the length carried
before the Structured Data Information Element encoding.
Because of the complex and repeated nature of the data, it is
potentially difficult for the Exporting Process to efficiently know
in advance the exact encoding size. In this case, the Exporting
Process may encode the available data starting at a fixed offset and
fill in the final length afterwards. Therefore, the three-byte
length encoding is RECOMMENDED for variable-length Information
Elements in all Template Records containing a Structured Data
Information Element, even if the encoded length can be less than 255
bytes, because the starting offset of the data is known in advance.
When encoding such data, an Exporting Process MUST take care to not
exceed the maximum allowed IPFIX message length of 65535 bytes as
specified in [RFC5101].
5.2. Recursive Structured Data
It is possible to define recursive relationships between IPFIX
structured data instances, for example, when representing a tree
structure. The simplest case of this might be a basicList, where
each element is itself a basicList, or a subTemplateList where one of
the fields of the referenced Template is itself a subTemplateList
referencing the same Template. Also, the Exporting Process MUST take
care when encoding recursively-defined structured data not to exceed
the maximum allowed length of an IPFIX Message (as noted in Length
Encoding Considerations).
5.3. Structured Data Information Elements Applicability in Options
Template Sets
Structured Data Information Elements MAY be used in Options Template
Sets.
As an example, consider a mediation function that must aggregate Data
Records from multiple Observation Point types:
Router 1, (interface 1)
Router 2, (linecard A)
Router 3, (linecard B)
Router 4, (linecard C, interface 2)
In order to encode the PSAMP Selection Sequence Report Interpretation
[RFC5476], the mediation function must express this combination of
Observation Points as a single new Observation Point. Recall from
[RFC5476] that the PSAMP Selection Sequence Report Interpretation
consists of the following fields:
Scope: selectionSequenceId
Non-Scope: one Information Element mapping the Observation Point
selectorId (one or more)
Without structured data, there is clearly no way to express the
complex aggregated Observation Point as "one Information Element
mapping the Observation Point". However, the desired result may be
easily achieved using the structured data types. Refer to Section
9.5. for an encoding example related to this case study.
Regarding the scope in the Options Template Record, the IPFIX
specification [RFC5101] mentions that "the IPFIX protocol doesn't
prevent the use of any Information Elements for scope". Therefore, a
Structured Data Information Element MAY be used as scope in an
Options Template Set.
Extending the previous example, the mediation function could export a
given name for this complex aggregated Observation Point:
Scope: Aggregated Observation Point (structured data)
Non-Scope: a new Information Element containing the name
5.4. Usage Guidelines for Equivalent Data Representations
Because basicList, subTemplateList, and subTemplateMultiList are all
lists, in several cases, there is more than one way to represent what
is effectively the same data structure. However, in some cases, one
approach has an advantage over the other, e.g., more compact, uses
fewer resources, and is therefore preferred over an alternate
representation.
A subTemplateList can represent the same simple list of single-valued
Information Elements as a basicList, if the Template referenced by
the subTemplateList contains only one single-valued Information
Element. Although the encoding is more compact than a basicList by
two bytes, using a subTemplateList, in this case, requires a new
Template per Information Element. The basicList requires no
additional Template and is therefore RECOMMENDED in this case.
Although a subTemplateMultiList with one Element can represent the
contents of a subTemplateList, the subTemplateMultiList carries two
additional bytes (Element Length). It is also potentially useful to
a Collecting Process to know in advance that a subTemplateList
directly indicates that list element types are consistent. The
subTemplateList Information Element is therefore RECOMMENDED in this
case.
The Semantic field in a subTemplateMultiList indicates the top-level
relationship among the series of Data Records corresponding to the
different Template Records, within this Structured Data Information
Element. If a semantic is required to describe the relationship
among the different Data Records corresponding to a single Template
ID within the subTemplateMultiList, then an encoding based on a
basicList of subTemplateLists should be used; refer to Section 5.6
for more information. Alternatively, if a semantic is required to
describe the relationship among all Data Records within a
subTemplateMultiList (regardless of the Template Record), an encoding
based on a subTemplateMultiList with one Data Record corresponding to
a single Template ID can be used.
Note that the referenced Information Element(s) in the Structured
Data Information Elements can be taken from the IPFIX information
model [RFC5102], the PSAMP information model [RFC5477], any of the
Information Elements defined in the IANA IPFIX registry [IANA-IPFIX],
or enterprise-specific Information Elements.
If a Template Record contains a subTemplateList as the only field, a
Set encoding as specified in the IPFIX protocol specifications
[RFC5101] should be considered, unless:
- A relationship among multiple list elements must be exported, in
which case, the semantic from the IPFIX Structured Data Information
Element can convey this relationship.
- The Exporting Process wants to convey the number of elements in the
list, even in the special cases of zero or one element in the list.
Indeed, the case of an empty list cannot be represented with the
IPFIX protocol specifications [RFC5101]. In the case of a single
element list, the Template Record specified in the IPFIX protocol
specification [RFC5101] could be used. However, on the top of the
Template Record with the subTemplateList to export multiple list
elements, this supplementary Template would impose some extra
management, both on the Exporting Process and on the Collecting
Process, which might have to correlate the information from two
Template Records.
Similarly, if a Template Record contains a subTemplateMultiList as
the only field, an IPFIX Message as described in the IPFIX protocol
specification [RFC5101] should be considered, unless:
- A relationship among top-level list elements must be exported, in
which case, the semantic from the IPFIX Structured Data Information
Element can convey this relationship.
- The Exporting Process wants to convey the number of Data Records
corresponding to every Template in the subTemplateMultiList.
5.5. Padding
The Exporting Process MAY insert some padding octets in structured
data field values in a Data Record by including the 'paddingOctets'
Information Element as described in [RFC5101], Section 3.3.1. The
paddingOctets Information Element can be included in a Template
Record referenced by a structured data Information Element for this
purpose.
5.6. Semantic
Semantic interpretations of received Data Records at or beyond the
Collecting Process remain explicitly undefined, unless that data is
transmitted using this extension with explicit structured data type
semantic information.
It is not the Exporter's role to check the validity of the semantic
representation of Data Records.
More complex semantics can be expressed as a combination of the
Semantic Data Information Elements specified in this document.
For example, the export of the AS10 AS20 AS30 AS40 {AS50,AS60} BGP
AS-PATH would be reported as a basicList of two elements, each
element being a basicList of BGP AS, with the top-level structured
data type semantic of "ordered". The first element would contain a
basicList composed of (AS10,AS20,AS30,AS40) and the respective
structured data type semantic of "ordered", while the second element
would contain a basicList composed of (AS50, AS60) and the respective
structured data type semantic of "exactlyOneOf". A high-level Data
Record diagram would be represented as:
BGP AS-PATH = (basicList, ordered,
(basicList, ordered, AS10,AS20,AS30,AS40),
(basicList, exactlyOneOf, AS50, AS60)
)
If a semantic is required to describe the relationship among the
different Data Records corresponding to a single Template ID within
the subTemplateMultiList, then an encoding based on a basicList of
subTemplateLists should be used, as shown in the next case study.
Case study 1:
In this example, an Exporter monitoring security attacks must export
a list of security events consisting of attackers and targets. For
the sake of the example, assume that the Collector can differentiate
the attacker (which is expressed using source fields) from the target
(which is expressed using destination fields). Imagine that
attackers A1 or A2 may attack targets T1 and T2.
The first case uses a subTemplateMultiList composed of two Template
Records, one representing the attacker and one representing the
target, each of them containing an IP address and a port.
Attacker Template Record = (src IP address, src port)
Target Template Record = (dst IP address, dst port)
A high-level Data Record diagram would be represented as:
Alert = (subTemplateMultiList, allOf,
(Attacker Template Record, A1, A2),
(Target Template Record, T1, T2)
)
The Collecting Process can only conclude that the list of attackers
(A1, A2) and the list of targets (T1, T2) are present, without
knowing the relationship amongst attackers and targets. The
Exporting Process would have to explicitly call out the relationship
amongst attackers and targets as the top-level semantic offered by
the subTemplateMultiList isn't sufficient.
The only proper encoding for the previous semantic (i.e., attacker A1
or A2 may attack target T1 and T2) uses a basicList of
subTemplateLists and is represented as follows:
Attacker Template Record = (src IP address, src port)
Target Template Record = (dst IP address, dst port)
Alert = (basicList, allOf,
(subTemplateList, exactlyOneOf, attacker A1, A2)
(subTemplateList, allOf, target T1, T2)
)
Case study 2:
In this example, an Exporter monitoring security attacks must export
a list of attackers and targets. For the sake of the example, assume
that the Collector can differentiate the attacker (which is expressed
using source fields) from the target (which is expressed using
destination fields). Imagine that attacker A1 or A2 is attacking
target T1, while attacker A3 is attacking targets T2 and T3. The
first case uses a subTemplateMultiList that contains Data Records
corresponding to two Template Records, one representing the attacker
and one representing the target, each of them containing an IP
address and a port.
Attacker Template Record = (src IP address, src port)
Target Template Record = (dst IP address, dst port)
A high-level Data Record diagram would be represented as:
Alert = (subTemplateMultiList, allOf,
(Attacker Template Record, A1, A2, A3),
(Target Template Record, T1, T2, T3)
)
The Collecting Process can only conclude that the list of attackers
(A1, A2, A3), and the list of targets (T1, T2, T3) are present,
without knowing the relationship amongst attackers and targets.
The second case could use a Data Record definition composed of the
following:
Alert = (subTemplateMultiList, allOf,
(Attacker Template Record, A1, A2),
(Target Template Record, T1),
(Attacker Template Record, A3),
(Target Template Record, T2, T3)
)
With the above representation, the Collecting Process can infer that
the alert consists of the list of attackers (A1, A2), target (T1),
attacker (A3), and list of targets (T2, T3). From the sequence in
which attackers and targets are encoded, the Collector can possibly
deduce that some relationship exists among (A1, A2, T1) and (A2, T1,
T2) but cannot understand what it is exactly. So, there is a need
for the Exporting Process to explicitly define the relationship
between the attackers, and targets and the top-level semantic of the
subTemplateMultiList is not sufficient.
The only proper encoding for the previous semantic (i.e., attacker A1
or A2 attacks target T1, attacker A3 attacks targets T2 and T3) uses
a basicList of subTemplateLists and is represented as follows:
Participant P1 =
(basicList, allOf,
(subTemplateList, exactlyOneOf, attacker A1, A2)
(subTemplateList, undefined, target T1)
)
Participant P2 =
(basicList, allOf,
(subTemplateList, undefined, attacker A3,
(subTemplateList, allOf, targets T2, T3)
)
The security alert is represented as a subTemplateList of
participants.
Alert =
(subTemplateList, allOf, Participant P1, Participant P2)
Note that, in the particular case of a single element in a Structured
Data Information Element, the Semantic field is actually not very
useful since it specifies the relationship among multiple elements.
Any choice of allOf, exactlyOneOf, or OneOrMoreOf would provide the
same result semantically. Therefore, in case of a single element in
a Structured Data Information Element, the default "undefined"
semantic SHOULD be used.
6. Template Management
This section introduces some more specific Template management and
Template Withdrawal Message-related specifications compared to the
IPFIX protocol specification [RFC5101].
First of all, the Template ID uniqueness is unchanged compared to
[RFC5101]; the uniqueness is local to the Transport Session and
Observation Domain that generated the Template ID. In other words,
the Set ID used to export the Template Record does not influence the
Template ID uniqueness.
While [RFC5101] mentions that "if an Information Element is required
more than once in a Template, the different occurrences of this
Information Element SHOULD follow the logical order of their
treatments by the Metering Process", this rule MAY be ignored within
Structured Data Information Elements.
As specified in [RFC5101], Templates that are not used anymore SHOULD
be deleted. Deleting a Template implies that it MUST NOT be used
within subTemplateList and subTemplateMultiList anymore. Before
reusing a Template ID, the Template MUST be deleted. In order to
delete an allocated Template, the Template is withdrawn through the
use of a Template Withdrawal Message.
7. The Collecting Process's Side
This section introduces some more specific specifications to the
Collection Process compared to Section 9 in the IPFIX protocol
[RFC5101].
As opposed to the IPFIX specification in [RFC5101], IPFIX Messages
with IPFIX Structured Data Information Elements change the IPFIX
concept from the Collector's point of view as the data types are
present in the Data Records rather than in the Template Records. For
example, a basicList Information Element in a Template Record doesn't
specify the list element data type; this information is contained in
the Data Record. For example, in case of a subTemplateMultiList, the
Collecting Process must refer to the included Template Records in the
middle of the Data Record decode.
As described in [RFC5101], a Collecting Process MUST note the
Information Element identifier of any Information Element that it
does not understand and MAY discard that Information Element from the
Flow Record. Therefore, a Collection Process that does not support
the extension specified in this document can ignore the Structured
Data Information Elements in a Data Record, or it can ignore Data
Records containing these new Structured Data Information Elements
while continuing to process other Data Records.
If the structured data contains the "undefined" structured data type
semantic, the Collecting Process MAY attempt to draw its own
conclusion in terms of the semantic contained in the Data Record.
8. Defining New Information Elements Based on the New Abstract Data
Types
This document specifies three new abstract data types: basicList,
subTemplateList, and subTemplateMultiList. As specified in
[RFC5102], the specification of new IPFIX Information Elements uses
the Template specified in Section 2.1 of [RFC5102]. This Template
mentioned existing and future the data types: "One of the types
listed in Section 3.1 of this document or in a future extension of
the information model". So new Information Elements can be specified
based on the three new abstract data types.
The authors anticipate the creation of both enterprise-specific and
IANA Information Elements based on the IPFIX structured data types.
For example, bgpPathList, bgpSequenceList, and bgpSetList, of
abstract types and semantics basicList/ordered, basicList/ordered,
and basicList/exactlyOneOf respectively, would define the complete
semantic of the list. This specification doesn't specify any new
Information Elements beyond the ones in Section 4.3.
9. Structured Data Encoding Examples
The following examples are created solely for the purpose of
illustrating how the extensions proposed in this document are
encoded.
9.1. Encoding a Multicast Data Record with basicList
Consider encoding a multicast Data Record containing the following
data:
---------------------------------------------------------------
Ingress If | Source IP | Destination IP | Egress Interfaces
---------------------------------------------------------------
9 192.0.2.201 233.252.0.1 1, 4, 8
---------------------------------------------------------------
Template Record for the multicast Flows, with the Template ID 256:
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 = 24 octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 256 | Field Count = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| ingressInterface = 10 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceIPv4Address = 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| DestinationIPv4Address = 12 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| basicList = 291 | Field Length = 0xFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Encoding basicList, Template Record
The list of outgoing interfaces is represented as a basicList with
semantic allOf, and the Length of the list is chosen to be encoded in
three bytes even though it may be less than 255 octets.
The Data Set is represented as follows:
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 = 256 | Length = 36 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ingressInterface = 9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv4Address = 192.0.2.201 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DestinationIPv4Address = 233.252.0.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | List Length = 17 | semantic=allOf|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface FieldId = 14 |egressInterface Field Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface value 1 = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface value 2 = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface value 3 = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Encoding basicList, Data Record, Semantic allOf
In the example above, the basicList contains fixed-length elements.
To illustrate how variable-length elements would be encoded, the same
example is shown below with variable-length interface names in the
basicList instead:
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 = 256 | Length = 44 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ingressInterface = 9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv4Address = 192.0.2.201 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DestinationIPv4Address = 233.252.0.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | List Length = 25 | semantic=allOf|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| InterfaceName FieldId = 82 | InterfaceName Field Len=0xFFFF|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length = 5 | 'F' | 'E' | '0' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| '/' | '0' | Length = 7 | 'F' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 'E' | '1' | '0' | '/' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| '1' | '0' | Length = 5 | 'F' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 'E' | '2' | '/' | '2' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: Encoding basicList, Data Record with Variable-Length
Elements, Semantic allOf
9.2. Encoding a Load-Balanced Data Record with a basicList
Consider encoding a load-balanced Data Record containing the
following data:
---------------------------------------------------------------
Ingress If | Source IP | Destination IP | Egress Interfaces
---------------------------------------------------------------
9 192.0.2.201 233.252.0.1 1, 4, 8
---------------------------------------------------------------
So the Data Record egressed from either interface 1, 4, or 8. The
Data Set is represented as follows:
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 = 256 | Length = 36 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ingressInterface = 9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv4Address = 192.0.2.201 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DestinationIPv4Address = 233.252.0.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | List Length = 17 |sem=exactlyOne |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface FieldId = 14 |egressInterface Field Length=4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface value 1 = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface value 2 = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface value 3 = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note: sem=exactlyOne represents semantic=exactlyOneOf
Figure 14: Encoding basicList, Data Record, Semantic exactlyOneOf
9.3. Encoding subTemplateList
As explained in Section 2.2, multiple pairs of
(observationTimeMicroseconds, digestHashValue) must be collected from
two different Observation Points to passively compute the one-way
delay across the network. This data can be exported with an
optimized Data Record that consists of the following attributes:
5-tuple
{ observationTimeMicroseconds 1, digestHashValue 1 }
{ observationTimeMicroseconds 2, digestHashValue 2 }
{ observationTimeMicroseconds 3, digestHashValue 3 }
{ ... , ... }
A subTemplateList is best suited for exporting the list of
(observationTimeMicroseconds, digestHashValue). For illustration
purposes, the number of elements in the list is 5; in practice, it
could be more.
------------------------------------------------------------------
srcIP | dstIP | src | dst |proto| one-way delay
| | Port | Port | | metrics
------------------------------------------------------------------
192.0.2.1 192.0.2.105 1025 80 6 Time1, 0x0x91230613
Time2, 0x0x91230650
Time3, 0x0x91230725
Time4, 0x0x91230844
Time5, 0x0x91230978
------------------------------------------------------------------
The following Template is defined for exporting the one-way delay
metrics:
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 = 16 octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 257 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| observationTimeMicrosec=324 | Field Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| digestHashValue = 326 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
"octetCount" and "packetCount" don't exist. Per RFC5102 and IANA's IPFIX registry, the correct names are octetTotalCount and packetTotalCount.
NB correct usage in the figure on page 43 and in Figure 20 indicates that these are not the DeltaCount form.
As explained in Section 4.5.3, a subTemplateMultiList is used to
export a list of mixed-type content where each top-level element
corresponds to a different Template Record.
To illustrate this, consider the Data Record with the following
attributes:
5-tuple (Flow Keys), octetCount, packetCount
attributes for filtering
selectorId,
selectorAlgorithm
attributes for sampling
selectorId,
selectorAlgorithm,
samplingPacketInterval,
samplingPacketSpace
This example demonstrates that the Selector Report Interpretation
[RFC5476] can be encoded with the subTemplateMultiList. More
specifically, the example describes Property Match Filtering Selector
Report Interpretation [RFC5476] used for filtering purposes, and the
Systemic Count-Based Sampling as described in Section 6.5.2.1 of
[RFC5476]. Some traffic will be filtered according to match
properties configured, some will be sampled, some will be filtered
and sampled, and some will not be filtered or sampled.
A subTemplateMultiList is best suited for exporting this variable
data. A Template is defined for filtering attributes and another
Template is defined for sampling attributes. A Data Record can
contain data corresponding to either of the Templates, both of them,
or neither of them.
Consider the example below where the following Data Record contains
both filtering and sampling attributes.
Key attributes of the Data Record:
------------------------------------------------------------------
srcIP | dstIP | src | dst | proto | octetCount | packet
| | Port | Port | | | Count
------------------------------------------------------------------
2001:DB8::1 2001:DB8::2 1025 80 6 108000 120
------------------------------------------------------------------
Filtering attributes:
-------------------------------------------
selectorId | selectorAlgorithm
-------------------------------------------
100 5 (Property Match Filtering)
-------------------------------------------
Sampling attributes:
For Systemic Count-Based Sampling as defined in Section 6.5.2.1 of
[RFC5476] the required algorithm-specific Information Elements are:
samplingPacketInterval: number of packets selected in a row
samplingPacketSpace: number of packets between selections
Example of a simple 1-out-of-100 systematic count-based Selector
definition, where the samplingPacketInterval is 1 and the
samplingPacketSpace is 99.
--------------------------------------------------------------
selectorId | selectorAlgorithm | sampling | sampling
| | Packet | Packet
| | Interval | Space
--------------------------------------------------------------
15 1 (Count-Based Sampling) 1 99
--------------------------------------------------------------
To represent the Data Record, the following Template Records are
defined:
Template for filtering attributes: 259
Template for sampling attributes: 260
Template for Flow Record: 261
Flow record (261)
| (sourceIPv6Address)
| (destinationIPv6Address)
| (sourceTransportPort)
| (destinationTransportPort)
| (protocolIdentifier)
| (octetTotalCount)
| (packetTotalCount)
|
+------ filtering attributes (259)
| (selectorId)
| (selectorAlgorithm)
|
+------ sampling attributes (260)
| (selectorId)
| (selectorAlgorithm)
| (samplingPacketInterval)
| (samplingPacketSpace)
The following Template Record is defined for filtering attributes:
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 = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 259 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| selectorId = 302 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| selectorAlgorithm = 304 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 18: Encoding subTemplateMultiList, Template for Filtering
Attributes
The Template for sampling attributes is defined as follows:
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 = 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 260 | Field Count = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| selectorId = 302 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| selectorAlgorithm = 304 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| samplingPacketInterval = 305| Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| samplingPacketSpace = 306 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 19: Encoding subTemplateMultiList, Template for Sampling
Attributes
Note that while selectorAlgorithm is defined as unsigned16, and
samplingPacketInterval and samplingPacketSpace are defined as
unsigned32, they are compressed down to 1 octet here as allowed by
Reduced Size Encoding in Section 6.2 of the IPFIX protocol
specifications [RFC5101].
Template for the Flow Record is defined as shown 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Set ID = 2 | Length = 40 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 261 | Field Count = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceIPv6Address = 27 | Field Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationIPv6Address = 28 | Field Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceTransportPort = 7 | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationTransportPort=11 | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| protocolIdentifier = 4 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| octetTotalCount = 85 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| packetTotalCount = 86 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| subTemplateMultiList = 293 | Field Length = 0XFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 20: Encoding subTemplateMultiList, Template for Flow Record
A subTemplateMultiList with semantic allOf is used to export the
filtering and sampling attributes. The Length field of the
subTemplateMultiList is chosen to be encoded in three bytes even
though it may be less than 255 octets.
The Data Record is encoded as follows:
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 = 261 | Length = 73 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv6Address = ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 2001:DB8::1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destinationIPv6Address = ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 2001:DB8::2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceTransportPort = 1025 | destinationTransportPort = 80 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| protocol = 6 | octetTotalCount = 108000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | packetTotalCount = 120 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | 255 | Attributes List Length = 21 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|semantic=allOf | Filtering Template ID = 259 |Filtering Attr |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...Length = 9 | selectorId = ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 100 |selectorAlg = 5| Sampling Template ID = 260 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sampling Attributes Length=11 | selectorId = ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 15 |selectorAlg = 1| Interval = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Space = 99 |
+-+-+-+-+-+-+-+-+
Figure 21: Encoding subTemplateMultiList, Data Set
9.5. Encoding an Options Template Set Using Structured Data
As described in Section 5.3, consider a mediation function that must
aggregate Data Records from different Observation Points.
Say Observation Point 1 consists of one or more interfaces,
Observation Points 2 and 3 consist of one or more linecards, and
Observation Point 4 consists of one or more interfaces and one or
more linecards. Without structured data, a Template would have to be
defined for every possible combination to interpret the data
corresponding to each of the Observation Points. However, with
structured data, a basicList can be used to encode the list of
interfaces and another basicList can be used to encode the list of
linecards.
For the sake of simplicity, each Observation Point shown below has
the IP address corresponding to the Router and an <interface> or
<linecard> or <linecard and interface>. This can very well be
extended to include a list of interfaces and a list of linecards
using basicLists as explained above.
Observation Point 1: Router 1, (interface 1)
Observation Point 2: Router 2, (linecard A)
Observation Point 3: Router 3, (linecard B)
Observation Point 4: Router 4, (linecard C, interface 2)
The mediation function wishes to express this as a single Observation
Point, in order to encode the PSAMP Selection Sequence Report
Interpretation (SSRI). Recall from [RFC5476] that the PSAMP
Selection Sequence Report Interpretation consists of the following
fields:
Scope: selectionSequenceId
Non-Scope: one Information Element mapping the
Observation Point
selectorId (one or more)
For example, the Observation Point detailed above may be encoded in a
PSAMP Selection Sequence Report Interpretation as shown below:
Selection Sequence 7 (Filter->Sampling):
Observation Point: subTemplateMultiList.
Router 1 (IP address = 192.0.2.11), (interface 1)
Router 2 (IP address = 192.0.2.12), (linecard A)
Router 3 (IP address = 192.0.2.13), (linecard B)
Router 4 (IP address = 192.0.2.14), (linecard C, interface 2)
selectorId: 5 (Filter, match IPv4SourceAddress 192.0.2.1)
selectorId: 10 (Sampler, Random 1 out-of ten)
The following Templates are defined to represent the PSAMP SSRI:
Template for representing PSAMP SSRI: 262
Template for representing interface: 263
Template for representing linecard: 264
Template for representing linecard and interface: 265
PSAMP SSRI (262)
| (SelectionSequenceId)
|
+--- Observation Point 1 (263)
| (exporterIPv4Address)
| (Interface Id)
|
+--- Observation Point 2 and 3 (264)
| (exporterIPv4Address)
| (linecard)
|
+--- Observation Point 4 (265)
| (exporterIPv4Address)
| (linecard)
| (Interface Id)
|
| (selectorId 1)
| (selectorId 2)
Note that the example could further be improved with a basicList
of selectorId if many Selector IDs have to be reported.
Figure 22: PSAMP SSRI to Be Encoded
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 = 26 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 262 | Field Count = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scope Field Count = 1 |0| selectionSequenceId = 301 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Scope 1 Length = 4 |0| subTemplateMultiList = 293 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 0xFFFF |0| selectorId = 302 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 4 |0| selectorId = 302 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 23: Options Template Record for PSAMP SSRI Using
subTemplateMultiList
A subTemplateMultiList with semantic allOf is used to encode the
list of Observation Points.
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 = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 263 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| exporterIPv4Address = 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| ingressInterface = 10 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 24: PSAMP SSRI, Template Record for interface
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 = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 264 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| exporterIPv4Address = 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| lineCardId = 141 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 25: PSAMP SSRI, Template Record for linecard
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 = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 265 | Field Count = 3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| exporterIPv4Address = 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| lineCardId = 141 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| ingressInterface = 10 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 26: PSAMP SSRI, Template Record for linecard and interface
The PSAMP SSRI Data Set is represented as follows:
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 = 262 | Length = 68 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| selectionSequenceId = 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | Observation Point List Len=49 |semantic=allOf |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP1 Template ID = 263 | OP1 Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router 1 exporterIPv4Address = 192.0.2.11 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP1 ingressInterface = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP2&OP3 Template ID = 264 | OP2 & OP3 Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router 2 exporterIPv4Address = 192.0.2.12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP2 lineCardId = A |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router 3 exporterIPv4Address = 192.0.2.13 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP3 lineCardId = B |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP4 Template ID = 265 | OP4 Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Router 4 exporterIPv4Address = 192.0.2.14 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP4 lineCardId = C |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OP4 ingressInterface = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| selectorId = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| selectorId = 10 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 27: Example of a PSAMP SSRI Data Record, Encoded Using a
subTemplateMultiList
Note that the Data Record above contains multiple instances of
Template 264 to represent Observation Point 2 (Router2, linecard A)
and Observation Point 3 (Router3, linecard B). Instead, if a single
Observation Point had both linecard A and linecard B, a basicList
would be used to represent the list of linecards.
10. Relationship with the Other IPFIX Documents
10.1. Relationship with Reducing Redundancy
"Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet
Sampling (PSAMP) Reports" [RFC5473] describes a bandwidth saving
method for exporting Flow or packet information using the IP Flow
Information Export (IPFIX) protocol.
It discusses the commonPropertiesID Information Element for exporting
Common Properties.
EID 2884 (Verified) is as follows:Section: 10.1
Original Text:
"Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet
Sampling (PSAMP) Reports" [RFC5473] describes a bandwidth saving
method for exporting Flow or packet information using the IP Flow
Information Export (IPFIX) protocol.
It defines the commonPropertiesID Information Element for exporting
Common Properties.
Corrected Text:
"Reducing Redundancy in IP Flow Information Export (IPFIX) and Packet
Sampling (PSAMP) Reports" [RFC5473] describes a bandwidth saving
method for exporting Flow or packet information using the IP Flow
Information Export (IPFIX) protocol.
It discusses the commonPropertiesID Information Element for exporting
Common Properties.
Notes:
s/defines/discusses/
- commonPropertiesId is not defined in [RFC5473], but in [RFC5101]. [RFC5473] doesn't have any IANA actions.
10.1.1. Encoding Structured Data Element Using Common Properties
When Structured Data Information Elements contain repeated elements,
these elements may be replaced with a commonPropertiesID Information
Element as specified in [RFC5473]. The replaced elements may include
the basicList, subTemplateList, and subTemplateMultiList Information
Elements.
This technique might help reducing the bandwidth requirements for the
export. However, a detailed analysis of the gain has not been done;
refer to Section 8.3 of [RFC5473] for further considerations.
10.1.2. Encoding Common Properties Elements with Structured Data
Information Element
Structured Data Information Element MAY be used to define a list of
commonPropertiesID, as a replacement for the specifications in
[RFC5473].
Indeed, the example in Figures 1 and 2 of [RFC5473] can be encoded
with the specifications in this document.
+----------------+-------------+---------------------------+
| sourceAddressA | sourcePortA | <Flow1 information> |
+----------------+-------------+---------------------------+
| sourceAddressA | sourcePortA | <Flow2 information> |
+----------------+-------------+---------------------------+
| sourceAddressA | sourcePortA | <Flow3 information> |
+----------------+-------------+---------------------------+
| sourceAddressA | sourcePortA | <Flow4 information> |
+----------------+-------------+---------------------------+
| ... | ... | ... |
+----------------+-------------+---------------------------+
Figure 28: Common and Specific Properties Exported Together
[RFC5473]
+------------------------+-----------------+-------------+
| index for properties A | sourceAddressA | sourcePortA |
+------------------------+-----------------+-------------+
| ... | ... | ... |
+------------------------+-----------------+-------------+
+------------------------+---------------------------+
| index for properties A | <Flow1 information> |
+------------------------+---------------------------+
| index for properties A | <Flow2 information> |
+------------------------+---------------------------+
| index for properties A | <Flow3 information> |
+------------------------+---------------------------+
| index for properties A | <Flow4 information> |
+------------------------+---------------------------+
Figure 29: Common and Specific Properties Exported Separately
According to [RFC5473]
+----------------+-------------+---------------------------+
| sourceAddressA | sourcePortA | <Flow1 information> |
+----------------+-------------+---------------------------+
| <Flow2 information> |
+---------------------------+
| <Flow3 information> |
+---------------------------+
| <Flow4 information> |
+---------------------------+
| ... |
+---------------------------+
Figure 30: Common and Specific Properties Exported with
Structured Data Information Element
The example in Figure 28 could be encoded with a basicList if the
<Flow information> represents a single Information Element, with a
subTemplateList if the <Flow information> represents a Template
Record, or with a subTemplateMultiList if the <Flow information> is
composed of different Template Records.
Using Structured Data Information Elements as a replacement for the
techniques specified in "Reducing Redundancy in IP Flow Information
Export (IPFIX) and Packet Sampling (PSAMP) Reports" [RFC5473] offers
the advantage that a single Template Record is defined. Hence, the
Collector's job is simplified in terms of Template management and
combining Template/Options Template Records.
However, it must be noted that using Structured Data Information
Elements as a replacement for the techniques specified in "Reducing
Redundancy in IP Flow Information Export (IPFIX) and Packet Sampling
(PSAMP) Reports" only applies to simplified cases. For example, the
"Multiple Data Reduction" (Section 7.1 [RFC5473]) might be too
complex to encode with Structured Data Information Elements.
10.2. Relationship with Guidelines for IPFIX Testing
[RFC5471] presents a list of tests for implementers of IP Flow
Information Export (IPFIX) compliant Exporting Processes and
Collecting Processes.
Although [RFC5471] doesn't define any structured data element
specific tests, the Structured Data Information Elements can be used
in many of the [RFC5471] tests.
The [RFC5471] series of test could be useful because the document
specifies that every Information Element type should be tested.
However, not all cases from this document are tested in [RFC5471].
The following sections are especially noteworthy:
3.2.1. Transmission of Template with Fixed-Size Information
Elements
- each data type should be used in at least one test. The new
data types specified in Section 4.1 should be included in
this test.
3.2.2. Transmission of Template with Variable-Length Information
Elements
- this test should be expanded to include Data Records
containing variable length basicList, subTemplateList, and
subTemplateMultiList Information Elements.
3.3.1. Enterprise-Specific Information Elements
- this test should include the export of basicList,
subTemplateList, and subTemplateMultiList Information
Elements containing Enterprise-specific Information Elements,
e.g., see the example in Figure 2.
3.3.3. Multiple Instances of the Same Information Element in One
Template
- this test should verify that multiple instances of the
basicList, subTemplateList, and subTemplateMultiList
Information Elements are accepted.
3.5. Stress/Load Tests
- since the structured data types defined here allow modeling
of complex data structures, they may be useful for stress
testing both Exporting Processes and Collecting Processes.
10.3. Relationship with IPFIX Mediation Function
The Structured Data Information Elements would be beneficial for the
export of aggregated Data Records in mediation function, as was
demonstrated with the example of the aggregated Observation Point in
Section 5.3.
11. IANA Considerations
This document specifies several new IPFIX abstract data types, a
new IPFIX Data Type Semantic, and several new Information
Elements. Furthermore, this document updates the schema at
http://www.iana.org/assignments/xml-registry/schema/ipfix.xsd with
the changes specified in Appendix A.
EID 2874 (Verified) is as follows:Section: 11
Original Text:
This document specifies several new IPFIX abstract data types, a new
IPFIX Data Type Semantic, and several new Information Elements.
Corrected Text:
This document specifies several new IPFIX abstract data types, a
new IPFIX Data Type Semantic, and several new Information
Elements. Furthermore, this document updates the schema at
http://www.iana.org/assignments/xml-registry/schema/ipfix.xsd with
the changes specified in Appendix A.
Notes:
Agreed addition of "Furthermore ,,. Appendix A." was overlooked during AUTH48.
A new IPFIX registry has been created, and the existing IPFIX
Information Element registry has been updated as detailed below.
EID 2873 (Verified) is as follows:Section: 11
Original Text:
Two new IPFIX registries have been created, and the existing IPFIX
Information Element registry has been updated as detailed below.
Corrected Text:
A new IPFIX registry has been created, and the existing IPFIX
Information Element registry has been updated as detailed below.
Notes:
Only one new registry has been created - for the "structured data types semantics", per section 11.4 of the document.
11.1. New Abstract Data Types
Section 4.1 of this document specifies several new IPFIX abstract
data types. Per Section 6 of the IPFIX information model [RFC5102],
new abstract data types can be added to the IPFIX information model
in the IPFIX Information Element Data Types registry.
Abstract data types that have been added to the IPFIX Information
Element Data Types registry are listed below.
11.1.1. basicList
The type "basicList" represents a list of any Information Element
used for single-valued data types.
11.1.2. subTemplateList
The type "subTemplateList" represents a list of a structured data
type, where the data type of each list element is the same and
corresponds with a single Template Record.
11.1.3. subTemplateMultiList
The type "subTemplateMultiList" represents a list of structured data
types, where the data types of the list elements can be different and
correspond with different Template definitions.
11.2. New Data Type Semantics
Section 4.2 of this document specifies a new IPFIX Data Type
Semantic. Per Section 3.2 of the IPFIX information model [RFC5102],
new data type semantics can be added to the IPFIX information model.
Therefore, the IANA IPFIX informationElementSemantics registry
[IANA-IPFIX], which contains all the data type semantics from Section
3.2 of [RFC5102], has been augmented with the "list" value below.
11.2.1. list
A list is a structured data type, being composed of a sequence of
elements, e.g., Information Element, Template Record.
11.3. New Information Elements
Section 4.3 of this document specifies several new Information
Elements that have been created in the IPFIX Information Element
registry [IANA-IPFIX].
New Information Elements that have been added to the IPFIX
Information Element registry are listed below.
11.3.1. basicList
Name: basicList
Description:
Specifies a generic Information Element with a basicList abstract
data type. Examples include a list of port numbers, and a list of
interface indexes.
Abstract Data Type: basicList
Data Type Semantics: list
ElementId: 291
Status: current
11.3.2. subTemplateList
Name: subTemplateList
Description:
Specifies a generic Information Element with a subTemplateList
abstract data type.
Abstract Data Type: subTemplateList
Data Type Semantics: list
ElementId: 292
Status: current
11.3.3. subTemplateMultiList
Name: subTemplateMultiList
Description:
Specifies a generic Information Element with a
subTemplateMultiList abstract data type.
Abstract Data Type: subTemplateMultiList
Data Type Semantics: list
ElementId: 293
Status: current
11.4. New Structured Data Semantics
Section 4.4 of this document specifies a series of new IPFIX
structured data type semantics, which is expressed as an 8-bit value.
This requires the creation of a new "IPFIX Structured Data Types
Semantics" IPFIX subregistry [IANA-IPFIX].
Entries may be added to this subregistry subject to a Standards
Action [RFC5226]. Initially, this registry includes all the
structured data type semantics listed below.
11.4.1. undefined
Name: undefined
Description: The "undefined" structured data type semantic specifies
that the semantic of list elements is not specified and that, if a
semantic exists, then it is up to the Collecting Process to draw its
own conclusions. The "undefined" structured data type semantic is
the default structured data type semantic.
Value: 0xFF
Reference: RFC 6313
11.4.2. noneOf
Name: noneOf
Description: The "noneOf" structured data type semantic specifies
that none of the elements are actual properties of the Data Record.
Value: 0x00
Reference: RFC 6313
11.4.3. exactlyOneOf
Name: exactlyOneOf
Description: The "exactlyOneOf" structured data type semantic
specifies that only a single element from the structured data is an
actual property of the Data Record. This is equivalent to a logical
XOR operation.
Value: 0x01
Reference: RFC 6313
11.4.4. oneOrMoreOf
Name: oneOrMoreOf
Description: The "oneOrMoreOf" structured data type semantic
specifies that one or more elements from the list in the structured
data are actual properties of the Data Record. This is equivalent to
a logical OR operation.
Value: 0x02
Reference: RFC 6313
11.4.5. allOf
Name: allOf
Description: The "allOf" structured data type semantic specifies that
all of the list elements from the structured data are actual
properties of the Data Record.
Value: 0x03
Reference: RFC 6313
11.4.6. ordered
Name: ordered Description: The "ordered" structured data type
semantic specifies that elements from the list in the structured data
are ordered.
Value: 0x04
Reference: RFC 6313
12. Security Considerations
The addition of complex data types necessarily complicates the
implementation of the Collector. This could easily result in new
security vulnerabilities (e.g., buffer overflows); this creates
additional risk in cases where either Datagram Transport Layer
Security (DTLS) is not used or if the Observation Point and Collector
belong to different trust domains. Otherwise, the same security
considerations as for the IPFIX protocol [RFC5101] and the IPFIX
information model [RFC5102] apply.
13. References
13.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC5101] Claise, B., Ed., "Specification of the IP Flow
Information Export (IPFIX) Protocol for the Exchange of
IP Traffic Flow Information", RFC 5101, January 2008.
[RFC5102] Quittek, J., Bryant, S., Claise, B., Aitken, P., and J.
Meyer, "Information Model for IP Flow Information
Export", RFC 5102, January 2008.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
13.2. Informative References
[RFC3917] Quittek, J., Zseby, T., Claise, B., and S. Zander,
"Requirements for IP Flow Information Export (IPFIX)",
RFC 3917, October 2004.
[RFC5103] Trammell, B. and E. Boschi, "Bidirectional Flow Export
Using IP Flow Information Export (IPFIX)", RFC 5103,
January 2008.
[RFC5470] Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,
"Architecture for IP Flow Information Export", RFC 5470,
March 2009.
[RFC5471] Schmoll, C., Aitken, P., and B. Claise, "Guidelines for
IP Flow Information Export (IPFIX) Testing", RFC 5471,
March 2009.
[RFC5472] Zseby, T., Boschi, E., Brownlee, N., and B. Claise, "IP
Flow Information Export (IPFIX) Applicability", RFC
5472, March 2009.
[RFC5473] Boschi, E., Mark, L., and B. Claise, "Reducing
Redundancy in IP Flow Information Export (IPFIX) and
Packet Sampling (PSAMP) Reports", RFC 5473, March 2009.
[RFC5475] Zseby, T., Molina, M., Duffield, N., Niccolini, S., and
F. Raspall, "Sampling and Filtering Techniques for IP
Packet Selection", RFC 5475, March 2009.
[RFC5476] Claise, B., Ed., Johnson, A., and J. Quittek, "Packet
Sampling (PSAMP) Protocol Specifications", RFC 5476,
March 2009.
[RFC5477] Dietz, T., Claise, B., Aitken, P., Dressler, F., and G.
Carle, "Information Model for Packet Sampling Exports",
RFC 5477, March 2009.
[IANA-IPFIX] IANA, "IP Flow Information Export (IPFIX) Entities",
<http://www.iana.org/>.
14. Acknowledgements
The authors would like to thank Zhipu Jin, Nagaraj Varadharajan,
Brian Trammel, Atsushi Kobayashi, and Rahul Patel for their feedback,
and Gerhard Muenz, for proofreading the document.
Appendix A. Additions to XML Specification of IPFIX Information
Elements and Abstract Data Types
This appendix contains additions to the machine-readable description
of the IPFIX information model coded in XML in Appendices A and B in
[RFC5102]. Note that this appendix is of informational nature, while
the text in Section 4 (generated from this appendix) is normative.
The following field definitions are appended to the IPFIX information
model in Appendix A of [RFC5102].
<field name="basicList"
dataType="basicList"
group="structured-data"
dataTypeSemantics="List"
elementId="291" applicability="all" status="current">
<description>
<paragraph>
Represents a list of zero or more instances of
any Information Element, primarily used for
single-valued data types. Examples include a list of port
numbers, list of interface indexes, and a list of AS in a
BGP AS-PATH.
</paragraph>
</description>
</field>
<field name="subTemplateList"
dataType="subTemplateList"
group="structured-data"
dataTypeSemantics="List"
elementId="292" applicability="all" status="current">
<description>
<paragraph>
Represents a list of zero or more instances of a
structured data type, where the data type of each list
element is the same and corresponds with a single
Template Record. Examples include a structured data type
composed of multiple pairs of ("MPLS label stack entry
position", "MPLS label stack value"), a structured data
type composed of performance metrics, and a structured data
type composed of multiple pairs of IP address.
</paragraph>
</description>
</field>
<field name="subTemplateMultiList"
dataType="subTemplateMultiList"
group="structured-data"
dataTypeSemantics="List"
elementId="293" applicability="all" status="current">
<description>
<paragraph>
Represents a list of zero or more instances of
structured data types, where the data type of each list
element can be different and corresponds with
different Template definitions. Examples include, a
structured data type composed of multiple access-list
entries, where entries can be composed of different
criteria types.
</paragraph>
</description>
</field>
The following structured data type semantic definitions are appended
to the IPFIX information model in Appendix A of [RFC5102].
<structuredDataTypeSemantics>
<structuredDataTypeSemantic name="undefined" value="255">
<description>
<paragraph>
The "undefined" structured data type semantic specifies
that the semantic of list elements is not specified and
that, if a semantic exists, then it is up to the
Collecting Process to draw its own conclusions. The
"undefined" structured data type semantic is the default
structured data type semantic.
</paragraph>
</description>
</structuredDataTypeSemantic>
<structuredDataTypeSemantic name="noneOf" value="0">
<description>
<paragraph>
The "noneOf" structured data type semantic specifies
that none of the elements are actual properties of the
Data Record.
</paragraph>
</description>
</structuredDataTypeSemantic>
<structuredDataTypeSemantic name="exactlyOneOf" value="1">
<description>
<paragraph>
The "exactlyOneOf" structured data type semantic
specifies that only a single element from the structured
data is an actual property of the Data Record. This is
equivalent to a logical XOR operation.
</paragraph>
</description>
</structuredDataTypeSemantic>
<structuredDataTypeSemantic name="oneOrMoreOf" value="2">
<description>
<paragraph>
The "oneOrMoreOf" structured data type semantic
specifies that one or more elements from the list in the
structured data are actual properties of the Data
Record. This is equivalent to a logical OR operation.
</paragraph>
</description>
</structuredDataTypeSemantic>
<structuredDataTypeSemantic name="allOf" value="3">
<description>
<paragraph>
The "allOf" structured data type semantic specifies that
all of the list elements from the structured data are
actual properties of the Data Record.
</paragraph>
</description>
</structuredDataTypeSemantic>
<structuredDataTypeSemantic name="ordered" value="4">
<description>
<paragraph>
The "ordered" structured data type semantic specifies
that elements from the list in the structured data are
ordered.
</paragraph>
</description>
</structuredDataTypeSemantic>
</structuredDataTypeSemantics>
The following schema definitions are appended to the abstract data
types defined in Appendix B of [RFC5102]. This schema and its
namespace are registered by IANA at
http://www.iana.org/assignments/xml-registry/schema/ipfix.xsd.
<simpleType name="dataType">
<restriction base="string">
<enumeration value="basicList">
<annotation>
<documentation>
Represents a list of zero or more instances of
any Information Element, primarily used for
single-valued data types. Examples include a list of port
numbers, a list of interface indexes, and a list of AS in a
BGP AS-PATH.
</documentation>
</annotation>
</enumeration>
<enumeration value="subTemplateList">
<annotation>
<documentation>
Represents a list of zero or more instances of a
structured data type, where the data type of each list
element is the same and corresponds with a single
Template Record. Examples include a structured data type
composed of multiple pairs of ("MPLS label stack entry
position", "MPLS label stack value"), a structured
data type composed of performance metrics, and a
structured data type composed of multiple pairs of IP
address.
</documentation>
</annotation>
</enumeration>
<enumeration value="subTemplateMultiList">
<annotation>
<documentation>
Represents a list of zero or more instances of
structured data types, where the data type of each
list element can be different and corresponds with
different Template definitions. An example is a
structured data type composed of multiple
access-list entries, where entries can be
composed of different criteria types.
</documentation>
</annotation>
</enumeration>
</restriction>
</simpleType>
<simpleType name="dataTypeSemantics">
<restriction base="string">
<enumeration value="List">
<annotation>
<documentation>
Represents an arbitrary-length sequence of structured
data elements, either composed of regular Information
Elements or composed of data conforming to a Template
Record.
</documentation>
</annotation>
</enumeration>
</restriction>
</simpleType>
<complexType name="structuredDataTypeSemantics">
<sequence>
<element name="structuredDataTypeSemantic"
minOccurs="1" maxOccurs="unbounded">
<complexType>
<sequence>
<element name="description" type="text"/>
</sequence>
<attribute name="name" type="string" use="required"/>
<attribute name="value" type="unsignedByte" use="required"/>
</complexType>
</element>
</sequence>
</complexType>
<element name="structuredDataTypeSemantics"
type="structuredDataTypeSemantics">
<annotation>
<documentation>
Structured data type semantics express the relationship
among multiple list elements in a structured data
Information Element.
</documentation>
</annotation>
</element>
Appendix B. Encoding IPS Alert Using Structured Data Information
Elements
In this section, an IPS alert example is used to demonstrate how
complex data and multiple levels of hierarchy can be encoded using
Structured Data Information Elements. Also, this example
demonstrates how a basicList of subTemplateLists can be used to
represent semantics at multiple levels in the hierarchy.
An IPS alert consists of the following mandatory attributes:
signatureId, protocolIdentifier, and riskRating. It can also contain
zero or more participants, and each participant can contain zero or
more attackers and zero or more targets. An attacker contains the
attributes sourceIPv4Address and applicationId, and a target contains
the attributes destinationIPv4Address and applicationId.
Note that the signatureId and riskRating Information Element fields
are created for these examples only; the Field IDs are shown as N/A.
The signatureId helps to uniquely identify the IPS signature that
triggered the alert. The riskRating identifies the potential risk,
on a scale of 0-100 (100 being most serious), of the traffic that
triggered the alert.
Consider the example described in case study 2 of Section 5.6. The
IPS alert contains participants encoded as a subTemplateList with
semantic allOf. Each participant uses a basicList of
subTemplateLists to represent attackers and targets. For the sake of
simplicity, the alert has two participants P1 and P2. In participant
P1, attacker A1 or A2 attacks target T1. In participant P2, attacker
A3 attacks targets T2 and T3.
Participant P1:
(basicList, allOf,
(subTemplateList, exactlyOneOf, attacker A1, A2)
(subTemplateList, undefined, target T1)
)
Participant P2:
(basicList, allOf,
(subTemplateList, undefined, attacker A3,
(subTemplateList, allOf, targets T2, T3)
)
Alert :
(subTemplateList, allOf, Participant P1, Participant P2)
------------------------------------------------------------------
| | | participant
sigId |protocol| risk | attacker | target
| Id | Rating | IP | appId | IP | appId
------------------------------------------------------------------
1003 17 10 192.0.2.3 103 192.0.2.103 3001
192.0.2.4 104
192.0.2.5 105 192.0.2.104 4001
192.0.2.105 5001
------------------------------------------------------------------
Participant P1 contains:
Attacker A1: (IP, appId)=(192.0.2.3, 103)
Attacker A2: (IP, appId)=(192.0.2.4, 104)
Target T1: (IP, appId)= (192.0.2.103, 3001)
Participant P2 contains:
Attacker A3: (IP, appId) = (192.0.2.5, 105)
Target T2: (IP, appId)= (192.0.2.104, 4001)
Target T3: (IP, appId)= (192.0.2.105, 5001)
To represent an alert, the following Templates are defined:
Template for target (268)
Template for attacker (269)
Template for participant (270)
Template for alert (271)
alert (271)
| (signatureId)
| (protocolIdentifier)
| (riskRating)
|
+------- participant (270)
|
+------- attacker (269)
| (sourceIPv4Address)
| (applicationId)
|
+------- target (268)
| (destinationIPv4Address)
| (applicationId)
Note that the attackers are always composed of a single
applicationId, while the targets typically have multiple
applicationIds; for the sake of simplicity, this example shows only
one applicationId in the target.
Template Record for target, with the Template ID 268:
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 = 16 octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 268 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationIPv4Address = 12 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| applicationId = 95 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 31: Encoding IPS Alert, Template for Target
Template Record for attacker, with the Template ID 269:
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 = 16 octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 269 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceIPv4Address = 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| applicationId = 95 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 32: Encoding IPS Alert, Template for Attacker
Template Record for participant, with the Template ID 270:
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 = 12 octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 270 | Field Count = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| basicList = 291 | Field Length = 0xFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 33: Encoding IPS Alert, Template for Participant
The Template Record for the participant has one basicList Information
Element, which is a list of subTemplateLists of attackers and
targets.
Template Record for IPS alert, with the Template ID 271:
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 = 24 octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 271 | Field Count = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| signatureId = N/A | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| protocolIdentifier = 4 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| riskRating = N/A | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| subTemplateList = 292 | Field Length = 0xFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 34: Encoding IPS Alert, Template for IPS Alert
The subTemplateList in the alert Template Record contains a list of
participants.
The Length of basicList and subTemplateList are encoded in three
bytes even though they may be less than 255 octets.
The Data Set is represented as follows:
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 = 271 | Length = 102 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| signatureId = 1003 | protocolId=17 | riskRating=10 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 |participant List Length = 91 |semantic=allOf |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| participant Template ID = 270 | 255 | P1 List Len = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 41 | semantic=allOf| P1 List Field ID = 292 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P1 List Field ID Len = 0xFFFF | 255 |P1 attacker ...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| List Len = 19 |sem=exactlyOne | P1 attacker Template ID = 269 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P1 attacker A1 sourceIPv4Address = 192.0.2.3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P1 attacker A1 applicationId = 103 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P1 attacker A2 sourceIPv4Address = 192.0.2.4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P1 attacker A2 applicationId = 104 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | P1 target List Len = 11 | sem=undefined |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P1 target Template ID = 268 | P1 target T1 destinationIPv4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Address = 192.0.2.103 |P1 target T1 applicationId =...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 3001 | 255 | P2 List Len = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 41 | semantic=allOf| P2 List Field ID = 292 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P2 List Field ID Len = 0xFFFF | 255 |P2 attacker ...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| List Len = 11 | sem=undefined | P2 attacker Template ID = 269 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P2 attacker A3 sourceIPv4Address = 192.0.2.5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P2 attacker A3 applicationId = 105 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | P2 target List Len = 19 |semantic=allOf |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| P2 target Template ID = 268 | P2 target T2 destinationIPv4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Address = 192.0.2.104 |P2 target T2 applicationId =...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 4001 | P2 target T3 destinationIPv4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Address = 192.0.2.105 |P2 target T3 applicationId =...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 5001 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note: sem=exactlyOne represents semantic=exactlyOneOf
Figure 35: Encoding IPS Alert, Data Set
Authors' Addresses
Benoit Claise
Cisco Systems, Inc.
De Kleetlaan 6a b1
Diegem 1813
Belgium
Phone: +32 2 704 5622
EMail: bclaise@cisco.com
Gowri Dhandapani
Cisco Systems, Inc.
13615 Dulles Technology Drive
Herndon, Virginia 20171
United States
Phone: +1 408 853 0480
EMail: gowri@cisco.com
Paul Aitken
Cisco Systems, Inc.
96 Commercial Quay
Commercial Street
Edinburgh, EH6 6LX
United Kingdom
Phone: +44 131 561 3616
EMail: paitken@cisco.com
Stan Yates
Cisco Systems, Inc.
7100-8 Kit Creek Road
PO Box 14987
Research Triangle Park, North Carolina 27709-4987
United States
Phone: +1 919 392 8044
EMail: syates@cisco.com