Internet Engineering Task Force (IETF) T. Graf
Request for Comments: 9951 Swisscom
Category: Standards Track B. Claise
ISSN: 2070-1721 Huawei
A. Huang-Feng
INSA-Lyon
March
April 2026
Export of Delay Performance Metrics in IP Flow Information Export
(IPFIX)
Abstract
This document specifies new IP Flow Information Export (IPFIX)
Information Elements to export the On-Path delay at each Operations,
Administration, and Maintenance (OAM) transit and decapsulating
nodes. The On-Path delay is defined as the delay between the OAM
header encapsulating node and each OAM header transit and OAM header
decapsulating nodes. This delay measurement is computed by an On-
Path Telemetry protocol and is exported by the IPFIX process.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9951.
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. Terminology
3. Solution
4. Performance Metrics
4.1. IP One-Way Delay Hybrid Type I Performance Metrics
4.1.1. Summary
4.1.2. Description
4.1.3. Reference
4.1.4. Change Controller
4.1.5. Version of Registry Format
4.2. Metric Definition
4.2.1. Reference Definition
4.2.2. Fixed Parameters
4.3. Method of Measurement
4.3.1. Reference Methods
4.3.2. Packet Stream Generation
4.3.3. Traffic Filtering (Observation) Details
4.3.4. Sampling Distribution
4.3.5. Runtime Parameters and Data Format
4.3.6. Roles
4.4. Output
4.4.1. Type
4.4.2. Reference Definition
4.4.3. Administrative Items
4.4.4. Comments and Remarks
5. Use Cases
6. IANA Considerations
6.1. Performance Metrics
6.2. IPFIX Entities
6.2.1. pathDelayMeanDeltaMicroseconds
6.2.2. pathDelayMinDeltaMicroseconds
6.2.3. pathDelayMaxDeltaMicroseconds
6.2.4. pathDelaySumDeltaMicroseconds
7. Operational Considerations
7.1. Time Accuracy
7.2. Mean Delay
7.3. Reduced-Size Encoding
7.4. Measurement Interval
7.5. In-Packet OAM Application
8. Security Considerations
9. References
9.1. Normative References
9.2. Informative References
Appendix A. IPFIX Encoding Examples
A.1. Aggregated On-Path Delay Examples
A.1.1. Template Record and Data Set with Mean Delta
A.1.2. Template Record and Data Set with Sum Delta
Acknowledgements
Authors' Addresses
1. Introduction
Network operators usually maintain statistical views of delay across
their networks to support diagnostics and performance analysis.
These views assist in identifying the location, extent, and potential
causes of abnormal delay affecting specific customer traffic or
services. To achieve this, delay-related metrics need to be reported
from devices covering both data and control planes. Further, in
order to understand which customers are affected, delay-related
metrics need to be reported in the context of the customer data
plane. This correlation enables the detection of changes in
forwarding paths, such as updated intermediate hops or interfaces,
and of the resulting impact on delay experienced by customer traffic.
Delay measurements in the network are computed using an On-Path
Telemetry protocol, which inserts metadata into the data-plane packet
when entering the monitored domain [RFC9232]. To compute delay
measurements, the On-Path Telemetry protocol inserts a timestamp
reference when entering the OAM encapsulating node. Implementation
examples are In situ Operations, Administration, and Maintenance
(IOAM) [RFC9197] or Enhanced Alternate Marking [ENH-ALT-MARKING].
Two modes of On-Path Telemetry are generally recognized: passport
mode, in which only the OAM header decapsulating node of the OAM
domain reports metrics; and postcard mode, in which OAM header
transit nodes also export On-Path Telemetry data. Both modes enable
exposure of per-hop performance metrics, including delay
accumulation. The approach defined in this document is primarily
applicable to postcard mode.
To enable the export of the delay-related metrics via IPFIX
[RFC7011], this document defines four new IPFIX Information Elements
(IEs), exposing the On-Path delay on OAM header transit and
decapsulating nodes, following the principles of postcard mode.
This enables the computation of delay metrics (minimum, maximum, and
mean) directly on the OAM header transit and decapsulating node,
allowing aggregation within the Flow Record.
As these IEs represent performance metrics, they are also registered
in the IANA "Performance Metrics Registry" [IANA-PERF-METRIC] in
accordance with [RFC8911].
2. Terminology
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 defines the following terms:
OAM Header Encapsulating Node:
Receives the IP packets, encapsulates the packets with an OAM
header, and adds the timestamp into the OAM header.
OAM Header Transit Node:
Receives the IP packets, then measures the delay between the
timestamp in the packet and the timestamp when the packet was
received.
OAM Header Decapsulating Node:
Receives the IP packets, computes the delay between the timestamp
in the packet and the timestamp when the packet was received, and
removes the OAM header from the packet.
This document makes use of the terms defined in [RFC7011], [RFC8911]
and [RFC7799].
The following terms are used as defined in [RFC7011]:
* Collector
* Exporter
* Flow
* Flow Record
* IPFIX
* IPFIX Information Elements (IEs)
* Observation Point
The following terms are used as defined in [RFC8911]:
* Performance Metric
* Performance Metrics Registry
* Registered Performance Metric
The following term is used as defined in Section 3.8 of [RFC7799]:
* Hybrid Type I
3. Solution
In line with the guidelines for Registered Performance Metric
requesters and reviewers [RFC8911], each metric is specified with its
required characteristics (e.g., Identifier, Name, URI, Status,
Requester, Revision, Description) to ensure comparability of
measurement results across implementations and environments. These
characteristics are registered in the IANA "Performance Metrics
Registry" [IANA-PERF-METRIC]. Metric naming follows the
"MetricType_Method_SubTypeMethod_... Spec_Units_Output" convention
defined in Section 7.1.2 of [RFC8911].
This document defines the following performance metrics and IPFIX
Information Elements:
+=============================+================================+
| Performance Metric | IPFIX Information Element |
+=============================+================================+
| OWDelay_HybridType1_I | pathDelayMeanDeltaMicroseconds |
| P_RFC9951_Seconds_Mean (27) | (530) |
+-----------------------------+--------------------------------+
| OWDelay_HybridType1_I | pathDelayMinDeltaMicroseconds |
| P_RFC9951_Seconds_Min (28) | (531) |
+-----------------------------+--------------------------------+
| OWDelay_HybridType1_I | pathDelayMaxDeltaMicroseconds |
| P_RFC9951_Seconds_Max (29) | (532) |
+-----------------------------+--------------------------------+
| OWDelay_HybridType1_I | pathDelaySumDeltaMicroseconds |
| P_RFC9951_Seconds_Sum (30) | (533) |
+-----------------------------+--------------------------------+
Table 1: Mapping Between IPFIX IEs and Performance Metrics
Assuming time synchronization on devices, the delay is measured by
calculating the difference between the timestamp imposed with On-Path
Telemetry in the packet at an OAM header encapsulating node and the
timestamp exported in the IPFIX flow record Flow Record from the OAM header
transit and OAM header decapsulating nodes. The lowest, highest,
mean, and the sum of measured path delay can be exported, thanks to
the different IPFIX IE specifications.
On-Path Telemetry Domain
.........................................
. .
. D1 .
. x-------> .
. .
. D2 .
. x--------------------> .
. .
. D3 .
. x----------------------------------> .
. .
(H1) -----> (R0) ------> (R1) ------> (R2) -------> (R3) -----> (H2)
Host 1 Encapsulating Transit Transit Decapsulating Host 2
Node Node 1 Node 2 Node
. .
. .
.........................................
Figure 1: Delay Use Case: Packets Flow from Host 1 to Host 2
In the use case shown in Figure 1, using On-Path Telemetry to export
the delay metrics, the node R1 exports the delay D1, the node R2
exports the delay D2, and the OAM header decapsulating node R3
exports the total delay D3 for the same flow using IPFIX.
This solution enables the computation of delay metrics (minimum,
maximum, and mean) directly on the OAM header transit and
decapsulating node, allowing aggregation within the Flow Record.
This reduces both export bandwidth and processing requirements on the
Collector. To compute these metrics locally, the Exporter's Metering
Process must perform per-packet caching and processing, particularly
when computing mean delay under Flow Aggregation [RFC7015]. A less
computationally intensive alternative is to export the sum of delays,
allowing the Collector to compute the mean via a simple division
using the packet count.
In contrast, if no delay processing occurs on the OAM header transit
or decapsulating node, each packet must be exported as an individual
Flow Record, including timestamp information, as specified in
[IPFIX-ALT-MARK]. The Collector must then compute the delay metrics
and reconstruct the aggregated Flow Record accordingly.
4. Performance Metrics
This section defines four new performance metrics following the
template defined in Section 11 of [RFC8911].
4.1. IP One-Way Delay Hybrid Type I Performance Metrics
This section specifies four performance metrics for the Hybrid Type I
assessment of IP One-Way Delay; they have been registered in the IANA
"Performance Metrics Registry" [IANA-PERF-METRIC].
All column entries besides the Identifier, Name, URI, Description,
Reference Description (Output only) categories are the same; thus,
this section defines four closely related performance metrics. As a
result, IANA has assigned corresponding URIs to each of the four
registered performance metrics.
4.1.1. Summary
This category includes multiple indexes of the registered performance
metrics: the element Identifier and Metric Name.
4.1.1.1. ID (Identifier)
IANA has allocated the numeric Identifiers 27, 28, 29, and 30 for the
four Named Metric Entries in the following section.
4.1.1.2. Name
27: OWDelay_HybridType1_IP_RFC9951_Seconds_Mean
28: OWDelay_HybridType1_IP_RFC9951_Seconds_Min
29: OWDelay_HybridType1_IP_RFC9951_Seconds_Max
30: OWDelay_HybridType1_IP_RFC9951_Seconds_Sum
4.1.1.3. URI
URI:
<https://www.iana.org/assignments/performance-metrics/
OWDelay_HybridType1_IP_RFC9951_Seconds_Mean>
URI:
<https://www.iana.org/assignments/performance-metrics/
OWDelay_HybridType1_IP_RFC9951_Seconds_Min>
URI:
<https://www.iana.org/assignments/performance-metrics/
OWDelay_HybridType1_IP_RFC9951_Seconds_Max>
URI:
<https://www.iana.org/assignments/performance-metrics/
OWDelay_HybridType1_IP_RFC9951_Seconds_Sum>
4.1.2. Description
OWDelay_HybridType1_IP_RFC9951_Seconds_Mean:
This metric assesses the mean of one-way delays of all
successfully forwarded IP packets constituting a single Flow. The
measurement of one-way delay is based on a single Observation
Point [RFC7011] somewhere in the network.
OWDelay_HybridType1_IP_RFC9951_Seconds_Min:
This metric assesses the minimum of one-way delays of all
successfully forwarded IP packets constituting a single Flow. The
measurement of one-way delay is based on a single Observation
Point [RFC7011] somewhere in the network.
OWDelay_HybridType1_IP_RFC9951_Seconds_Max:
This metric assesses the maximum of one-way delays of all
successfully forwarded IP packets constituting a single Flow. The
measurement of one-way delay is based on a single Observation
Point [RFC7011] somewhere in the network.
OWDelay_HybridType1_IP_RFC9951_Seconds_Sum:
This metric assesses the sum of one-way delays of all successfully
forwarded IP packets constituting a single Flow. The measurement
of one-way delay is based on a single Observation Point [RFC7011]
somewhere in the network.
4.1.3. Reference
RFC 9951
4.1.4. Change Controller
IETF
4.1.5. Version of Registry Format
1.0
4.2. Metric Definition
This category includes columns to prompt the entry of all necessary
details related to the metric definition, including the immutable
document reference and values of input factors, called "Fixed
Parameters".
4.2.1. Reference Definition
See [RFC6049] and [RFC7679] in the Normative References
(Section 9.1).
Section 3.4 of [RFC7679] provides the reference definition of the
singleton (single value) one-way delay metric. Section 4.4 of
[RFC7679] provides the reference definition expanded to cover a
multi-value sample. Note that terms such as "singleton" and "sample"
are defined in Section 11 of [RFC2330].
With the Observation Point [RFC7011] typically located between the
hosts participating in the IP Flow, the one-way delay metric requires
one individual measurement between the Observation Point and sourcing
host, such that the Spatial Composition [RFC6049] of the measurements
yields a one-way delay singleton.
This document specifies how to export the performance metric using
IPFIX.
4.2.2. Fixed Parameters
None
4.3. Method of Measurement
This category includes columns for references to relevant sections of
the RFC(s) and any supplemental information needed to ensure an
unambiguous method for implementations.
4.3.1. Reference Methods
The foundational methodology for this metric is defined in Section 4
of [RFC7323] using the Timestamps option with modifications that
allow application at a mid-path Observation Point [RFC7011].
4.3.2. Packet Stream Generation
This is the time when the packet is being received at the OAM header
encapsulating node. The timestamp format depends on the On-Path
Telemetry implementation. For IOAM, Section 4.4.1 of [RFC9197]
describes the supported timestamps. Sections 4.4.2.3 and 4.4.2.4 of
[RFC9197] describe where the timestamp is being inserted. For the
Enhanced Alternate Marking Method, Section 2 of [ENH-ALT-MARKING] and
Section 3.2 of [RFC9947] define the supported timestamp encodings and
granularity.
4.3.3. Traffic Filtering (Observation) Details
Runtime Parameters (in the following sections) may be used for
Traffic Filtering.
4.3.4. Sampling Distribution
This metric requires a partial sample of all packets that qualify
according to the Traffic Filter criteria.
4.3.5. Runtime Parameters and Data Format
Runtime Parameters are input factors that must be determined,
configured into a measurement system, and reported with the results
for the context to be complete.
The Hybrid Type I metering parameters must be reported to provide the
complete measurement context. As an example, if the IPFIX Metering
Process is used, then the IPFIX Metering Process parameters (IPFIX
Template Record, potential traffic filters, and potential sampling
method and parameters) that generate the Flow Records must be
reported to provide the complete measurement context. At a minimum,
the following fields are required:
Src: The IP address of the host in the host A Role (format ipv4-
address-no-zone value for IPv4 or ipv6-address-no-zone value for
IPv6; see Section 4 of [RFC9911]).
Dst: The IP address of the host in the host B Role (format ipv4-
address-no-zone value for IPv4 or ipv6-address-no-zone value for
IPv6; see Section 4 of [RFC9911]).
T0: T time, the start of a measurement interval (format "date/time"
as specified in Section 5.6 of [RFC3339]; see also "date-and-time"
in Section 3 of [RFC9911]). The UTC Time Zone is required by
Section 6.1 of [RFC2330]. When T0 is "all-zeros", a start time is
unspecified, and Tf is to be interpreted as the duration of the
measurement interval. The start time is controlled through other
means.
Tf: A time, the end of a measurement interval (format "date/time" as
specified in Section 5.6 of [RFC3339]; see also "date-and-time" in
Section 3 of [RFC9911]). The UTC Time Zone is required by
Section 6.1 of [RFC2330]. When T0 is "all-zeros", an ending time
and date are ignored, and Tf is interpreted as the duration of the
measurement interval.
4.3.6. Roles
Host A: Launches an IP packet to start the Flow.
Host B: Receives the IP packet to start the Flow.
OAM Header Encapsulating Node: Receives the IP packets, encapsulates
the packets with the OAM header, and adds the timestamp into the
OAM header.
OAM Header Transit Node: Receives the IP packets, measures the delay
between the timestamp in the packet and the timestamp when the
packet was received.
OAM Header Decapsulating Node: Receives the IP packets, computes the
delay between the timestamp in the packet and the timestamp when
the packet was received, and removes the OAM header from the
packet.
4.4. Output
This category specifies all details of the output of measurements
using the metric.
4.4.1. Type
OWDelay Types are discussed in the subsections below.
4.4.2. Reference Definition
For all output types:
OWDelay_HybridType1_IP: The one-way delay of one IP packet is a
Singleton.
singleton.
For each <statistic> Singleton, singleton, one of the following subsections
applies.
4.4.2.1. OWDelay_HybridType1_IP_RFC9951_Seconds_Mean
Similar to Section 7.4.2.2 of [RFC8912], the mean SHALL be calculated
using the conditional distribution of all packets with a finite value
of one-way delay (undefined delays are excluded) -- a single value,
as follows:
See Section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and see Section 5
of [RFC6703] for background on this analysis choice.
See Section 4.2.2 of [RFC6049] for details on calculating this
statistic; see also Section 4.2.3 of [RFC6049].
Mean: The time value of the result is expressed in units of
microseconds, as a positive value of type decimal64 with fraction
digits = 9 (similar to decimal64 in YANG, Section 9.3 of
[RFC6020]) with a resolution of 0.001 microseconds (1.0 ns), and
with lossless conversion to/from the 64-bit NTP timestamp as per
Section 6 of [RFC5905].
4.4.2.2. OWDelay_HybridType1_IP_RFC9951_Seconds_Min
Similar to Section 7.4.2.3 of [RFC8912], the minimum SHALL be
calculated using the conditional distribution of all packets with a
finite value of one-way delay (undefined delays are excluded) -- a
single value, as follows:
See Section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and see Section 5
of [RFC6703] for background on this analysis choice.
See Section 4.3.2 of [RFC6049] for details on calculating this
statistic; see also Section 4.3.3 of [RFC6049].
Min: The time value of the result is expressed in units of
microseconds, as a positive value of type decimal64 with fraction
digits = 9 (similar to decimal64 in YANG, Section 9.3 of
[RFC6020]) with a resolution of 0.001 microseconds (1.0 ns), and
with lossless conversion to/from the 64-bit NTP timestamp as per
Section 6 of [RFC5905].
4.4.2.3. OWDelay_HybridType1_IP_RFC9951_Seconds_Max
Similar to Section 7.4.2.4 of [RFC8912], the maximum SHALL be
calculated using the conditional distribution of all packets with a
finite value of one-way delay (undefined delays are excluded) -- a
single value, as follows:
See Section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and see Section 5
of [RFC6703] for background on this analysis choice.
See Section 4.3.2 of [RFC6049] for a closely related method for
calculating this statistic; see also Section 4.3.3 of [RFC6049]. The
formula is as follows:
Max = (FiniteDelay[j])
such that for some index, j, where 1 <= j <= N
FiniteDelay[j] >= FiniteDelay[n] for all n
where all packets n = 1 through N have finite singleton delays.
Max: The time value of the result is expressed in units of
microseconds, as a positive value of type decimal64 with fraction
digits = 9 (similar to decimal64 in YANG, Section 9.3 of
[RFC6020]) with a resolution of 0.001 microseconds (1.0 ns), and
with lossless conversion to/from the 64-bit NTP timestamp as per
Section 6 of [RFC5905].
4.4.2.4. OWDelay_HybridType1_IP_RFC9951_Seconds_Sum
The sum SHALL be calculated using the conditional distribution of all
packets with a finite value of one-way delay (undefined delays are
excluded) -- a single value, as follows:
See Section 4.1 of [RFC3393] for details on the conditional
distribution to exclude undefined values of delay, and see Section 5
of [RFC6703] for background on this analysis choice.
See Section 4.3.5 of [RFC6049] for details on calculating this
statistic; however, in this case, FiniteDelay or MaxDelay MAY be
used.
Sum: The time value of the result is expressed in units of
microseconds, as a positive value of type decimal64 with fraction
digits = 9 (similar to decimal64 in YANG, Section 9.3 of
[RFC6020]) with a resolution of 0.001 microseconds (1.0 ns), and
with lossless conversion to/from the 64-bit NTP timestamp as per
Section 6 of [RFC5905].
4.4.2.5. Metric Units
* Mean
* Min
* Max
* Sum
The one-way delay of the IP Flow singleton is expressed in
microseconds.
4.4.2.6. Calibration
A clock synchronization between the nodes of the monitored OAM domain
is needed to compute representative delay measurements at the OAM
header transit and decapsulating nodes. NTP, as defined in
[RFC5905], can be used for synchronizing the clocks of the monitored
nodes.
4.4.3. Administrative Items
4.4.3.1. Status
Current
4.4.3.2. Requester
RFC 9951
4.4.3.3. Revision
1.0
4.4.3.4. Revision Date
2026-MM-DD
4.4.4. Comments and Remarks
None
5. Use Cases
The measured On-Path delay can be aggregated with Flow Aggregation as
defined in [RFC7015] to the following device and control-plane
dimensions [IANA-IPFIX] to determine:
* With node id and egressInterface(14), on which node which logical
egress interfaces have been contributing to how much delay.
* With node id and egressPhysicalInterface(253), on which node which
physical egress interfaces have been contributing to how much
delay.
* With ipNextHopIPv4Address(15) or ipNextHopIPv6Address(62), the
forwarding path to which next-hop IP contributed to how much
delay.
* With mplsTopLabelIPv4Address(47) or destinationIPv6Address and
srhActiveSegmentIPv6(495), the forwarding path to which MPLS top-
label IPv4 address or IPv6 destination address and Segment Routing
over IPv6 (SRv6) active segment contributed to how much delay.
* BGP communities [RFC1997] are often used for setting a path
priority or service selection. With
bgpDestinationExtendedCommunityList(488) or
bgpDestinationCommunityList(485) or
bgpDestinationLargeCommunityList(491), which group of prefixes
accumulated at which node how much delay.
* With destinationIPv4Address(13), destinationTransportPort(11),
protocolIdentifier(4), and sourceIPv4Address(8), or equivalent
IPFIX IEs for IPv6, the forwarding path delay on each node from
each IPv4 source address to a specific application in the network.
Let us consider Figure 1 as a topology example. Table 2 shows the
aggregated delay per each node, ingressInterface(10),
egressInterface(14), destinationIPv6Address(28), and
srhActiveSegmentIPv6(495) measured at ingress.
+===========+===========+======+=============+=============+=======+
| ingress | egress | Node | destination | srhActive | Path |
| Interface | Interface | | IPv6Address | SegmentIPv6 | Delay |
+===========+===========+======+=============+=============+=======+
| 271 | 276 | R0 | | | 0 µs |
+-----------+-----------+------+-------------+-------------+-------+
| 301 | 312 | R1 | 2001:db8::1 | 2001:db8::3 | 22 µs |
+-----------+-----------+------+-------------+-------------+-------+
| 22 | 27 | R2 | 2001:db8::2 | 2001:db8::3 | 42 µs |
+-----------+-----------+------+-------------+-------------+-------+
| 852 | 854 | R3 | 2001:db8::3 | 2001:db8::3 | 122 |
| | | | | | µs |
+-----------+-----------+------+-------------+-------------+-------+
Table 2: Example Table of Measured Delay at Ingress, Ascending
by Delay
6. IANA Considerations
6.1. Performance Metrics
IANA has add four new performance metrics in the "Performance Metrics
Registry" [RFC8911] with the four templates defined in Section 3.
6.2. IPFIX Entities
IANA has registered new IPFIX IEs (see Table 3) in the "IPFIX
Information Elements" registry in the "IP Flow Information Export
(IPFIX) Entities" registry group [IANA-IPFIX] and assigned the
following code points.
+===========+================================+
| ElementID | Name |
+===========+================================+
| 530 | pathDelayMeanDeltaMicroseconds |
+-----------+--------------------------------+
| 531 | pathDelayMinDeltaMicroseconds |
+-----------+--------------------------------+
| 532 | pathDelayMaxDeltaMicroseconds |
+-----------+--------------------------------+
| 533 | pathDelaySumDeltaMicroseconds |
+-----------+--------------------------------+
Table 3: New IPFIX IEs in the "IPFIX
Information Elements" Registry
6.2.1. pathDelayMeanDeltaMicroseconds
Name: pathDelayMeanDeltaMicroseconds
ElementID: 530
Description: This Information Element identifies the mean path delay
of all packets in the Flow, in microseconds, between an OAM header
encapsulating node and the local node with the OAM domain (either
an OAM header transit node or an OAM header decapsulating node),
according to OWDelay_HybridType1_IP_RFC9951_Seconds_Mean in the
IANA "Performance Metrics Registry".
Abstract Data Type: unsigned32
Data Type Semantics: deltaCounter
Reference: RFC 9951
Additional Information: OWDelay_HybridType1_IP_RFC9951_Seconds_Mean
in the IANA "Performance Metrics Registry".
6.2.2. pathDelayMinDeltaMicroseconds
Name: pathDelayMinDeltaMicroseconds
ElementID: 531
Description: This Information Element identifies the lowest path
delay of all packets in the Flow, in microseconds, between an OAM
header encapsulating node and the local node with the OAM domain
(either an OAM header transit node or an OAM header decapsulating
node), according to the OWDelay_HybridType1_IP_RFC9951_Seconds_Min
in the IANA "Performance Metrics Registry".
Abstract Data Type: unsigned32
Data Type Semantics: deltaCounter
Reference: RFC 9951
Additional Information: OWDelay_HybridType1_IP_RFC9951_Seconds_Min
in the IANA "Performance Metrics Registry".
6.2.3. pathDelayMaxDeltaMicroseconds
Name: pathDelayMaxDeltaMicroseconds
ElementID: 532
Description: This Information Element identifies the highest path
delay of all packets in the Flow, in microseconds, between an OAM
header encapsulating node and the local node with the OAM domain
(either an OAM header transit node or an OAM header decapsulating
node), according to OWDelay_HybridType1_IP_RFC9951_Seconds_Max in
the IANA "Performance Metrics Registry".
Abstract Data Type: unsigned32
Data Type Semantics: deltaCounter
Reference: RFC 9951
Additional Information: OWDelay_HybridType1_IP_RFC9951_Seconds_Max
in the IANA "Performance Metrics Registry".
6.2.4. pathDelaySumDeltaMicroseconds
Name: pathDelaySumDeltaMicroseconds
ElementID: 533
Description: This Information Element identifies the sum of the path
delay of all packets in the Flow, in microseconds, between an OAM
header encapsulating node and the local node with the OAM domain
(either an OAM header transit node or an OAM header decapsulating
node), according to OWDelay_HybridType1_IP_RFC9951_Seconds_Sum in
the IANA "Performance Metrics Registry".
Abstract Data Type: unsigned64
Data Type Semantics: deltaCounter
Reference: RFC 9951
Additional Information: OWDelay_HybridType1_IP_RFC9951_Seconds_Sum
in the IANA "Performance Metrics Registry".
7. Operational Considerations
7.1. Time Accuracy
In terms of clock precision, the same recommendation as defined in
Section 4.5 of [RFC5153] for IPFIX applies to this document as well.
7.2. Mean Delay
The mean (average) path delay can be calculated by dividing the
pathDelaySumDeltaMicroseconds(533) by the packetDeltaCount(2) at the
IPFIX data collection in order to offload at the collection time instead of the IPFIX
Exporter from
calculating the mean for every Flow at the export time.
7.3. Reduced-Size Encoding
Unsigned64 has been chosen as the type for
pathDelaySumDeltaMicroseconds to support cases with large delay
numbers and where many packets are being accounted. As an example, a
specific Flow Record with path delay of 100 milliseconds cannot
observe more than 42949 packets without overflowing the unsigned32
counter. The procedure described in Section 6.2 of [RFC7011] may be
applied to reduce network bandwidth between the IPFIX Exporter and
Collector if unsigned32 would be large enough without wrapping
around.
7.4. Measurement Interval
The delay metrics are computed for the Flow Record lifetime by
comparing the OAM timestamps in each received packet with the
timestamp when they were received. For a long-running Flow, the
IPFIX Metering Process might miss the temporal distribution of the
delay (for example, a longer delay only at the beginning of the
Flow). If this is an operational problem, the IPFIX Metering Process
might be configured with a smaller expiration timeout (see "Flow
Expiration", Section 5.1.1 of [RFC5470]).
7.5. In-Packet OAM Application
Multiple methods can be used to compute the delay performance metrics
defined in this document. Some examples of such methods are IOAM
[RFC9197] and Enhanced Alternate Marking [ENH-ALT-MARKING].
For IOAM, these performance metrics can be computed using the Edge-
to-Edge and the Direct Exporting Option-Type.
IOAM Edge-to-Edge Option-Type, as described in Section 4.6 of
[RFC9197], can use bits 2 and 3. In this case, timestamps are
encoded as defined in Sections 4.4.2.3 and 4.4.2.4 of [RFC9197].
This timestamp can be used to compute the delay between an OAM header
encapsulating node and the decapsulating node.
The IOAM Direct Exporting Option-Type, as described in [RFC9326], can
use the Extension-Flag defined in [IOAM-DEX] to insert a timestamp in
the OAM header encapsulating node. The timestamp is encoded as
defined in Sections 4.4.2.3 and 4.4.2.4 of [RFC9197]. This timestamp
can be used to compute the delay between the inserted timestamp and
the OAM header transit and decapsulating node.
For the Enhanced Alternate Marking Method, Section 2 of
[ENH-ALT-MARKING] and Section 3.2 of [RFC9947] define that, within
the metaInfo, a nanosecond timestamp can be encoded in an OAM header
encapsulating node and be read at the OAM header intermediate and
decapsulating node to calculate the on-path delay. [RFC9343] defines
how this can be applied to the IPv6 extensions header, and [RFC9947]
defines how this can be applied to the SRv6 Segment Routing Header
[RFC8754].
Given that the delay measurements are computed with the timestamp
introduced on the OAM header encapsulating node, regardless of the
approach, implementations should document at which point of the
forwarding plane this timestamp is introduced (e.g., the time at
which the packet was received by the node, the time at which the
packet was transmitted by the node, etc.). Based on this
information, different actions can be taken.
8. Security Considerations
The IPFIX Information Elements introduced in this document do not
directly introduce security issues. Rather, they define a set of
performance metrics that may, for privacy or business issues, be
considered sensitive information.
For example, exporting delay metrics may make attacks possible for
the receiver of this information; otherwise, this would only be
possible for direct observers of the reported Flows along the data
path.
IPFIX collectors MUST ensure that IPFIX data originates from trusted
sources. Accepting IPFIX data from unauthenticated sources could
lead to data spoofing, policy misapplication, or denial of service.
Therefore, the underlying protocol used to exchange the information
described here must apply appropriate procedures to guarantee the
integrity and confidentiality of the exported information. These
protocols are defined in separate documents; specifically, see the
IPFIX security considerations in Section 11 of [RFC7011].
Implementations SHOULD also refer to [BCP195] for additional details.
9. References
9.1. Normative References
[BCP195] Best Current Practice 195,
<https://www.rfc-editor.org/info/bcp195>.
At the time of writing, this BCP comprises the following:
Moriarty, K. and S. Farrell, "Deprecating TLS 1.0 and TLS
1.1", BCP 195, RFC 8996, DOI 10.17487/RFC8996, March 2021,
<https://www.rfc-editor.org/info/rfc8996>.
Sheffer, Y., Saint-Andre, P., and T. Fossati,
"Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 9325, DOI 10.17487/RFC9325, November
2022, <https://www.rfc-editor.org/info/rfc9325>.
[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>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>.
[RFC5905] Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
"Network Time Protocol Version 4: Protocol and Algorithms
Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
<https://www.rfc-editor.org/info/rfc5905>.
[RFC6049] Morton, A. and E. Stephan, "Spatial Composition of
Metrics", RFC 6049, DOI 10.17487/RFC6049, January 2011,
<https://www.rfc-editor.org/info/rfc6049>.
[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/info/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/info/rfc7012>.
[RFC7323] Borman, D., Braden, B., Jacobson, V., and R.
Scheffenegger, Ed., "TCP Extensions for High Performance",
RFC 7323, DOI 10.17487/RFC7323, September 2014,
<https://www.rfc-editor.org/info/rfc7323>.
[RFC7679] Almes, G., Kalidindi, S., Zekauskas, M., and A. Morton,
Ed., "A One-Way Delay Metric for IP Performance Metrics
(IPPM)", STD 81, RFC 7679, DOI 10.17487/RFC7679, January
2016, <https://www.rfc-editor.org/info/rfc7679>.
[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>.
[RFC8911] Bagnulo, M., Claise, B., Eardley, P., Morton, A., and A.
Akhter, "Registry for Performance Metrics", RFC 8911,
DOI 10.17487/RFC8911, November 2021,
<https://www.rfc-editor.org/info/rfc8911>.
[RFC8912] Morton, A., Bagnulo, M., Eardley, P., and K. D'Souza,
"Initial Performance Metrics Registry Entries", RFC 8912,
DOI 10.17487/RFC8912, November 2021,
<https://www.rfc-editor.org/info/rfc8912>.
9.2. Informative References
[ENH-ALT-MARKING]
Zhou, T., Ed., Fioccola, G., Liu, Y., Cociglio, M., Pang,
R., Xiong, L., Lee, S., and W. Li, "Enhanced Alternate
Marking Method", Work in Progress, Internet-Draft, draft-
zhou-ippm-enhanced-alternate-marking-18, 5 December 2025,
<https://datatracker.ietf.org/doc/html/draft-zhou-ippm-
enhanced-alternate-marking-18>.
[IANA-IPFIX]
IANA, "IP Flow Information Export (IPFIX) Entities",
<https://www.iana.org/assignments/ipfix>.
[IANA-PERF-METRIC]
IANA, "Performance Metrics",
<https://www.iana.org/assignments/performance-metrics>.
[IOAM-DEX] Huang Feng, A., Francois, P., Claise, B., and T. Graf,
"Timestamp extension for In Situ Operations,
Administration, and Maintenance (IOAM) Direct Export",
Work in Progress, Internet-Draft, draft-ahuang-ippm-dex-
timestamp-ext-00, 15 February 2023,
<https://datatracker.ietf.org/doc/html/draft-ahuang-ippm-
dex-timestamp-ext-00>.
[IPFIX-ALT-MARK]
Graf, T., Fioccola, G., Zhou, T., and Y. Zhu, "IP Flow
Information Export (IPFIX) Alternate-Marking Information
Elements", Work in Progress, Internet-Draft, draft-ietf-
opsawg-ipfix-alt-mark-05, 27 February 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-
ipfix-alt-mark-05>.
[RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities
Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996,
<https://www.rfc-editor.org/info/rfc1997>.
[RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis,
"Framework for IP Performance Metrics", RFC 2330,
DOI 10.17487/RFC2330, May 1998,
<https://www.rfc-editor.org/info/rfc2330>.
[RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation
Metric for IP Performance Metrics (IPPM)", RFC 3393,
DOI 10.17487/RFC3393, November 2002,
<https://www.rfc-editor.org/info/rfc3393>.
[RFC5153] Boschi, E., Mark, L., Quittek, J., Stiemerling, M., and P.
Aitken, "IP Flow Information Export (IPFIX) Implementation
Guidelines", RFC 5153, DOI 10.17487/RFC5153, April 2008,
<https://www.rfc-editor.org/info/rfc5153>.
[RFC5470] Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek,
"Architecture for IP Flow Information Export", RFC 5470,
DOI 10.17487/RFC5470, March 2009,
<https://www.rfc-editor.org/info/rfc5470>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6703] Morton, A., Ramachandran, G., and G. Maguluri, "Reporting
IP Network Performance Metrics: Different Points of View",
RFC 6703, DOI 10.17487/RFC6703, August 2012,
<https://www.rfc-editor.org/info/rfc6703>.
[RFC7015] Trammell, B., Wagner, A., and B. Claise, "Flow Aggregation
for the IP Flow Information Export (IPFIX) Protocol",
RFC 7015, DOI 10.17487/RFC7015, September 2013,
<https://www.rfc-editor.org/info/rfc7015>.
[RFC7799] Morton, A., "Active and Passive Metrics and Methods (with
Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799,
May 2016, <https://www.rfc-editor.org/info/rfc7799>.
[RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J.,
Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header
(SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020,
<https://www.rfc-editor.org/info/rfc8754>.
[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>.
[RFC9232] Song, H., Qin, F., Martinez-Julia, P., Ciavaglia, L., and
A. Wang, "Network Telemetry Framework", RFC 9232,
DOI 10.17487/RFC9232, May 2022,
<https://www.rfc-editor.org/info/rfc9232>.
[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>.
[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>.
[RFC9911] Schönwälder, J., Ed., "Common YANG Data Types", RFC 9911,
DOI 10.17487/RFC9911, December 2025,
<https://www.rfc-editor.org/info/rfc9911>.
[RFC9947] Fioccola, G., Zhou, T., Mishra, G., Wang, X., Zhang, G.,
and M. Cociglio, "Application of the Alternate-Marking
Method to the Segment Routing Header", RFC 9947,
DOI 10.17487/RFC9947, March 2026,
<https://www.rfc-editor.org/info/rfc9947>.
Appendix A. IPFIX Encoding Examples
This appendix represents two different encodings for the newly
introduced IEs. Let's take Figure 1 as a topology example. Table 4
shows the aggregated delay with ingressInterface, egressInterface,
destinationIPv6Address, and srhActiveSegmentIPv6.
+--------------------------------+-------------+
| ingressInterface | 271 |
+--------------------------------+-------------+
| egressInterface | 276 |
+--------------------------------+-------------+
| destinationIPv6Address | 2001:db8::3 |
+--------------------------------+-------------+
| srhActiveSegmentIPv6 | 2001:db8::2 |
+--------------------------------+-------------+
| packetDeltaCount | 5 |
+--------------------------------+-------------+
| pathDelayMeanDeltaMicroseconds | 36 µs |
+--------------------------------+-------------+
| pathDelayMinDeltaMicroseconds | 22 µs |
+--------------------------------+-------------+
| pathDelayMaxDeltaMicroseconds | 74 µs |
+--------------------------------+-------------+
Table 4: Aggregated Delay with
egressInterface and srhActiveSegmentIPv6
A.1. Aggregated On-Path Delay Examples
A.1.1. Template Record and Data Set with Mean Delta
With encoding in Figure 2, the mean (average) path delay is
calculated on the exporting node.
* Ingress interface => ingressInterface
* Egress interface => egressInterface
* IPv6 destination address => destinationIPv6Address
* Active SRv6 Segment => srhActiveSegmentIPv6
* Packet Delta Count => packetDeltaCount
* Minimum One-Way Delay => pathDelayMinDeltaMicroseconds (531)
* Maximum One-Way Delay => pathDelayMaxDeltaMicroseconds (532)
* Mean One-Way Delay => pathDelayMeanDeltaMicroseconds (530)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SET ID = 2 | Length = 40 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 256 | Field Count = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| ingressInterface = 10 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| egressInterface = 14 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationIPv6Address = 28 | Field Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| srhActiveSegmentIPv6 = 495 | Field Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| packetDeltaCount = 5 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| pathDelayMeanDelta.. = 530 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| pathDelayMinDelta.. = 531 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| pathDelayMaxDelta.. = 532 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: Template Record for pathDelayMeanDeltaMicroseconds
The data set is represented as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SET ID = 256 | Length = 60 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ingressInterface = 271 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface = 276 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destinationIPv6Address = |
| ... |
| ... |
| 2001:db8::2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| srhActiveSegmentIPv6 = ... |
| ... |
| ... |
| 2001:db8::3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| packetDeltaCount = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pathDelayMeanDeltaMicroseconds = 36 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pathDelayMinDeltaMicroseconds = 22 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pathDelayMaxDeltaMicroseconds = 74 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Data Set Encoding for pathDelayMeanDeltaMicroseconds
A.1.2. Template Record and Data Set with Sum Delta
With encoding in Figure 4, the mean (average) path delay is
calculated on the IPFIX data collection.
* Ingress interface => ingressInterface
* Egress interface => egressInterface
* IPv6 destination address => destinationIPv6Address
* Active SRv6 Segment => srhActiveSegmentIPv6
* Packet Delta Count => packetDeltaCount
* Minimum One-Way Delay => pathDelayMinDeltaMicroseconds (531)
* Maximum One-Way Delay => pathDelayMaxDeltaMicroseconds (532)
* Sum of One-Way Delay => pathDelaySumDeltaMicroseconds (533)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SET ID = 2 | Length = 40 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Template ID = 257 | Field Count = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| ingressInterface = 10 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| egressInterface = 14 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| destinationIPv6Address = 28 | Field Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| srhActiveSegmentIPv6 = 495 | Field Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| packetDeltaCount = 5 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| pathDelayMinDelta.. = 531 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| pathDelayMaxDelta.. = 532 | Field Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|0| pathDelaySumDelta.. = 533 | Field Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Template Record for pathDelaySumDeltaMicroseconds.
The data set is represented as follows:
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SET ID = 257 | Length = 64 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ingressInterface = 271 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| egressInterface = 276 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| destinationIPv6Address = |
| ... |
| ... |
| 2001:db8::2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| srhActiveSegmentIPv6 = ... |
| ... |
| ... |
| 2001:db8::3 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| packetDeltaCount = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pathDelayMinDeltaMicroseconds = 22 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pathDelayMaxDeltaMicroseconds = 74 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| pathDelaySumDeltaMicroseconds = 180 |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Data Set Encoding for pathDelaySumDeltaMicroseconds
Acknowledgements
The authors would like to thank Al Morton (Rest in Peace, Al), Justin
Iurman, Giuseppe Fioccola, Yannick Buchs, Menachem Dodge, Martin
Duke, Behcet Sarikaya, Mahesh Jethanandani, Linda Dunbar, Deb Cooley,
Mike Bishop, Tim Wicinski, Gunter Van de Velde, and Éric Vyncke for
their review and valuable comments. Special thanks to Paul Aitken
(as IPFIX Designated Expert), Greg Mirsky (as IP Performance Metrics
Designated Expert), and to Med Boucadair for their very detailed
feedback.
Authors' Addresses
Thomas Graf
Swisscom
Binzring 17
CH-8045 Zurich
Switzerland
Email: thomas.graf@swisscom.com
Benoit Claise
Huawei
Email: benoit@everything-ops.net
Alex Huang-Feng
INSA-Lyon
Lyon
France
Email: alex.huang-feng@insa-lyon.fr