IPFIX Working Group B. Trammell
Internet-Draft ETH Zurich
Intended status: Informational May 22, 2013
Expires: November 23, 2013
Textual Representation of IPFIX Abstract Data Types
draft-trammell-ipfix-text-adt-01.txt
Abstract
This document defines UTF-8 representations for IPFIX abstract data
types, to support interoperable usage of the IPFIX Information
Elements with protocols based on textual encodings.
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Table of Contents
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1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Identifying Information Elements . . . . . . . . . . . . . . 3
4. Data Type Encodings . . . . . . . . . . . . . . . . . . . . . 3
4.1. octetArray . . . . . . . . . . . . . . . . . . . . . . . 3
4.2. unsigned* . . . . . . . . . . . . . . . . . . . . . . . . 3
4.3. signed* . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.4. float* . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.5. boolean . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.6. macAddress . . . . . . . . . . . . . . . . . . . . . . . 6
4.7. string . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.8. dateTime* . . . . . . . . . . . . . . . . . . . . . . . . 6
4.9. ipv4Address . . . . . . . . . . . . . . . . . . . . . . . 6
4.10. ipv6Address . . . . . . . . . . . . . . . . . . . . . . . 6
4.11. basicList, subTemplateList, and subTemplateMultiList . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. Example . . . . . . . . . . . . . . . . . . . . . . 8
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
The IPFIX Information Model, as defined by the IANA IPFIX Information
Element Registry, provides a rich set of Information Elements for
description of information about network entities and network traffic
data, and abstract data types for these Information Elements. The
IPFIX Protocol Specification [I-D.ietf-ipfix-protocol-rfc5101bis], in
turn, defines a big-endian binary encoding for these abstract data
types suitable for use with the IPFIX Protocol.
However, present and future operations and management protocols and
applications may use textual encodings, and generic framing and
structure as in JSON or XML. A definition of canonical textual
encodings for the IPFIX abstract data types would allow this set of
Information Elements to be used for such applications, and for these
applications to interoperate with IPFIX applications at the
Information Element definition level.
Note that templating or other mechanisms for data description for
such applications and protocols are application specific, and
therefore out of scope for this document: only Information Element
identification and data value representation are defined here.
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2. Terminology
Capitalized terms defined in the IPFIX Protocol Specification
[I-D.ietf-ipfix-protocol-rfc5101bis] and the IPFIX Information Model
[I-D.ietf-ipfix-information-model-rfc5102bis] are used in this
document as defined in those documents. In addition, this document
defines the following terminology for its own use:
Enclosing Context
Textual representation of IPFIX data values is applied to use the
IPFIX Information Model within some existing textual format (e.g.
XML, JSON). This outer format is referred to as the Enclosing
Context within this document. Enclosing Contexts define escaping
and quoting rules for represented data values.
3. Identifying Information Elements
The IPFIX Information Element Registry [iana-ipfix-assignments]
defines a set of Information Elements and numbered by Information
Element Identifiers, and named for human-readability. These
Information Element Identifiers are meant for use with the IPFIX
protocol, and have little meaning when applying the IPFIX Information
Element Registry to textual representations.
Instead, applications using textual representations of Information
Elements SHOULD use Information Element names to identify them; see
Appendix A for examples illustrating this principle.
4. Data Type Encodings
[FIXME frontmatter]
This section uses ABNF [RFC5234], including the Core Rules in
Appendix B, to describe the format of textual representations of
IPFIX abstract data types.
4.1. octetArray
[FIXME: native hex strings for comparative human readabilty.]
4.2. unsigned*
First, in the special case that the unsigned Information Element has
identifier semantics, and refers to a set of codepoints, either in an
external registry, a sub-registry, or directly in the description of
the Information Element, then the name or short description for that
codepoint MAY be used to improve readability.
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If the Enclosing Context defines a representation for unsigned
integers, that representation SHOULD be used.
Otherwise, the values of Information Elements of an unsigned integer
type may be represented either as unprefixed base-10 (decimal)
strings, or as base-16 (hexadecimal) strings prefixed by '0x'; in
ABNF:
unsigned = 1*DIGIT / '0x' 1*HEXDIG
Leading zeroes are allowed in either encoding, and do not signify
base-8 (octal) encoding.
The encoded value must be in range for the corresponding abstract
data type or Information Element. Out of range values should be
interpreted as clipped to the implicit range for the Information
Element as defined by the abstract data type, or to the explicit
range of the Information Element if defined. Minimum and maximum
values for abstract data types are shown in Table 1 below.
+------------+---------+----------------------+
| type | minimum | maximum |
+------------+---------+----------------------+
| unsigned8 | 0 | 255 |
| unsigned16 | 0 | 65536 |
| unsigned32 | 0 | 4294967295 |
| unsigned64 | 0 | 18446744073709551615 |
+------------+---------+----------------------+
Table 1: Ranges for unsigned abstract data types
4.3. signed*
If the Enclosing Context defines a representation for signed
integers, that representation SHOULD be used.
Otherwise, the values of Information Elements of signed integer types
should be represented as optionally-prefixed base-10 (decimal)
strings. In ABNF:
sign = "+" / "-"
signed = [sign] 1*DIGIT
If the sign is omitted, it is assumed to be positive. Leading zeroes
are allowed, and do not signify base-8 (octal) encoding.
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The encoded value must be in range for the corresponding abstract
data type or Information Element. Out of range values should be
interpreted as clipped to the implicit range for the Information
Element as defined by the abstract data type, or to the explicit
range of the Information Element if defined. Minimum and maximum
values for abstract data types are shown in Table 2 below.
+----------+----------------------+----------------------+
| type | minimum | maximum |
+----------+----------------------+----------------------+
| signed8 | -128 | +127 |
| signed16 | -32768 | +32767 |
| signed32 | -2147483648 | +2147483647 |
| signed64 | -9223372036854775808 | +9223372036854775807 |
+----------+----------------------+----------------------+
Table 2: Ranges for signed abstract data types
4.4. float*
If the Enclosing Context defines a representation for floating point
numbers, that representation SHOULD be used.
Otherwise, the values of Information Elements of float32 or float64
types are represented as an optionally sign-prefixed, optionally
base-10 exponent-suffixed, floating point decimal number. In ABNF:
sign = "+" / "-"
exponent = 'e' 1*3DIGIT
right-decimal = '.' 0*DIGIT
mantissa = 1*DIGIT [right-decimal]
float = [sign] mantissa [exponent]
The expressed value is ( mantissa * 10 ^ exponent ). If the sign is
omitted, it is assumed to be positive. If the exponent is omitted,
it is assumed to be zero. Leading zeroes may appear in the mantissa
and/or the exponent.
4.5. boolean
If the Enclosing Context defines a representation for boolean values,
that representation SHOULD be used.
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Otherwise, a true boolean value should be represented with the
literal string 1, and a false boolean value with the literal string
0. In ABNF:
boolean-yes = "1"
boolean-no = "0"
boolean = boolean-yes / boolean-no
4.6. macAddress
MAC addresses are represented as IEEE 802 MAC-48 addresses,
hexadecimal bytes, most significant byte first, separated by colons.
In ABNF:
macaddress = 2*HEXDIG 5*( ":" 2*HEXDIG )
4.7. string
As Information Elements of the string type are simply UTF-8 encoded
strings, they are represented directly, subject to the escaping and
encoding rules of the Enclosing Context. If the Enclosing Context
cannot natively represent UTF-8 characters, the escaping facility
provided by the Enclosing Context must be used for non-representable
characters. Additionally, strings containing characters reserved in
the Enclosing Context (e.g. markup characters, quotes) must be
escaped or quoted according to the rules of the Enclosing Context.
4.8. dateTime*
Timestamp data types are represented as in [RFC3339].
[FIXME: elaborate, and explain precision rules]
4.9. ipv4Address
IPv4 addresses are represented in dotted-quad format, most-
significant-byte first. In ABNF:
ipv4address = 1*3DIGIT 3*( "." 1*3DIGIT )
[FIXME: elaborate]
4.10. ipv6Address
IP version 6 addresses are represented as in section 2.2 of
[RFC4291], as updated by section 4 of [RFC5952].
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[FIXME: elaborate]
4.11. basicList, subTemplateList, and subTemplateMultiList
These abstract data types, defined for IPFIX Structured Data
[RFC6313], do not represent actual data types; they are instead
designed to provide a mechanism by which complex structure below the
template level. It is assumed that protocols using textual
Information Element representation will provide their own structure.
Therefore, Information Elements of these Data Types MUST NOT be used
in textual representations.
5. Security Considerations
[FIXME: content would be nice]
6. IANA Considerations
This document has no considerations for IANA.
7. References
7.1. Normative References
[I-D.ietf-ipfix-protocol-rfc5101bis]
Claise, B. and B. Trammell, "Specification of the IP Flow
Information eXport (IPFIX) Protocol for the Exchange of
Flow Information", draft-ietf-ipfix-protocol-rfc5101bis-06
(work in progress), February 2013.
[RFC3339] Klyne, G., Ed. and C. Newman, "Date and Time on the
Internet: Timestamps", RFC 3339, July 2002.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, January 2008.
[RFC5952] Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
Address Text Representation", RFC 5952, August 2010.
[iana-ipfix-assignments]
Internet Assigned Numbers Authority, , "IP Flow
Information Export Information Elements
(http://www.iana.org/assignments/ipfix/ipfix.xml)",
November 2012.
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7.2. Informative References
[I-D.ietf-ipfix-information-model-rfc5102bis]
Claise, B. and B. Trammell, "Information Model for IP Flow
Information eXport (IPFIX)", draft-ietf-ipfix-information-
model-rfc5102bis-10 (work in progress), February 2013.
[I-D.ietf-ipfix-ie-doctors]
Trammell, B. and B. Claise, "Guidelines for Authors and
Reviewers of IPFIX Information Elements", draft-ietf-
ipfix-ie-doctors-07 (work in progress), October 2012.
[RFC6313] Claise, B., Dhandapani, G., Aitken, P., and S. Yates,
"Export of Structured Data in IP Flow Information Export
(IPFIX)", RFC 6313, July 2011.
Appendix A. Example
In this section, we examine an IPFIX Template and a Data Record
defined by that Template, and show how that Data Record would be
represented in JSON according to the specification in this document.
Note that this is specifically NOT a recommendation for a particular
representation, merely an illustration of the encodings in this
document.
[FIXME improve frontmatter] Figure 1 shows a Template in IEspec
format as defined in section 9.1 of [I-D.ietf-ipfix-ie-doctors]. A
Message containing this Template and a Data Record is shown in Figure
2, and a corresponding JSON Object using the text format defined in
this document is shown in Figure 3.
flowStartMilliseconds(152)<dateTimeMilliseconds>[8]
flowEndMilliseconds(153)<dateTimeMilliseconds>[8]
octetDeltaCount(1)<unsigned64>[4]
packetDeltaCount(2)<unsigned64>[4]
sourceIPv6Address(27)<ipv4Address>[4]{key}
destinationIPv6Address(28)<ipv4Address>[4]{key}
sourceTransportPort(7)<unsigned16>[2]{key}
destinationTransportPort(11)<unsigned16>[2]{key}
protocolIdentifier(4)<unsigned8>[1]{key}
tcpControlBits(6)<unsigned8>[1]
flowEndReason(136)<unsigned8>[1]
Figure 1: Sample flow template (IPFIX)
1 2 3 4 5 6
0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2 4 6 8 0 2
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| 0x000a | length 135 | export time 1352140263 | msg
| sequence 0 | domain 1 | hdr
| SetID 2 | length 52 | tid 256 | fields 11 | tmpl
| IE 152 | length 8 | IE 153 | length 8 | set
| IE 1 | length 4 | IE 2 | length 4 |
| IE 27 | length 16 | IE 28 | length 16 |
| IE 7 | length 2 | IE 11 | length 2 |
| IE 4 | length 1 | IE 6 | length 1 |
| IE 136 | length 1 | SetID 256 | length 83 | data
| start time 1352140261135 | set
| end time 1352140262880 |
| octets 195383 | packets 88 |
| sip6 |
| 2001:0db8:000c:1337:0000:0000:0000:0002 |
| dip6 |
| 2001:0db8:000c:1337:0000:0000:0000:0003 |
| sp 80 | dp 32991 | prt 6 | tcp 19| fe 3 |
+-------------------------------------------------------+
Figure 2: IPFIX message containing sample flow
{
"flowStartMilliseconds": "2012-11-05 18:31:01.135",
"flowEndMilliseconds": "2012-11-05 18:31:02.880",
"octetDeltaCount": 195383,
"packetDeltaCount": 88,
"sourceIPv6Address": "2001:db8:c:1337::2",
"destinationIPv6Address": "2001:db8:c:1337::3",
"sourceTransportPort": 80,
"destinationTransportPort": 32991,
"protocolIdentifier": "tcp",
"tcpControlBits": 19,
"flowEndReason": 3
}
Figure 3: JSON object containing sample flow
Author's Address
Brian Trammell
Swiss Federal Institute of Technology Zurich
Gloriastrasse 35
8092 Zurich
Switzerland
Phone: +41 44 632 70 13
Email: trammell@tik.ee.ethz.ch
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