OPSAWG M. Boucadair
Internet-Draft Orange
Intended status: Standards Track T. Reddy.K
Expires: 4 August 2023 Nokia
31 January 2023
Export of UDP Options Information in IP Flow Information Export (IPFIX)
draft-boucadair-opsawg-tsvwg-udp-ipfix-04
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 4 August 2023.
Copyright Notice
Copyright (c) 2023 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 . . . . . . . . . . . . . . . . . 2
3. UDP Options at a Glance . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
5.1. udpOptions . . . . . . . . . . . . . . . . . . . . . . . 4
5.2. udpExID . . . . . . . . . . . . . . . . . . . . . . . . . 5
5.3. udpUnsafeExID . . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 6
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
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 5). A brief overview of UDP option is provided in
Section 3.
2. Conventions and Definitions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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This document uses the terms defined in Section 3 of
[I-D.ietf-tsvwg-udp-options] and [RFC7011].
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 5.1 introduces a new IE to export the observed UDP options.
Options indicated by Kind values in the range 0-191 are called SAFE
options because they do not alter the UDP data payload. Such options
can be silently ignored by receivers without affecting the meaning of
the UDP user data (Section 9 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 to ignore (Section 10 of
[I-D.ietf-tsvwg-udp-options]).
[I-D.ietf-tsvwg-udp-options] reserves two options for experiements:
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 5.2 specifies a new IPFIX IE to export observed ExIDs
in the EXP options. Also, Section 5.3 specifies a new IPFIX to
export observed ExIDs in the UEXP options. Only 16-bits ExIDs are
supported.
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This document does not intend to elaborate operational guidance/
implications of UDP options. The document focuses exclusively on
exporting observed UDP options in datagrams. The motivation for
exporting such data is similar to the one for exporting TCP options
(tcpOptions IE) or IPv6 Extension Headers (ipv6ExtensionHeaders).
4. Security Considerations
This document does not introduce new security considerations other
than those already discussed in [RFC7012].
The reader may refer to Section 22 of [I-D.ietf-tsvwg-udp-options]
for the security considerations related to UDP options.
5. 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].
5.1. udpOptions
* Name: udpOptions
* ElementID: TBD1
* Description: Observed UDP options of a Flow. The information is
encoded in a set of bit fields. To cover the 0-255 kind range, up
to 255 flags can be set in the value field. The 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: unsigned
* 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]
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5.2. udpExID
* Name: udpExID
* ElementID: TBD2
* Description: Observed Expermients 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]
5.3. udpUnsafeExID
* Name: udpUnsafeExID
* ElementID: TBD3
* Description: Observed Expermients 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
* 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]
6. References
6.1. Normative References
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[I-D.ietf-tsvwg-udp-options]
Touch, J. D., "Transport Options for UDP", Work in
Progress, Internet-Draft, draft-ietf-tsvwg-udp-options-19,
27 December 2022, <https://datatracker.ietf.org/doc/html/
draft-ietf-tsvwg-udp-options-19>.
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
DOI 10.17487/RFC0768, August 1980,
<https://www.rfc-editor.org/rfc/rfc768>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/rfc/rfc2119>.
[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>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>.
6.2. Informative References
[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-04, 9 September 2022,
<https://datatracker.ietf.org/doc/html/draft-ietf-tsvwg-
udp-options-dplpmtud-04>.
[IANA-IPFIX]
"IP Flow Information Export (IPFIX) Entities", n.d.,
<https://www.iana.org/assignments/ipfix/ipfix.xhtml>.
[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>.
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[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.
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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