Internet DRAFT - draft-ietf-opsawg-tsvwg-udp-ipfix
draft-ietf-opsawg-tsvwg-udp-ipfix
OPSAWG M. Boucadair
Internet-Draft Orange
Intended status: Standards Track T. Reddy.K
Expires: 26 July 2024 Nokia
23 January 2024
Export of UDP Options Information in IP Flow Information Export (IPFIX)
draft-ietf-opsawg-tsvwg-udp-ipfix-07
Abstract
This document specifies new IP Flow Information Export (IPFIX)
Information Elements for UDP options.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the Operations and
Management Area Working Group Working Group mailing list
(opsawg@ietf.org), which is archived at
https://mailarchive.ietf.org/arch/browse/opsawg/.
Source for this draft and an issue tracker can be found at
https://github.com/boucadair/udp-ipfix.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on 26 July 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3
3. UDP Options at a Glance . . . . . . . . . . . . . . . . . . . 3
4. New UDP IPFIX Information Elements . . . . . . . . . . . . . 4
4.1. udpOptions . . . . . . . . . . . . . . . . . . . . . . . 4
4.2. udpSafeExperimentalOptionExID . . . . . . . . . . . . . . 5
4.3. udpUnsafeExperimentalOptionExID . . . . . . . . . . . . . 5
5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Normative References . . . . . . . . . . . . . . . . . . 8
8.2. Informative References . . . . . . . . . . . . . . . . . 8
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
IP Flow Information Export (IPFIX) [RFC7011] is a protocol that is
widely deployed in operators networks for traffic management
purposes. The protocol specifies the encoding of a set of basic data
types and how the various Information Elements (IEs) are transmitted.
In order to support the export of new flow-related measurement data,
new IEs can be defined and registered in a dedicated IANA registry
[IANA-IPFIX] for interoperability.
This document specifies new IPFIX Information Elements for UDP
options (Section 4). A brief overview of UDP options is provided in
Section 3.
The IE specified in Section 4.1 uses the new abstract data type
defined in [I-D.ietf-opsawg-ipfix-tcpo-v6eh].
Examples to illustrate the use of the new IPFIX Information Elements
are provided in Section 5.
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2. Conventions and Definitions
This document uses the IPFIX-specific terminology (e.g., Flow)
defined in Section 2 of [RFC7011]. As in [RFC7011], these IPFIX-
specific terms have the first letter of a word capitalized.
Also, this document uses the terms defined in Section 3 of
[I-D.ietf-tsvwg-udp-options].
3. UDP Options at a Glance
UDP [RFC0768] does not support an extension mechanism similar to the
options supported by other transport protocols, such as TCP
[RFC9293], SCTP [RFC9260], or DCCP [RFC4340]. Such a mechanism can
be useful for various applications, e.g., discover a path MTU or
share timestamps. To fill that void, [I-D.ietf-tsvwg-udp-options]
extends UDP with a mechanism to insert extensions in datagrams. To
do so, and unlike the conventional approach that relies upon
transport headers, [I-D.ietf-tsvwg-udp-options] uses trailers.
Concretely, UDP options are placed in the surplus area (that is, the
area of an IP payload that follows a UDP packet). See Figure 1. An
example of the use of UDP options is described in
[I-D.ietf-tsvwg-udp-options-dplpmtud].
IP transport payload
<------------------------------------------------->
+--------+---------+----------------------+------------------+
| IP Hdr | UDP Hdr | UDP user data | surplus area |
+--------+---------+----------------------+------------------+
<------------------------------>
UDP Length
Figure 1: Surplus Area
Section 4.1 introduces a new IE to export the observed UDP options.
Options indicated by Kind values in the range 0-191 are called SAFE
options. Such options can be silently ignored by legacy receivers
because they do not alter the UDP user data (Section 11 of
[I-D.ietf-tsvwg-udp-options]).
Options indicated by Kind values in the range 192-255 are called
UNSAFE options. Such options are not safe for legacy receivers to
ignore because they alter the UDP user data (Section 12 of
[I-D.ietf-tsvwg-udp-options]).
UDP options occur per-packet within a Flow and can be inserted at any
time in the Flow.
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[I-D.ietf-tsvwg-udp-options] reserves two options for experiments:
the Experimental option (EXP, Kind=127) for SAFE options and the
UNSAFE Experimental option (UEXP, Kind=254). For both options,
Experimental ID (ExIDs) are used to differentiate concurrent use of
these options. Known ExIDs are expected to be registered within
IANA. Section 4.2 specifies a new IPFIX IE to export observed ExIDs
in the EXP options. Also, Section 4.3 specifies a new IPFIX IE to
export observed ExIDs in the UEXP options. Only 16-bit ExIDs are
supported in [I-D.ietf-tsvwg-udp-options].
This document does not intend to elaborate operational guidance/
implications of UDP options. The document focuses exclusively on
exporting observed UDP options in datagrams.
4. New UDP IPFIX Information Elements
Note: "URL_IANA_UDP_OPTIONS" is the URL of the "UDP Option Kind
Numbers" registry group while "URL_IANA_UDP_ExIDs" is the URL of
the "UDP Experimental Option Experiment Identifiers (UDP ExIDs)"
registry that will be created by IANA as per Section 25 of
[I-D.ietf-tsvwg-udp-options].
4.1. udpOptions
Name: udpOptions
ElementID: TBD1
Description: Observed UDP options in a Flow. The information is
encoded in a set of bit fields.
Options are mapped to bits according to their option numbers. UDP
option kind 0 corresponds to the least-significant bit in the
udpOptions IE while kind 255 corresponds to the most-significant
bit of the IE. A bit is set to 1 if the corresponding UDP option
is observed in the Flow. The bit is set to 0 if the option is not
observed in the Flow.
To cover the 0-255 kind range, up to 256 flags can be set in the
value field. The reduced-size encoding specified in Section 6.2
of [RFC7011] is followed whenever fewer octets are needed to
report observed UDP options. For example, if only option kinds <=
32 are observed, then the value can be encoded as unsigned32, or
if only option kinds <= 63 are observed, then the value can be
encoded as unsigned64.
Abstract Data Type: unsigned256
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Data Type Semantics: flags
Additional Information: See the assigned UDP options in the "UDP
Option Kind Numbers" registry at [URL_IANA_UDP_OPTIONS].
See [I-D.ietf-tsvwg-udp-options] for more details about UDP
options.
Reference: This-Document
4.2. udpSafeExperimentalOptionExID
Name: udpSafeExperimentalOptionExID
ElementID: TBD2
Description: Observed Experiments ID (ExIDs) in the Experimental
option (EXP, Kind=127).
The information is encoded in a set of 16-bit fields. Each 16-bit
field carries the observed ExID in an EXP option.
Abstract Data Type: octetArray
Data Type Semantics: identifier
Additional Information: See the assignments in the "UDP Experimental
Option Experiment Identifiers (UDP ExIDs)" registry at
[URL_IANA_UDP_ExIDs].
See [I-D.ietf-tsvwg-udp-options] for more details about ExIDs.
Reference: This-Document
4.3. udpUnsafeExperimentalOptionExID
Name: udpUnsafeExperimentalOptionExID
ElementID: TBD3
Description: Observed Experiments ID (ExIDs) in the UNSAFE
Experimental option (UEXP, Kind=254).
The information is encoded in a set of 16-bit fields. Each 16-bit
field carries the observed ExID in an UEXP option.
Abstract Data Type: octetArray
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Data Type Semantics: identifier
Additional Information: See the assignments in the "UDP Experimental
Option Experiment Identifiers (UDP ExIDs)" registry at
[URL_IANA_UDP_ExIDs].
See [I-D.ietf-tsvwg-udp-options] for more details about ExIDs.
Reference: This-Document
5. Examples
Given UDP kind allocation in Section 10 of
[I-D.ietf-tsvwg-udp-options] and the option mapping defined in
Section 4.1 of this document, fewer octets are likely to be used for
Flows with mandatory UDP options.
Figure 2 shows an example of reported values in a udpOptions IE for a
Flow in which End of Options List (EOL) and Alternate payload
checksum (APC) options are observed. One octet is sufficient to
report these observed options. Concretely, the reported udpOptions
IE will be set to 0x05.
MSB LSB
1 25
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 ... 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+...+-+-+-+-+-+-+-+-+
|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0|0| |0|0|0|0|0|1|0|1|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-++-+-+-+-+...+-+-+-+-+-+-+-+-+
Figure 2: An Example of udpOptions IE
Let us now consider a UDP Flow in which both SAFE and UNSAFE
Experimental options are observed. Let us also consider that the
observed SAFE Experimental options have ExIDs set to 0x9858 and
0xE2D4, and UNSAFE Experimental options have ExIDs set to 0xC3D9 and
0x9858. As shown in Figure 3, the following IEs are used to report
these observed ExIDs:
1. udpSafeExperimentalOptionExID IE set to 0x9858E2D4 to report
observed ExIDs of SAFE Experimental options.
2. udpUnsafeExperimentalOptionExID IE set to 0xC3D99658 to report
the ExIDs of the observed UNSAFE Experimental options.
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udpSafeExperimentalOptionExID IE:
MSB LSB
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0x9858 | 0xE2D4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
udpUnsafeExperimentalOptionExID IE:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0xC3D9 | 0x9658 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Example of UDP Experimental option IEs
6. Security Considerations
This document does not introduce new security considerations other
than those already discussed in Section 8 of [RFC7012].
The reader may refer to Section 22 of [I-D.ietf-tsvwg-udp-options]
for the security considerations related to UDP options.
7. IANA Considerations
This document requests IANA to add the following new IEs to the IANA
registry entitled "IP Flow Information Export (IPFIX) Entities"
[IANA-IPFIX]:
+=======+=================================+================+
| Value | Name | Reference |
+=======+=================================+================+
| TBD1 | udpOptions | Section 4.1 of |
| | | This-Document |
+-------+---------------------------------+----------------+
| TBD2 | udpSafeExperimentalOptionExID | Section 4.2 of |
| | | This-Document |
+-------+---------------------------------+----------------+
| TBD3 | udpUnsafeExperimentalOptionExID | Section 4.3 of |
| | | This-Document |
+-------+---------------------------------+----------------+
Table 1: New IPFIX Information Elements
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8. References
8.1. Normative References
[I-D.ietf-tsvwg-udp-options]
Touch, J. D., "Transport Options for UDP", Work in
Progress, Internet-Draft, draft-ietf-tsvwg-udp-options-28,
17 November 2023, <https://datatracker.ietf.org/doc/html/
draft-ietf-tsvwg-udp-options-28>.
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/rfc/rfc768>.
[RFC7011] Claise, B., Ed., Trammell, B., Ed., and P. Aitken,
"Specification of the IP Flow Information Export (IPFIX)
Protocol for the Exchange of Flow Information", STD 77,
RFC 7011, DOI 10.17487/RFC7011, September 2013,
<https://www.rfc-editor.org/rfc/rfc7011>.
[RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model
for IP Flow Information Export (IPFIX)", RFC 7012,
DOI 10.17487/RFC7012, September 2013,
<https://www.rfc-editor.org/rfc/rfc7012>.
8.2. Informative References
[I-D.ietf-opsawg-ipfix-tcpo-v6eh]
Boucadair, M. and B. Claise, "Extended TCP Options and
IPv6 Extension Headers IPFIX Information Elements", Work
in Progress, Internet-Draft, draft-ietf-opsawg-ipfix-tcpo-
v6eh-08, 17 January 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-
ipfix-tcpo-v6eh-08>.
[I-D.ietf-tsvwg-udp-options-dplpmtud]
Fairhurst, G. and T. Jones, "Datagram PLPMTUD for UDP
Options", Work in Progress, Internet-Draft, draft-ietf-
tsvwg-udp-options-dplpmtud-11, 4 January 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-tsvwg-
udp-options-dplpmtud-11>.
[IANA-IPFIX]
"IP Flow Information Export (IPFIX) Entities", n.d.,
<https://www.iana.org/assignments/ipfix/ipfix.xhtml>.
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[RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram
Congestion Control Protocol (DCCP)", RFC 4340,
DOI 10.17487/RFC4340, March 2006,
<https://www.rfc-editor.org/rfc/rfc4340>.
[RFC9260] Stewart, R., Tüxen, M., and K. Nielsen, "Stream Control
Transmission Protocol", RFC 9260, DOI 10.17487/RFC9260,
June 2022, <https://www.rfc-editor.org/rfc/rfc9260>.
[RFC9293] Eddy, W., Ed., "Transmission Control Protocol (TCP)",
STD 7, RFC 9293, DOI 10.17487/RFC9293, August 2022,
<https://www.rfc-editor.org/rfc/rfc9293>.
Acknowledgments
Thanks to Benoît Claise for the discussion on the ordering of IPFIX
IEs. Thanks to Paul Aitken for the review and comments.
Thanks to Tommy Pauly for the tsvart review and Joe Touch for the
intdir review.
Thanks to Thomas Graf for the Shepherd review.
Authors' Addresses
Mohamed Boucadair
Orange
35000 Rennes
France
Email: mohamed.boucadair@orange.com
Tirumaleswar Reddy.K
Nokia
India
Email: kondtir@gmail.com
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