In Situ Operations, Administration, and Maintenance (IOAM) Template Option
draft-mbci-ippm-ioam-template-option-02
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| Document | Type | Active Internet-Draft (individual) | |
|---|---|---|---|
| Authors | Tal Mizrahi , Frank Brockners , Alexander Clemm , Justin Iurman , Shwetha Bhandari , Tianran Zhou , Ramon Bister | ||
| Last updated | 2026-06-30 | ||
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| Intended RFC status | (None) | ||
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draft-mbci-ippm-ioam-template-option-02
IPPM T. Mizrahi
Internet-Draft Huawei
Intended status: Standards Track F. Brockners
Expires: 1 January 2027 Cisco
A. Clemm
Sympotech
J. Iurman
University of Liege
S. Bhandari
Databricks
T. Zhou
Huawei
R. Bister
Ostschweizer Fachhochschule - OST
30 June 2026
In Situ Operations, Administration, and Maintenance (IOAM) Template
Option
draft-mbci-ippm-ioam-template-option-02
Abstract
In situ measurement is performed by incorporating performance related
information into in-flight data packets. This document specifies a
new IOAM Option-Type that has a fixed length and can be updated by
transit nodes along the path. It enables lightweight monitoring
while maintaining a constant length that is not changed in-flight and
is not affected by the number of hops in the network.
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 https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on 1 January 2027.
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Copyright Notice
Copyright (c) 2026 IETF Trust and the persons identified as the
document authors. All rights reserved.
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
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirement Language . . . . . . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
4. Requirements for the IOAM Template Option-Type . . . . . . . 4
5. In situ Template Option-Type . . . . . . . . . . . . . . . . 4
6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. IOAM Data Aggregation Along The Path . . . . . . . . . . 6
6.2. Transit Measurement Template . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
8. Implementation Status . . . . . . . . . . . . . . . . . . . . 8
9. Security Considerations . . . . . . . . . . . . . . . . . . . 8
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . 9
10.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 10
1. Introduction
In Situ Operations, Administration, and Maintenance (IOAM) [RFC9197]
is used for measuring and monitoring a network by incorporating
measurement and operational data into some or all of the data
packets. [RFC9197] has defined several Option-Types, intended for
different purposes.
This document introduces a new IOAM Option-Type that can be
incorporated into data packets and updated by transit nodes along the
path. Compared to existing IOAM Trace Option-Types, the new Option-
Type provides performance information using data fields that have a
constant length.
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There are several in-progress proposals that use a fixed-size
telemetry header, including [I-D.cxx-ippm-ioamaggr],
[I-D.mzbc-ippm-transit-measurement-option],
[I-D.xiao-ippm-ioam-trace-extensions],
[I-D.filsfils-ippm-path-tracing], [I-D.ravi-ippm-csig], and
[I-D.shi-ippm-congestion-measurement-data]. These proposals can
potentially benefit from the IOAM Option-Type that is presented in
this document.
2. Conventions
2.1. Requirement 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.
2.2. Terminology
Abbreviations used in this document:
IOAM: In-situ Operations, Administration, and Maintenance
OAM: Operations, Administration, and Maintenance
The terms Option-Type, encapsulating node, decapsulating node, and
transit node are defined in [RFC9197].
3. Use Cases
There is a set of use cases that the current IOAM Option-Types do not
support. This section lists a set of use cases for the IOAM Template
Option-Type.
* Aggregated information: aggregated information across several
nodes, e.g., [I-D.cxx-ippm-ioamaggr]. Many applications
interested in telemetry data across a path are not focused on
individual node's telemetry, but on an aggregated metric that can
provide a more holistic picture. Aggregating IOAM data along a
network path meets this requirement. IOAM nodes do not only
retrieve information, but also perform functions such as sum,
average, minimum, or maximum of a given data parameter and carry
the result to the next IOAM node in an IOAM data field.
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* Congestion information: information relating to the congestion
status can be collected from nodes along the path, e.g.,
[I-D.ravi-ippm-csig] providing a finer level of granularity than
conventional ECN while limiting the congestion status to a fixed
size.
* Combined information: a combination of aggregated information and
congestion-related information can be collected along the path,
e.g., [I-D.mzbc-ippm-transit-measurement-option], while using a
fixed size.
4. Requirements for the IOAM Template Option-Type
This section lists requirements for the IOAM Template Option-Type:
* Templates supported MUST have a fixed length and fixed structure.
Fixed length and structure are to simplify parsing of the Option-
Type.
* Each templates is a composition of one or more data fields.
* Data fields within a template can have different sizes (e.g., 8
bits, 16 bits, 32 bits).
* Templates MUST align to 4 octet boundaries. If necessary, padding
fields are used to guarantee 4-octet alignment.
* Data fields within a Template can be read-only for IOAM nodes or
read-write for IOAM nodes, depending on their use.
* The IOAM Template Option-Type SHOULD support IETF defined (IANA
registry) Templates for use-cases which are defined by the IETF as
well as custom/deployment specific templates, that are defined by
the operator and are specific to a deployment.
5. In situ Template Option-Type
This document defines a new IOAM Option-Type, the Template Option-
Type. The length of the Template Option-Type MUST NOT be modified by
IOAM transit nodes. However, IOAM transit nodes MAY modify the
option data in the Template Option-Type. Figure 1 presents the
format of this Option-Type.
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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 | Template-ID | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Template-Data depending on the Template-ID value ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: Template Option-Type
An IOAM node that complies to this draft MUST support the following
fields, as depicted in Figure 1:
Namespace-ID: A 16-bit namespace identifier, as defined in
[RFC9197].
Template-ID: An 8-bit identifier that specifies the template that
follows. A new registry is defined for this field, as specified
in Section 7. The value 0 has been assigned, indicating "No
Option Data". Assignments of values 1 to 127 are controlled by
IANA. Values 128 to 255 can be defined by an operator for a
specific deployment.
Length: An 8-bit length that specifies the size of the Template-Data
in multiples of 4 octets.
Template-Data: The data that follows the Template-ID has a constant
length. The semantics and length of the data are determined by
the Template-ID. The option data might consist of more than one
sub-field.
The specification of the Template-ID values and the corresponding
option data formats is outside the scope of this document.
As in [RFC9197], the Template Option-Type can be incorporated into
all or a subset of the traffic that is forwarded by the encapsulating
node. Notably, this option adds a fixed and low overhead to data
packets, which remains constant along the path.
6. Examples
The section lists examples of how the template option can be used.
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6.1. IOAM Data Aggregation Along The Path
[I-D.cxx-ippm-ioamaggr] describes use cases to aggregate IOAM data
along a network path. Rather than just collecting data at IOAM
nodes, data is collected and processed by the IOAM nodes - using
functions like sum, average, minimum, or maximum of a given data
parameter - and the result stored in a data field called "Aggregate"
(see below). The Template Option can be used to support this use-
case with the following example template:
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 | TBD_1 | Length=3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IOAM Data Param | Aggregator | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Aggregate |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Auxil-data Node-Id | Hop Count |
+---------------------------------------------------------------+
Figure 2: Aggregation Template
IOAM Data Param: This field identifies the data parameter that is to
be aggregated across the nodes. It MUST be set by the IOAM
encapsulating node. IOAM transit nodes MUST NOT change it.
Identification of data parameters is dependent on the
administrative domain and assigned by the network administrator.
It is conceivable to subject this to standardization and/or the
introduction of a separate IANA registry at some point in the
future.
Aggregator: This 8-bit field identifies the aggregation function
that is to be applied. Its value MUST be set by the IOAM
encapsulating node. IOAM transit nodes MUST not change it. The
following aggregators are defined: Sum, Min, Max, Average.
Flags: This 8-bit field allows to indicate errors that were
encountered when attempting to perform the requested aggregation
along the path. An intermediate node that encounters an error
during processing of the IOAM Aggregation that prevents it from
updating the aggregate as requested MUST set the corresponding
flag to 1. In order to facilitate troubleshooting, it also MUST
set the value of the Auxil-data Node-ID field in the template to
its own Node-ID. The encapsulating node MUST set the value of
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Flags to zero upon transmission. When an intermediate node
encounters receives a packet in which any of the Flags are non-
zero, the node MUST NOT perform further IOAM operations on that
packet; instead, the IOAM data MUST be forwarded as-is unchanged.
The following flags are defined:
Flag 1: Aggregator not supported
Flag 2: Unsupported IOAM data parameter
Flag 3: Unsupported Namespace
Flag 4: Any other error
Aggregate: This 32-bit field contains the aggregated value. Its
value is initialized by the encapsulating node,in general by
simply recording the value of its data parameter that is to be
aggregated. The field is updated by each subsequent node pre the
requested aggregation, including IOAM transit nodes as well as the
IOAM decapsulating node (prior to performing decapsulation).
Auxil-data Node ID : For certain aggregators such as min and max,
this field can be used to identify the node at which the the min
or max was encountered. In the case of errors that are
encountered along the path, this field is used to indicate the
node at which the error occurred, as indicated when a
corresponding error flag has been set.
Hop Count : Records the number of nodes along the path that
successfully processed the IOAM aggregation request. It is set to
1 by the encapsulating node and is incremented by each subsequent
node. One use for this concerns facilitating the computation of
an average (by dividing a sum by the number of nodes).
Please note that the template for IOAM data aggregation is included
here only to illustrate possible use cases for the IOAM template
option. For a more detailed discussion of IOAM data aggregation, of
the data parameter fields involved, as well as of associated design
decisions, please refer to [I-D.cxx-ippm-ioamaggr].
6.2. Transit Measurement Template
The use case that is presented in
[I-D.mzbc-ippm-transit-measurement-option] provides aggregated
transit delay information, as well as congestion status of transit
nodes, as shown in the following template:
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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 | TBD_2 | Length=2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Accumulated Delay |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Count | Status Bitmap |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Transit Measurement Template
Accumulated Delay: represents the sum of the transit delay values in
nanoseconds along the path of the packet, including the current
node.
Hop Count/Status Bitmap: indicates the devices along the path that
have experienced congestion. Hop Count is a one-octet field that
indicates the number of hops since the encapsulating node, and is
updated by each transit node. Status Bitmap is a three octet
field that represents the congestion status of each transit node
along the path. The value '1' indicates that the current packet
was enqueued in a queue that is congested.
7. IANA Considerations
To be added to a future version of this document.
8. Implementation Status
A Proof-of-Concept of the template option along with the aggregation
trace template has been implemented at OST. It is planned to have
the Proof-of-Concept feature in a hackathon project at IETF 126 July
2026 in Vienna. More details will be provided in a future version of
the document.
9. Security Considerations
The security considerations of IOAM in general are discussed in
[RFC9197]. The Template Option-Type may be used for reconnaissance,
which in turn can facilitate other types of attacks. As in other
types of IOAM data fields, a malicious attacker can manipulate the
field values in order to create a false illusion of nonexistent
network issues or prevent the detection of actual ones.
10. References
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10.1. Normative References
[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/info/rfc2119>.
[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/info/rfc8174>.
[RFC9197] 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,
May 2022, <https://www.rfc-editor.org/info/rfc9197>.
10.2. Informative References
[I-D.cxx-ippm-ioamaggr]
Clemm, A., Metzger, Bister, R., and S. Dellsperger,
"Aggregation Trace Option for In-situ Operations,
Administration, and Maintenance (IOAM)", Work in Progress,
Internet-Draft, draft-cxx-ippm-ioamaggr-05, 2 May 2026,
<https://datatracker.ietf.org/doc/html/draft-cxx-ippm-
ioamaggr-05>.
[I-D.filsfils-ippm-path-tracing]
Filsfils, C., Abdelsalam, A., Camarillo, P., Yufit, M.,
Su, Y., Matsushima, S., Valentine, M., and Dhamija, "Path
Tracing in SRv6 networks", Work in Progress, Internet-
Draft, draft-filsfils-ippm-path-tracing-05, 4 January
2026, <https://datatracker.ietf.org/doc/html/draft-
filsfils-ippm-path-tracing-05>.
[I-D.mzbc-ippm-transit-measurement-option]
Mizrahi, T., Zhou, T., Belkar, S., and R. Cohen, "The
Transit Measurement Option", Work in Progress, Internet-
Draft, draft-mzbc-ippm-transit-measurement-option-07, 5
January 2026, <https://datatracker.ietf.org/doc/html/
draft-mzbc-ippm-transit-measurement-option-07>.
[I-D.ravi-ippm-csig]
Ravi, A., Dukkipati, N., Mehta, N., and J. Kumar,
"Congestion Signaling (CSIG)", Work in Progress, Internet-
Draft, draft-ravi-ippm-csig-01, 2 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ravi-ippm-
csig-01>.
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[I-D.shi-ippm-congestion-measurement-data]
Fioccola, G., Zhou, T., Zhao, G., and Z. Li, "Data Fields
for Congestion Measurement", Work in Progress, Internet-
Draft, draft-shi-ippm-congestion-measurement-data-06, 22
June 2026, <https://datatracker.ietf.org/doc/html/draft-
shi-ippm-congestion-measurement-data-06>.
[I-D.xiao-ippm-ioam-trace-extensions]
Min, X., Liu, Y., and C. Lin, "Extensions to IOAM Trace
Option for Carrying Fixed-Size Data", Work in Progress,
Internet-Draft, draft-xiao-ippm-ioam-trace-extensions-03,
12 April 2026, <https://datatracker.ietf.org/doc/html/
draft-xiao-ippm-ioam-trace-extensions-03>.
Authors' Addresses
Tal Mizrahi
Huawei
Matam
Haifa 3190501
Israel
Email: tal.mizrahi.phd@gmail.com
Frank Brockners
Cisco Systems, Inc.
Hansaallee 249, 3rd Floor
40549 DUESSELDORF
Germany
Email: fbrockne@cisco.com
Alexander Clemm
Sympotech
Los Gatos, CA,
United States of America
Email: ludwig@clemm.org
Justin Iurman
University of Liege
10, Allee de la decouverte (B28)
4000 Sart-Tilman
Belgium
Email: justin.iurman@uliege.be
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Shwetha Bhandari
Databricks
Angkor West Building Bagmane Capital Tech Park Ferns City Doddanekkundi
Mahadevpura Bengaluru, Karnataka 560048
India
Email: shwetha.bhandari@databricks.com
Tianran Zhou
Huawei
156 Beiqing Rd.
Beijing
100095
China
Email: zhoutianran@huawei.com
Ramon Bister
Ostschweizer Fachhochschule - OST
Switzerland
Email: ramon.bister@ost.ch
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