Internet-Draft New TCP and IPv6 EH IPFIX IEs February 2023
Boucadair & Claise Expires 12 August 2023 [Page]
Intended Status:
Standards Track
M. Boucadair
B. Claise

Extended TCP Options and IPv6 Extension Headers IPFIX Information Elements


This document specifies new IPFIX Information Elements (IEs) to solve some issues with existing ipv6ExtensionHeaders and tcpOptions IPFIX IEs, especially the ability to export any observed IPv6 Extension Headers or TCP options.

Discussion Venues

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Table of Contents

1. Introduction

This document specifies new IPFIX Information Elements (IEs) to solve a set of issues encountered with the current specifications of ipv6ExtensionHeaders (for IPv6 Extension Headers (EHs)) and tcpOptions (to export TCP options). More details about these issues are provided in the following sub-sections.

1.1. ipv6ExtensionHeaders Issues

The current specification of ipv6ExtensionHeaders IPFIX IE does not:

  • Cover the full EHs range (Section 4 of [RFC8200]).
  • Specify how to automatically update the IANA IPFIX registry ([IANA-IPFIX]) when a new value is assigned in [IPv6-EH].
  • Specify the procedure to follow when all bits are exhausted.

1.2. tcpOptions Issues

Only TCP options having a kind =< 63 can be included in a tcpOptions IPFIX IE. The specification of the tcpOptions IPFIX IE does not describe how any observed TCP option in a packet can be exported using IPFIX. Also, there is no way to report the observed Experimental Identifiers (ExIDs) that are carried in shared TCP options (kind=253 or 254) [RFC6994].

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.

This document uses the IPFIX-specific terminology (Information Element, Template, Collector, Data Record, Flow Record, Exporting Process, Collecting Process, etc.) defined in Section 2 of [RFC7011]. As in [RFC7011], these IPFIX-specific terms have the first letter of a word capitalized.

3. ipv6ExtensionHeadersFull Information Element

This document requests IANA to add this new IPFIX IE to the IPFIX registry:

4. TCP Options

4.1. New Information Elements for the Full TCP Options Range: tcpOptionsFull

This document requests IANA to add this new IPFIX IE to the IPFIX registry:

  • Name: tcpOptionsFull
  • ElementID: TBD2
  • Description: TCP options in packets of this Flow. The information is encoded in a set of bit fields. For each TCP option, there is a bit in this set. The bit is set to 1 if any observed packet of this Flow contains the corresponding TCP option. Otherwise, if no observed packet of this Flow contained the respective TCP option, the value of the corresponding bit is 0.

    Options are mapped to bits according to their option numbers. Option number X is mapped to bit X. TCP option numbers are maintained by IANA.

    The value can be encoded in fewer octets as per the guidelines in Section 6.2 of [RFC7011].

  • Abstract Data Type: unsigned
  • Data Type Semantics: flags
  • Reference: [This-Document]
  • Additional Information: See the assigned TCP option kinds at [IANA-TCP]. See [RFC9293] for the general definition of TCP options.

4.2. New Information Elements for Shared TCP Options

ExIDs can be either 2 or 4 bytes in length [RFC6994]. Two new IPFIX IEs are defined to accomodate these two lengths without introducing extra complexity in mixing both types in the same IPFIX IE.

This document requests IANA to add the following new IPFIX IEs to the IANA IPFIX registry [IANA-IPFIX].

4.2.1. tcpExID16 Information Element

  • Name: tcpExID16
  • ElementID: TBD3
  • Description: Observed 2-byte Expermients IDs (ExIDs) in a shared TCP option (Kind=253 or 254). The information is encoded in a set of 16-bit fields. Each 16-bit field carries the observed 2-byte ExID in a shared option.
  • Abstract Data Type: octetArray
  • Data Type Semantics: identifier
  • Additional Information: See assigned 16-bit ExIDs at [IANA-TCP-EXIDs].
  • Reference: [This-Document]

4.2.2. tcpExID32 Information Element

  • Name: tcpExID32
  • ElementID: TBD4
  • Description: Observed 4-byte Expermients ID (ExIDs) in a shared TCP option (Kind=253 or 254). The information is encoded in a set of 16-bit fields. Each 32-bit field carries the observed 4-byte ExID in a shared option.
  • Abstract Data Type: octetArray
  • Data Type Semantics: identifier
  • Additional Information: See assigned 32-bit ExIDs at [IANA-TCP-EXIDs].
  • Reference: [This-Document]

5. Security Considerations

IPFIX security considerations are discussed in Section 8 of [RFC7012].

6. IANA Considerations

A set of requested IANA actions are described in the main document. These actions are not repeated here.

7. Normative References

IANA, "IP Flow Information Export (IPFIX) Entities", <>.
IANA, "Transmission Control Protocol (TCP) Parameters, TCP Option Kind Numbers", <>.
IANA, "Transmission Control Protocol (TCP) Parameters, TCP Experimental Option Experiment Identifiers (TCP ExIDs)", <>.
IANA, "Internet Protocol Version 6 (IPv6) Parameters, IPv6 Extension Header Types", <>.
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Touch, J., "Shared Use of Experimental TCP Options", RFC 6994, DOI 10.17487/RFC6994, , <>.
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, , <>.
Claise, B., Ed. and B. Trammell, Ed., "Information Model for IP Flow Information Export (IPFIX)", RFC 7012, DOI 10.17487/RFC7012, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.
Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6) Specification", STD 86, RFC 8200, DOI 10.17487/RFC8200, , <>.
Eddy, W., Ed., "Transmission Control Protocol (TCP)", STD 7, RFC 9293, DOI 10.17487/RFC9293, , <>.


Thanks to Paul Aitken for the review.

Authors' Addresses

Mohamed Boucadair
Benoit Claise