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(The document does seem to have the reference to RFC 2119 which the ID-Checklist requires). -- The document date (May 30, 2020) is 1420 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) -- Obsolete informational reference (is this intentional?): RFC 8321 (Obsoleted by RFC 9341) Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 6MAN Working Group G. Fioccola 3 Internet-Draft T. Zhou 4 Intended status: Standards Track Huawei 5 Expires: December 1, 2020 M. Cociglio 6 Telecom Italia 7 F. Qin 8 China Mobile 9 May 30, 2020 11 IPv6 Application of the Alternate Marking Method 12 draft-ietf-6man-ipv6-alt-mark-00 14 Abstract 16 This document describes how the Alternate Marking Method can be used 17 as the passive performance measurement tool in an IPv6 domain and 18 reports implementation considerations. It proposes how to define a 19 new Extension Header Option to encode alternate marking technique and 20 both Hop-by-Hop Options Header and Destination Options Header are 21 considered. 23 Requirements Language 25 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 26 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 27 document are to be interpreted as described in BCP 14 RFC 2119 28 [RFC2119] RFC 8174 [RFC8174] when, and only when, they appear in all 29 capitals, as shown here. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at https://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on December 1, 2020. 48 Copyright Notice 50 Copyright (c) 2020 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (https://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 66 2. Alternate Marking application to IPv6 . . . . . . . . . . . . 3 67 3. Definition of the AltMark Option . . . . . . . . . . . . . . 4 68 3.1. Data Fields Format . . . . . . . . . . . . . . . . . . . 4 69 4. Use of the AltMark Option . . . . . . . . . . . . . . . . . . 5 70 5. Alternate Marking Method Operation . . . . . . . . . . . . . 7 71 5.1. Packet Loss Measurement . . . . . . . . . . . . . . . . . 7 72 5.2. Packet Delay Measurement . . . . . . . . . . . . . . . . 8 73 5.3. Flow Monitoring Identification . . . . . . . . . . . . . 9 74 5.3.1. Uniqueness of FlowMonID . . . . . . . . . . . . . . . 10 75 5.4. Multipoint and Clustered Alternate Marking . . . . . . . 10 76 5.5. Data Collection and Calculation . . . . . . . . . . . . . 11 77 6. Security Considerations . . . . . . . . . . . . . . . . . . . 11 78 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 79 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 80 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 81 9.1. Normative References . . . . . . . . . . . . . . . . . . 12 82 9.2. Informative References . . . . . . . . . . . . . . . . . 12 83 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 85 1. Introduction 87 [RFC8321] and [I-D.ietf-ippm-multipoint-alt-mark] describe a passive 88 performance measurement method, which can be used to measure packet 89 loss, latency and jitter on live traffic. Since this method is based 90 on marking consecutive batches of packets, the method is often 91 referred as Alternate Marking Method. 93 The Alternate Marking Method has become mature to be implemented and 94 encoded in the IPv6 protocol and this document defines how it can be 95 used to measure packet loss and delay metrics in IPv6. 97 The format of the IPv6 addresses is defined in [RFC4291] while 98 [RFC8200] defines the IPv6 Header, including a 20-bit Flow Label and 99 the IPv6 Extension Headers. The Segment Routing Header (SRH) is 100 defined in [RFC8754]. 102 [I-D.fioccola-v6ops-ipv6-alt-mark] reported a summary on the possible 103 implementation options for the application of the Alternate Marking 104 Method in an IPv6 domain. This document, starting from the outcome 105 of [I-D.fioccola-v6ops-ipv6-alt-mark], introduces a new TLV that can 106 be encoded in the Options Headers (both Hop-by-Hop or Destination) 107 for the purpose of the Alternate Marking Method application in an 108 IPv6 domain. The case of SRH ([RFC8754]) is also discussed, anyway 109 this is valid for all the types of Routing Header (RH). 111 2. Alternate Marking application to IPv6 113 The Alternate Marking Method requires a marking field. As mentioned, 114 several alternatives have been analysed in 115 [I-D.fioccola-v6ops-ipv6-alt-mark] such as IPv6 Extension Headers, 116 IPv6 Address and Flow Label. 118 The only correct and robust choice that can actually be standardized 119 would be the use of a new TLV to be encoded in the Options Header 120 (Hop-by-Hop or Destination Option). 122 This approach is compliant with [RFC8200] indeed the Alternate 123 Marking application to IPv6 involves the following operations: 125 o The source node is the only one that writes the Option Header to 126 mark alternately the flow (for both Hop-by-Hop and Destination 127 Option). 129 o In case of Hop-by-Hop Option Header carrying Alternate Marking 130 bits, it is not inserted or deleted, but can be read by any node 131 along the path. The intermediate nodes may be configured to 132 support this Option or not. Anyway this does not impact the 133 traffic since the measurement can be done only for the nodes 134 configured to read the Option. 136 o In case of Destination Option Header carrying Alternate Marking 137 bits, it is not processed, inserted, or deleted by any node along 138 the path until the packet reaches the destination node. Note 139 that, if there is also a Routing Header (RH), any visited 140 destination in the route list can process the Option Header. 142 Hop-by-Hop Option Header is also useful to signal to routers on the 143 path to process the Alternate Marking, anyway it is to be expected 144 that some routers cannot process it unless explicitly configured. 146 The optimization of both implementation and scaling of the Alternate 147 Marking Method is also considered and a way to identify flows is 148 required. The Flow Monitoring Identification field (FlowMonID), as 149 introduced in the next sections, goes in this direction and it is 150 used to identify a monitored flow. 152 Note that the FlowMonID is different from the Flow Label field of the 153 IPv6 Header ([RFC8200]). Flow Label is used for application service, 154 like load-balancing/equal cost multi-path (LB/ECMP) and QoS. 155 Instead, FlowMonID is only used to identify the monitored flow. The 156 reuse of flow label field for identifying monitored flows is not 157 considered since it may change the application intent and forwarding 158 behaviour. Furthermore the flow label may be changed en route and 159 this may also violate the measurement task. Those reasons make the 160 definition of the FlowMonID necessary for IPv6. Flow Label and 161 FlowMonID within the same packet have different scope, identify 162 different flows, and associate different uses. 164 An important point that will also be discussed in this document is 165 the the uniqueness of the FlowMonID and how to allow disambiguation 166 of the FlowMonID in case of collision. [RFC6437] states that the 167 Flow Label cannot be considered alone to avoid ambiguity since it 168 could be accidentally or intentionally changed en route for 169 compelling operational security reasons and this could also happen to 170 the IP addresses that can change due to NAT. But the Alternate 171 Marking is usually applied in a controlled domain, which would not 172 have NAT and there is no security issue that would necessitate 173 rewriting Flow Labels. So, for the purposes of this document, both 174 IP addresses and Flow Label should not change in flight and, in some 175 cases, they could be considered together with the FlowMonID for 176 disambiguation. 178 3. Definition of the AltMark Option 180 The desired choice is to define a new TLV for the Options Extension 181 Headers, carrying the data fields dedicated to the alternate marking 182 method. 184 3.1. Data Fields Format 186 The following figure shows the data fields format for enhanced 187 alternate marking TLV. This AltMark data is expected to be 188 encapsulated in the IPv6 Options Headers (Hop-by-Hop or Destination 189 Option). 191 0 1 2 3 192 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 1 193 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 194 | Option Type | Opt Data Len | 195 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 196 | FlowMonID |L|D| Reserved | 197 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 199 where: 201 o Option Type: 8 bit identifier of the type of Option that needs to 202 be allocated. Unrecognised Types MUST be ignored on receipt. For 203 Hop-by-Hop Options Header or Destination Options Header, [RFC8200] 204 defines how to encode the three high-order bits of the Option Type 205 field. The two high-order bits specify the action that must be 206 taken if the processing IPv6 node does not recognize the Option 207 Type; for AltMark these two bits MUST be set to 00 (skip over this 208 Option and continue processing the header). The third-highest- 209 order bit specifies whether or not the Option Data can change en 210 route to the packet's final destination; for AltMark the value of 211 this bit MUST be set to 0 (Option Data does not change en route). 213 o Opt Data Len: The length of the Option Data Fields of this Option 214 in bytes. 216 o FlowMonID: 20 bits unsigned integer. The FlowMon identifier is 217 described hereinafter. 219 o L: Loss flag for Packet Loss Measurement as described hereinafter; 221 o D: Delay flag for Single Packet Delay Measurement as described 222 hereinafter; 224 o Reserved: is reserved for future use. These bits MUST be set to 225 zero on transmission and ignored on receipt. 227 4. Use of the AltMark Option 229 The AltMark Option is the best way to implement the Alternate Marking 230 method and can be carried by the Hop-by-Hop Options header and the 231 Destination Options header. In case of Destination Option, it is 232 processed only by the source and destination nodes: the source node 233 inserts and the destination node removes it. While, in case of Hop- 234 by-Hop Option, it may be examined by any node along the path, if 235 explicitly configured to do so. In this way an unrecognized Hop-by- 236 Hop Option may be just ignored without impacting the traffic. 238 So it is important to highlight that the Option Layout can be used 239 both as Destination Option and as Hop-by-Hop Option depending on the 240 Use Cases and it is based on the chosen type of performance 241 measurement. In general, it is needed to perform both end to end and 242 hop by hop measurements, and the alternate marking methodology 243 allows, by definition, both performance measurements. Anyway, in 244 many cases the end-to-end measurement is not enough and it is 245 required also the hop-by-hop measurement, so the most complete choice 246 is the Hop-by-Hop Options Header. 248 IPv6, as specified in [RFC8200], allows nodes to optionally process 249 Hop-by-Hop headers. Specifically the Hop-by-Hop Options header is 250 not inserted or deleted, but may be examined or processed by any node 251 along a packet's delivery path, until the packet reaches the node (or 252 each of the set of nodes, in the case of multicast) identified in the 253 Destination Address field of the IPv6 header. Also, it is expected 254 that nodes along a packet's delivery path only examine and process 255 the Hop-by-Hop Options header if explicitly configured to do so. 257 The Hop-by-Hop Option defined in this document is designed to take 258 advantage of the property of how Hop-by-Hop options are processed. 259 Nodes that do not support this Option SHOULD ignore them. This can 260 mean that, in this case, the performance measurement does not account 261 for all links and nodes along a path. 263 Another application that can be mentioned is the presence of a 264 Routing Header, in particular it is possible to consider SRv6. SRv6 265 leverages the Segment Routing header which consists of a new type of 266 routing header. Like any other use case of IPv6, Hop-by-Hop and 267 Destination Options are useable when SRv6 header is present. Because 268 SRv6 is a routing header, Destination Options before the routing 269 header are processed by each destination in the route list. 271 In summary, it is possible to list the alternative possibilities: 273 o Destination Option => measurement only by node in Destination 274 Address. 276 o Hop-by-Hop Option => every router on the path with feature 277 enabled. 279 o Destination Option + SRH => every node that is an identity in the 280 SR path. 282 In general, Hop-by-Hop and Destination Options are the most suitable 283 ways to implement Alternate Marking. 285 It is worth mentioning that new Hop-by-Hop Options are not strongly 286 recommended in [RFC7045] and [RFC8200], unless there is a clear 287 justification to standardize it, because nodes may be configured to 288 ignore the Options Header, drop or assign packets containing an 289 Options Header to a slow processing path. In case of the AltMark 290 data fields described in this document, the motivation to standardize 291 a new Hop-by-Hop Option is that it is needed for OAM. An 292 intermediate node can read it or not but this does not affect the 293 packet behavior. The source node is the only one that writes the 294 Hop-by-Hop Option to mark alternately the flow, so, the performance 295 measurement can be done for those nodes configured to read this 296 Option, while the others are simply not considered for the metrics. 298 In addition to the previous alternatives, for legacy network it is 299 possible to mention a non-conventional application of the Destination 300 Option for the hop by hop usage. [RFC8200] defines that the nodes 301 along a path examine and process the Hop-by-Hop Options header only 302 if Hop-by-Hop processing is explicitly configured. On the other 303 hand, using the Destination Option for hop by hop action would cause 304 worse performance than Hop-by-Hop. The only motivation for the hop 305 by hop usage of Destination Options can be for compatibility reasons 306 but in general it is not recommended. 308 5. Alternate Marking Method Operation 310 This section describes how the method operates. [RFC8321] introduces 311 several alternatives but in this section the most applicable methods 312 are reported and a new fied is introduced to facilitate the 313 deployment and improve the scalability. 315 5.1. Packet Loss Measurement 317 The measurement of the packet loss is really straightforward. The 318 packets of the flow are grouped into batches, and all the packets 319 within a batch are marked by setting the L bit (Loss flag) to a same 320 value. The source node can switch the value of the L bit between 0 321 and 1 after a fixed number of packets or according to a fixed timer, 322 and this depends on the implementation. By counting the number of 323 packets in each batch and comparing the values measured by different 324 network nodes along the path, it is possible to measure the packet 325 loss occurred in any single batch between any two nodes. Each batch 326 represents a measurable entity unambiguously recognizable by all 327 network nodes along the path. 329 It is important to mention that for the application of this method 330 there are two elements to consider: the clock error between network 331 nodes and the network delay. These can create offsets between the 332 batches and out-of-order of the packets. The consequence is that it 333 is necessary to define a waiting interval where to get stable 334 counters and to avoid these issues. In addition this implies that 335 the length of the batches MUST be chosen large enough so that it is 336 not affected by those factors. 338 L bit=1 ----------+ +-----------+ +---------- 339 | | | | 340 L bit=0 +-----------+ +-----------+ 341 Batch n ... Batch 3 Batch 2 Batch 1 342 <---------> <---------> <---------> <---------> <---------> 344 Traffic Flow 345 ===========================================================> 346 L bit ...1111111111 0000000000 11111111111 00000000000 111111111... 347 ===========================================================> 349 Figure 1: Packet Loss Measurement and Single-Marking Methodology 350 using L bit 352 5.2. Packet Delay Measurement 354 The same principle used to measure packet loss can be applied also to 355 one-way delay measurement. Delay metrics MAY be calculated using the 356 two possibilities: 358 1. Single-Marking Methodology: This approach uses only the L bit to 359 calculate both packet loss and delay. In this case, the D flag 360 MUST be set to zero on transmit and ignored by the monitoring 361 points. The alternation of the values of the L bit can be used 362 as a time reference to calculate the delay. Whenever the L bit 363 changes and a new batch starts, a network node can store the 364 timestamp of the first packet of the new batch, that timestamp 365 can be compared with the timestamp of the first packet of the 366 same batch on a second node to compute packet delay. Anyway this 367 measurement is accurate only if no packet loss occurs and if 368 there is no packet reordering at the edges of the batches. A 369 different approach can also be considered and it is based on the 370 concept of the mean delay. The mean delay for each batch is 371 calculated by considering the average arrival time of the packets 372 for the relative batch. There are limitations also in this case 373 indeed, each node needs to collect all the timestamps and 374 calculate the average timestamp for each batch. In addition the 375 information is limited to a mean value. 377 2. Double-Marking Methodology: This approach is more complete and 378 uses the L bit only to calculate packet loss and the D bit (Delay 379 flag) is fully dedicated to delay measurements. The idea is to 380 use the first marking with the L bit to create the alternate flow 381 and, within the batches identified by the L bit, a second marking 382 is used to select the packets for measuring delay. The D bit 383 creates a new set of marked packets that are fully identified 384 over the network, so that a network node can store the timestamps 385 of these packets; these timestamps can be compared with the 386 timestamps of the same packets on a second node to compute packet 387 delay values for each packet. The most efficient and robust mode 388 is to select a single double-marked packet for each batch, in 389 this way there is no time gap to consider between the double- 390 marked packets to avoid their reorder. If a double-marked packet 391 is lost, the delay measurement for the considered batch is simply 392 discarded, but this is not a big problem because it is easy to 393 recognize the problematic batch and skip the measurement just for 394 that one. So in order to have more information about the delay 395 and to overcome out-of-order issues this method is preferred. 397 L bit=1 ----------+ +-----------+ +---------- 398 | | | | 399 L bit=0 +-----------+ +-----------+ 401 D bit=1 + + + + + 402 | | | | | 403 D bit=0 ------+----------+----------+----------+------------+----- 405 Traffic Flow 406 ===========================================================> 407 L bit ...1111111111 0000000000 11111111111 00000000000 111111111... 409 D bit ...0000010000 0000010000 00000100000 00001000000 000001000... 410 ===========================================================> 412 Figure 2: Double-Marking Methodology using L bit and D bit 414 Similar to packet delay measurement (both for Single Marking and 415 Double Marking), the method can also be used to measure the inter- 416 arrival jitter. 418 5.3. Flow Monitoring Identification 420 The Flow Monitoring Identification (FlowMonID) is required for some 421 general reasons: 423 First, it helps to reduce the per node configuration. Otherwise, 424 each node needs to configure an access-control list (ACL) for each 425 of the monitored flows. Moreover, using a flow identifier allows 426 a flexible granularity for the flow definition. 428 Second, it simplifies the counters handling. Hardware processing 429 of flow tuples (and ACL matching) is challenging and often incurs 430 into performance issues, especially in tunnel interfaces. 432 Third, it eases the data export encapsulation and correlation for 433 the collectors. 435 The FlowMon identifier field is to uniquely identify a monitored flow 436 within the measurement domain. The field is set at the source node. 437 The FlowMonID can be uniformly assigned by the central controller or 438 algorithmically generated by the source node. The latter approach 439 cannot guarantee the uniqueness of FlowMonID but it may be preferred 440 for local or private network, where the conflict probability is small 441 due to the large FlowMonID space. 443 5.3.1. Uniqueness of FlowMonID 445 It is important to note that if the 20 bit FlowMonID is set 446 independently and pseudo randomly there is a chance of collision. 447 So, in some cases, FlowMonID could not be sufficient for uniqueness. 449 In general the probability of a flow identifier uniqueness correlates 450 to the amount of entropy of the inputs. For instance, using the 451 well-known birthday problem in probability theory, if the 20 bit 452 FlowMonID is set independently and pseudo randomly without any 453 additional input entropy, there is a 50% chance of collision for just 454 1206 flows. For a 32 bit identifier the 50% threshold jumps to 455 77,163 flows and so on. So, for more entropy, FlowMonID can either 456 be combined with other identifying flow information in a packet (e.g. 457 it is possible to consider the hashed 3-tuple Flow Label, Source and 458 Destination addresses) or the FlowMonID size could be increased. 460 This issue is more visible when the FlowMonID is pseudo randomly 461 generated by the source node and there needs to tag it with 462 additional flow information to allow disambiguation. While, in case 463 of a centralized controller, the controller should set FlowMonID by 464 considering these aspects and instruct the nodes properly in order to 465 guarantee its uniqueness. 467 5.4. Multipoint and Clustered Alternate Marking 469 The Alternate Marking method can also be extended to any kind of 470 multipoint to multipoint paths, and the network clustering approach 471 allows a flexible and optimized performance measurement, as described 472 in [I-D.ietf-ippm-multipoint-alt-mark]. 474 The Cluster is the smallest identifiable subnetwork of the entire 475 Network graph that still satisfies the condition that the number of 476 packets that goes in is the same that goes out. With network 477 clustering, it is possible to use the partition of the network into 478 clusters at different levels in order to perform the needed degree of 479 detail. So, for Multipoint Alternate Marking, FlowMonID can identify 480 in general a multipoint-to-multipoint flow and not only a point-to- 481 point flow. 483 5.5. Data Collection and Calculation 485 The nodes enabled to perform performance monitoring collect the value 486 of the packet counters and timestamps. There are several 487 alternatives to implement Data Collection and Calculation, but this 488 is not specified in this document. 490 6. Security Considerations 492 This document aims to apply a method to perform measurements that 493 does not directly affect Internet security nor applications that run 494 on the Internet. However, implementation of this method must be 495 mindful of security and privacy concerns.There are two types of 496 security concerns: potential harm caused by the measurements and 497 potential harm to the measurements. 499 Security concerns are limited since the method implies modifications 500 to an Option of the data packets but this must be performed in a way 501 that doesn't alter the quality of service experienced by packets 502 subject to measurements and that preserves stability of nodes. In 503 addition, an attacker cannot gain information about network 504 performance from a monitoring node; it must use synchronized 505 monitoring nodes at multiple points on the path but this is very 506 difficult since the alternate methodology is applied only in the 507 context of a controlled domain. 509 Privacy concerns are also limited because the method only relies on 510 information contained in the Option Header without any release of 511 user data. 513 7. IANA Considerations 515 The Option Type should be assigned in IANA's "Destination Options and 516 Hop-by-Hop Options" registry. 518 This draft requests the following IPv6 Option Type assignments from 519 the Destination Options and Hop-by-Hop Options sub-registry of 520 Internet Protocol Version 6 (IPv6) Parameters 521 (https://www.iana.org/assignments/ipv6-parameters/). 523 Hex Value Binary Value Description Reference 524 act chg rest 525 ---------------------------------------------------------------- 526 TBD 00 0 tbd AltMark [This draft] 528 8. Acknowledgements 530 The authors would like to thank Bob Hinden, Ole Troan, Tom Herbert, 531 Stefano Previdi, Brian Carpenter, Eric Vyncke, Ron Bonica for the 532 precious comments and suggestions. 534 9. References 536 9.1. Normative References 538 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 539 Requirement Levels", BCP 14, RFC 2119, 540 DOI 10.17487/RFC2119, March 1997, 541 . 543 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 544 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 545 May 2017, . 547 [RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6 548 (IPv6) Specification", STD 86, RFC 8200, 549 DOI 10.17487/RFC8200, July 2017, 550 . 552 9.2. Informative References 554 [I-D.fioccola-v6ops-ipv6-alt-mark] 555 Fioccola, G., Velde, G., Cociglio, M., and P. Muley, "IPv6 556 Performance Measurement with Alternate Marking Method", 557 draft-fioccola-v6ops-ipv6-alt-mark-01 (work in progress), 558 June 2018. 560 [I-D.ietf-ippm-multipoint-alt-mark] 561 Fioccola, G., Cociglio, M., Sapio, A., and R. Sisto, 562 "Multipoint Alternate Marking method for passive and 563 hybrid performance monitoring", draft-ietf-ippm- 564 multipoint-alt-mark-09 (work in progress), March 2020. 566 [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing 567 Architecture", RFC 4291, DOI 10.17487/RFC4291, February 568 2006, . 570 [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, 571 "IPv6 Flow Label Specification", RFC 6437, 572 DOI 10.17487/RFC6437, November 2011, 573 . 575 [RFC7045] Carpenter, B. and S. Jiang, "Transmission and Processing 576 of IPv6 Extension Headers", RFC 7045, 577 DOI 10.17487/RFC7045, December 2013, 578 . 580 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 581 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 582 "Alternate-Marking Method for Passive and Hybrid 583 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 584 January 2018, . 586 [RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., 587 Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header 588 (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, 589 . 591 Authors' Addresses 593 Giuseppe Fioccola 594 Huawei 595 Riesstrasse, 25 596 Munich 80992 597 Germany 599 Email: giuseppe.fioccola@huawei.com 601 Tianran Zhou 602 Huawei 603 156 Beiqing Rd. 604 Beijing 100095 605 China 607 Email: zhoutianran@huawei.com 609 Mauro Cociglio 610 Telecom Italia 611 Via Reiss Romoli, 274 612 Torino 10148 613 Italy 615 Email: mauro.cociglio@telecomitalia.it 616 Fengwei Qin 617 China Mobile 618 32 Xuanwumenxi Ave. 619 Beijing 100032 620 China 622 Email: qinfengwei@chinamobile.com