IPFIX Working Group B. Claise
Internet-Draft G. Dhandapani
Intended Status: Standards Track S. Yates
Expires: September 7, 2010 P. Aitken
Cisco Systems, Inc.
March 7, 2010
Export of Structured Data in IPFIX
draft-ietf-ipfix-structured-data-01.txt
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Abstract
This document specifies an extension to IP Flow Information
eXport (IPFIX) protocol specification in [RFC5101] and the IPFIX
information model specified in [RFC5102] 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.
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].
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Table of Contents
1. Overview................................................... 7
1.1. IPFIX Documents Overview...............................7
1.2. Relationship between IPFIX and PSAMP...................7
2. Terminology.................................................8
2.1. New Terminology........................................8
3. Introduction................................................8
3.1. The IPFIX Track........................................9
3.2. The IPFIX Limitations.................................10
3.3. The Proposal..........................................12
4. Linkage with the Information Model.........................13
4.1. New Abstract Data Types...............................13
4.1.1. basicList........................................13
4.1.2. subTemplateList..................................13
4.1.3. subTemplateMultiList.............................14
4.2. New Data Type Semantic................................14
4.2.1. List.............................................14
4.3. New Information Elements..............................14
4.3.1. basicList........................................14
4.3.2. subTemplateList..................................15
4.3.3. subTemplateMultiList.............................15
4.4. Encoding of IPFIX Data Types..........................15
4.4.1. basicList........................................15
4.4.2. subTemplateList..................................18
4.4.3. subTemplateMultiList.............................19
5. Structured Data Format.....................................21
5.1. Length Encoding Considerations........................21
5.2. Recursive Structured Data.............................22
5.3. Structured Data Information Elements Applicability in
Options Template Sets......................................22
5.4. Usage Guidelines for Equivalent Data Representations..23
5.5. Padding...............................................24
6. Template Management........................................24
7. The Collecting Process's Side..............................25
8. Structured Data Encoding Examples..........................25
8.1. Encoding BasicList....................................25
8.2. Encoding subTemplateList..............................27
8.3. Encoding subTemplateMultiList.........................30
8.4. Encoding an Options Template Set using Structured Data35
9. Relationship with the Other IFPIX Documents................39
9.1. Relationship with Reducing Redundancy.................39
9.1.1. Encoding Structured Data Element using Common
Properties..............................................39
9.1.2. Encoding Common Properties elements With Structured
Data Element............................................40
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9.2. Relationship with Guidelines for IPFIX Testing........42
9.3. Relationship with Bidirectional Flow Export...........43
9.4. Relationship with IPFIX Mediation Function............43
10. IANA Considerations.......................................43
10.1. New Abstract Data Types..............................44
10.1.1. basicList.......................................44
10.1.2. subTemplateList.................................44
10.1.3. subTemplateMultiList............................44
10.2. New Data Type Semantics..............................44
10.2.1. list............................................45
10.3. New Information Elements.............................45
10.3.1. basicList.......................................45
10.3.2. subTemplateList.................................45
10.3.3. subTemplateMultiList............................45
11. Security Considerations...................................46
12. References................................................46
12.1. Normative References.................................46
12.2. Informative References...............................46
13. Acknowledgement...........................................47
14. Authors' Addresses........................................47
Appendix A. XML Specification of IPFIX Information
Elements and Abstract Data Types..............................48
Appendix B. Example of Biflow Encoding using Structured
Data Information Elements.....................................51
Appendix C. Encoding IPS Alert using Structured Data
Information Elements..........................................54
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Table of Figures
Figure A: basicList Information Element Encoding.................16
Figure B: basicList Encoding with Enterprise Number..............17
Figure C: Variable-Length basicList Information Element Encoding
(Length < 255 octets) ........................................17
Figure D: Variable-Length basicList Information Element Encoding
(Length 0 to 65535 octets) ...................................17
Figure E: subTemplateList Encoding...............................18
Figure F: Variable-Length subTemplateList Information Element
Encoding (Length < 255 octets) ...............................19
Figure G: Variable-Length subTemplateList Information Element
Encoding (Length 0 to 65535 octets) ..........................19
Figure H: subTemplateMultiList Encoding..........................20
Figure I: Variable-Length subTemplateMultiList Information Element
Encoding (Length < 255 octets) ...............................21
Figure J: Variable-Length subTemplateMultiList Information Element
Encoding (Length 0 to 65535 octets) ..........................21
Figure K: Encoding basicList, Template Record....................26
Figure L: Encoding basicList, Data Record........................27
Figure M: BasicList Encoding with Variable-Length Elements.......27
Figure N: Encoding subTemplateList, Template for One-Way Delay
Metrics ......................................................28
Figure O: Encoding subTemplateList, Template Record..............29
Figure P: Encoding subTemplateList, Data Set.....................30
Figure Q: Encoding subTemplateMultiList, Template for
Classification Attributes ....................................33
Figure R: Encoding subTemplateMultiList, Template for Sampling
Attributes ...................................................33
Figure S: Encoding subTemplateMultiList, Template for Flow Record34
Figure T: Encoding subTemplateMultiList, Data Set................35
Figure U: PSAMP SSRI to be encoded..............................37
Figure V: Options Template Record for PSAMP SSRI using
subTemplateMultiList .........................................37
Figure W: PSAMP SSRI, Template Record for interface..............37
Figure X: PSAMP SSRI, Template Record for linecard...............38
Figure Y: PSAMP SSRI, Template Record for linecard and interface.38
Figure Z: Example of a PSAMP SSRI Data Record, Encoded using a
subTemplateMultiList .........................................39
Figure ZA: Common and Specific Properties Exported Together
[RFC5473] ....................................................40
Figure ZB: Common and Specific Properties Exported Separately
according to [RFC5473] .......................................41
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Figure ZC: Common and Specific Properties Exported with Structured
Data Information Element .....................................41
Figure B0: Using a subTemplateList to represent a Biflow.........51
Figure B1: Template for the Biflow Fields........................52
Figure B2: Template for the Key Fields...........................52
Figure B3: Biflow Data Set Encoded using Structured Data.........53
Figure C0: Encoding IPS Alert, Template for Target...............55
Figure C1: Encoding IPS Alert, Template for Attacker.............56
Figure C2: Encoding IPS Alert, Template for Participant..........56
Figure C3: Encoding IPS Alert, Template for IPS Alert............57
Figure C4: Encoding IPS Alert, Data Set..........................58
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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]
presents 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.
The "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.
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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. Terminology
IPFIX-specific terminology used in this document is defined in
Section 2 of the IPFIX protocol specification [RFC5101] and
Section 3 of PSAMP protocol specification [RFC5476]. As in
[RFC5101], these IPFIX-specific terms have the first letter of a
word capitalized when used in this document.
2.1. New Terminology
Structured Data Information Element
One of the Information Elements supporting structured data,
i.e., the basicList, subTemplateList, or subTemplateMultiList
Information Elements.
3. 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 important that, when dealing with highly granular
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information such as Flow information, a push mechanism (as opposed
to a pull mechanism, such as SNMP) is the only solution for
routers... whose primary function is to route packet. Indeed,
polling short-live 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 and time.
Typically, it would be beneficial if access routers could export
Flow Records, composed of the counters before and after the WAN
optimization mechanism, 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 RFC5101 would give part of the
solution.
3.1. The IPFIX Track
The IPFIX working group has specified a protocol to export IP 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, etc.).
The IPFIX protocol specification [RFC5101] specifies that IP
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
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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, 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.
3.2. 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 hardcoded 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,
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IANA will not be able to assign the new Information Element next
to the other ones in the registry, which might cause some
confusion.
Clearly a real structured data type composed of ("label stack
entry position", "label stack value") pairs, potentially repeated
multiple times in Flow Records would be more 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 from the
following two Information Elements, collected from two different
Observation Points:
- Packet arrival time: observationTimeMicroseconds [RFC5477]
- Packet ID: digestHashValue [RFC5477]
Ideally, the measurement at the second Observation Point should
start a little bit later than at the first Observation Point,
allowing the packets to arrive at the destination. In practice,
this implies that many pairs of (observationTimeMicroseconds,
digestHashValue) must be exported for each Observation Point, even
if some optimization based on Hash-Based Filtering [RFC5475] is
used. Instead of exporting repetitive information as part of
every single Flow Record (for example, the 5 tuple), an optimized
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
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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 C8. for a specific example related to
this case study.
3.3. The Proposal
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
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types called basicList, subTemplateList, and subTemplateMultiList.
These are defined in Section 4.1.
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.
4. Linkage with the Information Model
As in the IPFIX Protocol specification [RFC5101], the new
Information Elements specified in Section 4.3. below 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 single Information Element, primarily used for single-
valued data types. For example, 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. For example, 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, a
structured data type composed of multiple pairs of IP address,
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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. For example, 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, as described
below.
4.2.1. List
A list represents an arbitrary-length sequence of structured data
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. For example, a list of
port numbers, a list of interface indexes, etc.
EDITOR'S NOTE: while waiting for IANA to assign this new
Information Element identifier, the value XXX is used in all the
examples.
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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.
EDITOR'S NOTE: while waiting for IANA to assign this new
Information Element identifier, the value YYY is used in all the
examples.
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.
EDITOR'S NOTE: while waiting for IANA to assign this new
Information Element identifier, the value ZZZ is used in all the
examples.
4.4. Encoding of IPFIX Data Types
The following sections define the encoding of the data types
defined in Section 4.1. above.
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, we RECOMMEND these are
encoded as a Variable-Length Information Element as described in
Section 7 of [RFC5101], with the length carried in one or three
octets before the Structured Data Information Element encoding.
4.4.1. 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
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| Field ID | Element Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BasicList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure A: basicList Information Element Encoding
Field ID
The Field ID is the Information Element identifier of the
Information Element(s) contained in the list.
Element Length
The Element Length indicates the length of each element or
contains the value 0xFFFF if the length is encoded as for a
variable-length Information Element.
BasicList Content
A Collection 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, the Field ID is shown with the
Enterprise bit (most significant bit) set to 0. If instead 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|1| Field ID | Element Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Enterprise Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| BasicList Content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure B: basicList Encoding with Enterprise Number
Also note that, if a basicList has zero elements, the encoded data
contains the Field ID, the Element Length and the four-byte
Enterprise Number (if present); the BasicList Content is empty.
The Element Length field is effectively part of a header, so even
in the case of a zero-element list with no Enterprise Number, it
MUST NOT be omitted.
If the basicList is encoded as a Variable-Length Information
Element in less than 255 octets, it is encoded with the Length 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (< 255)| basicList Information Element |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... continuing as needed |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure C: Variable-Length basicList Information Element Encoding
(Length < 255 octets)
If the basicList is encoded as a Variable-Length Information
Element in 255 or more octets, it is encoded with the Length 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) | ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| basicList Information Element |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure D: Variable-Length basicList Information Element Encoding
(Length 0 to 65535 octets)
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4.4.2. subTemplateList
The subTemplateList Information Element represents a list of zero
or more instances of Template data. 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID | SubTemplateList Content |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure E: subTemplateList Encoding
Template ID
The Template ID is the ID of the template used to encode and
decode the SubTemplateList Content.
SubTemplateList Content
The SubTemplateList Content consists of zero or more instances
of Data Records corresponding to the Template ID. A
Collecting Process decodes the Data Records 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 just the Template ID; the SubTemplateList Content is
empty.
If the subTemplateList is encoded as a Variable-Length Information
Element in less than 255 octets, it is encoded with the Length per
Section 7 of [RFC5101] as follows:
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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)| subTemplateList Information Element |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... continuing as needed |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure F: Variable-Length subTemplateList Information Element
Encoding (Length < 255 octets)
If the subTemplateList is encoded as a Variable-Length Information
Element in 255 or more octets, it is encoded with the Length 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) | ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... SubTemplateList continuing as needed |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure G: Variable-Length subTemplateList Information Element
Encoding (Length 0 to 65535 octets)
4.4.3. subTemplateMultiList
Whereas each top-level element in a subTemplateList Information
Element corresponds with a single Template ID and therefore has
the same data type, sometimes it is useful for a list to contain
elements of more than one data type. To support this case, each
top-level element in a subTemplateMultiList Information Element
carries a Template ID and Length. The following diagram shows how
a subTemplateMultiList Information Element is encoded within a
Data Record. Note that the subTemplateMultiList encoding is
consistent with 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element 1 Template Id | Element 1 Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element 1 Content ... |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element 2 Template Id | Element 2 Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element 2 content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element N Template Id | Element N Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Element N content ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure H: subTemplateMultiList Encoding
Element Length
The total length of the Element encoding, including the 2
bytes for the Template Id and the 2 bytes for the Element
Length field itself.
Element Template ID
Unlike the subTemplateList Information Element, each list
element contains an Element Length and Element Template ID
which specifies the encoding of the following Element Content.
Element Content
The Element Content consists of zero or more instances of Data
Records corresponding to the Element Template ID. A
Collecting Process decodes the Data Records until no further
data remains. 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 and the Length is set to
zero.
If the subTemplateMultiList is encoded as a Variable-Length
Information Element in less than 255 octets, it is encoded with
the Length per Section 7 of [RFC5101] as follows:
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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)| subTemplateMultiList Information Element |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... continuing as needed |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure I: Variable-Length subTemplateMultiList Information Element
Encoding (Length < 255 octets)
If the subTemplateMultiList is encoded as a Variable-Length
Information Element in 255 or more octets, it is encoded with the
Length 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) | IE |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... continuing as needed |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure J: Variable-Length subTemplateMultiList Information
Element 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. In
the normal case where the number and length of elements can vary
from record to record, these Information Elements are encoded as
variable-length Information Elements as described in Section 7 of
[RFC5101].
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; as a result, data may be
recursively encoded starting at a fixed offset, with the final
length only known and filled in afterwards.
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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.
An Exporting Process MUST take care when encoding such data to not
exceed the maximum allowed length of an IPFIX Message, 65535
bytes, respecting the IPFIX specifications [RFC5101] that imposes:
"The IPFIX Message Header 16-bit Length field limits the length of
an IPFIX Message to 65535 octets, including the header".
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. When encoding
recursively-defined structured data, each leaf element of the
encoded structure MUST be terminated with a zero-length element.
This implies that variable-length encoding as described in Section
7 of [RFC5101] MUST be used when such a recursive relationship
exists. Also, the Exporting Process MUST take care that, when
encoding recursively-defined structured data, to not 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, (line card A)
Router 3, (line card B)
Router 4, (line card C, interface 2)
In order to encode the PSAMP Selection Sequence Report
Interpretation [RFC5476], the mediation function must express this
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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 8.4. 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, etc., and is therefore
preferred over an alternate representation.
A subTemplateList can represent the same simple list of single-
value 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 list 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
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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.
Similarly, although a basicList of single-element subTemplateList
Information Elements can represent the same mixed-type content as
a subTemplateMultiList, a basicList instance carries four
additional bytes (Element Length and Field ID), so the
subTemplateMultiList is more compact and is therefore RECOMMENDED
in this case. The basicList is best suited for exporting
recurrence of a single Information Element.
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], or any of
the Information Elements defined in the IANA IPFIX registry.
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 Structured Data
Information Element for this purpose.
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 not be
followed for the Structured Data Information Elements.
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As specified in [RFC5101], Templates that are not used anymore
SHOULD be deleted. 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 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.
8. Structured Data Encoding Examples
The following examples are created solely for the purpose of
illustrating how the extensions proposed in this document are
encoded.
8.1. Encoding BasicList
Consider encoding a multicast flow 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:
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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 = XXX | Field Length = 0xFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure K: Encoding basicList, Template Record
The list of outgoing interfaces is represented as a basicList, 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 = 35 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ingressInterface = 9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv4Address = 192.0.2.201 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DestinationIPv4Address = 233.252.0.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | List Length = 16 |egressInterface|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|... Field Id=14| egressInterf. Field Length = 4|egressInterface|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... value 1 = 1 |egressInterface|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... value 2 = 4 |egressInterface|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... value 3 = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure L: Encoding basicList, Data Record
In the example above, the BasicList contains fixed-length elements.
To illustrate how variable-length elements would be encoded, the
same example is shown next 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 = 43 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ingressInterface = 9 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv4Address = 192.0.2.201 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DestinationIPv4Address = 233.252.0.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | List Length = 24 |0| IF_NAME ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|... FieldId=82 | Field Length = 0xFFFF | Length = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 'F' | 'E' | '0' | '/' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| '0' | Length = 7 | 'F' | 'E' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| '1' | '0' | '/' | '1' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| '0' | Length = 5 | 'F' | 'E' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| '2' | '/' | '2' |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure M: BasicList Encoding with Variable-Length Elements
8.2. Encoding subTemplateList
As explained in Section 3.2. , multiple pairs of
(observationTimeMicroseconds, digestHashValue) must be collected
from two different Observation Points to compute passively the
one-way delay across the network. This data can be exported with
an optimized Flow Record that consists of the following
attributes:
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure N: Encoding subTemplateList, Template for One-Way Delay
Metrics
The Template Record for the Optimized Flow Record is 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 = 32 octets |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 258 | Field Count = 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceIPv4Address = 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationIPv4Address = 12 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceTransportPort = 7 | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationTransportPort= 11| Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| protocolIdentifier = 4 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| subTemplateList = YYY | Field Length = 0xFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure O: Encoding subTemplateList, Template Record
The list of (observationTimeMicroseconds, digestHashValue) is
exported as a subTemplateList. The Length of the subTemplatelist
is chosen to be encoded in three bytes even though it may be less
than 255 octets.
The Data Record 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 = 258 | Length = 82 octets |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv4Address = 192.0.2.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destinationIPV4Address = 192.0.2.105 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceTransportPort = 1025 | destinationTransportPort = 80 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol = 6 | 255 | one-way metrics list len = 62 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID=257 | octets 1-2 of TimeValue1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 3-6 of TimeValue1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 7-8 of TimeValue1 | digestHashValue 1 = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 0x0x91230613 | octets 1-2 of TimeValue2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 3-6 of TimeValue2 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 7-8 of TimeValue2 | digestHashValue 2 = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 0x0x91230650 | octets 1-2 of TimeValue3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 3-6 of TimeValue3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 7-8 of TimeValue3 | digestHashValue 3 = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 0x0x91230725 | octets 1-2 of TimeValue4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 3-6 of TimeValue4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 7-8 of TimeValue4 | digestHashValue 4 = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 0x0x91230844 | octets 1-2 of TimeValue5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 3-6 of TimeValue5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... octets 7-8 of TimeValue5 | digestHashValue 5 = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 0x0x91230978 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure P: Encoding subTemplateList, Data Set
8.3. Encoding subTemplateMultiList
As explained in Section 4.4.3. , 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 Flow Record with the following
attributes:
5 tuple (Flow Keys), octetCount, packetCount
attributes for classification
selectorId,
selectorAlgorithm
attributes for sampling
selectorId,
selectorAlgorithm,
samplingPacketInterval,
samplingPacketSpace
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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 classification
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
be sampled.
A subTemplateMultiList is best suited for exporting this variable
data. A Template is defined for classification attributes and
another Template is defined for sampling attributes. A Flow Record
can contain data corresponding to either of the Templates, both or
none.
Consider the example below where the following Flow Record contains
both classification and sampling attributes.
Key attributes of the Flow Record:
------------------------------------------------------------------
srcIP | dstIP | src | dst |proto|octetCount|packet
| | Port | Port | | |Count
------------------------------------------------------------------
192.0.2.1 192.0.2.105 1025 80 6 108000 120
------------------------------------------------------------------
Classification 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
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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 Flow Record, the following Template Records are
defined:
Template for classification attributes: 259
Template for sampling attributes: 260
Template for Flow Record: 261
Flow record (261)
| (sourceIPv4Address)
| (destinationIPv4Address)
| (sourceTransportPort)
| (destinationTransportPort)
| (protocolIdentifier)
| (octetTotalCount)
| (packetTotalCount)
|
+------ classification attributes (259)
| (selectorId)
| (selectorAlgorithm)
|
+------ sampling attributes (260)
| (selectorId)
| (selectorAlgorithm)
| (samplingPacketInterval)
| (samplingPacketSpace)
The following Template Record is defined for classification
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
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Set ID = 2 | Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 259 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| selectorId = 302 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| selectorAlgorithm = 304 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure Q: Encoding subTemplateMultiList, Template for
Classification Attributes
Note that while selectorId is defined as unsigned64, it is
compressed down to 4 octet here as allowed by Reduced Size
Encoding in Section 6.2 of the IPFIX protocol specifications
[RFC5101].
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| samplingPacketInteval = 305 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| samplingPacketSpace = 306 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure R: Encoding subTemplateMultiList, Template for Sampling
Attributes
Note that while 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].
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Note that while selectorId is defined as unsigned64, it is
compressed down to 4 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| sourceIPv4Address = 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationIPv4Address = 12 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|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 = ZZZ | Field Length = 0XFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure S: Encoding subTemplateMultiList, Template for Flow Record
A subTemplateMultiList is used to export the classification and
sampling attributes. The Length 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 = 48 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv4Address = 192.0.2.1 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destinationIPv4Address = 192.0.2.105 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceTransportPort = 1025 | destinationTransportPort = 80 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| protocol = 6 | octetTotalCount = 108000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | packetTotalCount = 120 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | 255 | Attributes List Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Classify Template ID = 259 | Classif. Attributes Length = 9|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| selectorId = 100 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|selectorAlg = 5| Sampling Template ID = 260 |Sampling Attr.|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length = 11 | selectorId = 15 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |selectorAlg = 1| Interval = 1 | Space = 99 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure T: Encoding subTemplateMultiList, Data Set
8.4. Encoding an Options Template Set using Structured Data
As described in Section 5.3. , consider a mediation function that
must aggregate Data Records from multiple different Observation
Points.
Say Observation Point 1 consists of one or more interfaces,
Observation Points 2 and 3 consist of one or more line cards, and
Observation Point 4 consists of one or more interfaces and one or
more line cards. Without the support for 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 the support for structured data, a
basicList can be used to encode the list of interfaces and another
basicList can be used to encode the list of line cards.
For the sake of simplicity, each Observation Point shown below has
an <interface> or <linecard> or <line card and interface>. This
can very well be extended to include a list of interfaces and a
list of linecards using basicLists as explained above.
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Observation Point 1: Router 1, (interface 1)
Observation Point 2: Router 2, (line card A)
Observation Point 3: Router 3, (line card B)
Observation Point 4: Router 4, (line card 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, (interface 1)
Router 2, (line card A)
Router 3, (line card B)
Router 4, (line card 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)
| (Interface Id)
|
+--- Observation Point 2 and 3 (264)
| (line card)
|
+--- Observation Point 4 (265)
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| (line card)
| (Interface Id)
|
| (selectorId 1)
| (selectorId 2)
Figure U: 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 = ZZZ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 0xFFFF |0| selectorId = 302 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 4 |0| selectorId = 302 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure V: Options Template Record for PSAMP SSRI using
subTemplateMultiList
The subTemplateMultiList 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 = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 263 | Field Count = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| ingressInterface = 10 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure W: PSAMP SSRI, Template Record for interface
0 1 2 3
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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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 264 | Field Count = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| lineCardId = 141 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure X: 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 = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 265 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| lineCardId = 141 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| ingressInterface = 10 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure Y: PSAMP SSRI, Template Record for linecard and 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 = 262 | Length = 51 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| selectionSequenceId = 7 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | Observation Point List Len=32 | OP1_Template |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|... ID = 263 | OP1 Length = 8 | ingress ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... Interface = 1 | OP2,3 Template|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|... ID = 264 | OP2,3 Length = 12 |lineCardId=A...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...lineCardId = A |lineCardId=B...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...lineCardId = B |OP4 Template...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|... ID = 265 | OP4 Length = 12 |lineCardId=C...|
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...lineCardId = C | ingress ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ...Interface = 2 |selectorID ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| selectorId = 5 |selectorID ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| selectorId = 10 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure Z: 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 (line card A) and
Observation Point 3 (line card B). Instead, if a single
Observation Point had both line card A and line card B, a
basicList would be used to represent the list of line cards.
9. Relationship with the Other IFPIX Documents
9.1. 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 defines the commonPropertiesID Information Element for
exporting Common Properties.
9.1.1. 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.
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9.1.2. Encoding Common Properties elements With Structured Data
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 ZA: 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> |
+------------------------+---------------------------+
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Figure ZB: Common and Specific Properties Exported Separately
according to [RFC5473]
+----------------+-------------+---------------------------+
| sourceAddressA | sourcePortA | <Flow1 information> |
+----------------+-------------+---------------------------+
| <Flow2 information> |
+---------------------------+
| <Flow3 information> |
+---------------------------+
| <Flow4 information> |
+---------------------------+
| ... |
+---------------------------+
Figure ZC: Common and Specific Properties Exported with
Structured Data Information Element
The example in figure ZC 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 Collectors job in term of Template
management and combining Template/Options Template Records is
simplified.
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.
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9.2. 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 B.
. 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
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- 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.
9.3. Relationship with Bidirectional Flow Export
[RFC5103] describes a method for exporting bidirectional flow
information, and defines the biflowDirection Information Element
for this purpose.
[RFC5103] Biflows may be encoded in a subTemplateList or
subTemplateMultiList. The basicList requires recurrence of a
single element, so is not suitable for Biflows.
Encoding Biflows with subTemplateList or subTemplateMultiList
provides a more logical division of the information in both
directions, although this encoding incurs a small additional
bandwidth penalty.
An example of Biflow encoding using Structure Data Information
Elements and comparison with the [RFC5103] Biflow encoding is
shown in Appendix B.
9.4. Relationship with IPFIX Mediation Function
The Structured Data Information Elements would be beneficial for
the export of aggregated Data Records in mediation function, as
it was demonstrated with the example of the aggregated
Observation Point in Section 5.3.
10. IANA Considerations
This document specifies several new IPFIX abstract data types, a
new IPFIX Data Type Semantic, and several new Information
Elements.
These require the creation of two new IPFIX registries and
updating the existing IPFIX Information Element registry as
detailed below.
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10.1. 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. This requires creation of a new IPFIX
"abstract data types" registry at
http://www.iana.org/assignments/ipfix. This registry should
include all the abstract data types from Section 3.1 of [RFC5102].
Abstract data types to be added to the IPFIX "abstract data types"
registry are listed below.
10.1.1. basicList
The type "basicList" represents a list of any Information Element
used for single-valued data types.
10.1.2. 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.
10.1.3. 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.
10.2. 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. This requires creation of a new IPFIX "data
types semantics" registry at
http://www.iana.org/assignments/ipfix. This registry should
include all the data type semantics from Section 3.2 of [RFC5102].
Data type semantics to be added to the IPFIX "data types
semantics" registry are listed below.
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10.2.1. list
A list is a structured data type, being composed of a sequence of
elements e.g. Information Element, Template Record, etc.
10.3. New Information Elements
Section 4.3. of this document specifies several new Information
Elements which are to be created in the IPFIX Information Element
registry located at http://www.iana.org/assignments/ipfix.
New Information Elements to be added to the IPFIX Information
Element registry are listed below.
10.3.1. basicList
Name: basicList
Description:
Specifies a generic Information Element with a basicList abstract
data type. For example, a list of port numbers, a list of
interface indexes, etc.
Abstract Data Type: basicList
Data Type Semantics: list
ElementId: XXX (to be specified)
Status: current
10.3.2. subTemplateList
Name: subTemplateList
Description:
Specifies a generic Information Element with a subTemplateList
abstract data type.
Abstract Data Type: subTemplateList
Data Type Semantics: list
ElementId: YYY (to be specified)
Status: current
10.3.3. subTemplateMultiList
Name: subTemplateMultiList
Description:
Specifies a generic Information Element with a
subTemplateMultiList abstract data type.
Abstract Data Type: subTemplateMultiList
Data Type Semantics: list
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ElementId: ZZZ (to be specified)
Status: current
11. Security Considerations
The same security considerations as for the IPFIX Protocol
[RFC5101] apply.
12. References
12.1. Normative References
[RFC2119] S. Bradner, 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.
12.2. Informative References
[RFC3917] Quittek, J., Zseby, T., Claise, B., and S. Zander,
Requirements for IP Flow Information Export, 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.
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[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., "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.
13. Acknowledgement
The authors would like to thank Zhipu Jin, Nagaraj Varadharajan,
Brian Trammel, and Atsushi Kobayashi for their feedback.
14. 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, Virigina 20171
United States
Phone: +1 408 853 0480
EMail: gowri@cisco.com
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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
Paul Aitken
Cisco Systems (Scotland) Ltd.
96 Commercial Quay
Commercial Street
Edinburgh, EH6 6LX, United Kingdom
Phone: +44 131 561 3616
EMail: paitken@cisco.com
Appendix A. XML Specification of IPFIX Information Elements and
Abstract Data Types
<fieldDefinitions xmlns="urn:ietf:params:xml:ns:ipfix-info"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="urn:ietf:params:xml:ns:ipfix-info
ipfix-info.xsd">
<field name="basicList"
dataType="basicList"
group="structured-data"
dataTypeSemantics="List"
elementId="XXX" applicability="all" status="current">
<description>
<paragraph>
Represents a list of zero or more instances of
any single Information Element, primarily used for
single-valued data types. For example, a list of port
numbers, a list of interface indexes, a list of AS in a
BGP AS-PATH, etc.
</paragraph>
</description>
</field>
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<field name="subTemplateList"
dataType="subTemplateList"
group="structured-data"
dataTypeSemantics="List"
elementId="XXX" 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. For example, 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, a structured data
type composed of multiple pairs of IP address, etc.
</paragraph>
</description>
</field>
<field name="subTemplateMultiList"
dataType="subTemplateMultiList"
group="structured-data"
dataTypeSemantics="List"
elementId="XXX" 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. For example, a structured
data type composed of multiple access-list entries, where
entries can be composed of different criteria types.
</paragraph>
</description>
</field>
</fieldDefinitions>
<schema targetNamespace="urn:ietf:params:xml:ns:ipfix-info"
xmlns:ipfix="urn:ietf:params:xml:ns:ipfix-info"
xmlns="http://www.w3.org/2001/XMLSchema"
elementFormDefault="qualified">
<simpleType name="dataType">
<restriction base="string">
<enumeration value="basicList">
<annotation>
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<documentation>
Represents a list of zero or more instances of
any single Information Element, primarily used for
single-valued data types. For example, a list of port
numbers, a list of interface indexes, a list of AS in
a BGP AS-PATH, etc.
</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. For example, 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, a
structured data type composed of multiple pairs of IP
address, etc.
</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. For example, 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
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Elements or composed of data conforming to a Template
Record.
</documentation>
</annotation>
</enumeration>
</restriction>
</simpleType>
</schema>
Appendix B. Example of Biflow Encoding using Structured Data
Information Elements
Referring to [RFC5103] figure 1, a Biflow consists of two parts:
some "key" fields such as src/dst information (IP addresses,
ports), followed by a set of forward/reverse pairs.
Then looking at [RFC5103] figure 7, we see that the Reverse PEN
is repeated many times to indicate fields which were observed in
the reverse direction. Clearly that repetition is wasteful.
Looking back at [RFC5103] figure 1, it's clear that the encoding
can use a Template Record consisting of the Flow Keys followed
by a subTemplateList consisting of two elements: one for the
forward direction, the other for the reverse direction.
The subTemplateList uses a single Template Record to describe
the fields in both lists since they are a set of forward/reverse
pairs.
Uniflow Uniflow
+-------+-------+-----------------+ +-------+-------+-----------------+
| src A | dst B | counters/values | | src B | dst A | counters/values |
+-------+-------+-----------------+ +-------+-------+-----------------+
| | | |
V V V V
+-------+-------+---------------------+---------------------+
| src A | dst B | fwd counters/values | rev counters/values |
+-------+-------+---------------------+---------------------+
| | |
V V V
key fields fwd element rev element
Figure B0: Using a subTemplateList to represent a Biflow.
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The following example shows the example from Appendix A of
[RFC5103] encoded using a subTemplateList:
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 = 266 | Field Count = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| flowDirection 61 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| flowStartSeconds 150 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| octetTotalCount 85 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| packetTotalCount 86 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure B1: Template for the Biflow Fields
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 = 32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 267 | Field Count = 6 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceIPv4Address 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationIPv4Address 12 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceTransportPort 7 | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationTransportPort 11 | Field Length = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| protocolIdentifier 4 | Field Length = 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| subTemplateList = YYY | Field Length = 28 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure B2: Template for the Key Fields
The Template Record includes a subTemplateList for encoding the
BiFlow fields for the forward and reverse direction. Note that
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the subTemplateList is encoded using Fixed Length, as shown in the
above template definition.
Also, note that the overall template size is 24 + 32 = 56 octets,
compared with 64 octets in the [RFC5103] example - so a small
saving is achieved.
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 = 267 | Length = 45 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceIPv4Address = 192.0.2.2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destinationIPv4Address = 192.0.2.3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sourceTransportPort = 32770 | destinationTransportPort = 80 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| protocol = 6 | Template ID = 266 | dir = forward |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| flowStartSeconds = 2006-02-01 17:00:00 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| octetTotalCount = 18000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| packetTotalCount = 65 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| dir = reverse | flowStartSeconds = 2006-02-01 17:00:01 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | octetTotalCount = 128000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... | packetTotalCount = 110 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+
Figure B3: Biflow Data Set Encoded using Structured Data
Note that the Data Set length is 45, compared with 41 in RFC5103.
The four additional octets are due to the inclusion of the 16-bit
Template ID and two, 8-bit direction indicators.
Clearly structured data offers an alternative way to encode
Biflows. Although this may not be best suited if the number of
elements is small as in this example, it does offer a more robust
and scalable solution if multiple elements need to be encoded.
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Appendix C. Encoding IPS Alert using Structured Data Information
Elements
In this section, a contrived example of an IPS alert is used to
demonstrate how complex data and multiple levels of hierarchy can
be encoded using Structured Data Information Elements.
An IPS alert consists of the following mandatory attributes:
signatureId, protocolIdentifier and riskRating. It can also
contain zero or more participants, 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 attribute destinationIPv4Address and zero or
more occurrences of the attribute 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 following contrived example of an IPS alert. The
participant can contain attackers and targets in any order and the
sequence conveys some information to the Collector and needs to be
preserved. In the example below, we have attacker1 A1, target T1
and attacker A2 and this is encoded as a subTemplateMultiList.
------------------------------------------------------------------
| | | participant
sigId |protocol| risk | attacker | target
| Id | Rating | IP | appId | IP | appId(s)
------------------------------------------------------------------
1003 17 10 192.0.2.3 103 192.0.2.103 3001, 3002
192.0.2.4 104
------------------------------------------------------------------
Where attacker A1 is: (IP, appID)=(192.0.2.3, 103)
Where attacker A2 is: (IP, appID)=(192.0.2.4, 104)
Where target T1 is: (IP, appID)= (192.0.2.103, (3001, 3002))
To represent an alert, the following Templates are defined:
Template for target (268)
Template for attacker (269)
Template for participant (27)
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Template for alert (271)
alert (271)
| (signatureId)
| (protocolIdentifier)
| (riskRating)
|
+------- participant (270)
|
+------- attacker (269)
| (sourceIPv4Address)
| (applicationId)
|
+------- target (268)
| (destinationIPv4Address)
| (list of applicationId)
Note that the attackers are always composed of a single
applicationId, while the targets typically have multiple
applicationId.
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| basicList = XXX | Field Length = 0xFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure C0: Encoding IPS Alert, Template for Target
The list of applicationId in the target Template Record is
represented as a basicList.
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 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 269 | Field Count = 2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| sourceIPv4Address = 8 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| applicationId = 95 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure C1: 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| subTemplateMultiList = ZZZ | Field Length = 0xFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure C2: Encoding IPS Alert, Template for Participant
The Template Record for the participant has one
subTemplateMultiList Information Element, which is a list that can
include attackers and targets repeated in any order.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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|0| subTemplateList = YYY | Field Length = 0xFFFF |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure C3: Encoding IPS Alert, Template for IPS Alert
The subTemplateList in the alert Template Record contains a list
of participants. For the sake of simplicity, only one participant
is shown in the Data Set.
Note that a subTemplateList is used to encode the list of
participants. Each participant contains the list of attackers and
targets encoded using a subTemplateMultiList and a target contains
a basicList for encoding the list of applications.
The Length of basicList, subTemplateList and subTemplateMultiList
are 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 = 271 | Length = 63 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| signatureId = 1003 | protocolId=17 | riskRating=10 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 |participant List Length = 52 |participant ...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Template ID=270| 255 |subTemplateMultiList Length=47 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| attacker1 Template ID = 269 | attacker1 Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| attacker1 sourceIPv4Address = 192.0.2.3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| attacker1 applicationId = 103 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| target1 Template ID = 268 | Target1 Length = 23 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| target1 destinationIPv4Address = 192.0.2.103 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 255 | target1 appId List Length=12 |target1 appId..|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Field ID = 95 | target1 appId Field ID Len = 4|target1 appId =|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 3001 |target1 appId =|
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... 3002 | attacker2 ...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Template ID=269| attacker2 Length = 12 | attacker2 ...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... sourceIPv4Address = 192.0.2.4 | attacker2 ...|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... applicationId = 104 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure C4: Encoding IPS Alert, Data Set
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