Network Working Group T. Graf Internet-Draft Swisscom Intended status: Standards Track B. Claise Expires: 29 March 2025 Huawei A. Huang Feng INSA-Lyon 25 September 2024 Export of Delay Performance Metrics in IP Flow Information eXport (IPFIX) draft-ietf-opsawg-ipfix-on-path-telemetry-13 Abstract This document specifies new IP Flow Information Export (IPFIX) Information Elements to export the On-Path Telemetry measured delay on the OAM transit and decapsulating nodes. 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 29 March 2025. Copyright Notice Copyright (c) 2024 IETF Trust and the persons identified as the document authors. All rights reserved. Graf, et al. Expires 29 March 2025 [Page 1] Internet-Draft Delay Performance Metrics for IPFIX September 2024 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 . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Performance Metrics . . . . . . . . . . . . . . . . . . . . . 6 3.1. IP One-Way Delay Hybrid Type I Passive Performance Metrics . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1.1. Summary . . . . . . . . . . . . . . . . . . . . . . . 7 3.1.2. Description . . . . . . . . . . . . . . . . . . . . . 8 3.1.3. Change Controller . . . . . . . . . . . . . . . . . . 8 3.1.4. Version of Registry Format . . . . . . . . . . . . . 8 3.2. Metric Definition . . . . . . . . . . . . . . . . . . . . 8 3.2.1. Reference Definition . . . . . . . . . . . . . . . . 9 3.2.2. Fixed Parameters . . . . . . . . . . . . . . . . . . 9 3.3. Method of Measurement . . . . . . . . . . . . . . . . . . 9 3.3.1. Reference Methods . . . . . . . . . . . . . . . . . . 9 3.3.2. Packet Stream Generation . . . . . . . . . . . . . . 10 3.3.3. Traffic Filtering (Observation) Details . . . . . . . 10 3.3.4. Sampling Distribution . . . . . . . . . . . . . . . . 10 3.3.5. Runtime Parameters and Data Format . . . . . . . . . 10 3.3.6. Roles . . . . . . . . . . . . . . . . . . . . . . . . 11 3.4. Output . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.4.1. Type . . . . . . . . . . . . . . . . . . . . . . . . 11 3.4.2. Reference Definition . . . . . . . . . . . . . . . . 11 3.4.3. Administrative Items . . . . . . . . . . . . . . . . 14 3.4.4. Comments and Remarks . . . . . . . . . . . . . . . . 14 4. IPFIX Information Elements . . . . . . . . . . . . . . . . . 14 5. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 6.1. Performance Metrics . . . . . . . . . . . . . . . . . . . 16 6.2. IPFIX Entities . . . . . . . . . . . . . . . . . . . . . 16 6.2.1. pathDelayMeanDeltaMicroseconds . . . . . . . . . . . 17 6.2.2. pathDelayMinDeltaMicroseconds . . . . . . . . . . . . 18 6.2.3. pathDelayMaxDeltaMicroseconds . . . . . . . . . . . . 18 6.2.4. pathDelaySumDeltaMicroseconds . . . . . . . . . . . . 19 7. Operational Considerations . . . . . . . . . . . . . . . . . 19 7.1. Time Accuracy . . . . . . . . . . . . . . . . . . . . . . 19 7.2. Mean Delay . . . . . . . . . . . . . . . . . . . . . . . 19 7.3. Reduced-size encoding . . . . . . . . . . . . . . . . . . 19 Graf, et al. Expires 29 March 2025 [Page 2] Internet-Draft Delay Performance Metrics for IPFIX September 2024 7.4. Measurement Interval . . . . . . . . . . . . . . . . . . 20 7.5. In-Packet OAM Application . . . . . . . . . . . . . . . . 20 8. Security Considerations . . . . . . . . . . . . . . . . . . . 20 9. Implementation Status . . . . . . . . . . . . . . . . . . . . 21 9.1. FD.io VPP . . . . . . . . . . . . . . . . . . . . . . . . 21 9.2. Huawei VRP . . . . . . . . . . . . . . . . . . . . . . . 21 9.3. Fluvia . . . . . . . . . . . . . . . . . . . . . . . . . 22 9.4. Pmacct Data Collection . . . . . . . . . . . . . . . . . 22 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 22 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 22 11.1. Normative References . . . . . . . . . . . . . . . . . . 22 11.2. Informative References . . . . . . . . . . . . . . . . . 24 Appendix A. IPFIX Encoding Examples . . . . . . . . . . . . . . 26 A.1. Aggregated On-Path Dealay Examples . . . . . . . . . . . 27 A.1.1. Template Record and Data Set with Mean Delta . . . . 27 A.1.2. Template Record and Data Set with Sum Delta . . . . . 29 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 1. Introduction Network operators usually gather and maintain some forms of statistical delay view of their networks (or segments of their networks). That view is meant to help understanding where in the network, for which customer traffic or services, how much, and why abnormal delay is being accumulated. To that aim, delay-related data need to be reported from devices covering both data and control planes. In order to understand which customer traffic is affected, delay-related data need to be reported into customer data-plane context. That enables network operators to quickly identify when the control-plane updates the current path with a different set of intermediate hops (that is, a change of the forwarding path) and interfaces, how the path delay changes for which customer traffic. With On-Path Telemetry, described in the Network Telemetry Framework [RFC9232] and applied in In Situ Operations, Administration, and Maintenance (IOAM) Deployment [RFC9378] and Alternate Marking Deployment Framework [I-D.ietf-ippm-alt-mark-deployment], the path delay between two endpoints is measured by inserting a timestamp in the packet. At least two modes of On-Path Telemetry can be distinguished. Passport mode, where only the last hop in the forwarding path of the On-Path Telemetry domain exposes all the metrics, and postcard mode, where the metrics are also exposed in transit nodes. In both modes the forwarding path exposes performance metrics allowing to determine how much delay has been accumulated on which hop. The proposal in this document makes more sense for the postcard mode. Graf, et al. Expires 29 March 2025 [Page 3] Internet-Draft Delay Performance Metrics for IPFIX September 2024 In order to export the delay-related metrics via IPIFX [RFC7011], this document defines four new IPFIX Information Elements (IEs), exposing the On-Path delay on OAM transit and decapsulating nodes, following the postcard mode principles. Since these IPFIX IEs are performance metrics [RFC8911], they must be registered in the "IANA Performance Metric Registry [IANA-PERF-METRIC]. Following the guidelines for Registered Performance Metric Requesters and Reviewers [RFC8911], the different characteristics of the performance metrics (Identifier, Name, URI, Status, Requester, Revision, Revision Date, Description, etc.) must be clearly specified in the "IANA Performance Metric Registry [IANA-PERF-METRIC] in order for the measurement results using the Performance Metrics to be comparable even if they are performed using different implementations and in different networks. The first performance metric characteristic is the selection of a meaningful name, following the "MetricType_Method_SubTypeMethod_... Spec_Units_Output" naming convention (See Section 7.1.2 of [RFC8911]). +------------------------------------+-------------------------------+ | Performance Metric | IPFIX Information Element | +------------------------------------+-------------------------------+ |OWDelay_HybridType1_Passive_I |pathDelayMeanDeltaMicroseconds | |P_RFC[RFC-to-be]_Seconds_Mean (TBD1)|(TBD5) | +------------------------------------+-------------------------------+ |OWDelay_HybridType1_Passive_I |pathDelayMinDeltaMicroseconds | |P_RFC[RFC-to-be]_Seconds_Min (TBD2) |(TBD6) | +------------------------------------+-------------------------------+ |OWDelay_HybridType1_Passive_I |pathDelayMaxDeltaMicroseconds | |P_RFC[RFC-to-be]_Seconds_Max (TBD3) |(TBD7) | +------------------------------------+-------------------------------+ |OWDelay_HybridType1_Passive_I |pathDelaySumDeltaMicroseconds | |P_RFC[RFC-to-be]_Seconds_Sum (TBD4) |(TBD8) | +------------------------------------+-------------------------------+ 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 the OAM encapsulating node and the timestamp exported in the IPFIX flow record from the OAM transit and decapsulating nodes. The lowest, highest, mean, and/or the sum of measured path delay can be exported, thanks to the different IPFIX IE specifications. Graf, et al. Expires 29 March 2025 [Page 4] Internet-Draft Delay Performance Metrics for IPFIX September 2024 On-Path Telemetry Domain ......................................... . . . D1 . . x------> . . . . D2 . . x--------------------> . . . . D3 . . x-----------------------------------> . . . (H1) ------ (R1) ------- (R2) ------- (R3) -------- (R4) ------ (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 usecase shown in Figure 1 using On-path Telemetry to export the delay metrics, the node R2 exports the delay D1, the node R3 exports the delay D2 and the decapsulating node R4 exports the total delay D3 using IPFIX. The advantages of this solution is that the delay metrics (min, max, and mean) can be computed on the router, and aggregated directly within the Flow Record, saving export bandwidth and computation on the Collector. For the computation of the min, max, and mean delay metric to be computed locally on the router, the exporter Metering Process requires some local caching/processing computation (for each new packets in the flow), specifically the mean value. A less computational heavy solution for the router is the export of the delay sum instead of the delay mean; on the Collector, the delay mean can easily be computed by a single division operation (using the packet count). The alternative, with any delay monitoring on the router, requires the export of every single packet as a separate Flow Record, including the timestamps information, for the Collector to compute delay metrics (min, max, and mean) and to recompute the aggregated Flow Record. Graf, et al. Expires 29 March 2025 [Page 5] Internet-Draft Delay Performance Metrics for IPFIX September 2024 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 makes use of the terms defined in [RFC7011] and [RFC9378]. The following terms are used as defined in [RFC7011]: * IPFIX * IPFIX Information Elements (IEs) * Flow * Flow Record * Exporter The following terms are used as defined in [RFC8911]: * Performance Metric * Registered Performance Metric * Performance Metrics Registry The following terms are used as defined in Section 5 of [I-D.ietf-opsawg-oam-characterization]: * Encapsulating node * Transit node * Decapsulating node The following terms are used as defined in Section 3.8 of [RFC7799]: * Hybrid Type I Passive 3. Performance Metrics This section defines the new performance metrics following the template defined in Section 11 of [RFC8911]. Graf, et al. Expires 29 March 2025 [Page 6] Internet-Draft Delay Performance Metrics for IPFIX September 2024 IANA Note (to be removed): RFC 8192 Section 4 was taken a guiding example. 3.1. IP One-Way Delay Hybrid Type I Passive Performance Metrics This section specifies four performance metrics for the Hybrid Type I Passive assessment of IP One-Way Delay, to be registered in the "IANA Performance Metric Registry [IANA-PERF-METRIC]. All column entries besides the Identifier, Name, URI, Description, Output, and Reference Method 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. 3.1.1. Summary This category includes multiple indexes of the registered performance metrics: the element Identifier and Metric Name. 3.1.1.1. ID (Identifier) IANA has allocated the numeric Identifiers TBD1, TBD2, TBD3, and TBD4 for the four Named Metric Entries in the following section. RFC EDITOR NOTE: please replace TBD1, TBD2, TBD3, and TBD4. 3.1.1.2. Name TBD1: OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Mean TBD2: OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Min TBD3: OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Max TBD4: OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum RFC EDITOR NOTE: please replace [RFC-to-be]. 3.1.1.3. URI URI: https://www.iana.org/assignments/performance-metrics/ OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Mean URI: https://www.iana.org/assignments/performance-metrics/ OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Min Graf, et al. Expires 29 March 2025 [Page 7] Internet-Draft Delay Performance Metrics for IPFIX September 2024 URI: https://www.iana.org/assignments/performance-metrics/ OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Max URI: https://www.iana.org/assignments/performance-metrics/ OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum RFC EDITOR NOTE: please replace TBD1, TBD2, TBD3, and TBD4. 3.1.2. Description * OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Mean: This metric assesses the mean of one-way delays of all successfully forwarded IP packets constituting a single Flow. We consider the measurement of one-way delay based on a single Observation Point (OP) [RFC7011] somewhere in the network. * OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Min: This metric assesses the minimum of one-way delays of all successfully forwarded IP packets constituting a single Flow. We consider the measurement of one-way delay based on a single Observation Point (OP) [RFC7011] somewhere in the network. * OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Max: This metric assesses the maximum of one-way delays of all successfully forwarded IP packets constituting a single Flow. We consider the measurement of one-way delay based on a single Observation Point (OP) [RFC7011] somewhere in the network. * OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum: This metric assesses the sum of one-way delays of all successfully forwarded IP packets constituting a single Flow. We consider the measurement of one-way delay based on a single Observation Point (OP) [RFC7011] somewhere in the network. 3.1.3. Change Controller IETF 3.1.4. Version of Registry Format 1.0 3.2. 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". Graf, et al. Expires 29 March 2025 [Page 8] Internet-Draft Delay Performance Metrics for IPFIX September 2024 3.2.1. Reference Definition 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, . [RFC7679] Morton, A. and E. Stephan, "Spatial Composition of Metrics", RFC 6049, DOI 10.17487/RFC6049, January 2011, . [RFC6049] 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 2 of [RFC2330]. With the OP [RFC7011] typically located between the hosts participating in the IP Flow, the one-way delay metric requires one individual measurement between the OP 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. 3.2.2. Fixed Parameters None 3.3. 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. 3.3.1. 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 OP [RFC7011]. Graf, et al. Expires 29 March 2025 [Page 9] Internet-Draft Delay Performance Metrics for IPFIX September 2024 3.3.2. Packet Stream Generation The timestamp when the packet is being received at OAM encapsulating node. Format depends on On-Path Telemetry implementation. For IOAM, Section 4.4.1 of [RFC9197] describes what kind of timestamps are supported. Section 4.4.2.3 and 4.4.2.4 describe where the timestamp is being inserted. For the Enhanced Alternate Marking Method, Section 2 of [I-D.zhou-ippm-enhanced-alternate-marking] describes timestamp encoding and granularity. 3.3.3. Traffic Filtering (Observation) Details Runtime Parameters (in the following sections) may be used for Traffic Filtering. 3.3.4. Sampling Distribution This metric requires a partial sample of all packets that qualify according to the Traffic Filter criteria. 3.3.5. 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 [RFC6991]). 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 [RFC6991]). T0: T time, the start of a measurement interval (format "date/time" Graf, et al. Expires 29 March 2025 [Page 10] Internet-Draft Delay Performance Metrics for IPFIX September 2024 as specified in Section 5.6 of [RFC3339]; see also "date-and-time" in Section 3 of [RFC6991]). 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 [RFC6991]). The UTC Time Zone is required by Section 6.1 of [RFC2330]. When T0 is "all-zeros", an ending time and date is ignored and Tf is interpreted as the duration of the measurement interval. 3.3.6. Roles host A: Launches an IP packet to start the Flow. host B: Receives the IP packet to start the Flow. Encapsulating Node: Receives the IP Flow packets and encapsulates the timestamp into the packet. Transit Node: Receives the IP Flow packets and measures the delay between the timestamp in the packet and the timestamp when the packet was received. Decapsulating Node: Receives the IP Flow packets and 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. 3.4. Output This category specifies all details of the output of measurements using the metric. 3.4.1. Type OWDelay Types are discussed in the subsections below. 3.4.2. Reference Definition For all output types: OWDelay_HybridType1_Passive_IP: The one-way delay of one IP packet is a Singleton Graf, et al. Expires 29 March 2025 [Page 11] Internet-Draft Delay Performance Metrics for IPFIX September 2024 For each Singleton one of the following subsections applies. 3.4.2.1. OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_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 seconds, as a positive value of type decimal64 with fraction digits = 9 (similar to the decimal64 in YANG, Section 9.3 of [RFC6020]) with a resolution of 0.000000001 seconds (1.0 ns), and with lossless conversion to/from the 64-bit NTP timestamp as per Section 6 of [RFC5905]. 3.4.2.2. OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_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 seconds, as a positive value of type decimal64 with fraction digits = 9 (similar to the decimal64 in YANG, Section 9.3 of [RFC6020]) with a resolution of 0.000000001 seconds (1.0 ns), and with lossless conversion to/from the 64-bit NTP timestamp as per Section 6 of [RFC5905]. Graf, et al. Expires 29 March 2025 [Page 12] Internet-Draft Delay Performance Metrics for IPFIX September 2024 3.4.2.3. OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_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 seconds, as a positive value of type decimal64 with fraction digits = 9 (similar to the decimal64 in YANG, Section 9.3 of [RFC6020]) with a resolution of 0.000000001 seconds (1.0 ns), and with lossless conversion to/from the 64-bit NTP timestamp as per Section 6 of [RFC5905]. 3.4.2.4. OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_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 seconds, as a positive value of type decimal64 with fraction digits = 9 (similar to the decimal64 in YANG, Section 9.3 of [RFC6020]) with a resolution of 0.000000001 seconds (1.0 ns), and with lossless conversion to/from the 64-bit NTP timestamp as per Section 6 of [RFC5905]. Graf, et al. Expires 29 March 2025 [Page 13] Internet-Draft Delay Performance Metrics for IPFIX September 2024 3.4.2.5. Metric Units * Mean * Min * Max * Sum The one-way delay of the IP Flow singleton is expressed in seconds. 3.4.2.6. Calibration A clock synchronization between the nodes of the monitored OAM domain is needed to compute representative delay measurements at the transit and decapsulating nodes. NTP, as defined in [RFC5905], can be used for synchronizing the clocks of the monitored nodes. 3.4.3. Administrative Items 3.4.3.1. Status Current 3.4.3.2. Requester This RFC RFC EDITOR NOTE: please replace This RFC text by the RFC issued from this document 3.4.3.3. Revision 1.0 3.4.3.4. Revision Date RFC Date 3.4.4. Comments and Remarks none 4. IPFIX Information Elements This section specifies the following new IPFIX IEs: Graf, et al. Expires 29 March 2025 [Page 14] Internet-Draft Delay Performance Metrics for IPFIX September 2024 pathDelayMeanDeltaMicroseconds 32-bit unsigned integer that identifies the mean path delay of all packets in the Flow, in microseconds, between the OAM encapsulating node and the local node with the OAM domain (either an OAM transit node or an OAM decapsulating node). pathDelayMinDeltaMicroseconds 32-bit unsigned integer that identifies the lowest path delay of all packets in the Flow, in microseconds, between the OAM encapsulating node and the local node with the OAM domain (either an OAM transit node or an OAM decapsulating node). pathDelayMaxDeltaMicroseconds 32-bit unsigned integer that identifies the highest path delay of all packets in the Flow, in microseconds, between the OAM encapsulating node and the local node with the OAM domain (either an OAM transit node or an OAM decapsulating node). pathDelaySumDeltaMicroseconds 64-bit unsigned integer that identifies the sum of the path delay of all packets in the Flow, in microseconds, between the OAM encapsulating node and the local node with the OAM domain (either an OAM transit node or an OAM decapsulating node). 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 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 SRv6 active segment contributed to how much delay. Graf, et al. Expires 29 March 2025 [Page 15] Internet-Draft Delay Performance Metrics for IPFIX September 2024 * 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 the example depicted in Figure 1 from Section 1 as topology example. Below example table shows the aggregated delay per each node, ingressInterface,(10) egressInterface(14), destinationIPv6Address(28) and srhActiveSegmentIPv6(495). +-----------+-----------+------+-------------+-------------+------------+ | ingress | egress | Node | destination | srhActive | Path Delay | | Interface | Interface | | IPv6Address | SegmentIPv6 | | +-----------+-----------+------+-------------+-------------+------------+ | 271 | 276 | R1 | 2001:db8::2 | 2001:db8::4 | 0 us | +-----------+-----------+------+-------------+-------------+------------+ | 301 | 312 | R2 | 2001:db8::3 | 2001:db8::4 | 22 us | +-----------+-----------+------+-------------+-------------+------------+ | 22 | 27 | R3 | 2001:db8::4 | 2001:db8::4 | 42 us | +-----------+-----------+------+-------------+-------------+------------+ | 852 | 854 | R4 | 2001:db8::4 | 2001:db8::4 | 122 us | +-----------+-----------+------+-------------+-------------+------------+ Table 2: Example table of measured delay. Ascending by delay. 6. IANA Considerations 6.1. Performance Metrics This document requests IANA to add four new performance metrics under the "Performance Metrics" registry [RFC8911] with the four templates defined in Section 3. 6.2. IPFIX Entities This document requests IANA to register new IPFIX IEs (see table 3) under the "IPFIX Information Elements" registry [RFC7012] available at "IANA IP Flow Information Export (IPFIX) Entities Registry [IANA-IPFIX] and assign the following initial code points. Graf, et al. Expires 29 March 2025 [Page 16] Internet-Draft Delay Performance Metrics for IPFIX September 2024 +-------+--------------------------------+ |Element| Name | | ID | | +-------+--------------------------------+ | TBD5 | pathDelayMeanDeltaMicroseconds | | | | +-------+--------------------------------+ | TBD6 | pathDelayMinDeltaMicroseconds | | | | +-------+--------------------------------+ | TBD7 | pathDelayMaxDeltaMicroseconds | | | | +-------+--------------------------------+ | TBD8 | pathDelaySumDeltaMicroseconds | | | | +-------+--------------------------------+ Table 3: New IPFIX IEs in the "IPFIX Information Elements" Registry Note to the RFC-Editor: * Please replace TBD5 - TBD8 with the values allocated by IANA * Please replace all instances of [RFC-to-be] in this section with the RFC number assigned to this document 6.2.1. pathDelayMeanDeltaMicroseconds Name: pathDelayMeanDeltaMicroseconds ElementID: TBD5 Description: This Information Element identifies the mean path delay of all packets in the Flow, in microseconds, between the OAM encapsulating node and the local node with the OAM domain (either an OAM transit node or an OAM decapsulating node), according to OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Mean in the IANA Performance Metric Registry. Abstract Data Type: unsigned32 Data Type Semantics: deltaCounter Reference: [RFC-to-be] Additional Information: OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Mean in the IANA Performance Metric Registry. Graf, et al. Expires 29 March 2025 [Page 17] Internet-Draft Delay Performance Metrics for IPFIX September 2024 6.2.2. pathDelayMinDeltaMicroseconds Name: pathDelayMinDeltaMicroseconds ElementID: TBD6 Description: This Information Element identifies the lowest path delay of all packets in the Flow, in microseconds, between the OAM encapsulating node and the local node with the OAM domain (either an OAM transit node or an OAM decapsulating node), according to the OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Min in the IANA Performance Metric Registry. Abstract Data Type: unsigned32 Data Type Semantics: deltaCounter Reference: [RFC-to-be] Additional Information: OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Min in the IANA Performance Metric Registry. 6.2.3. pathDelayMaxDeltaMicroseconds Name: pathDelayMaxDeltaMicroseconds ElementID: TBD7 Description: This Information Element identifies the highest path delay of all packets in the Flow, in microseconds, between the OAM encapsulating node and the local node with the OAM domain (either an OAM transit node or an OAM decapsulating node), according to OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Max in the IANA Performance Metric Registry. Abstract Data Type: unsigned32 Data Type Semantics: deltaCounter Reference: [RFC-to-be] Additional Information: OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Max in the IANA Performance Metric Registry. Graf, et al. Expires 29 March 2025 [Page 18] Internet-Draft Delay Performance Metrics for IPFIX September 2024 6.2.4. pathDelaySumDeltaMicroseconds Name: pathDelaySumDeltaMicroseconds ElementID: TBD8 Description: This Information Element identifies the sum of the path delay of all packets in the Flow, in microseconds, between the OAM encapsulating node and the local node with the OAM domain (either an OAM transit node or an OAM decapsulating node), according to OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum in the IANA Performance Metric Registry. Abstract Data Type: unsigned64 Data Type Semantics: deltaCounter Reference: [RFC-to-be] Additional Information: OWDelay_HybridType1_Passive_IP_RFC[RFC-to-be]_Seconds_Sum in the IANA Performance Metric Registry. 7. Operational Considerations 7.1. Time Accuracy The same recommendation as defined in Section 4.5 of [RFC5153] for IPFIX applies in terms of clock precision to this document as well. 7.2. Mean Delay The mean (average) path delay can be calculated by dividing the pathDelaySumDeltaMicroseconds(TBD8) by the packetDeltaCount(2) at the IPFIX data collection in order to offload the IPFIX Exporter from calculating the mean for every Flow at export time. 7.3. Reduced-size encoding Unsigned64 has been chosen as 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. Graf, et al. Expires 29 March 2025 [Page 19] Internet-Draft Delay Performance Metrics for IPFIX September 2024 7.4. Measurement Interval The delay metrics are computed for the Flow Record life time. For long-running Flow, we might miss the temporal distribution of the delay (for example, a longer delay only at the beginning of Flow). If this is an operational problem, the IPFIX Metering Process might be configured with a smaller expiration timeout (see Section 5.1.1. Flow Expiration[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 [I-D.zhou-ippm-enhanced-alternate-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 Section 4.4.2.3 and 4.4.2.4 of [RFC9197]. This timestamp can be used to compute the delay between the encapsulating node and the decapsulating node. IOAM Direct Exporting Option-Type, as described in [RFC9326], can use the Extension-Flag defined in [I-D.ahuang-ippm-dex-timestamp-ext] to insert a timestamp in the encapsulating node. The timestamp is encoded as defined in Section 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 transit and decapsulating node. For the Enhanced Alternate Marking Method, Section 2 of [I-D.zhou-ippm-enhanced-alternate-marking] defines that, within the metaInfo, a nanosecond timestamp can be encoded in the encapsulating node and be read at the intermediate and decapsulating node to calculate the on-path delay. [RFC9343] defines how this can be applied to the IPv6 data-plane and [I-D.fz-spring-srv6-alt-mark] defines how this can be applied to the Segment Routing Header in SRv6. 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. Graf, et al. Expires 29 March 2025 [Page 20] Internet-Draft Delay Performance Metrics for IPFIX September 2024 For example, exporting delay metrics may make attacks possible for the receiver of this information; this would otherwise only be possible for direct observers of the reported Flows along the data path. The underlying protocol used to exchange the information described here must therefore apply appropriate procedures to guarantee the integrity and confidentiality of the exported information. These protocols are defined in separate documents, specifically the IPFIX protocol document [RFC7011]. 9. Implementation Status Note to the RFC-Editor: Please remove this section before publishing. 9.1. FD.io VPP INSA Lyon implemented the following IEs as part of a prototype in the FD.io VPP (Vector Packet Processing) platform: * pathDelayMeanDeltaMicroseconds * pathDelayMaxDeltaMicroseconds * pathDelayMinDeltaMicroseconds * pathDelaySumDeltaMicroseconds The open source code can be obtained here: [INSA-Lyon-VPP] and was validated at the IETF 116 hackathon. 9.2. Huawei VRP Huawei implemented the following IEs as part of a a production implementation in the VRP platform: * pathDelayMeanDeltaMicroseconds * pathDelayMaxDeltaMicroseconds * pathDelayMinDeltaMicroseconds * pathDelaySumDeltaMicroseconds The implementation was validated at the IETF 116 hackathon. Graf, et al. Expires 29 March 2025 [Page 21] Internet-Draft Delay Performance Metrics for IPFIX September 2024 9.3. Fluvia NTT Com implemented the following IEs in the Fluvia Exporter: * pathDelayMeanDeltaMicroseconds * pathDelayMaxDeltaMicroseconds * pathDelayMinDeltaMicroseconds * pathDelaySumDeltaMicroseconds The open source code can be obtained here: [NTT-Fluvia] and was validated at the IETF 118 hackathon. 9.4. Pmacct Data Collection Paolo Lucente implemented the IE pathDelayMeanDeltaMicroseconds by dividing IE pathDelaySumDeltaMicroseconds by IE packetDeltaCount in the open source Network Telemetry data collection project pmacct. The source code can be obtained here: [Paolo-Lucente-Pmacct] and was validated at the IETF 116 hackathon. 10. Acknowledgements The authors would like to thank Al Morton (Rest in Peace Al), Justin Iurman, Giuseppe Fioccola and Yannick Buchs 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 his very detailed feedback. 11. References 11.1. Normative References [I-D.ietf-opsawg-oam-characterization] Pignataro, C. and A. Farrel, "Guidelines for Charactering "OAM"", Work in Progress, Internet-Draft, draft-ietf- opsawg-oam-characterization-03, 29 August 2024, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Graf, et al. Expires 29 March 2025 [Page 22] Internet-Draft Delay Performance Metrics for IPFIX September 2024 [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, . [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, . [RFC6049] Morton, A. and E. Stephan, "Spatial Composition of Metrics", RFC 6049, DOI 10.17487/RFC6049, January 2011, . [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, . [RFC7012] Claise, B., Ed. and B. Trammell, Ed., "Information Model for IP Flow Information Export (IPFIX)", RFC 7012, DOI 10.17487/RFC7012, September 2013, . [RFC7323] Borman, D., Braden, B., Jacobson, V., and R. Scheffenegger, Ed., "TCP Extensions for High Performance", RFC 7323, DOI 10.17487/RFC7323, September 2014, . [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, . [RFC7799] Morton, A., "Active and Passive Metrics and Methods (with Hybrid Types In-Between)", RFC 7799, DOI 10.17487/RFC7799, May 2016, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8911] Bagnulo, M., Claise, B., Eardley, P., Morton, A., and A. Akhter, "Registry for Performance Metrics", RFC 8911, DOI 10.17487/RFC8911, November 2021, . Graf, et al. Expires 29 March 2025 [Page 23] Internet-Draft Delay Performance Metrics for IPFIX September 2024 [RFC8912] Morton, A., Bagnulo, M., Eardley, P., and K. D'Souza, "Initial Performance Metrics Registry Entries", RFC 8912, DOI 10.17487/RFC8912, November 2021, . 11.2. Informative References [I-D.ahuang-ippm-dex-timestamp-ext] Feng, A. H., 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, . [I-D.fz-spring-srv6-alt-mark] Fioccola, G., Zhou, T., Cociglio, M., Mishra, G. S., wang, X., and G. Zhang, "Application of the Alternate Marking Method to the Segment Routing Header", Work in Progress, Internet-Draft, draft-fz-spring-srv6-alt-mark-09, 9 August 2024, . [I-D.ietf-ippm-alt-mark-deployment] Fioccola, G., Keyi, Z., Graf, T., Nilo, M., and L. Zhang, "Alternate Marking Deployment Framework", Work in Progress, Internet-Draft, draft-ietf-ippm-alt-mark- deployment-01, 3 July 2024, . [I-D.zhou-ippm-enhanced-alternate-marking] Zhou, T., 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-15, 27 May 2024, . [IANA-IPFIX] "IANA IP Flow Information Export (IPFIX) Entities Registry", . Graf, et al. Expires 29 March 2025 [Page 24] Internet-Draft Delay Performance Metrics for IPFIX September 2024 [IANA-PERF-METRIC] "IANA Performance Metric Registry", . [INSA-Lyon-VPP] "INSA Lyon, FD.io VPP implementation", . [NTT-Fluvia] "NTT Com, Fluvia Exporter", . [Paolo-Lucente-Pmacct] "Paolo Lucente, Pmacct open source Network Telemetry Data Collection", . [RFC1997] Chandra, R., Traina, P., and T. Li, "BGP Communities Attribute", RFC 1997, DOI 10.17487/RFC1997, August 1996, . [RFC2330] Paxson, V., Almes, G., Mahdavi, J., and M. Mathis, "Framework for IP Performance Metrics", RFC 2330, DOI 10.17487/RFC2330, May 1998, . [RFC3393] Demichelis, C. and P. Chimento, "IP Packet Delay Variation Metric for IP Performance Metrics (IPPM)", RFC 3393, DOI 10.17487/RFC3393, November 2002, . [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, . [RFC5470] Sadasivan, G., Brownlee, N., Claise, B., and J. Quittek, "Architecture for IP Flow Information Export", RFC 5470, DOI 10.17487/RFC5470, March 2009, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . Graf, et al. Expires 29 March 2025 [Page 25] Internet-Draft Delay Performance Metrics for IPFIX September 2024 [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, . [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", RFC 6991, DOI 10.17487/RFC6991, July 2013, . [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, . [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, . [RFC9232] Song, H., Qin, F., Martinez-Julia, P., Ciavaglia, L., and A. Wang, "Network Telemetry Framework", RFC 9232, DOI 10.17487/RFC9232, May 2022, . [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, . [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, . [RFC9378] Brockners, F., Ed., Bhandari, S., Ed., Bernier, D., and T. Mizrahi, Ed., "In Situ Operations, Administration, and Maintenance (IOAM) Deployment", RFC 9378, DOI 10.17487/RFC9378, April 2023, . Appendix A. IPFIX Encoding Examples This appendix represents two different encodings for the newly introduced IEs. Taking Figure 1 from Section 1 as topology example. Below example Table 4 shows the aggregated delay with ingressInterface, egressInterface, destinationIPv6Address and srhActiveSegmentIPv6. Graf, et al. Expires 29 March 2025 [Page 26] Internet-Draft Delay Performance Metrics for IPFIX September 2024 +------ +------+-----------+-----------+------+---------+---------+---------+---------+ |ingress|egress|destination|srhActive |packet|pathDelay|pathDelay|pathDelay|pathDelay| |Inter |Inter |IPv6Address|SegmentIPv6|Delta |MeanDelta|MinDelta |MaxDelta |SumDelta | |face |face | | |Count |Micro.. |Micro.. |Micro.. |Micro.. | +-------+------+-----------+-----------+------+---------+---------+---------+---------+ | 271 | 276 |2001:db8::4|2001:db8::2| 5 | 36 us | 22 us | 74 us | 180 us | +-------+------+-----------+-----------+------+---------+---------+---------+---------+ Table 4: Aggregated delay with egressInterface and srhActiveSegmentIPv6 A.1. Aggregated On-Path Dealay 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 => srhIPv6ActiveSegment * Packet Delta Count => packetDeltaCount * Minimum One-Way Delay => pathDelayMinDeltaMicroseconds (TBD6) * Maximum One-Way Delay => pathDelayMaxDeltaMicroseconds (TBD7) * Mean One-Way Delay => pathDelayMeanDeltaMicroseconds (TBD5) Graf, et al. Expires 29 March 2025 [Page 27] Internet-Draft Delay Performance Metrics for IPFIX September 2024 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| srhIPv6ActiveSegment = 495 | Field Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| packetDeltaCount = 5 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| pathDelayMeanDelta.. = TBD5 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| pathDelayMinDelta.. = TBD6 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| pathDelayMaxDelta.. = TBD7 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Template Record for pathDelayMeanDeltaMicroseconds The data set is represented as follows: Graf, et al. Expires 29 March 2025 [Page 28] Internet-Draft Delay Performance Metrics for IPFIX September 2024 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhIPv6ActiveSegment = ... | | ... | | ... | | 2001:db8::4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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 => srhIPv6ActiveSegment * Packet Delta Count => packetDeltaCount * Minimum One-Way Delay => pathDelayMinDeltaMicroseconds (TBD6) Graf, et al. Expires 29 March 2025 [Page 29] Internet-Draft Delay Performance Metrics for IPFIX September 2024 * Maximum One-Way Delay => pathDelayMaxDeltaMicroseconds (TBD7) * Sum of One-Way Delay => pathDelaySumDeltaMicroseconds (TBD8) 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| srhIPv6ActiveSegment = 495 | Field Length = 16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| packetDeltaCount = 5 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| pathDelayMinDelta.. = TBD6 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| pathDelayMaxDelta.. = TBD7 | Field Length = 4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| pathDelaySumDelta.. = TBD8 | Field Length = 8 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: Template Record for pathDelaySumDeltaMicroseconds The data set is represented as follows: Graf, et al. Expires 29 March 2025 [Page 30] Internet-Draft Delay Performance Metrics for IPFIX September 2024 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 = 60 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ingressInterface = 271 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | egressInterface = 276 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | destinationIPv6Address = | | ... | | ... | | 2001:db8::2 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | srhIPv6ActiveSegment = ... | | ... | | ... | | 2001:db8::4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | packetDeltaCount = 5 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | pathDelayMinDeltaMicroseconds = 22 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | pathDelayMaxDeltaMicroseconds = 74 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | pathDelaySumDeltaMicroseconds = 180 | | ... | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: Data Set Encoding for pathDelaySumDeltaMicroseconds Authors' Addresses Thomas Graf Swisscom Binzring 17 CH-8045 Zurich Switzerland Email: thomas.graf@swisscom.com Benoit Claise Huawei Email: benoit.claise@huawei.com Graf, et al. Expires 29 March 2025 [Page 31] Internet-Draft Delay Performance Metrics for IPFIX September 2024 Alex Huang Feng INSA-Lyon Lyon France Email: alex.huang-feng@insa-lyon.fr Graf, et al. Expires 29 March 2025 [Page 32]