<?xml version="1.0"encoding="utf-8"?> <?xml-stylesheet type="text/xsl" href="rfc2629.xslt" ?> <!-- generated by https://github.com/cabo/kramdown-rfc2629 version 1.2.13 -->encoding="UTF-8"?> <!DOCTYPE rfcSYSTEM "rfc2629.dtd"[ <!ENTITY nbsp " "> <!ENTITY zwsp "​"> <!ENTITY nbhy "‑"> <!ENTITY wj "⁠"> ]><?rfc toc="yes"?> <?rfc sortrefs="yes"?> <?rfc symrefs="yes"?> <?rfc comments="yes"?><rfc xmlns:xi="http://www.w3.org/2001/XInclude" ipr="trust200902" docName="draft-ietf-mpls-rfc6374-sfl-10"category="std">number="9571" obsoletes="" updates="" submissionType="IETF" category="std" consensus="true" xml:lang="en" tocInclude="true" sortRefs="true" symRefs="true" version="3"> <!-- xml2rfc v2v3 conversion 3.6.0 --> <front> <titleabbrev="RFC6374-SFL">RFC6374abbrev="SFL">Extension of RFC 6374-Based Performance Measurement Using Synonymous Flow Labels</title> <seriesInfo name="RFC" value="9571"/> <author initials="S."surname="Bryant (Ed)"surname="Bryant" fullname="StewartBryant"> <organization>Futurewei Technologies Inc.</organization>Bryant" role="editor"> <organization>University of Surrey</organization> <address> <email>sb@stewartbryant.com</email> </address> </author> <author initials="G." surname="Swallow" fullname="George Swallow"><organization>Southend Technical Center</organization><organization>Independent</organization> <address> <email>swallow.ietf@gmail.com</email> </address> </author> <author initials="M." surname="Chen"fullname="Machfullname="Mach(Guoyi) Chen"> <organization>Huawei</organization> <address> <email>mach.chen@huawei.com</email> </address> </author> <author initials="G." surname="Fioccola" fullname="Giuseppe Fioccola"> <organization>Huawei Technologies</organization> <address> <email>giuseppe.fioccola@huawei.com</email> </address> </author> <author initials="G." surname="Mirsky" fullname="Gregory Mirsky"> <organization>ZTE Corp.</organization> <address> <email>gregimirsky@gmail.com</email> </address> </author> <dateyear="2021" month="March" day="05"/> <workgroup>MPLS Working Group</workgroup>year="2024" month="May"/> <workgroup>MPLS</workgroup> <keyword>Performance Measurement</keyword> <keyword>OAM</keyword> <abstract> <t>RFC 6374 describes methods of making loss and delay measurements on Label Switched Paths (LSPs) primarily as they are used in MPLS Transport Profile (MPLS-TP) networks. This document describes a method of extendingRFC 6374the performance measurements (specified in RFC 6374) from flows carried over MPLS-TP to flows carried over generic MPLS LSPs. In particular, it extends the technique to allow loss and delay measurements to be made onmulti-point to pointmultipoint-to-point LSPs and introduces some additional techniques to allow more sophisticated measurements to be made in both MPLS-TP and generic MPLS networks.</t> </abstract> </front> <middle> <section anchor="introduction"title="Introduction">numbered="true" toc="default"> <name>Introduction</name> <t><xreftarget="RFC6374"/>target="RFC6374" format="default"/> was originally designed for use as an Operations, Administration, and Maintenance (OAM) protocol for use with MPLS Transport Profile (MPLS-TP) <xreftarget="RFC5921"/>target="RFC5921" format="default"/> LSPs. MPLS-TP only supports point-to-point andpoint-to-multi-pointpoint-to-multipoint LSPs. This document describes how to useRFC6374<xref target="RFC6374" format="default"/> in the generic MPLScase,case and also introduces a number of more sophisticated measurements of applicability to both cases.</t> <t><xreftarget="RFC8372"/>target="RFC8372" format="default"/> describes the requirement for introducing flow identities when usingRFC6374 <xref target="RFC6374"/>packetLoss Measurements (LM).loss measurements described in <xref target="RFC6374" format="default"/>. Insummary RFC6374 usessummary, <xref target="RFC6374" format="default"/> describes use of theloss-measurementloss measurement (LM)packetmessage as the packet accounting demarcation point.UnfortunatelyUnfortunately, this gives rise to a number of problems that may lead to significant packet accounting errors in certain situations. For example:</t><t><list style="numbers"> <t>Where<ol spacing="normal" type="1"><li>Where a flow is subjected toEqual Cost Multi-PathEqual-Cost Multipath (ECMP)treatmenttreatment, packets can arrive out of order with respect to the LMpacket.</t> <t>Wherepacket.</li> <li>Where a flow is subjected to ECMP treatment, packets can arrive at different hardware interfaces, thus requiring reception of an LM packet on one interface to trigger a packet accounting action on a different interfacewhichthat may not be co-located with it. This is a difficult technical problem to address with the required degree ofaccuracy.</t> <t>Evenaccuracy.</li> <li>Even where there is no ECMP (forexampleexample, on RSVP-TE, MPLS-TPLSPsLSPs, andpseudowires(PWs))pseudowires (PWs)), local processing may be distributed over a number of processor cores, leading to synchronizationproblems.</t> <t>Linkproblems.</li> <li>Link aggregation techniques <xreftarget="RFC7190"/>target="RFC7190" format="default"/> may also lead to synchronizationissues.</t> <t>Someissues.</li> <li>Some forwarder implementations have a long pipeline between processing a packet and incrementing the associated counter, again leading to synchronizationdifficulties.</t> </list></t>difficulties.</li> </ol> <t>An approach to mitigating these synchronizationissueissues is described in <xreftarget="RFC8321"/> in whichtarget="RFC9341" format="default"/> -- the packets are batched by thesendersender, and each batch is marked in some way such that adjacent batches can be easily recognized by the receiver.</t> <t>An additional problem arises where the LSP is amulti-point to point LSP,multipoint-to-point LSP since MPLS does not include a source address in the packet. Network management operations require the measurement of packet loss between a source and destination. It is thus necessary to introduce somesource specificsource-specific information into the packet to identify packet batches from a specific source.</t> <t><xreftarget="RFC8957"/>target="RFC8957" format="default"/> describes a method of encodingper flowper-flow instructions in an MPLS label stack using a technique called Synonymous Flow Labels(SFL)(SFLs), in which labelswhichthat mimic the behavior of other labels provide the packet batch identifiers and enable theper batchper-batch packet accounting. This memo specifies how SFLs are used to performRFC6374packet loss andRFC6374delaymeasurements.</t>measurements as described in <xref target="RFC6374" format="default"/>.</t> <t> When the terms "performance measurement method," "Query," "packet," or "message" are used in this document, they refer to a performance measurement method, Query, packet, or message as specified in <xref target="RFC6374"/>. </t> </section> <section anchor="requirements-language"title="Requirements Language"> <t>Thenumbered="true" toc="default"> <name>Requirements Language</name> <t> The key words“MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “NOT RECOMMENDED”, “MAY”,"<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and“OPTIONAL”"<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as described inBCP 14BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they appear in all capitals, as shownhere.</t>here. </t> </section> <section anchor="rfc6374-packet-loss-measurement-with-sfl"title="RFC6374 Packetnumbered="true" toc="default"> <name>Packet Loss Measurementwith SFL">Using SFL</name> <t>The data service packets of the flow being instrumented are grouped into batches, and all the packets within a batch are marked with the SFL <xreftarget="RFC8372"/>target="RFC8372" format="default"/> corresponding to that batch. The sender counts the number of packets in the batch. When the batch has completed and the sender is confident that all of the packets in that batch will have been received, the sender issuesan RFC6374a Query message to determine the number actually received and hence the number of packets lost. TheRFC6374Query message is sent using the same SFL as the corresponding batch of data service packets. The format of the Query and Response packets is described in <xreftarget="RFC6374SFL"/>.</t>target="sec-RFC6374SFL" format="default"/>.</t> </section> <section anchor="SPD"title="RFC6374 Singlenumbered="true" toc="default"> <name>Single Packet DelayMeasurement"> <t>RFC6374Measurement Using SFL</name> <t><xref target="RFC6374" format="default"/> describes how to measure the packet delay by measuring the transit time ofan RFC6374a packet over an LSP. Such a packet may not need to be carried over an SFL since the delay over a particular LSP should be a function of the Traffic Class (TC) bits.</t> <t>However, where SFLs are being used to monitor packet loss or wherelabel inferredlabel-inferred scheduling is used <xreftarget="RFC3270"/>target="RFC3270" format="default"/>, then the SFL would beREQUIRED<bcp14>REQUIRED</bcp14> to ensure that theRFC6374packetwhichthat was being used as a proxy for a data service packet experienced a representative delay. The format ofan RFC6374a packet carried over the LSP using an SFL is shown in <xreftarget="RFC6374SFL"/>.</t>target="sec-RFC6374SFL" format="default"/>.</t> </section> <section anchor="data-service-packet-delay-measurement"title="Datanumbered="true" toc="default"> <name>Data Service Packet DelayMeasurement">Measurement</name> <t>Where it is desired to more thoroughly instrument a packet flow and to determine the delay of a number ofpacketspackets, it is undesirable to send a large number ofRFC6374packets acting asaproxy data service packets (see <xreftarget="SPD"/>).target="SPD" format="default"/>). A method of directly measuring the delay characteristics of a batch of packets is therefore needed.</t> <t>Given the long intervals over which it is necessary to measure packet loss, it is not necessarily the case that the batch times for the two measurement types would be identical. Thus, we use a technique that permits the two measurementsareto be made concurrently and yet relativelyindependentindependently from each other. The notion that they are relatively independent arises from the potential for the two batches to overlap in time, in which case either the delay batch time will need to be cut short or the loss time will need to be extended to allow correct reconciliation of the various counters.</t> <t>The problem is illustrated in <xreftarget="FIGDM"/> below:</t>target="fig1"/>.</t> <figuretitle="RFC6734 Queryanchor="fig1"> <name>Query Packet withSFL" anchor="FIGDM"><artwork><![CDATA[ (1)SFL</name> <artwork> (Case 1) AAAAAAAAAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB SFLMarkingmarking of a packet batch for loss measurement(2)(Case 2) AADDDDAAAABBBBBBBBBBAAAAAAAAAABBBBBBBBBB SFLMarkingmarking of a subset of the packets for delay(3)(Case 3) AAAAAAAADDDDBBBBBBBBAAAAAAAAAABBBBBBBBBB SFLMarkingmarking of a subset of the packets across a packet loss measurement boundary(4)(Case 4) AACDCDCDAABBBBBBBBBBAAAAAAAAAABBBBBBBBBBTheA case of multiple delay measurements within a packet loss measurement where A&and B are packets where loss is beingmeasuredmeasured. C&and D arepacektspackets where loss and delayisare beingmeasured ]]></artwork></figure>measured. </artwork></figure> <t>Incase 1 of <xref target="FIGDM"/>Case 1, we showthe casewhere loss measurement alone is being carried out on the flow under analysis. For illustrativepurposespurposes, consider that 10 packets are used in each flow in the time interval being analyzed.</t> <t>Now considercase 2 of <xref target="FIGDM"/>Case 2, where a small batch of packets need to be analyzed for delay. These are marked with a different SFLtypetype, indicating that they are to be monitored for both loss and delay. The SFL=A indicates loss batch A, and SFL=D indicates a batch of packets that are to be instrumented for delay, but SFL D is synonymous with SFL A, which in turn is synonymous with the underlying Forwarding Equivalence Class (FEC). Thus, a packet markedD"D" will be accumulated into the A loss batch, into the delaystatisticsstatistics, and will be forwarded as normal. Whether the packet is actually counted twice (for loss and delay) or whether the two counters are reconciled during reporting is a local matter.</t> <t>Now considercase 3 of <xref target="FIGDM"/>Case 3, where a small batch of packetsareis marked for delay across a loss batch boundary. These packets need to be considered as a part of batch A or a part of batch B, and anyRFC6374Query needs to take place after allthepackets A or D (whichever option is chosen) have arrived at the receivingLSR.</t>Label Switching Router (LSR).</t> <t>Now considercase 4 of <xref target="FIGDM"/>. HereCase 4. Here, we have a case where it is required to take a number of delay measurements within a batch of packets that we are measuring for loss. To dothisthis, we need two SFLs for delay (C and D) and alternate between them (on adelay batch by delay batchdelay-batch-by-delay-batch basis) for the purposes of measuring the delay characteristics of the different batches of packets.</t> </section> <section anchor="some-simplifying-rules"title="Somenumbered="true" toc="default"> <name>Some SimplifyingRules">Rules</name> <t>It is possible to construct a large set of overlapping measurementtypes,types in terms of loss, delay, loss anddelaydelay, and batch overlap. If we allow all combinations of cases, this leads to configuration,testingtesting, and implementation complexityand henceand, hence, increased costs. The following simplifying rules represent the default case:</t><t><list style="numbers"> <t>Any<ol spacing="normal" type="1"><li>Any system that needs to measure delayMUST<bcp14>MUST</bcp14> be able to measureloss.</t> <t>Anyloss.</li> <li>Any system that is to measure delayMUST<bcp14>MUST</bcp14> be configured to measure loss. Whether the loss statistics are collected or not is a localmatter.</t> <t>Amatter.</li> <li>A delay measurementMAY<bcp14>MAY</bcp14> start at any point during a loss measurement batch, subject to rule4.</t> <t>A4.</li> <li>A delay measurement intervalMUST<bcp14>MUST</bcp14> be short enough that it will complete before the enclosing loss batchcompletes.</t> <t>Thecompletes.</li> <li>The duration of a second delay batch (D in <xreftarget="FIGDM"/> batchtarget="fig1"/>) must be such that all packets from the packets belonging to a first delay batch (C in <xreftarget="FIGDM"/>)willtarget="fig1"/>) will have been received before the second delay batch completes. This condition is satisfied when the time to send a batch is long compared to the network propagationtime,time and is a parameter that can be established by the networkoperator.</t> </list></t>operator.</li> </ol> <t>Given that the sender controls both the start and duration of a loss and a delay packet batch, these rules are readily implemented in the control plane.</t> </section> <section anchor="multiple-packet-delay-characteristics"title="Multiplenumbered="true" toc="default"> <name>Multiple Packet DelayCharacteristics">Characteristics</name> <t>A number of methods are describedwhichthat add to the set of measurements originally specified in <xreftarget="RFC6374"/>.target="RFC6374" format="default"/>. Each of these methods has different characteristics and different processing demands on the packet forwarder. The choice of method will depend on the type of diagnostic that the operator seeks.</t> <t>ThreeMethodsmethods are discussed:</t><t><list style="numbers"> <t>Time Buckets</t> <t>Classic<ol spacing="normal" type="1"><li>Time Buckets</li> <li>Classic StandardDeviation</t> <t>Average Delay</t> </list></t>Deviation</li> <li>Average Delay</li> </ol> <section anchor="method-1-time-buckets"title="Methodnumbered="true" toc="default"> <name>Method 1: TimeBuckets">Buckets</name> <t>In thismethodmethod, the receiving LSR measures the inter-packet gap, classifies the delay into a number of delaybucketsbuckets, and records the number of packets in each bucket. As an example, if the operator were concerned about packets with a delay of up to1us, 2us, 4us, 8us,1 μs, 2 μs, 4 μs, 8 μs, and over8us8 μs, then there would be fivebucketsbuckets, and packets that arrived up to1us1 μs would cause the1us"up to 1 μs" bucket counter toincrease,increase. Likewise, for those that arrived between1us1 μs and2us2 μs, the2us"2 μs" bucket counter wouldincreaseincrease, etc. Inpracticepractice, it might be better in terms of processing and potential parallelismif,if both the "up to 1 μs" and "2 μs" counters were incremented when a packet had a delay relative to its predecessor of2us, then both the up to 1us and the 2us counter were incremented,2 μs, and any more detailed information was calculated in the analytics system.</t> <t>This method allows the operator to see more structure in the jitter characteristics than simply measuring the averagejitter,jitter and avoids the complication of needing to perform aper packet multiply,per-packet multiply but will probably need the time intervals between buckets to be programmable by the operator.</t> <t>The packet format of a Time Bucket Jitter MeasurementMessagemessage is shown below:</t> <figuretitle="Timeanchor="FIGBucket"> <name>Time Bucket Jitter Measurement MessageFormat" anchor="FIGBucket"><artwork><![CDATA[Format</name> <artwork name="" type="" align="left" alt=""><![CDATA[ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Flags | Control Code | Message Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | QTF | RTF | RPTF | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session Identifier | DS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of | Reserved 1 | | Buckets | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Intervalin 10ns units(in 10 ns units) | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Numberpktsof Pkts in Bucket 1 | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ~~ ~+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of Pkts in Bucket N | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ~ ~ TLV Block ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork></figure>]]></artwork> </figure> <t>The Version, Flags, Control Code, Message Length,QTF, RTF, RPTF,Querier Timestamp Format (QTF), Responder Timestamp Format (RTF), Responder's Preferred Timestamp Format (RPTF), Session Identifier,ReservedReserved, andDS FieldsDifferentiated Services (DS) fields are as defined insection 3.2 of RFC6374.<xref target="RFC6374" sectionFormat="of" section="3.2"/>. The remaining fields, which are unsigned integers, are as follows:</t><figure><artwork><![CDATA[ o Number<ul empty="false"> <li>Number of Buckets in themeasurement o Reservedmeasurement.</li> <li>Reserved 1 must be sent as zero and ignored onreceipt o Interval in 10ns unitsreceipt.</li> <li>Interval (in 10 ns units) is the inter-packet interval for thisbucket o Numberbucket.</li> <li>Number of Pkts in Bucket 1 is the number of packets found inthis bucket. ]]></artwork></figure>the first bucket.</li> <li>Number of Pkts in Bucket N is the number of packets found in the Nth bucket, where N is the value in the Number of Buckets field.</li> </ul> <t>There will be a number of Interval/Number pairs depending on the number of buckets being specified by the Querier. Ifan RFC6374a message is being used to configure thebuckets, (i.e.buckets (i.e., the responder is creating or modifying the buckets according to the intervals in the Query message), then theResponder MUSTresponder <bcp14>MUST</bcp14> respond with 0 packets in each bucket until it has been configured for a full measurement period. This indicates that it was configured at the time of the last response message, andthusthus, the response is valid for the whole interval. As per the<xref target="RFC6374"/>convention in <xref target="RFC6374" format="default"/>, the Number ofpktsPkts in Bucket fields are included in the Query message and set to zero.</t><t>Out of band<t>Out-of-band configuration is permitted by this mode of operation.</t> <t>Note this is a departure from the normal fixed format used inRFC6374.</t><xref target="RFC6374" format="default"/>.</t> <t>Thetime bucket jitter measurementTime Bucket Jitter Measurement message is carried over an LSP in the way described in <xreftarget="RFC6374"/>target="RFC6374" format="default"/> and over an LSP with an SFL as described in <xreftarget="RFC6374SFL"/>.</t>target="sec-RFC6374SFL" format="default"/>.</t> </section> <section anchor="method-2-classic-standard-deviation"title="Method 2numbered="true" toc="default"> <name>Method 2: Classic StandardDeviation">Deviation</name> <t>In this method, provision is made for reporting the following delay characteristics:</t><t><list style="numbers"> <t>Number<ol spacing="normal" type="1"><li>Number of packets in the batch(n).</t> <t>Sum(n)</li> <li>Sum of delays in a batch(S)</t> <t>Maximum Delay.</t> <t>Minimum Delay.</t> <t>Sum(S)</li> <li>Maximum delay</li> <li>Minimum delay</li> <li>Sum of squares ofInter-packetinter-packet delay(SS).</t> </list></t>(SumS)</li> </ol> <t>Characteristics 1 and 2 give the mean delay. Measuring the delay of each pair in the batch is discussed in <xreftarget="PPDM"/>.</t>target="PPDM" format="default"/>.</t> <t>Characteristics 3 and 4 give the outliers.</t> <t>Characteristics 1,22, and 5 can be used to calculate the variance of the inter-packetgap andgap, hence the standard deviation giving a view of the distribution of packet delays and hence the jitter. The equation for the variance (var) is given by:</t><figure><artwork><![CDATA[<artwork><![CDATA[ var =(SS(SumS - S*S/n)/(n-1)]]></artwork></figure>]]></artwork> <t>There is some concern over the use of this algorithm for measuringvariance,variance becauseSSSumS and S*S/n can be similar numbers, particularly where variance is low.HoweverHowever, the methodcommendsis acceptable because itself bydoes notrequiringrequire a division in the hardware.</t> <section anchor="multi-packet-delay-measurement-message-format"title="Multi-Packetnumbered="true" toc="default"> <name>Multi-packet Delay Measurement MessageFormat">Format</name> <t>The packet format of aMulti-PacketMulti-packet Delay MeasurementMessagemessage is shown below:</t> <figuretitle="Multi-packetanchor="FIGMPM"> <name>Multi-packet Delay Measurement MessageFormat" anchor="FIGMPM"><artwork><![CDATA[Format</name> <artwork name="" type="" align="left" alt=""><![CDATA[ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Flags | Control Code | Message Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | QTF | RTF | RPTF | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session Identifier | DS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of Packets | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sum of Delays for Batch | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Minimum Delay | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Maximum Delay | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sum of squares of Inter-packet delay | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ~ ~ TLV Block ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork></figure>]]></artwork> </figure> <t>The Version, Flags, Control Code, Message Length, QTF, RTF, RPTF, Session Identifier,ReservedReserved, and DSFieldsfields are as defined insection 3.2 of RFC6374.<xref target="RFC6374" sectionFormat="of" section="3.2"/>. The remaining fields are as follows:</t><figure><artwork><![CDATA[ o Number<ul empty="false"> <li>Number of Packets is the number of packets in thisbatch o Sumbatch.</li> <li>Sum of Delays for Batch is the duration of the batch in the time measurement format specified in the RTFfield. o Minimumfield.</li> <li>Minimum Delay is the minimum inter-packet gap observed during the batch in the time format specified in the RTFfield. o Maximumfield.</li> <li>Maximum Delay is the maximum inter-packet gap observed during the batch in the time format specified in the RTFfield. ]]></artwork></figure>field.</li> </ul> <t>Themulti-packet delay measurementMulti-packet Delay Measurement message is carried over an LSP in the way described in <xreftarget="RFC6374"/>target="RFC6374" format="default"/> and over an LSP with an SFL as described in <xreftarget="RFC6374SFL"/>.</t>target="sec-RFC6374SFL" format="default"/>.</t> </section> </section> <section anchor="PPDM"title="Per Packetnumbered="true" toc="default"> <name>Per-Packet DelayMeasurement">Measurement</name> <t>If detailed packet delay measurement isrequiredrequired, then it might be possible to record the inter-packet gap for each packet pair. In cases other thanexception casesthe exceptions of slow flows or small batch sizes, this would create a large(per packet)(per-packet) demand on storage in the instrumentation system, a large bandwidthtofor such a storage system and large bandwidthtofor the analytics system. Such a measurement technique is outside the scope of this document.</t> </section> <section anchor="average-delay"title="Average Delay">numbered="true" toc="default"> <name>Average Delay</name> <t>Introduced in <xreftarget="RFC8321"/>target="RFC9341" format="default"/> is the concept of aone wayone-way delay measurement in which the average time of arrival of a set of packets is measured. In thisapproachapproach, the packet istime-stampedtimestamped atarrivalarrival, and theResponderresponder returns the sum of thetime-stampstimestamps and the number oftimes-tamps.timestamps. Fromthisthis, the analytics engine can determine the mean delay. An alternative model is that theResponderresponder returns thetime stamptimestamp of the first and last packet and the number of packets. Thislaterlatter method has the advantage of allowing the average delay to be determined at a number of points along the packet path and allowing the components of the delay to be characterized. Unless specifically configured otherwise, the responder may return either or both types ofresponseresponse, and the analytics engine should process the response appropriately.</t> <t>The packet format of an Average Delay MeasurementMessagemessage is shown below:</t> <figuretitle="Averageanchor="FIGAD"> <name>Average Delay Measurement MessageFormat" anchor="FIGAD"><artwork><![CDATA[Format</name> <artwork name="" type="" align="left" alt=""><![CDATA[ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Version| Flags | Control Code | Message Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | QTF | RTF | RPTF | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Session Identifier | DS | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of Packets | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time of First Packet | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Time of Last Packet | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Sum of Timestamps of Batch | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ ~ ~ TLV Block ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork></figure>]]></artwork> </figure> <t>The Version, Flags, Control Code, Message Length, QTF, RTF, RPTF, Session Identifier, and DSFieldsfields are as defined insection 3.2 of RFC6374.<xref target="RFC6374" sectionFormat="of" section="3.2"/>. The remaining fields are as follows:</t><figure><artwork><![CDATA[ o Number<ul empty="false"> <li>Number of Packets is the number of packets in thisbatch. o Timebatch.</li> <li>Time of First Packet is the time of arrival of the first packet in thebatch. o Timebatch.</li> <li>Time of Last Packet is the time of arrival of the last packet in thebatch. o Sumbatch.</li> <li>Sum of Timestamps ofBatch. ]]></artwork></figure>Batch.</li> </ul> <t>Theaverage delay measurementAverage Delay Measurement message is carried over an LSP in the way described in <xreftarget="RFC6374"/>target="RFC6374" format="default"/> and over an LSP with an SFL as described in <xreftarget="RFC6374SFL"/>.target="sec-RFC6374SFL" format="default"/>. As is the convention withRFC6374,<xref target="RFC6374" format="default"/>, the Query message contains placeholders for the Response message. The placeholders are sent as zero.</t> </section> </section> <section anchor="sampled-measurement"title="Sampled Measurement">numbered="true" toc="default"> <name>Sampled Measurement</name> <t>In the discussion sofarfar, it has been assumed that we would measure the delay characteristics of every packet in a delay measurement interval defined by an SFL of constant color. In <xreftarget="RFC8321"/>target="RFC9341" format="default"/>, the concept of a sampled measurement is considered. Thatisis, theResponderresponder only measures a packet at the start of a group of packets being marked for delay measurement by a particular color, rather than every packet in the marked batch. A measurement interval is not defined by the duration of a marked batch of packets but the interval between a pair ofRFC6374packets taking a readout of the delay characteristic. This approach has the advantage that the measurement is not impacted by ECMP effects.</t> <t>This sampled approach may be used if supported by theResponderresponder and configured by theopertor.</t>operator.</t> </section> <sectionanchor="RFC6374SFL" title="Carrying RFC6374anchor="sec-RFC6374SFL" numbered="true" toc="default"> <name>Carrying Packets over an LSPusingUsing anSFL">SFL</name> <t>We illustrate the packet format ofan RFC6374a Query message using SFLs for the case of an MPLSdirect loss measurementDirect Loss Measurement in <xreftarget="Figure1"/>.</t>target="Figure1" format="default"/>.</t> <figuretitle="RFC6734 Queryanchor="Figure1"> <name>Query Packet withSFL" anchor="Figure1"><artwork><![CDATA[SFL</name> <artwork name="" type="" align="left" alt=""><![CDATA[ +-------------------------------+ | | | LSP | | Label | +-------------------------------+ | | | Synonymous Flow | | Label | +-------------------------------+ | | | GAL | | | +-------------------------------+ | | | ACH Type = 0xA | | | +-------------------------------+ | | |RFC6374Measurement Message | | | | +-------------------------+ | | | | | | | Fixed-format | | | | portion of msg | | | | | | | +-------------------------+ | | | | | | | Optional SFL TLV | | | | | | | +-------------------------+ | | | | | | | Optional Return | | | | Information | | | | | | | +-------------------------+ | | | +-------------------------------+]]></artwork></figure>]]></artwork> </figure> <t>The MPLS label stack is exactly the same as that used for the user data service packets being instrumented except for the inclusion of the Generic Associated Channel Label (GAL) <xreftarget="RFC5586"/>target="RFC5586" format="default"/> to allow the receiver to distinguish between normal data packets and OAM packets. Since the packet loss measurements are being made on the data service packets, anRFC6374 direct loss measurementMPLS Direct Loss Measurement is being made,andwhich is indicated by the type field in theACHAssociated Channel Header (ACH) (Type = 0x000A).</t> <t>TheRFC6374measurement message consists oftheup to threecomponents, the RFC6374components as follows.</t> <ul> <li> <t>The fixed-format portion of the messageas specified in <xref target="RFC6374"/>is carried over the ACH channel. The ACH channel typespecifiedspecifies the type of measurement being made (currently: loss,delaydelay, or loss anddelay) as specified in RFC6374.</t> <t>Two optional TLVs MAY also be carried if needed.delay).</t> </li> <li> <t>(Optional) Thefirst is theSFL TLV specified in <xreftarget="sfltlv"/>. Thistarget="sfltlv" format="default"/> <bcp14>MAY</bcp14> be carried if needed. It is used to provide the implementation with a reminder of the SFL that was used to carry theRFC6374message. This is needed because a number of MPLS implementations do not provide the MPLS label stack to the MPLS OAM handler. This TLV is required ifRFC6374messages are sent over UDP <xreftarget="RFC7876"/>.target="RFC7876" format="default"/>. This TLVMUST<bcp14>MUST</bcp14> be included unless, by some method outside the scope of this document, it is known that this information is not needed by theRFC6374 Responder.</t> <t>The second set of information that mayresponder.</t> </li> <li> <t>(Optional) The Return Information <bcp14>MAY</bcp14> beneeded is the return information thatcarried if needed. It allows the responder send theRFC6374response to the Querier. This is not needed if the response is requestedin-bandin band and the MPLS construct being measured is apoint to pointpoint-to-point LSP, but it otherwiseMUST<bcp14>MUST</bcp14> be carried. Thereturn addressReturn Address TLV is defined in <xreftarget="RFC6374"/>target="RFC6374" format="default"/>, and the optional UDP Return Object is defined in <xreftarget="RFC7876"/>.</t>target="RFC7876" format="default"/>.</t> </li> </ul> <t>Where a measurement other than an MPLSdirect loss measurementDirect Loss Measurement is to be made, the appropriateRFC6374measurement message is used (for example, one of the new types defined in thisdocument)document), and this is indicated to the receiver by the use of the corresponding ACH type.</t> <section anchor="sfltlv"title="RFC6374numbered="true" toc="default"> <name>Extending RFC 6374 with SFLTLV">TLV</name> <t>TheRFC6374<xref target="RFC6374" format="default"/> SFL TLV is shown in <xreftarget="Figure2"/>.target="Figure2" format="default"/>. This contains the SFL that was carried in the label stack, the FEC that was used to allocate theSFLSFL, and the indexinto(into the batch ofSLsSFLs that were allocated for theFECFEC) that corresponds to this SFL.</t> <figuretitle="SFL TLV" anchor="Figure2"><artwork><![CDATA[anchor="Figure2"> <name>SFL TLV</name> <artwork name="" type="" align="left" alt=""><![CDATA[ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length |MBZ| SFL Batch | SFL Index | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | SFL | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FEC | . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+]]></artwork></figure>]]></artwork> </figure> <t>Where:</t><figure><artwork><![CDATA[ Type Type is set<dl indent="15"> <dt>Type</dt><dd> Set to Synonymous Flow Label(SFL-TLV). Length(SFL-TLV).</dd> <dt>Length</dt><dd> The length of the TLV is as specified inRFC6374. MBZ MUST<xref target="RFC6374"/>.</dd> <dt>MBZ</dt><dd> <bcp14>MUST</bcp14> be sent as zero and ignored onreceive. SFL Batch The SFL batch that this SFL was allocated as partreceive.</dd> <dt>SFL Batch</dt><dd> An identifier for a collection ofsee [I-D.bryant-mpls-sfl-control] SPL Index TheSFLs grouped together for management and control purposes. </dd> <dt>SFL Index</dt><dd><t>The indexintoof this SFL within the list of SFLs that were assignedagainst the FEC that corresponds tofor theSFL.FEC.</t> <t> Multiple SFLs can be assigned to aFECFEC, each with different actions. This index is an optional convenience for use in mapping between the TLV and the associated data structures in the LSRs. The use of this feature is agreed upon between the two parties during configuration. It is notrequired,required but is a convenience for the receiver if both parties support thefacility, SFL Thefacility.</t></dd> <dt>SFL</dt><dd>The SFL used to deliver this packet. This is an MPLS labelwhichthat is a component of a label stack entry as defined inSection 2.1 of [RFC3032]. Reserved MUST<xref target="RFC3032" sectionFormat="of" section="2.1"/>.</dd> <dt>Reserved</dt><dd> <bcp14>MUST</bcp14> be sent as zero and ignored onreceive. FECreceive.</dd> <dt>FEC</dt><dd> The Forwarding Equivalence Class that was used to request this SFL. This is encoded as perSection 3.4.1 of [RFC5036] ]]></artwork></figure><xref target="RFC5036" sectionFormat="of" section="3.4.1"/>.</dd> </dl> <t>This information is needed to allow for operation with hardware that discards the MPLS label stack before passing the remainder of the stack to the OAM handler. By providing both the SFL and the FEC plus index into the array of allocatedSFLsSFLs, a number of implementation types are supported.</t> </section> </section> <section anchor="rfc6374-combined-loss-delay-measurement"title="RFC6374 Combined Loss-Delay Measurement">numbered="true" toc="default"> <name>Combined Loss/Delay Measurement Using SFL</name> <t>This mode of operation is not currently supported by this specification.</t> </section> <section anchor="PCSEC"title="Privacy Considerations">numbered="true" toc="default"> <name>Privacy Considerations</name> <t>The inclusion of originating and/or flow information in a packet provides more identity information and hence potentially degrades the privacy of the communication.WhilstWhile the inclusion of the additional granularity does allow greater insight into the flowcharacteristicscharacteristics, it does not specifically identify which node originated the packet other than by inspection of the network at the point ofingress,ingress or inspection of the control protocol packets. This privacy threat may be mitigated by encrypting the control protocol packets, regularly changing the synonymouslabelslabels, and by concurrently using a number of such labels.</t> </section> <section anchor="security-considerations"title="Security Considerations">numbered="true" toc="default"> <name>Security Considerations</name> <t>The security considerations documented in <xreftarget="RFC6374"/>target="RFC6374" format="default"/> and <xreftarget="RFC8372"/>target="RFC8372" format="default"/> (which in turn calls up <xreftarget="RFC7258"/>target="RFC5920" format="default"/> and <xreftarget="RFC5920"/>)target="RFC7258" format="default"/>) are applicable to this protocol.</t> <t>The issue noted in <xreftarget="PCSEC"/>target="PCSEC" format="default"/> is a security consideration. There are no other new security issues associated with the MPLSdataplane.data plane. Any control protocol used to request SFLs will need to ensure the legitimacy of the request.</t> <t>An attacker that manages to corrupt theRFC6374<xref target="RFC6374" format="default"/> SFL TLV in <xreftarget="sfltlv"/>target="sfltlv" format="default"/> could disrupt the measurements in a way that theRFC6374<xref target="RFC6374" format="default"/> responder is unable to detect. However, the networkopertatoroperator is likely to notice the anomalous network performance measurements, and in anycasecase, normal MPLS network securityproceeduresprocedures make this type of attack extremelyunlikley.</t>unlikely.</t> </section> <section anchor="iana-considerations"title="IANA Considerations">numbered="true" toc="default"> <name>IANA Considerations</name> <section anchor="allocation-of-mpls-generalized-associated-channel-g-ach-types"title="Allocationnumbered="true" toc="default"> <name>Allocation of MPLS Generalized Associated Channel (G-ACh)Types">Types</name> <t>As per the IANA considerations in <xreftarget="RFC5586"/>target="RFC5586" format="default"/> updated by <xreftarget="RFC7026"/>target="RFC7026" format="default"/> and <xreftarget="RFC7214"/>,target="RFC7214" format="default"/>, IANAis requested to allocatehas allocated the followingcodepontsvalues in the“MPLS"MPLS Generalized Associated Channel (G-ACh)Type”Types" registry, in the“Generic"Generic Associated Channel (G-ACh)Parameters” name space:</t> <figure><artwork><![CDATA[ Value Description Reference ----- --------------------------------- ----------- TBD RFC6374 TimeParameters" registry group:</t> <table anchor="tab-1"> <name/> <thead> <tr> <th>Value</th> <th>Description</th> <th>Reference</th> </tr> </thead> <tbody> <tr> <td>0x0010</td> <td>Time Bucket JitterMeasurement This TBD RFC6374 Multi-PacketMeasurement</td> <td>RFC 9571</td> </tr> <tr> <td>0x0011</td> <td>Multi-packet DelayThis Measurement TBD RFC6374 AverageMeasurement</td> <td>RFC 9571</td> </tr> <tr> <td>0x0012</td> <td>Average DelayMeasurement This ]]></artwork></figure>Measurement</td> <td>RFC 9571</td> </tr> </tbody> </table> </section> <section anchor="allocation-of-mpls-lossdelay-tlv-object"title="Allocationnumbered="true" toc="default"> <name>Allocation of MPLS Loss/Delay TLVObject">Object</name> <t>IANAis requested to allocate a newhas allocated the following TLV from the 0-127 range of theMPLS"MPLS Loss/Delay Measurement TLVObject RegistryObject" registry in the“Generic"Generic Associated Channel (G-ACh)Parameters” namespace:</t> <figure><artwork><![CDATA[ Type Description Reference ---- --------------------------------- --------- TBD SynonymousParameters" registry group:</t> <table anchor="tab-2"> <name/> <thead> <tr> <th>Type</th> <th>Description</th> <th>Reference</th> </tr> </thead> <tbody> <tr> <td>4</td> <td>Synonymous FlowLabel This ]]></artwork></figure> <t>A value of 4 is recommended.</t> <t>RFC Editor please delete this para <xref target="RFC3032"/><xref target="I-D.bryant-mpls-sfl-control"/><xref target="RFC5036"/></t>Label</td> <td>RFC 9571</td> </tr> </tbody> </table> </section> </section> </middle> <back> <references> <name>References</name> <references> <name>Normative References</name> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.3032.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7876.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5586.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.6374.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8957.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5036.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7026.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7214.xml"/> </references> <references> <name>Informative References</name> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.8372.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.3270.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5921.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7190.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.7258.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.5920.xml"/> <xi:include href="https://bib.ietf.org/public/rfc/bibxml/reference.RFC.9341.xml"/> </references> </references> <section anchor="acknowledgments"title="Acknowledgments">numbered="false" toc="default"> <name>Acknowledgments</name> <t>The authors thankBenjamin Kaduk and Elwyn Davies<contact fullname="Benjamin Kaduk"/> and <contact fullname="Elwyn Davies"/> for their thorough and thoughtful review of this document.</t> </section> <sectionanchor="contributing-authors" title="Contributing Authors"> <figure><artwork><![CDATA[ Zhenbin Li Huawei Email: lizhenbin@huawei.com Siva Sivabalan Ciena Corporation Email: ssivabal@ciena.com ]]></artwork></figure>anchor="contributors" numbered="false" toc="default"> <name>Contributors</name> <contact fullname="Zhenbin Li" > <organization>Huawei</organization> <address> <email>lizhenbin@huawei.com</email> </address> </contact> <contact fullname="Siva Sivabalan"> <organization>Ciena Corporation</organization> <address> <email>ssivabal@ciena.com</email> </address> </contact> </section></middle> <back> <references title='Normative References'> <reference anchor="I-D.bryant-mpls-sfl-control"> <front> <title>A Simple Control Protocol for MPLS SFLs</title> <author initials='S' surname='Bryant' fullname='Stewart Bryant'> <organization /> </author> <author initials='G' surname='Swallow' fullname='George Swallow'> <organization /> </author> <author initials='S' surname='Sivabalan' fullname='Siva Sivabalan'> <organization /> </author> <date month='December' day='7' year='2020' /> <abstract><t>In draft-ietf-mpls-sfl-framework the concept of MPLS synonymous flow labels (SFL) was introduced. This document describes a simple control protocol that runs over an associated control header to request, withdraw, and extend the lifetime of such labels. It is not the only control protocol that moght be used to support SFL, but it has the benefit of being able to be used without modifying of the existing MPLS control prodocols. The existance of this design is not intended to restrict the ability to enhance an existing MPLS control protocol to add a similar capability. A Querier MUST wait a configured time (suggested wait of 60 seconds) before re-attempting a Withdraw request. No more than three Withdraw requests SHOULD be made. These restricctions are to prevent overloading the control plane of the actioning router.</t></abstract> </front> <seriesInfo name='Internet-Draft' value='draft-bryant-mpls-sfl-control-09' /> <format type='TXT' target='http://www.ietf.org/internet-drafts/draft-bryant-mpls-sfl-control-09.txt' /> </reference> <reference anchor="RFC2119" target='https://www.rfc-editor.org/info/rfc2119'> <front> <title>Key words for use in RFCs to Indicate Requirement Levels</title> <author initials='S.' surname='Bradner' fullname='S. Bradner'><organization /></author> <date year='1997' month='March' /> <abstract><t>In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements.</t></abstract> </front> <seriesInfo name='BCP' value='14'/> <seriesInfo name='RFC' value='2119'/> <seriesInfo name='DOI' value='10.17487/RFC2119'/> </reference> <reference anchor="RFC8174" target='https://www.rfc-editor.org/info/rfc8174'> <front> <title>Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words</title> <author initials='B.' surname='Leiba' fullname='B. Leiba'><organization /></author> <date year='2017' month='May' /> <abstract><t>RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings.</t></abstract> </front> <seriesInfo name='BCP' value='14'/> <seriesInfo name='RFC' value='8174'/> <seriesInfo name='DOI' value='10.17487/RFC8174'/> </reference> <reference anchor="RFC3032" target='https://www.rfc-editor.org/info/rfc3032'> <front> <title>MPLS Label Stack Encoding</title> <author initials='E.' surname='Rosen' fullname='E. Rosen'><organization /></author> <author initials='D.' surname='Tappan' fullname='D. Tappan'><organization /></author> <author initials='G.' surname='Fedorkow' fullname='G. Fedorkow'><organization /></author> <author initials='Y.' surname='Rekhter' fullname='Y. Rekhter'><organization /></author> <author initials='D.' surname='Farinacci' fullname='D. Farinacci'><organization /></author> <author initials='T.' surname='Li' fullname='T. Li'><organization /></author> <author initials='A.' surname='Conta' fullname='A. Conta'><organization /></author> <date year='2001' month='January' /> <abstract><t>This document specifies the encoding to be used by an LSR in order to transmit labeled packets on Point-to-Point Protocol (PPP) data links, on LAN data links, and possibly on other data links as well. This document also specifies rules and procedures for processing the various fields of the label stack encoding. [STANDARDS-TRACK]</t></abstract> </front> <seriesInfo name='RFC' value='3032'/> <seriesInfo name='DOI' value='10.17487/RFC3032'/> </reference> <reference anchor="RFC7876" target='https://www.rfc-editor.org/info/rfc7876'> <front> <title>UDP Return Path for Packet Loss and Delay Measurement for MPLS Networks</title> <author initials='S.' surname='Bryant' fullname='S. Bryant'><organization /></author> <author initials='S.' surname='Sivabalan' fullname='S. Sivabalan'><organization /></author> <author initials='S.' surname='Soni' fullname='S. Soni'><organization /></author> <date year='2016' month='July' /> <abstract><t>RFC 6374 defines a protocol for Packet Loss and Delay Measurement for MPLS networks (MPLS-PLDM). This document specifies the procedures to be used when sending and processing out-of-band MPLS performance management Responses over an UDP/IP return path.</t></abstract> </front> <seriesInfo name='RFC' value='7876'/> <seriesInfo name='DOI' value='10.17487/RFC7876'/> </reference> <reference anchor="RFC5586" target='https://www.rfc-editor.org/info/rfc5586'> <front> <title>MPLS Generic Associated Channel</title> <author initials='M.' surname='Bocci' fullname='M. Bocci' role='editor'><organization /></author> <author initials='M.' surname='Vigoureux' fullname='M. Vigoureux' role='editor'><organization /></author> <author initials='S.' surname='Bryant' fullname='S. Bryant' role='editor'><organization /></author> <date year='2009' month='June' /> <abstract><t>This document generalizes the applicability of the pseudowire (PW) Associated Channel Header (ACH), enabling the realization of a control channel associated to MPLS Label Switched Paths (LSPs) and MPLS Sections in addition to MPLS pseudowires. In order to identify the presence of this Associated Channel Header in the label stack, this document also assigns one of the reserved MPLS label values to the Generic Associated Channel Label (GAL), to be used as a label based exception mechanism.</t></abstract> </front> <seriesInfo name='RFC' value='5586'/> <seriesInfo name='DOI' value='10.17487/RFC5586'/> </reference> <reference anchor="RFC6374" target='https://www.rfc-editor.org/info/rfc6374'> <front> <title>Packet Loss and Delay Measurement for MPLS Networks</title> <author initials='D.' surname='Frost' fullname='D. Frost'><organization /></author> <author initials='S.' surname='Bryant' fullname='S. Bryant'><organization /></author> <date year='2011' month='September' /> <abstract><t>Many service provider service level agreements (SLAs) depend on the ability to measure and monitor performance metrics for packet loss and one-way and two-way delay, as well as related metrics such as delay variation and channel throughput. This measurement capability also provides operators with greater visibility into the performance characteristics of their networks, thereby facilitating planning, troubleshooting, and network performance evaluation. This document specifies protocol mechanisms to enable the efficient and accurate measurement of these performance metrics in MPLS networks. [STANDARDS-TRACK]</t></abstract> </front> <seriesInfo name='RFC' value='6374'/> <seriesInfo name='DOI' value='10.17487/RFC6374'/> </reference> <reference anchor="RFC8957" target='https://www.rfc-editor.org/info/rfc8957'> <front> <title>Synonymous Flow Label Framework</title> <author initials='S.' surname='Bryant' fullname='S. Bryant'><organization /></author> <author initials='M.' surname='Chen' fullname='M. Chen'><organization /></author> <author initials='G.' surname='Swallow' fullname='G. Swallow'><organization /></author> <author initials='S.' surname='Sivabalan' fullname='S. Sivabalan'><organization /></author> <author initials='G.' surname='Mirsky' fullname='G. Mirsky'><organization /></author> <date year='2021' month='January' /> <abstract><t>RFC 8372 ("MPLS Flow Identification Considerations") describes the requirement for introducing flow identities within the MPLS architecture. This document describes a method of accomplishing this by using a technique called "Synonymous Flow Labels" in which labels that mimic the behavior of other labels provide the identification service. These identifiers can be used to trigger per-flow operations on the packet at the receiving label switching router.</t></abstract> </front> <seriesInfo name='RFC' value='8957'/> <seriesInfo name='DOI' value='10.17487/RFC8957'/> </reference> <reference anchor="RFC5036" target='https://www.rfc-editor.org/info/rfc5036'> <front> <title>LDP Specification</title> <author initials='L.' surname='Andersson' fullname='L. Andersson' role='editor'><organization /></author> <author initials='I.' surname='Minei' fullname='I. Minei' role='editor'><organization /></author> <author initials='B.' surname='Thomas' fullname='B. Thomas' role='editor'><organization /></author> <date year='2007' month='October' /> <abstract><t>The architecture for Multiprotocol Label Switching (MPLS) is described in RFC 3031. A fundamental concept in MPLS is that two Label Switching Routers (LSRs) must agree on the meaning of the labels used to forward traffic between and through them. This common understanding is achieved by using a set of procedures, called a label distribution protocol, by which one LSR informs another of label bindings it has made. This document defines a set of such procedures called LDP (for Label Distribution Protocol) by which LSRs distribute labels to support MPLS forwarding along normally routed paths. [STANDARDS-TRACK]</t></abstract> </front> <seriesInfo name='RFC' value='5036'/> <seriesInfo name='DOI' value='10.17487/RFC5036'/> </reference> <reference anchor="RFC7026" target='https://www.rfc-editor.org/info/rfc7026'> <front> <title>Retiring TLVs from the Associated Channel Header of the MPLS Generic Associated Channel</title> <author initials='A.' surname='Farrel' fullname='A. Farrel'><organization /></author> <author initials='S.' surname='Bryant' fullname='S. Bryant'><organization /></author> <date year='2013' month='September' /> <abstract><t>The MPLS Generic Associated Channel (G-ACh) is a generalization of the applicability of the pseudowire (PW) Associated Channel Header (ACH). RFC 5586 defines the concept of TLV constructs that can be carried in messages on the G-ACh by placing them in the ACH between the fixed header fields and the G-ACh message. These TLVs are called ACH TLVs</t><t>No Associated Channel Type yet defined uses an ACH TLV. Furthermore, it is believed that handling TLVs in hardware introduces significant problems to the fast path, and since G-ACh messages are intended to be processed substantially in hardware, the use of ACH TLVs is undesirable.</t><t>This document updates RFC 5586 by retiring ACH TLVs and removing the associated registry.</t></abstract> </front> <seriesInfo name='RFC' value='7026'/> <seriesInfo name='DOI' value='10.17487/RFC7026'/> </reference> <reference anchor="RFC7214" target='https://www.rfc-editor.org/info/rfc7214'> <front> <title>Moving Generic Associated Channel (G-ACh) IANA Registries to a New Registry</title> <author initials='L.' surname='Andersson' fullname='L. Andersson'><organization /></author> <author initials='C.' surname='Pignataro' fullname='C. Pignataro'><organization /></author> <date year='2014' month='May' /> <abstract><t>RFC 5586 generalized the applicability of the pseudowire Associated Channel Header (PW-ACH) into the Generic Associated Channel G-ACh. However, registries and allocations of G-ACh parameters had been distributed throughout different, sometimes unrelated, registries. This document coalesces these into a new "Generic Associated Channel (G-ACh) Parameters" registry under the "Multiprotocol Label Switching Architecture (MPLS)" heading. This document updates RFC 5586.</t><t>This document also updates RFCs 6374, 6378, 6427, and 6428.</t></abstract> </front> <seriesInfo name='RFC' value='7214'/> <seriesInfo name='DOI' value='10.17487/RFC7214'/> </reference> </references> <references title='Informative References'> <reference anchor="RFC8372" target='https://www.rfc-editor.org/info/rfc8372'> <front> <title>MPLS Flow Identification Considerations</title> <author initials='S.' surname='Bryant' fullname='S. Bryant'><organization /></author> <author initials='C.' surname='Pignataro' fullname='C. Pignataro'><organization /></author> <author initials='M.' surname='Chen' fullname='M. Chen'><organization /></author> <author initials='Z.' surname='Li' fullname='Z. Li'><organization /></author> <author initials='G.' surname='Mirsky' fullname='G. Mirsky'><organization /></author> <date year='2018' month='May' /> <abstract><t>This document discusses aspects to consider when developing a solution for MPLS flow identification. The key application that needs this solution is in-band performance monitoring of MPLS flows when MPLS is used to encapsulate user data packets.</t></abstract> </front> <seriesInfo name='RFC' value='8372'/> <seriesInfo name='DOI' value='10.17487/RFC8372'/> </reference> <reference anchor="RFC8321" target='https://www.rfc-editor.org/info/rfc8321'> <front> <title>Alternate-Marking Method for Passive and Hybrid Performance Monitoring</title> <author initials='G.' surname='Fioccola' fullname='G. Fioccola' role='editor'><organization /></author> <author initials='A.' surname='Capello' fullname='A. Capello'><organization /></author> <author initials='M.' surname='Cociglio' fullname='M. Cociglio'><organization /></author> <author initials='L.' surname='Castaldelli' fullname='L. Castaldelli'><organization /></author> <author initials='M.' surname='Chen' fullname='M. Chen'><organization /></author> <author initials='L.' surname='Zheng' fullname='L. Zheng'><organization /></author> <author initials='G.' surname='Mirsky' fullname='G. Mirsky'><organization /></author> <author initials='T.' surname='Mizrahi' fullname='T. Mizrahi'><organization /></author> <date year='2018' month='January' /> <abstract><t>This document describes a method to perform packet loss, delay, and jitter measurements on live traffic. This method is based on an Alternate-Marking (coloring) technique. A report is provided in order to explain an example and show the method applicability. This technology can be applied in various situations, as detailed in this document, and could be considered Passive or Hybrid depending on the application.</t></abstract> </front> <seriesInfo name='RFC' value='8321'/> <seriesInfo name='DOI' value='10.17487/RFC8321'/> </reference> <reference anchor="RFC3270" target='https://www.rfc-editor.org/info/rfc3270'> <front> <title>Multi-Protocol Label Switching (MPLS) Support of Differentiated Services</title> <author initials='F.' surname='Le Faucheur' fullname='F. Le Faucheur'><organization /></author> <author initials='L.' surname='Wu' fullname='L. Wu'><organization /></author> <author initials='B.' surname='Davie' fullname='B. Davie'><organization /></author> <author initials='S.' surname='Davari' fullname='S. Davari'><organization /></author> <author initials='P.' surname='Vaananen' fullname='P. Vaananen'><organization /></author> <author initials='R.' surname='Krishnan' fullname='R. Krishnan'><organization /></author> <author initials='P.' surname='Cheval' fullname='P. Cheval'><organization /></author> <author initials='J.' surname='Heinanen' fullname='J. Heinanen'><organization /></author> <date year='2002' month='May' /> <abstract><t>This document defines a flexible solution for support of Differentiated Services (Diff-Serv) over Multi-Protocol Label Switching (MPLS) networks. [STANDARDS-TRACK]</t></abstract> </front> <seriesInfo name='RFC' value='3270'/> <seriesInfo name='DOI' value='10.17487/RFC3270'/> </reference> <reference anchor="RFC5921" target='https://www.rfc-editor.org/info/rfc5921'> <front> <title>A Framework for MPLS in Transport Networks</title> <author initials='M.' surname='Bocci' fullname='M. Bocci' role='editor'><organization /></author> <author initials='S.' surname='Bryant' fullname='S. Bryant' role='editor'><organization /></author> <author initials='D.' surname='Frost' fullname='D. Frost' role='editor'><organization /></author> <author initials='L.' surname='Levrau' fullname='L. Levrau'><organization /></author> <author initials='L.' surname='Berger' fullname='L. Berger'><organization /></author> <date year='2010' month='July' /> <abstract><t>This document specifies an architectural framework for the application of Multiprotocol Label Switching (MPLS) to the construction of packet-switched transport networks. It describes a common set of protocol functions -- the MPLS Transport Profile (MPLS-TP) -- that supports the operational models and capabilities typical of such networks, including signaled or explicitly provisioned bidirectional connection-oriented paths, protection and restoration mechanisms, comprehensive Operations, Administration, and Maintenance (OAM) functions, and network operation in the absence of a dynamic control plane or IP forwarding support. Some of these functions are defined in existing MPLS specifications, while others require extensions to existing specifications to meet the requirements of the MPLS-TP.</t><t>This document defines the subset of the MPLS-TP applicable in general and to point-to-point transport paths. The remaining subset, applicable specifically to point-to-multipoint transport paths, is outside the scope of this document.</t><t>This document is a product of a joint Internet Engineering Task Force (IETF) / International Telecommunication Union Telecommunication Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and Pseudowire Emulation Edge-to-Edge (PWE3) architectures to support the capabilities and functionalities of a packet transport network as defined by the ITU-T. This document is not an Internet Standards Track specification; it is published for informational purposes.</t></abstract> </front> <seriesInfo name='RFC' value='5921'/> <seriesInfo name='DOI' value='10.17487/RFC5921'/> </reference> <reference anchor="RFC7190" target='https://www.rfc-editor.org/info/rfc7190'> <front> <title>Use of Multipath with MPLS and MPLS Transport Profile (MPLS-TP)</title> <author initials='C.' surname='Villamizar' fullname='C. Villamizar'><organization /></author> <date year='2014' month='March' /> <abstract><t>Many MPLS implementations have supported multipath techniques, and many MPLS deployments have used multipath techniques, particularly in very high-bandwidth applications, such as provider IP/MPLS core networks. MPLS Transport Profile (MPLS-TP) has strongly discouraged the use of multipath techniques. Some degradation of MPLS-TP Operations, Administration, and Maintenance (OAM) performance cannot be avoided when operating over many types of multipath implementations.</t><t>Using MPLS Entropy Labels (RFC 6790), MPLS Label Switched Paths (LSPs) can be carried over multipath links while also providing a fully MPLS-TP-compliant server layer for MPLS-TP LSPs. This document describes the means of supporting MPLS as a server layer for MPLS-TP. The use of MPLS-TP LSPs as a server layer for MPLS LSPs is also discussed.</t></abstract> </front> <seriesInfo name='RFC' value='7190'/> <seriesInfo name='DOI' value='10.17487/RFC7190'/> </reference> <reference anchor="RFC7258" target='https://www.rfc-editor.org/info/rfc7258'> <front> <title>Pervasive Monitoring Is an Attack</title> <author initials='S.' surname='Farrell' fullname='S. Farrell'><organization /></author> <author initials='H.' surname='Tschofenig' fullname='H. Tschofenig'><organization /></author> <date year='2014' month='May' /> <abstract><t>Pervasive monitoring is a technical attack that should be mitigated in the design of IETF protocols, where possible.</t></abstract> </front> <seriesInfo name='BCP' value='188'/> <seriesInfo name='RFC' value='7258'/> <seriesInfo name='DOI' value='10.17487/RFC7258'/> </reference> <reference anchor="RFC5920" target='https://www.rfc-editor.org/info/rfc5920'> <front> <title>Security Framework for MPLS and GMPLS Networks</title> <author initials='L.' surname='Fang' fullname='L. Fang' role='editor'><organization /></author> <date year='2010' month='July' /> <abstract><t>This document provides a security framework for Multiprotocol Label Switching (MPLS) and Generalized Multiprotocol Label Switching (GMPLS) Networks. This document addresses the security aspects that are relevant in the context of MPLS and GMPLS. It describes the security threats, the related defensive techniques, and the mechanisms for detection and reporting. This document emphasizes RSVP-TE and LDP security considerations, as well as inter-AS and inter-provider security considerations for building and maintaining MPLS and GMPLS networks across different domains or different Service Providers. This document is not an Internet Standards Track specification; it is published for informational purposes.</t></abstract> </front> <seriesInfo name='RFC' value='5920'/> <seriesInfo name='DOI' value='10.17487/RFC5920'/> </reference> </references></back><!-- ##markdown-source: H4sIAJCNQmAAA+09a28bR5Lf+1c0bOAg3VKMJduxYyBAZMlydCfFWlNJcLsI Ds2ZJjXRcIaZnpHM2N7ffvXqxwxJ2UHi2ySIFutI5HR3dXW9q7pmb29PZXVe VPNnumtne0+Vaou2tM/065Ojzx8+eaQnq6quVou6c/qkrG/1mZna0ikznTb2 Jjy2Nzk5U3mdVWYBY/PGzNq9wsKEi2Xp9ppZRg+5Wbm3/0DdwmLnF2cT/X3d XMPS+mVTd0uVmdbO62b1TLs2V8q1psr/15R1BTOurFPL4pn+Z1tnI+3qpm3s zMFvqwX/ktWLha1a94NSpmuv6uaZ0noP/k8/ReWe6clYP29Wpmr1zot813/F EE9ae2uaVh7w39UNQHrStV1jb22hL212VdVlPS+s06dVNvbP2YUpSgB7+pXj eaY0zRiAWoPi5VhPbk0JqOxD8NLCanb4HUEwqWFHtsoZgCIzpT6CvdpmuD6P HSPiv5rjZxshOB/rI5iuv/y5ya56H9PKX3cGNj5YZgGPjjN49Ksr+nrbNk+K Osvq0gz2WXTOLpd27etkwR6mB6vPZfx4JuM/AMV50bjr1QCGhght8B0B8I/L F/qobpbDs9VzGFMsaECCW6WqulmYtrixSHCne8djPnsmfCT4rK7api7xa2CW 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