IPPM Working Group X. He
Internet-Draft China Telecom
Intended status: Standards Track F. Brockners
Expires: 30 August 2025 Cisco
H. Song
Futurewei
G. Fioccola
Huawei
A. Wang
China Telecom
26 February 2025
IOAM Direct Exporting (DEX) Option Extensions for Incorporating the
Alternate-Marking Method
draft-he-ippm-ioam-dex-extensions-incorporating-am-01
Abstract
In situ Operations, Administration, and Maintenance (IOAM) is used
for recording and collecting operational and telemetry information.
Specifically, passport-based IOAM allows telemetry data generated by
each node along the path to be pushed into data packets when they
traverse the network, while postcard-based IOAM allows IOAM data
generated by each node to be directly exported without being pushed
into in-flight data packets. This document extends IOAM Direct
Export (DEX) Option-Type to integrate the Alternate-Marking Method
into IOAM.
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 30 August 2025.
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Copyright Notice
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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/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 4
4. Integrate the Alternate-Marking Method into IOAM DEX
Option . . . . . . . . . . . . . . . . . . . . . . . . . 5
5. The Extended DEX Option-Type Format . . . . . . . . . . . . . 6
6. The IOAM Operation . . . . . . . . . . . . . . . . . . . . . 8
6.1. Packet Loss Measurement . . . . . . . . . . . . . . . . . 9
6.2. Packet Delay Measurement . . . . . . . . . . . . . . . . 9
7. Flow Identification . . . . . . . . . . . . . . . . . . . . . 11
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8.1. IOAM Type . . . . . . . . . . . . . . . . . . . . . . . . 12
8.2. IOAM DEX Extension-Flags . . . . . . . . . . . . . . . . 12
9. Performance Considerations . . . . . . . . . . . . . . . . . 13
10. Security Considerations . . . . . . . . . . . . . . . . . . . 13
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 13
11.1. Normative References . . . . . . . . . . . . . . . . . . 13
11.2. Informative References . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
IOAM [RFC9197], which defines four possible IOAM-Option-Types: Pre-
allocated Trace, Incremental Trace, Proof of Transit (POT), and Edge-
to-Edge, is used for monitoring traffic in the network and for
incorporating IOAM data fields into in-flight data packets. IOAM
[RFC9197] is known as the passport mode, in which each node on the
path can add telemetry data to the user packets (i.e., stamps the
passport). IOAM Direct Export (DEX) [RFC9326] is used as a trigger
for IOAM nodes to directly export IOAM data to a receiving entity
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such as a collector, analyzer, or controller. IOAM DEX is also
referred as the postcard mode, in which each node directly exports
the telemetry data using an independent packet (i.e., sends a
postcard) while the user packets are unmodified.
The disadvantage of the passport mode is that if a packet is dropped
on the path, the IOAM data collected are also lost. So the passport
mode such as IOAM Trace Option-Type has no ability to monitor packet
drop and packet drop location.
IOAM DEX Option-Type can complement IOAM Trace Option-Type in that
even if a packet is dropped on the path, the partial data collected
are still available. By correlating the data from different nodes,
the number of the discarded packets can be counted accurately and
packet drop location can be pinpointed.
The Alternate-Marking [RFC9341] technique has been proven to work
well to perform packet loss, delay, and jitter measurements on live
traffic. RFC9343 describes how the Alternate-Marking Method can be
used to measure performance metrics in IPv6. It defines an Extension
Header Option to encode Alternate-Marking information in both the
Hop-by-Hop Options Header and Destination Options Header. In order
to facilitate the deployment and improve the scalability of the
Alternate-Marking Method, the Flow Monitoring Identification
(FlowMonID) field is introduced. The benefits of introducing
FlowMonID are obvious: First, it helps to reduce the per-node
configuration; Second, it simplifies the counters handling; Third, it
eases the data export encapsulation and correlation for the
collectors.
This document presents the problems and challenges currently faced by
IOAM in measuring performance metrics such as packet loss, delay, and
jitter. In order to augment IOAM in performance measurement, IOAM
DEX Option-Type is extended to incorporate the Alternate-Marking
Method into IOAM.
2. Conventions
2.1. 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.
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2.2. Terminology
Abbreviations used in this document:
DEX: Direct Exporting
FlowMonID: Flow Monitoring Identification
IOAM: In situ Operation, Administration, and Maintenance
MPN: Measurement Period Number
OAM: Operation, Administration, and Maintenance
SN: Sequence Number
3. Problem Statement
Although IOAM DEX Option-Type can complement IOAM Trace Option-Type
for monitoring packet loss, some issues have to be considered as
follows.
Issue 1: If an IOAM encapsulating node incorporates the DEX Option-
Type into all the traffic of interest it forwards, it may lead to an
excessive amount of exported data, which may overload the network and
the receiving entity. Therefore, an IOAM encapsulating node that
supports the DEX Option-Type MUST support the ability to incorporate
the DEX Option-Type selectively into a subset of the packets that are
forwarded by the IOAM encapsulating node.
Issue 2: In theory, if an IOAM encapsulating node incorporates the
DEX Option-Type into all the traffic it forwards, the fidelity of
packet loss measurement can be ensured. If the too small subset of
traffic or too low traffic sampling on an encapsulating node is
implemented, loss measurement results can not reflect the actual
packet drop, due to the fact that the transmitting packet interval
may not cover packet drop caused by instantaneous congestion such as
microbursts.
Issue 3: Because the IOAM data of the same user packet is generated
by every node along the path, the receiving entity needs more
processing overhead to correlate these data for packet loss
computation. The more user packets measured, the more processing
overhead is needed.
Issue 4: While using the Alternate-Marking Method, traffic flows are
split into consecutive blocks: each block represents a measurable
entity unambiguously recognizable by all network devices along the
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path. In contrast, based on IOAM DEX Option-Type, every IOAM node
directly exports an IOAM data to a receiving entity when every user
packet is forwarded, and the collected IOAM data are not split into
independent measurement blocks. It is the receiving entity's
responsibility to determine the measurement period for performance
metrics such as packet loss, delay, and jitter, which is not
beneficial to a unified measurement methodology.
4. Integrate the Alternate-Marking Method into IOAM DEX Option
To address the issues and challenges mentioned in Section 3, IOAM
needs to be augmented to implement performance measurement. The
Alternate-Marking Method has been widely employed in operators
networks. By integrating the Alternate-Marking Method into IOAM, the
benefits obtained include:
* While implementing performance measurement, an IOAM encapsulating
node may incorporate the DEX Option-Type into all packets of the
measured user traffic it forwards. Meanwhile, an IOAM
encapsulating node only needs to select a very small subset of the
packets that are forwarded for IOAM trace monitoring (e.g.,
1/10000 of all the traffic of interest), so the amount of exported
data is significantly reduced to mitigate the network and the
receiving entity. The IOAM operation is detailed in section 6.
* Using the Alternate-Marking Method, an IOAM encapsulating node
could color all the traffic of interest it forwards, not a subset
of the packets, thus the fidelity of performance measurement such
as packet loss can be ensured.
* When using the Alternate-Marking Method for loss measurement, in
Hop-by-Hop mode, every node along the path exports only a packet
carrying counter value of each measurement block including a batch
of packets; In End-to-End mode, only the IOAM encapsulating node
and the IOAM decapsulating node export a packet carrying counter
value of each measurement block. As a result, it mitigates the
network and the receiving entity greatly. Furthermore, compared
to IOAM DEX Option-Type, the receiving entity needs much less
processing overhead to correlate these counter values for packet
loss computation.
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* When using the Alternate-Marking Method, traffic flows are split
into consecutive blocks: each block represents a measurable entity
unambiguously recognizable by all network devices along the path,
thus the measurement period is completely determined by network
devices. The receiving entity does not need to concern about how
to determine measurement period, but only compute the result of
each measurement period. It is beneficial to a unified
measurement methodology.
* Furthermore, by incorporating the Alternate-Marking Method into
IOAM, only unique packet header encapsulation format is used for
both IOAM trace monitoring and performance measurement such as
packet loss, latency and jitter, thus simplifing the complexity of
forwarding chips.
5. The Extended DEX Option-Type Format
The format of the extended DEX Option-Type is depicted in Figure 1.
All fields are same as DEX Option-Type Format defined in RFC9326
except the Reserved field. The extended DEX Option-Type Format uses
the most significant 2 bits of the Reserved field.
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 |D|L| Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow ID (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence Number (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Measurement Period Number (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: The Extended DEX Option-Type Format
Where:
Namespace-ID: 16-bit identifier of the IOAM namespace, as defined in
[RFC9197].
Flags: 8-bit field, comprised of 8 1-bit subfields. Flags are
allocated by IANA.
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Extension-Flags: 8-bit field, comprised of 8 1-bit subfields.
Extension-Flags are allocated by IANA. Every bit in the Extension-
Flag field that is set to 1 indicates the existence of a
corresponding optional 4-octet field. Bit 0 (the most significant
bit) and bit 1 in the registry are allocated by [RFC9326], which are
specified as Flow ID and Sequence Number of the monitored traffic,
respectively. Bit 3 is specified as Measurement Period Number in
this document. An IOAM node that receives an extended DEX Option-
Type with an unknown flag set to 1 MUST ignore the corresponding
optional field.
IOAM-Trace-Type: 24-bit identifier that specifies which IOAM data
types are used and the corresponding IOAM-Data-Fields should be
exported. The format of this field is as defined in [RFC9197].
L: 1-bit Loss flag for Packet Loss Measurement as described in
Section 6.1.
D: 1-bit Delay flag for Single Packet Delay Measurement as described
in Section 6.2.
Reserved: 6-bit field, reserved for future use. These bits MUST be
set to zero on transmission and ignored on receipt.
Optional fields: The optional fields, if present, reside after the
Reserved field. The order of the optional fields is according to the
order of the respective bits, starting from the most significant bit,
that are enabled in the Extension-Flags field. Each optional field
is 4 octets long.
Flow ID: An optional 32-bit field representing the flow identifier.
If the actual Flow ID is shorter than 32 bits, it is zero padded in
its most significant bits. The field is set at the encapsulating
node and exported to the receiving entity by the forwarding nodes.
The Flow ID can be used to correlate the exported data of the same
flow from multiple nodes and from multiple packets. Flow ID values
are expected to be allocated in a way that avoids collisions. For
example, random assignment of Flow ID values can be subject to
collisions, while centralized allocation can avoid this problem. The
specification of the Flow ID allocation method is not within the
scope of this document.
Sequence Number: An optional 32-bit sequence number, starting from 0
and incremented by 1 for each packet from the same flow at the
encapsulating node that includes the DEX option. The Sequence
Number, when combined with the Flow ID, provides a convenient
approach to correlate the exported data from the same user packet.
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Measurement Period Number(MPN): An optional 32-bit field representing
the measurement period number of the monitored flow, starting from 0
and incremented by 1 for the specified flow with the same Flow ID.
The field is set at the encapsulating node and exported to the
receiving entity by the forwarding nodes. The MPN, when combined
with the Flow ID, provides a convenient approach to correlate the
exported data of the same flow during the same measurement period
from multiple nodes.
6. The IOAM Operation
The extended DEX Option-Type SHOULD support the three IOAM operation
modes: only IOAM trace monitoring; only performance measurement;
hybrid.
* Only IOAM trace monitoring: As DEX Option-Type does, an IOAM
encapsulating node that supports the Extended DEX Option-Type MUST
support the ability to incorporate the Extended DEX Option-Type
selectively into a subset of the monitored packets that are
forwarded by the IOAM encapsulating node. At the same time, it
MUST set corresponding bit flag to 1 in IOAM Trace-Type field of
the extended DEX Option-Type so that each node along the path
needs to generate the specified IOAM data exported to the
receiving entity. Also, it Must set the L flag and D flag of the
extended DEX Option-Type to zero on transmit and ignored by the
monitoring nodes.
* Only performance measurement: To ensure the fidelity of
performance measurement, an IOAM encapsulating node MUST
incorporate the extended DEX Option-Type into all packets of the
measured user traffic it forwards. Like the Alternate-Marking
Method [RFC9343], for packet loss measurement, it Must switch the
value of the L bit between 0 and 1 after a fixed number of packets
or according to a fixed timer; for packet delay measurement,
Single-Marking or Double-Marking methodology can be adopted by
switching the value of the L bit or D bit between 0 and 1. But it
Must set all 24 bits flag to 0 in IOAM Trace-Type field of the
extended DEX Option-Type so that each node along the path does not
need to generate the IOAM data exported to the receiving entity.
* Hybrid: To perform both IOAM trace monitoring and performance
measurement concurrently, an IOAM encapsulating node MUST
incorporate the extended DEX Option-Type into all the traffic of
interest it forwards. For performance measurement, an IOAM
encapsulating node MUST mark each packet it forwards in L flag and
D flag of the extended DEX Option-Type; for IOAM trace monitoring,
only a subset of the packets are selected by an IOAM encapsulating
node. For every selected packet, an IOAM encapsulating node MUST
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set corresponding bit flag to 1 in IOAM Trace-Type field of the
extended DEX Option-Type so that each node along the path needs to
generate the specified IOAM data exported to the receiving entity;
for all the other packets not selected, an IOAM encapsulating node
MUST set all 24 bits flag to 0 in IOAM Trace-Type field of the
extended DEX Option-Type, such that each node along the path does
not need to generate the IOAM data exported to the receiving
entity.
6.1. Packet Loss Measurement
The measurement of the packet loss is detailed in [RFC9341]and
[RFC9343]. The packets of the flow identified by Flow ID are grouped
into batches, and all the packets within a batch are marked by
setting the L bit (Loss flag) to a same value. The source node (IOAM
encapsulating node) can switch the value of the L bit between 0 and 1
after a fixed number of packets or according to a fixed timer, and
this depends on the implementation. The source node is the only one
that marks the packets to create the batches, while the intermediate
nodes only read the marking values and identify the packet batches.
By counting the number of packets in each batch and comparing the
values measured by different network nodes along the path, it is
possible to measure the packet loss that occurred in any single batch
between any two nodes. Each batch represents a measurable entity
recognizable by all network nodes along the path, which export the
counter value of this batch along with the Flow ID and the MPN (if it
exists) to the receiving entity (e.g., the collector).
6.2. Packet Delay Measurement
Delay metrics MAY be calculated using the following two
possibilities:
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Single-Marking Methodology: This approach uses only the L bit to
calculate both packet loss and delay. In this case, the D flag MUST
be set to zero on transmit and ignored by the monitoring points. The
alternation of the values of the L bit can be used as a time
reference to calculate the delay. Whenever the L bit changes and a
new batch starts, a network node can store the timestamp of the first
packet of the new batch; that timestamp can be compared with the
timestamp of the first packet of the same batch on a second node to
compute packet delay. But, this measurement is accurate only if no
packet loss occurs and if there is no packet reordering at the edges
of the batches. A different approach can also be considered, and it
is based on the concept of the mean delay. The mean delay for each
batch is calculated by considering the average arrival time of the
packets for the related batch. There are limitations also in this
case indeed; each node needs to collect all the timestamps and
calculate the average timestamp for each batch. In addition, the
information is limited to a mean value.
Double-Marking Methodology: This approach is more complete and uses
the L bit only to calculate packet loss, and the D bit (Delay flag)
is fully dedicated to delay measurements. The idea is to use the
first marking with the L bit to create the alternate flow and, within
the batches identified by the L bit, a second marking with the D bit
set to 1 is used to select the packets for measuring delay. The D
bit creates a new set of marked packets that are fully identified
over the network so that a forwarding node can store and export the
timestamps of these packets; these timestamps can be compared with
the timestamps of the same packets on a second node to compute packet
delay values for each packet. Sequence Number can be used to
identify multiple timestamps in different packets that pertain to the
same measurement block in case of packets out of order. It also can
be used to identify which double-marked packet is lost. The most
efficient and robust mode is to select a single double-marked packet
for each batch; in this way, there is no time gap to consider between
the double-marked packets to avoid their reorder. If a double-marked
packet is lost, the delay measurement for the considered batch is
simply discarded, but this is not a big problem because it is easy to
recognize the problematic batch and skip the measurement just for
that one.
In summary, the approach with Double Marking is better than the
approach with Single Marking. In the implementation, the timestamps
along with Flow ID, MPN and Sequence Number (if it exists) can be
sent out to the receiving entity that is responsible for the
calculation.
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7. Flow Identification
The Flow Identification (Flow ID) identifies the flow to be measured
and is required for some general reasons, which is described in
Section 5.3 of [RFC9343]. [RFC9343] uses 20-bit FlowMonID to
determine a monitored flow within the measurement domain. Compared
to the FlowMonID, the Flow ID in this document is a 32-bit field,
which amplifies the FlowMonID space by 4096 times. Accordingly, a
chance of collision is greatly reduced in a distributed way.
When the 32-bit Flow ID is used for every source node, if there are N
edge nodes (source nodes) in a large-scale operator network, and each
source node can generate a unique Flow ID for every measured flow
independently and randomly in a distributed way. Assuming that each
node randomly generates M different Flow IDs from the available K
flow identification space, then the total possible sample space (PSS)
is
the Nth power of C (K, M) (1)
and the total possible sample space without overlapping (PSSno)is
C1 (K, M)*C2 (K-M, M )*....*CN (k-(N-1)M, M) (2)
Theoritically, the collision probability (CP) is calculated as:
CP=1-PSSno/PSS (3)
Take K=32nd power of 2 as an example, which corresponds to 32-bit
Flow ID space. When the number N and M are given different values,
we can obtain the corresponding CP values shown in the following
table.
+----------------+--------+--------+--------+--------+--------+--------+
| | N=100 | N=100 | N=200 | N=200 | N=200 | N=200 |
| 32-bit Flow ID +--------+--------+--------+--------+--------+--------+
| | M=100 | M=200 | M=200 | M=300 | M=400 | M=500 |
+----------------+-------------+-------------+-------------+-----------+
| CP | 0.0115 | 0.0453 | 0.1692 | 0.3410 | 0.5235 | 0.6860 |
+----------------+--------+--------+--------+--------+--------+--------+
It is not difficult to observe that as the number of concurrent
monitored flows increases,the collision probability is rapidly
increasing. As shown in the table, when generating 10000 concurrent
flows, the CP is 0.0115; when generating 100000 concurrent flows, the
CP rises to 0.6860. If K=20th power of 2 is taken, which corresponds
to 20-bit Flow ID space, when generating 10000 concurrent flows, we
can calculate the collision probability will drastically rises to
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approximately 100%. In practical deployment scenarios of large-scale
networks, the concurrent measurement flows could reach orders of
magnitude of 100000 or even higher, thus the collision probability
will rise sharply.
It is preferred that Flow ID be assigned by the central controller.
Since the controller knows the network topology, it can allocate the
value properly to guarantee the uniqueness of Flow ID allocation.
In some cases where the central controller is not available and the
distributed way must be adopted, every source node (encapsulating
node) needs to allocate Flow ID independently. In order to avoid the
collision, Flow ID field may be devided into two sub-fields: NodeID
and FlowMonID. NodeID is assigned uniquely in measurement domain and
FlowMonID is assigned randomly and uniquely in a device. The length
allocation of the two sub-fields depends on practical implementation,
for example, NodeID uses 20 bits and FlowMonID uses 12 bits, or both
use an average of 16 bits.
8. IANA Considerations
8.1. IOAM Type
The "IOAM Option-Type" registry is defined in Section 7.1 of
[RFC9197].
IANA is requested to allocate the following code point from the "IOAM
Option-Type" registry as follows:
+==================+===============================+===============+
| IOAM Option-Type | Name | Reference |
+==================+===============================+===============+
| TBA | IOAM Extended DEX Option Type | This document |
+------------------+-------------------------------+---------------+
If possible, IANA is requested to allocate code point 5 (TBA-type).
8.2. IOAM DEX Extension-Flags
IANA has created the "IOAM DEX Extension-Flags" registry. This
registry includes 8 flag bits. Bit 0 (the most significant bit) and
bit 1 in the registry are allocated by [RFC9326].
IANA is requested to allocate bit 3 as Measurement Period Number in
the registry and described in Section 5.
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9. Performance Considerations
The extended DEX Option-Type triggers IOAM data (including IOAM trace
data and performance measurement data) to be collected and/or
exported packets to be exported to a receiving entity. In some
cases, this may impact the receiving entity's performance.
Therefore, the performance impact of these exported packets is
limited by taking two measures: at the encapsulating nodes by
selective DEX encapsulation and at the transit nodes by limiting
exporting rate, which are detailed in [RFC9326]. These two measures
ensure that direct exporting is used at a rate that does not
significantly affect the network bandwidth and does not overload the
receiving entity.
When performance measurement is implemented based on the Alternate-
Marking Method, in Hop-by-Hop mode for loss measurement, every node
along the path exports only a packet carrying counter value of each
measurement block including a batch of packets; In End-to-End mode
for loss measurement, only the IOAM encapsulating node and the IOAM
decapsulating node export a packet carrying counter value of each
measurement block. Meanwhile, an IOAM encapsulating node only needs
to select a very small subset of the packets that are forwarded for
IOAM trace monitoring (e.g., 1/10000 of all the traffic), so the
amount of exported data is significantly reduced to mitigate the
network and the receiving entity. In addition, compared with IOAM
DEX Option-Type for packet loss calculation, due to a significant
reduction in the number of exported packets, the receiving entity
needs much less processing overhead to correlate these counter values
for packet loss computation.
10. Security Considerations
The security considerations of IOAM in general are discussed in
[RFC9197], and the security considerations of IOAM DEX Option-Type
are discussed in [RFC9326]. There are not additional security
considerations in this extended IOAM DEX Option-Type.
11. References
11.1. 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>.
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[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>.
[RFC9326] 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, November 2022,
<https://www.rfc-editor.org/info/rfc9326>.
[RFC9341] Fioccola, G., Ed., Cociglio, M., Mirsky, G., Mizrahi, T.,
and T. Zhou, "Alternate-Marking Method", RFC 9341,
DOI 10.17487/RFC9341, December 2022,
<https://www.rfc-editor.org/info/rfc9341>.
[RFC9343] Fioccola, G., Zhou, T., Cociglio, M., Qin, F., and R.
Pang, "IPv6 Application of the Alternate-Marking Method",
RFC 9343, DOI 10.17487/RFC9343, December 2022,
<https://www.rfc-editor.org/info/rfc9343>.
11.2. Informative References
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>.
[RFC9486] Bhandari, S., Ed. and F. Brockners, Ed., "IPv6 Options for
In Situ Operations, Administration, and Maintenance
(IOAM)", RFC 9486, DOI 10.17487/RFC9486, September 2023,
<https://www.rfc-editor.org/info/rfc9486>.
Authors' Addresses
Xiaoming He
China Telecom
Email: hexm4@chinatelecom.cn
Frank Brockners
Cisco
Email: fbrockne@cisco.com
He, et al. Expires 30 August 2025 [Page 14]
Internet-Draft IOAM Direct Exporting (DEX) Option Exten February 2025
Haoyu Song
Futurewei
Email: haoyu.song@futurewei.com
Giuseppe Fioccola
Huawei
Email: giuseppe.fioccola@huawei.com
Aijun Wang
China Telecom
Email: wangaj3@chinatelecom.cn
He, et al. Expires 30 August 2025 [Page 15]