Internet-Draft Timestamp extension IOAM DEX February 2023
Huang Feng, et al. Expires 19 August 2023 [Page]
Network Working Group
Intended Status:
Standards Track
A. Huang Feng
P. Francois
B. Claise
T. Graf

Timestamp extension for In Situ Operations, Administration, and Maintenance (IOAM) Direct Export


This document extends the In Situ Operations, Administration, and Maintenance (IOAM) Direct Export option type to support timestamping by adding and defining two optional timestamp fields and corresponding flags.

Requirements Language

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.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at

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This Internet-Draft will expire on 19 August 2023.

Table of Contents

1. Introduction

Network operators wish to measure the On-Path delay across their networks to understand which part of the network causes how much delay and impact which applications. Network nodes can leverage IOAM [RFC9197] to add timestamps into the packet and export the raw data with [] or the calculated On-Path delay with [I-D.ietf-opsawg-ipfix-on-path-telemetry] to the IPFIX [RFC7011] collector.

In order to support Postcard-Based On-Path delay measurement, IOAM Direct Export Option-type (DEX) [RFC9326] needs to be extended with timestamps to accommodate delay monitoring.

This document defines two new Extension fields for IOAM DEX Option-type [RFC9326] to support an optional timestamp in the header.

2. Solution overview

The IOAM DEX Option-type format is defined in Section 3.2 [RFC9326]. To be able to measure the delay between the IOAM encapsulation node and the current IOAM node, the timestamp is added to the IOAM DEX option-type as illustrated in Figure 1.

This document proposes two optional fields to be included in the IOAM DEX option type format so that they can be enabled using IOAM DEX Extension-Flags. New Extension-Flags are allocated by IANA, as defined in Section 7. This document proposes using the bit 2 for the Timestamp Seconds and the bit 3 for the Timestamp Fraction.

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
|        Namespace-ID           |     Flags     |Extension-Flags|
|               IOAM-Trace-Type                 |   Reserved    |
|                         Flow ID (Optional)                    |
|                     Sequence Number  (Optional)               |
|                   Timestamp Seconds  (Optional)               |
|                  Timestamp Fraction  (Optional)               |
Figure 1: IOAM DEX Option-Type Format including the timestamps

While the Timestamp Seconds field can be used standalone, the Timestamp Fraction MUST be used in combination with the Timestamp Seconds field.

3. Timestamp Formats

The Timestamp Seconds and Timestamp Fraction field encoding format definitions are described in Section 5 of [RFC9197].

4. Export Method

While the Timestamp Seconds and Timestamp Fraction can be exported via IOAM raw export using [] and the calculated On-Path delay can be exported using IPFIX with [I-D.ietf-opsawg-ipfix-on-path-telemetry], the mechanism and associated formats for exporting the delay metrics are outside the scope of this document.

5. Use Cases

Possible interesting On-Path delay measurement use cases in combination with other key metrics is described in Section 5 of [I-D.ietf-opsawg-ipfix-on-path-telemetry].

6. Security Considerations

The security considerations for the IOAM DEX Option-type are described in [RFC9326]. This document adds no additional security considerations.

7. IANA Considerations

This document requests IANA to create the following two bits in the "IOAM DEX Extension-Flags" registry.

  Bit: 2
  Description: Timestamp Seconds
  Reference: this document
  Bit: 3
  Description: Timestamp Fraction
  Reference: this document

8. Acknowledgements

The authors would like to thank xxx for their review and valuable comments.

9. References

9.1. Normative References

Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <>.
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <>.
Brockners, F., Ed., Bhandari, S., Ed., and T. Mizrahi, Ed., "Data Fields for In Situ Operations, Administration, and Maintenance (IOAM)", RFC 9197, DOI 10.17487/RFC9197, , <>.
Song, H., Gafni, B., Brockners, F., Bhandari, S., and T. Mizrahi, "In Situ Operations, Administration, and Maintenance (IOAM) Direct Exporting", RFC 9326, DOI 10.17487/RFC9326, , <>.

9.2. Informative References

Graf, T., Claise, B., and A. H. Feng, "Export of On-Path Delay in IPFIX", Work in Progress, Internet-Draft, draft-ietf-opsawg-ipfix-on-path-telemetry-00, , <>.
Spiegel, M., Brockners, F., Bhandari, S., and R. Sivakolundu, "In-situ OAM raw data export with IPFIX", Work in Progress, Internet-Draft, draft-spiegel-ippm-ioam-rawexport-06, , <>.
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, , <>.

Authors' Addresses

Alex Huang Feng
Pierre Francois
Benoit Claise
Thomas Graf
Binzring 17
CH-8045 Zurich