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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SPRING Working Group R. Gandhi, Ed. 3 Internet-Draft C. Filsfils 4 Intended status: Informational Cisco Systems, Inc. 5 Expires: February 7, 2021 D. Voyer 6 Bell Canada 7 M. Chen 8 Huawei 9 B. Janssens 10 Colt 11 August 6, 2020 13 Performance Measurement Using TWAMP Light for Segment Routing Networks 14 draft-gandhi-spring-twamp-srpm-10 16 Abstract 18 Segment Routing (SR) leverages the source routing paradigm. SR is 19 applicable to both Multiprotocol Label Switching (SR-MPLS) and IPv6 20 (SRv6) data planes. This document describes procedure for sending 21 and processing probe query and response messages for Performance 22 Measurement (PM) in Segment Routing networks. The procedure uses the 23 messages defined in RFC 5357 (Two-Way Active Measurement Protocol 24 (TWAMP) Light) for Delay Measurement, and uses the messages defined 25 in this document for Loss Measurement. The procedure described is 26 applicable to SR-MPLS and SRv6 data planes and is used for both Links 27 and end-to-end SR Paths including SR Policies. 29 Status of This Memo 31 This Internet-Draft is submitted in full conformance with the 32 provisions of BCP 78 and BCP 79. 34 Internet-Drafts are working documents of the Internet Engineering 35 Task Force (IETF). Note that other groups may also distribute 36 working documents as Internet-Drafts. The list of current Internet- 37 Drafts is at https://datatracker.ietf.org/drafts/current/. 39 Internet-Drafts are draft documents valid for a maximum of six months 40 and may be updated, replaced, or obsoleted by other documents at any 41 time. It is inappropriate to use Internet-Drafts as reference 42 material or to cite them other than as "work in progress." 44 This Internet-Draft will expire on February 7, 2021. 46 Copyright Notice 48 Copyright (c) 2020 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (https://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the Simplified BSD License. 61 Table of Contents 63 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 64 2. Conventions Used in This Document . . . . . . . . . . . . . . 3 65 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 66 2.2. Abbreviations . . . . . . . . . . . . . . . . . . . . . . 4 67 2.3. Reference Topology . . . . . . . . . . . . . . . . . . . 4 68 3. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 5 69 3.1. Example Provisioning Model . . . . . . . . . . . . . . . 6 70 4. Probe Messages . . . . . . . . . . . . . . . . . . . . . . . 7 71 4.1. Probe Query Message . . . . . . . . . . . . . . . . . . . 7 72 4.1.1. Delay Measurement Query Message . . . . . . . . . . . 7 73 4.1.2. Loss Measurement Query Message . . . . . . . . . . . 8 74 4.1.3. Probe Query for Links . . . . . . . . . . . . . . . . 9 75 4.1.4. Probe Query for SR Policy . . . . . . . . . . . . . . 9 76 4.1.5. Control Code Field Extension for TWAMP Light Messages 11 77 4.1.6. Loss Measurement Query Message Extensions . . . . . . 12 78 4.2. Probe Response Message . . . . . . . . . . . . . . . . . 15 79 4.2.1. One-way Measurement Mode . . . . . . . . . . . . . . 16 80 4.2.2. Two-way Measurement Mode . . . . . . . . . . . . . . 16 81 4.2.3. Loss Measurement Response Message Extensions . . . . 18 82 4.3. Additional Probe Message Processing Rules . . . . . . . . 20 83 4.3.1. TTL and Hop Limit . . . . . . . . . . . . . . . . . . 21 84 4.3.2. Router Alert Option . . . . . . . . . . . . . . . . . 21 85 4.3.3. UDP Checksum . . . . . . . . . . . . . . . . . . . . 21 86 5. Performance Measurement for P2MP SR Policies . . . . . . . . 21 87 6. ECMP Support for SR Policies . . . . . . . . . . . . . . . . 22 88 7. Performance Delay and Liveness Monitoring . . . . . . . . . . 23 89 8. Security Considerations . . . . . . . . . . . . . . . . . . . 23 90 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 24 91 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 24 92 10.1. Normative References . . . . . . . . . . . . . . . . . . 24 93 10.2. Informative References . . . . . . . . . . . . . . . . . 24 95 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 28 96 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28 98 1. Introduction 100 Segment Routing (SR) leverages the source routing paradigm and 101 greatly simplifies network operations for Software Defined Networks 102 (SDNs). SR is applicable to both Multiprotocol Label Switching (SR- 103 MPLS) and IPv6 (SRv6) data planes. SR takes advantage of the Equal- 104 Cost Multipaths (ECMPs) between source and transit nodes, between 105 transit nodes and between transit and destination nodes. SR Policies 106 as defined in [I-D.ietf-spring-segment-routing-policy] are used to 107 steer traffic through a specific, user-defined paths using a stack of 108 Segments. Built-in SR Performance Measurement (PM) is one of the 109 essential requirements to provide Service Level Agreements (SLAs). 111 The One-Way Active Measurement Protocol (OWAMP) defined in [RFC4656] 112 and Two-Way Active Measurement Protocol (TWAMP) defined in [RFC5357] 113 provide capabilities for the measurement of various performance 114 metrics in IP networks using probe messages. These protocols rely on 115 control-channel signaling to establish a test-channel over an UDP 116 path. The TWAMP Light [Appendix I in RFC5357] [BBF.TR-390] provides 117 simplified mechanisms for active performance measurement in Customer 118 IP networks by provisioning UDP paths and eliminates the need for 119 control-channel signaling. As described in Appendix A of [RFC8545], 120 TWAMP Light mechanism is informative only. These protocols lack 121 support for direct-mode Loss Measurement (LM) to detect actual 122 Customer data traffic loss which is required in SR networks. 124 This document describes procedures for sending and processing probe 125 query and response messages for Performance Measurement in SR 126 networks. The procedure uses the messages defined in [RFC5357] 127 (TWAMP Light) for Delay Measurement (DM), and uses the messages 128 defined in this document for Loss Measurement. The procedure 129 described is applicable to SR-MPLS and SRv6 data planes and is used 130 for both Links and end-to-end SR Paths including SR Policies and 131 Flex-Algo IGP Paths. This document also defines mechanisms for 132 handling ECMPs of SR Paths for performance delay measurement. Unless 133 otherwise described, the messages defined in [RFC5357] are not 134 modified by this document. 136 2. Conventions Used in This Document 138 2.1. Requirements Language 140 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 141 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 142 document are to be interpreted as described in [RFC2119] [RFC8174] 143 when, and only when, they appear in all capitals, as shown here. 145 2.2. Abbreviations 147 BSID: Binding Segment ID. 149 DM: Delay Measurement. 151 ECMP: Equal Cost Multi-Path. 153 HMAC: Hashed Message Authentication Code. 155 LM: Loss Measurement. 157 MPLS: Multiprotocol Label Switching. 159 NTP: Network Time Protocol. 161 OWAMP: One-Way Active Measurement Protocol. 163 PM: Performance Measurement. 165 PSID: Path Segment Identifier. 167 PTP: Precision Time Protocol. 169 SID: Segment ID. 171 SL: Segment List. 173 SR: Segment Routing. 175 SRH: Segment Routing Header. 177 SR-MPLS: Segment Routing with MPLS data plane. 179 SRv6: Segment Routing with IPv6 data plane. 181 TC: Traffic Class. 183 TWAMP: Two-Way Active Measurement Protocol. 185 2.3. Reference Topology 187 In the reference topology shown below, the sender node R1 initiates a 188 performance measurement probe query message and the reflector node R5 189 sends a probe response message for the query message received. The 190 probe response message is typically sent to the sender node R1. 192 SR is enabled on nodes R1 and R5. The nodes R1 and R5 may be 193 directly connected via a Link or there exists a Point-to-Point (P2P) 194 SR Path e.g. SR Policy [I-D.ietf-spring-segment-routing-policy] on 195 node R1 (called head-end) with destination to node R5 (called tail- 196 end). 198 t1 t2 199 / \ 200 +-------+ Query +-------+ 201 | | - - - - - - - - - ->| | 202 | R1 |=====================| R5 | 203 | |<- - - - - - - - - - | | 204 +-------+ Response +-------+ 205 \ / 206 t4 t3 207 Sender Reflector 209 Reference Topology 211 3. Overview 213 For one-way and two-way delay measurements in Segment Routing 214 networks, the probe messages defined in [RFC5357] are used. For 215 direct-mode and inferred-mode loss measurements, the messages defined 216 in this document are used. For both Links and end-to-end SR Paths 217 including SR Policies and Flex-Algo IGP Paths, no PM state for delay 218 or loss measurement need to be created on the reflector node R5. 220 Separate UDP destination port numbers are user-configured for delay 221 and loss measurements. As specified in [RFC8545], the reflector 222 supports the destination UDP port 862 for delay measurement probe 223 messages by default. This UDP port however, is not used for loss 224 measurement probe messages defined in this document. The sender uses 225 the UDP port number following the guidelines specified in Section 6 226 in [RFC6335]. The same destination UDP port is used for Links and SR 227 Paths and the reflector is unaware if the query is for the Links or 228 SR Paths. The number of UDP ports with PM functionality needs to be 229 minimized due to limited hardware resoucres. 231 For Performance Measurement, probe query and response messages are 232 sent as following: 234 o For delay measurement, the probe messages are sent on the 235 congruent path of the data traffic by the sender node, and are 236 used to measure the delay experienced by the actual data traffic 237 flowing on the Links and SR Policies. 239 o For loss measurement, the probe messages are sent on the congruent 240 path of the data traffic by the sender node, and are used to 241 collect the receive traffic counters for the incoming link or 242 incoming SID where the probe query messages are received at the 243 reflector node (incoming link or incoming SID needed since the 244 reflector node does not have PM state present). 246 The In-Situ Operations, Administration, and Maintenance (IOAM) 247 mechanisms for SR-MPLS defined in [I-D.gandhi-mpls-ioam-sr] and for 248 SRv6 defined in [I-D.ali-spring-ioam-srv6] are used to carry PM 249 information such as timestamp in-band as part of the data packets, 250 and are outside the scope of this document. 252 3.1. Example Provisioning Model 254 An example of a provisioning model and typical measurement parameters 255 for each user-configured destination UDP port for performance delay 256 and loss measurements is shown in the following Figure 1: 258 +------------+ 259 | Controller | 260 +------------+ 261 Destination UDP Port / \ Destination UDP port 262 Measurement Protocol / \ Measurement Protocol 263 Measurement Type / \ Measurement Type 264 Delay/Loss / \ Delay/Loss 265 Authentication Mode & Key / \ Authentication Mode & Key 266 Timestamp Format / \ Loss Measurement Mode 267 Delay Measurement Mode / \ 268 Loss Measurement Mode / \ 269 v v 270 +-------+ +-------+ 271 | | | | 272 | R1 |============| R5 | 273 | | SR Path | | 274 +-------+ Or Link +-------+ 275 Sender Reflector 277 Figure 1: Example Provisioning Model 279 Example of Measurement Protocol is TWAMP Light, example of the 280 Timestamp Format is PTPv2 [IEEE1588] or NTP and example of the Loss 281 Measurement mode is inferred-mode or direct-mode. 283 The mechanisms to provision the sender and reflector nodes are 284 outside the scope of this document. The provisioning model is not 285 used for signaling the PM parameters between the reflector and sender 286 nodes in SR networks. 288 The reflector node R5 uses the parameters for the timestamp format 289 and delay measurement mode (i.e. one-way or two-way mode) from the 290 received probe query message. 292 4. Probe Messages 294 4.1. Probe Query Message 296 The probe messages defined in [RFC5357] are used for delay 297 measurement for Links and end-to-end SR Paths including SR Policies. 298 For loss measurement, the probe messages defined in this document are 299 used. 301 The sender IPv4 or IPv6 address is used as the source address. The 302 reflector IPv4 or IPv6 address is used as the destination address. 303 In the case of SR Policy with IPv4 endpoint of 0.0.0.0 or IPv6 304 endpoint of ::0 [I-D.ietf-spring-segment-routing-policy], the address 305 in the range of 127/8 for IPv4 or ::FFFF:127/104 for IPv6 is used as 306 the destination address, respectively. 308 4.1.1. Delay Measurement Query Message 310 The message content for delay measurement probe query message using 311 UDP header [RFC0768] is shown in Figure 2. The DM probe query 312 message is sent with user-configured Destination UDP port number for 313 DM. The Destination UDP port cannot be used as Source port for DM, 314 since the message does not have any indication to distinguish between 315 the query and response message. The payload of the DM probe query 316 message contains the delay measurement message defined in 317 Section 4.1.2 of [RFC5357]. For symmetrical size query and response 318 messages as defined in [RFC6038], the DM probe query message contains 319 the payload format defined in Section 4.2.1 of [RFC5357]. 321 +---------------------------------------------------------------+ 322 | IP Header | 323 . Source IP Address = Sender IPv4 or IPv6 Address . 324 . Destination IP Address = Reflector IPv4 or IPv6 Address . 325 . Protocol = UDP . 326 . . 327 +---------------------------------------------------------------+ 328 | UDP Header | 329 . Source Port = As chosen by Sender . 330 . Destination Port = User-configured Port for Delay Measurement. 331 . . 332 +---------------------------------------------------------------+ 333 | Payload = DM Message as specified in Section 4.2.1 of RFC 5357| 334 . Payload = DM Message as specified in Section 4.1.2 of RFC 5357. 335 . . 336 +---------------------------------------------------------------+ 338 Figure 2: DM Probe Query Message 340 Timestamp field is eight bytes and use the format defined in 341 Section 4.2.1 of [RFC5357]. It is recommended to use the IEEE 1588v2 342 Precision Time Protocol (PTP) truncated 64-bit timestamp format 343 [IEEE1588] as specified in [RFC8186], with hardware support in 344 Segment Routing networks. 346 4.1.1.1. Delay Measurement Authentication Mode 348 When using the authenticated mode for delay measurement, the matching 349 authentication type (e.g. HMAC-SHA-256) and key are user-configured 350 on both the sender and reflector nodes. A separate user-configured 351 destination UDP port is used for the delay measurement in 352 authentication mode due to the different probe message format. 354 4.1.2. Loss Measurement Query Message 356 The message content for loss measurement probe query message using 357 UDP header [RFC0768] is shown in Figure 3. The LM probe query 358 message is sent with user-configured Destination UDP port number for 359 LM, which is a different Destination UDP port number than DM. 360 Separate Destination UDP ports are used for direct-mode and inferred- 361 mode loss measurements. The Destination UDP port cannot be used as 362 Source port for LM, since the message does not have any indication to 363 distinguish between the query and response message. The LM probe 364 query message contains the payload for loss measurement as defined in 365 Figure 7 and Figure 8. 367 +---------------------------------------------------------------+ 368 | IP Header | 369 . Source IP Address = Sender IPv4 or IPv6 Address . 370 . Destination IP Address = Reflector IPv4 or IPv6 Address . 371 . Protocol = UDP . 372 . . 373 +---------------------------------------------------------------+ 374 | UDP Header | 375 . Source Port = As chosen by Sender . 376 . Destination Port = User-configured Port for Loss Measurement . 377 . . 378 +---------------------------------------------------------------+ 379 | Payload = LM Message as specified in Figure 7 or 8 | 380 . . 381 +---------------------------------------------------------------+ 383 Figure 3: LM Probe Query Message 385 4.1.2.1. Loss Measurement Authentication Mode 387 When using the authenticated mode for loss measurement, the matching 388 authentication type (e.g. HMAC-SHA-256) and key are user-configured 389 on both the sender and reflector nodes. A separate user-configured 390 destination UDP port is used for the loss measurement in 391 authentication mode due to the different message format. 393 4.1.3. Probe Query for Links 395 The probe query message as defined in Figure 2 for delay measurement 396 and Figure 3 for loss measurement are used for Links which may be 397 physical, virtual or LAG (bundle), LAG (bundle) member, numbered/ 398 unnumbered Links. The probe messages are pre-routed over the Link 399 for both delay and loss measurement. 401 4.1.4. Probe Query for SR Policy 403 The performance delay and loss measurement for segment routing is 404 applicable to both end-to-end SR-MPLS and SRv6 Policies. 406 4.1.4.1. Probe Query Message for SR-MPLS Policy 408 The probe query messages for performance measurement of an end-to-end 409 SR-MPLS Policy is sent using its SR-MPLS header containing the MPLS 410 segment list as shown in Figure 4. 412 0 1 2 3 413 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 1 414 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 415 | Segment(1) | TC |S| TTL | 416 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 417 . . 418 . . 419 . . 420 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 421 | Segment(n) | TC |S| TTL | 422 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 423 | PSID | TC |S| TTL | 424 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 425 | Message as shown in Figure 2 for DM or Figure 3 for LM | 426 . . 427 +---------------------------------------------------------------+ 429 Figure 4: Example Probe Query Message for SR-MPLS Policy 431 The Segment List (SL) can be empty to indicate Implicit NULL label 432 case for a single-hop SR Policy. 434 The Path Segment Identifier (PSID) 435 [I-D.ietf-spring-mpls-path-segment] of the SR-MPLS Policy is used for 436 accounting received traffic on the egress node for loss measurement. 438 4.1.4.2. Probe Query Message for SRv6 Policy 440 An SRv6 Policy setup using the SRv6 Segment Routing Header (SRH) and 441 a Segment List as defined in [RFC8754]. The SRv6 network programming 442 is defined in [I-D.ietf-spring-srv6-network-programming]. The probe 443 query messages for performance measurement of an end-to-end SRv6 444 Policy is sent using its SRH with Segment List as shown in Figure 5. 445 The procedure defined for upper-layer header processing for SRv6 SIDs 446 in [I-D.ietf-spring-srv6-network-programming] is used to process the 447 UDP header in the received probe query messages. 449 +---------------------------------------------------------------+ 450 | IP Header | 451 . Source IP Address = Sender IPv6 Address . 452 . Destination IP Address = Destination IPv6 Address . 453 . . 454 +---------------------------------------------------------------+ 455 | SRH as specified in RFC 8754 | 456 . . 457 . . 458 +---------------------------------------------------------------+ 459 | IP Header (as needed) | 460 . Source IP Address = Sender IPv6 Address . 461 . Destination IP Address = Reflector IPv6 Address . 462 . . 463 +---------------------------------------------------------------+ 464 | UDP Header | 465 . Source Port = As chosen by Sender . 466 . Destination Port = User-configured Port . 467 . . 468 +---------------------------------------------------------------+ 469 | Payload = DM Message as specified in Section 4.2.1 of RFC 5357| 470 . Payload = DM Message as specified in Section 4.1.2 of RFC 5357. 471 . Payload = LM Message as specified in Figure 7 or 8 . 472 . . 473 +---------------------------------------------------------------+ 475 Figure 5: Example Probe Query Message for SRv6 Policy 477 4.1.5. Control Code Field Extension for TWAMP Light Messages 479 In this document, the Control Code field is defined for delay and 480 loss measurement probe query messages for TWAMP Light in 481 unauthenticated and authenticated modes. The modified delay 482 measurement probe query message format is shown in Figure 6. This 483 message format is backwards compatible with the message format 484 defined in [RFC5357] as its reflectors ignore the received field 485 (previously identified as MBZ). With this field, the reflector node 486 does not require any additional SR state for PM (recall that in SR 487 networks, the state is in the probe packet and signaling of the 488 parameters is avoided). The usage of the Control Code is not limited 489 to the SR paths and can be used for non-SR paths in a network. 491 . . 492 . . 493 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 494 | Timestamp | 495 | | 496 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 497 | Error Estimate | MBZ | 498 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 499 | MBZ |Se Control Code| 500 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 501 . . 502 . . 504 Figure 6: Sender Control Code in TWAMP Light DM Message 506 Sender Control Code: Set as follows in TWAMP Light probe query 507 message. 509 In a Query: 511 0x0: Out-of-band Response Requested. Indicates that the probe 512 response is not required over the same path in the reverse 513 direction. This is also the default behavior. 515 0x1: In-band Response Requested. Indicates that this query has 516 been sent over a bidirectional path and the probe response is 517 required over the same path in the reverse direction. 519 0x2: No Response Requested. 521 4.1.6. Loss Measurement Query Message Extensions 523 In this document, TWAMP Light probe query messages for loss 524 measurement are defined as shown in Figure 7 and Figure 8. The 525 message formats are hardware efficient due to well-known locations of 526 the counters and payload small in size. They are stand-alone and 527 similar to the delay measurement message formats (e.g. location of 528 the Counter and Timestamp). They also do not require backwards 529 compatibility and support for the existing DM message formats from 530 [RFC5357] as different user-configured destination UDP port is used 531 for loss measurement. 533 0 1 2 3 534 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 1 535 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 536 | Sequence Number | 537 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 538 | Transmit Counter | 539 | | 540 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 541 |X|B| Reserved | Block Number | MBZ | 542 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 543 | MBZ |Se Control Code| 544 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 545 | | 546 . . 547 . Packet Padding . 548 . . 549 | | 550 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 552 Figure 7: TWAMP Light LM Probe Query Message - Unauthenticated Mode 553 0 1 2 3 554 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 1 555 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 556 | Sequence Number | 557 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 558 | MBZ (12 octets) | 559 | | 560 | | 561 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 562 | Transmit Counter | 563 | | 564 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 565 |X|B| Reserved | Block Number | MBZ | 566 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 567 | MBZ |Se Control Code| 568 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 569 | HMAC (16 octets) | 570 | | 571 | | 572 | | 573 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 574 | | 575 . . 576 . Packet Padding . 577 . . 578 | | 579 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 581 Figure 8: TWAMP Light LM Probe Query Message - Authenticated Mode 583 Sequence Number (32-bit): As defined in [RFC5357]. 585 Transmit Counter (64-bit): The number of packets or octets sent by 586 the sender node in the query message and by the reflector node in the 587 response message. The counter is always written at the well-known 588 location in the probe query and response messages. 590 Receive Counter (64-bit): The number of packets or octets received at 591 the reflector node. It is written by the reflector node in the probe 592 response message. 594 Sender Counter (64-bit): This is the exact copy of the transmit 595 counter from the received query message. It is written by the 596 reflector node in the probe response message. 598 Sender Sequence Number (32-bit): As defined in [RFC5357]. 600 Sender TTL: As defined in Section 7.1. 602 LM Flags: The meanings of the Flag bits are: 604 X: Extended counter format indicator. Indicates the use of 605 extended (64-bit) counter values. Initialized to 1 upon creation 606 (and prior to transmission) of an LM query and copied from an LM 607 Query to an LM response message. Set to 0 when the LM message is 608 transmitted or received over an interface that writes 32-bit 609 counter values. 611 B: Octet (byte) count. When set to 1, indicates that the Counter 612 1-4 fields represent octet counts. The octet count applies to all 613 packets within the LM scope, and the octet count of a packet sent 614 or received includes the total length of that packet (but excludes 615 headers, labels, or framing of the channel itself). When set to 616 0, indicates that the Counter fields represent packet counts. 618 Block Number (8-bit): The Loss Measurement using Alternate-Marking 619 method defined in [RFC8321] requires to color the data traffic. To 620 be able to correlate the transmit and receive traffic counters of the 621 matching color, the Block Number (or color) of the traffic counters 622 is carried by the probe query and response messages for loss 623 measurement. The Block Number can also be used to aggregate 624 performance metrics collected. 626 HMAC: The probe message in authenticated mode includes a key Hashed 627 Message Authentication Code (HMAC) [RFC2104] hash. Each probe query 628 and response messages are authenticated by adding Sequence Number 629 with Hashed Message Authentication Code (HMAC) TLV. It can use HMAC- 630 SHA-256 truncated to 128 bits (similarly to the use of it in IPSec 631 defined in [RFC4868]); hence the length of the HMAC field is 16 632 octets. 634 HMAC uses its own key and the mechanism to distribute the HMAC key is 635 outside the scope of this document. 637 In authenticated mode, only the sequence number is encrypted, and the 638 other payload fields are sent in clear text. The probe message may 639 include Comp.MBZ (Must Be Zero) variable length field to align the 640 packet on 16 octets boundary. 642 4.2. Probe Response Message 644 The probe response message is sent using the IP/UDP information from 645 the received probe query message. The content of the probe response 646 message is shown in Figure 9. 648 +---------------------------------------------------------------+ 649 | IP Header | 650 . Source IP Address = Reflector IPv4 or IPv6 Address . 651 . Destination IP Address = Source IP Address from Query . 652 . Protocol = UDP . 653 . . 654 +---------------------------------------------------------------+ 655 | UDP Header | 656 . Source Port = As chosen by Reflector . 657 . Destination Port = Source Port from Query . 658 . . 659 +---------------------------------------------------------------+ 660 | Payload = DM Message as specified in Section 4.2.1 of RFC 5357| 661 . Payload = LM Message as specified in Figure 12 or 13 . 662 . . 663 +---------------------------------------------------------------+ 665 Figure 9: Probe Response Message 667 4.2.1. One-way Measurement Mode 669 In one-way measurement mode, the probe response message as defined in 670 Figure 9 is sent back out-of-band to the sender node, for both Links 671 and SR Policies. The Sender Control Code is set to "Out-of-band 672 Response Requested". In this delay measurement mode, as per 673 Reference Topology, all timestamps t1, t2, t3, and t4 are collected 674 by the probes. However, only timestamps t1 and t2 are used to 675 measure one-way delay as (t2 - t1). 677 4.2.2. Two-way Measurement Mode 679 In two-way measurement mode, when using a bidirectional path, the 680 probe response message as defined in Figure 9 is sent back to the 681 sender node on the congruent path of the data traffic on the same 682 reverse direction Link or associated reverse SR Policy 683 [I-D.ietf-pce-sr-bidir-path]. The Sender Control Code is set to "In- 684 band Response Requested". In this delay measurement mode, as per 685 Reference Topology, all timestamps t1, t2, t3, and t4 are collected 686 by the probes. All four timestamps are used to measure two-way delay 687 as ((t4 - t1) - (t3 - t2)). 689 Specifically, the probe response message is sent back on the incoming 690 physical interface where the probe query message is received. This 691 is required for example, in case of two-way measurement mode for Link 692 delay. 694 4.2.2.1. Probe Response Message for SR-MPLS Policy 696 The message content for sending probe response message for two-way 697 performance measurement of an end-to-end SR-MPLS Policy is shown in 698 Figure 10. 700 0 1 2 3 701 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 1 702 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 703 | Segment(1) | TC |S| TTL | 704 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 705 . . 706 . . 707 . . 708 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 709 | Segment(n) | TC |S| TTL | 710 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 711 | Message as shown in Figure 9 | 712 . . 713 +---------------------------------------------------------------+ 715 Figure 10: Example Probe Response Message for SR-MPLS Policy 717 The Path Segment Identifier (PSID) 718 [I-D.ietf-spring-mpls-path-segment] of the forward SR Policy in the 719 probe query can be used to find the associated reverse SR Policy 720 [I-D.ietf-pce-sr-bidir-path] to send the probe response message for 721 two-way measurement of SR Policy. 723 4.2.2.2. Probe Response Message for SRv6 Policy 725 The message content for sending probe response message on the 726 congruent path of the data traffic for two-way performance 727 measurement of an end-to-end SRv6 Policy with SRH is shown in 728 Figure 11. The procedure defined for upper-layer header processing 729 for SRv6 SIDs in [I-D.ietf-spring-srv6-network-programming] is used 730 to process the UDP header in the received probe response messages. 732 +---------------------------------------------------------------+ 733 | IP Header | 734 . Source IP Address = Reflector IPv6 Address . 735 . Destination IP Address = Destination IPv6 Address . 736 . . 737 +---------------------------------------------------------------+ 738 | SRH as specified in RFC 8754 | 739 . . 740 . . 741 +---------------------------------------------------------------+ 742 | IP Header (as needed) | 743 . Source IP Address = Reflector IPv6 Address . 744 . Destination IP Address = Source IPv6 Address from Query . 745 . . 746 +---------------------------------------------------------------+ 747 | UDP Header | 748 . Source Port = As chosen by Sender . 749 . Destination Port = User-configured Port . 750 . . 751 +---------------------------------------------------------------+ 752 | Payload = DM Message as specified in Section 4.2.1 of RFC 5357| 753 . Payload = LM Message as specified in Figure 12 or 13 . 754 . . 755 +---------------------------------------------------------------+ 757 Figure 11: Example Probe Response Message for SRv6 Policy 759 4.2.3. Loss Measurement Response Message Extensions 761 In this document, TWAMP Light probe response message formats are 762 defined for loss measurement as shown in Figure 12 and Figure 13. 764 0 1 2 3 765 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 1 766 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 767 | Sequence Number | 768 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 769 | Transmit Counter | 770 | | 771 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 772 |X|B| Reserved | Block Number | MBZ | 773 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 774 | Receive Counter | 775 | | 776 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 777 | Sender Sequence Number | 778 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 779 | Sender Counter | 780 | | 781 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 782 |X|B| Reserved |Sender Block Nu| MBZ | 783 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 784 | Sender TTL | | 785 +-+-+-+-+-+-+-+-+ + 786 | | 787 . . 788 . Packet Padding . 789 . . 790 | | 791 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 793 Figure 12: TWAMP Light LM Probe Response Message - Unauthenticated 794 Mode 796 0 1 2 3 797 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 1 798 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 799 | Sequence Number | 800 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 801 | MBZ (12 octets) | 802 | | 803 | | 804 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 805 | Transmit Counter | 806 | | 807 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 808 |X|B| Reserved | Block Number | MBZ | 809 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 810 | MBZ (4 octets) | 811 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 812 | Receive Counter | 813 | | 814 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 815 | MBZ (8 octets) | 816 | | 817 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 818 | Sender Sequence Number | 819 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 820 | MBZ (12 octets) | 821 | | 822 | | 823 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 824 | Sender Counter | 825 | | 826 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 827 |X|B| Reserved |Sender Block Nu| MBZ | 828 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 829 | MBZ (4 octets) | 830 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 831 | Sender TTL | | 832 +-+-+-+-+-+-+-+-+ | 833 | MBZ (15 octets) | 834 | | 835 | | 836 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 837 | HMAC (16 octets) | 838 | | 839 | | 840 | | 841 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 842 | | 843 . . 844 . Packet Padding . 845 . . 846 | | 847 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 849 Figure 13: TWAMP Light LM Probe Response Message - Authenticated Mode 851 4.3. Additional Probe Message Processing Rules 853 The processing rules defined in this section are applicable to TWAMP 854 Light messages for delay and loss measurement for Links and end-to- 855 end SR Paths including SR Policies. 857 4.3.1. TTL and Hop Limit 859 The TTL field in the IPv4 and MPLS headers of the probe query 860 messages is set to 255 [RFC5357]. Similarly, the Hop Limit field in 861 the IPv6 and SRH headers of the probe query messages is set to 255 862 [RFC5357]. 864 When using the Destination IPv4 Address from the 127/8 range, the TTL 865 field in the IPv4 header is set to 1 [RFC8029]. Similarly, when 866 using the Destination IPv6 Address from the ::FFFF:127/104 range, the 867 Hop Limit field in the IPv6 header is set to 1. 869 For Link performance delay and loss measurements, the TTL or Hop 870 Limit field in the probe message is set to 1 in both one-way and two- 871 way measurement modes. 873 4.3.2. Router Alert Option 875 The Router Alert IP option (RAO) [RFC2113] is not set in the probe 876 messages. 878 4.3.3. UDP Checksum 880 The UDP Checksum Complement for delay and loss measurement messages 881 follows the procedure defined in [RFC7820] and can be optionally used 882 with the procedures defined in this document. 884 For IPv4 and IPv6 probe messages, where the hardware is not capable 885 of re-computing the UDP checksum or adding checksum complement 886 [RFC7820], the sender node sets the UDP checksum to 0 [RFC6936] 887 [RFC8085]. The receiving node bypasses the checksum validation and 888 accepts the packets with UDP checksum value 0 for the UDP port being 889 used for delay and loss measurements. 891 5. Performance Measurement for P2MP SR Policies 893 The Point-to-Multipoint (P2MP) SR Path that originates from a root 894 node terminates on multiple destinations called leaf nodes (e.g. 895 P2MP SR Policy [I-D.ietf-pim-sr-p2mp-policy] or P2MP Transport 896 [I-D.shen-spring-p2mp-transport-chain]). 898 The procedures for delay and loss measurement described in this 899 document for P2P SR Policies are also equally applicable to the P2MP 900 SR Policies. The procedure for one-way measurement is defined as 901 following: 903 o The sender root node sends probe query messages using the Tree-SID 904 defined in [I-D.ietf-pim-sr-p2mp-policy] for the P2MP SR-MPLS 905 Policy as shown in Figure 14. 907 o The probe query messages can contain the replication SID as 908 defined in [I-D.ietf-spring-sr-replication-segment]. 910 o Each reflector leaf node sends its IP address in the Source 911 Address of the probe response messages as shown in Figure 14. 912 This allows the sender root node to identify the reflector leaf 913 nodes of the P2MP SR Policy. 915 o The P2MP root node measures the delay and loss performance for 916 each P2MP leaf node of the end-to-end P2MP SR Policy. 918 0 1 2 3 919 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 1 920 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 921 | Tree-SID | TC |S| TTL | 922 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 923 . . 924 . . 925 . . 926 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 927 | Message as shown in Figure 2 for DM or Figure 3 for LM | 928 . . 929 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 931 Figure 14: Example Probe Query with Tree-SID for SR-MPLS Policy 933 The probe query messages can also be sent using the scheme defined 934 for P2MP Transport using Chain Replication that may contain Bud SID 935 as defined in [I-D.shen-spring-p2mp-transport-chain]. 937 The considerations for two-way mode for performance measurement for 938 P2MP SR Policy (e.g. for bidirectional SR Path) are outside the scope 939 of this document. 941 6. ECMP Support for SR Policies 943 An SR Policy can have ECMPs between the source and transit nodes, 944 between transit nodes and between transit and destination nodes. 945 Usage of Anycast SID [RFC8402] by an SR Policy can result in ECMP 946 paths via transit nodes part of that Anycast group. The probe 947 messages need to be sent to traverse different ECMP paths to measure 948 performance delay of an SR Policy. 950 Forwarding plane has various hashing functions available to forward 951 packets on specific ECMP paths. The mechanisms described in 952 [RFC8029] and [RFC5884] for handling ECMPs are also applicable to the 953 performance measurement. In IPv4 header of the probe messages, 954 sweeping of Destination Address in 127/8 range can be used to 955 exercise particular ECMP paths. As specified in [RFC6437], Flow 956 Label field in the outer IPv6 header can also be used for sweeping. 958 The considerations for performance loss measurement for different 959 ECMP paths of an SR Policy are outside the scope of this document. 961 7. Performance Delay and Liveness Monitoring 963 Liveness monitoring is required for connectivity verification and 964 continuity check in an SR network. The procedure defined in this 965 document for delay measurement using the TWAMP Light probe messages 966 can also be applied to liveness monitoring of Links and SR Paths. 967 The one-way or two-way measurement mode can be used for liveness 968 monitoring. Liveness failure is notified when consecutive N number 969 of probe response messages are not received back at the sender node, 970 where N is locally provisioned value. Note that failure detection 971 interval and scale for number of probes need to account for the 972 processing of the probe query messages which need to be punted from 973 the forwarding fast path (to slow path or control plane) and response 974 messages need to be injected on the reflector node. This is enhanced 975 by using the probes in loopback mode as described in 976 [I-D.gandhi-spring-sr-enhanced-plm]. 978 8. Security Considerations 980 The performance measurement is intended for deployment in well- 981 managed private and service provider networks. As such, it assumes 982 that a node involved in a measurement operation has previously 983 verified the integrity of the path and the identity of the far-end 984 reflector node. 986 If desired, attacks can be mitigated by performing basic validation 987 and sanity checks, at the sender, of the counter or timestamp fields 988 in received measurement response messages. The minimal state 989 associated with these protocols also limits the extent of measurement 990 disruption that can be caused by a corrupt or invalid message to a 991 single query/response cycle. 993 Use of HMAC-SHA-256 in the authenticated mode protects the data 994 integrity of the probe messages. SRv6 has HMAC protection 995 authentication defined for SRH [RFC8754]. Hence, probe messages for 996 SRv6 may not need authentication mode. Cryptographic measures may be 997 enhanced by the correct configuration of access-control lists and 998 firewalls. 1000 9. IANA Considerations 1002 This document does not require any IANA action. 1004 10. References 1006 10.1. Normative References 1008 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 1009 DOI 10.17487/RFC0768, August 1980, 1010 . 1012 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1013 Requirement Levels", BCP 14, RFC 2119, 1014 DOI 10.17487/RFC2119, March 1997, 1015 . 1017 [RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M. 1018 Zekauskas, "A One-way Active Measurement Protocol 1019 (OWAMP)", RFC 4656, DOI 10.17487/RFC4656, September 2006, 1020 . 1022 [RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J. 1023 Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)", 1024 RFC 5357, DOI 10.17487/RFC5357, October 2008, 1025 . 1027 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1028 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1029 May 2017, . 1031 10.2. Informative References 1033 [IEEE1588] 1034 IEEE, "1588-2008 IEEE Standard for a Precision Clock 1035 Synchronization Protocol for Networked Measurement and 1036 Control Systems", March 2008. 1038 [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed- 1039 Hashing for Message Authentication", RFC 2104, 1040 DOI 10.17487/RFC2104, February 1997, 1041 . 1043 [RFC2113] Katz, D., "IP Router Alert Option", RFC 2113, 1044 DOI 10.17487/RFC2113, February 1997, 1045 . 1047 [RFC4868] Kelly, S. and S. Frankel, "Using HMAC-SHA-256, HMAC-SHA- 1048 384, and HMAC-SHA-512 with IPsec", RFC 4868, 1049 DOI 10.17487/RFC4868, May 2007, 1050 . 1052 [RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow, 1053 "Bidirectional Forwarding Detection (BFD) for MPLS Label 1054 Switched Paths (LSPs)", RFC 5884, DOI 10.17487/RFC5884, 1055 June 2010, . 1057 [RFC6038] Morton, A. and L. Ciavattone, "Two-Way Active Measurement 1058 Protocol (TWAMP) Reflect Octets and Symmetrical Size 1059 Features", RFC 6038, DOI 10.17487/RFC6038, October 2010, 1060 . 1062 [RFC6335] Cotton, M., Eggert, L., Touch, J., Westerlund, M., and S. 1063 Cheshire, "Internet Assigned Numbers Authority (IANA) 1064 Procedures for the Management of the Service Name and 1065 Transport Protocol Port Number Registry", BCP 165, 1066 RFC 6335, DOI 10.17487/RFC6335, August 2011, 1067 . 1069 [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, 1070 "IPv6 Flow Label Specification", RFC 6437, 1071 DOI 10.17487/RFC6437, November 2011, 1072 . 1074 [RFC6936] Fairhurst, G. and M. Westerlund, "Applicability Statement 1075 for the Use of IPv6 UDP Datagrams with Zero Checksums", 1076 RFC 6936, DOI 10.17487/RFC6936, April 2013, 1077 . 1079 [RFC7820] Mizrahi, T., "UDP Checksum Complement in the One-Way 1080 Active Measurement Protocol (OWAMP) and Two-Way Active 1081 Measurement Protocol (TWAMP)", RFC 7820, 1082 DOI 10.17487/RFC7820, March 2016, 1083 . 1085 [RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N., 1086 Aldrin, S., and M. Chen, "Detecting Multiprotocol Label 1087 Switched (MPLS) Data-Plane Failures", RFC 8029, 1088 DOI 10.17487/RFC8029, March 2017, 1089 . 1091 [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage 1092 Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, 1093 March 2017, . 1095 [RFC8186] Mirsky, G. and I. Meilik, "Support of the IEEE 1588 1096 Timestamp Format in a Two-Way Active Measurement Protocol 1097 (TWAMP)", RFC 8186, DOI 10.17487/RFC8186, June 2017, 1098 . 1100 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 1101 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 1102 "Alternate-Marking Method for Passive and Hybrid 1103 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 1104 January 2018, . 1106 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 1107 Decraene, B., Litkowski, S., and R. Shakir, "Segment 1108 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 1109 July 2018, . 1111 [RFC8545] Morton, A., Ed. and G. Mirsky, Ed., "Well-Known Port 1112 Assignments for the One-Way Active Measurement Protocol 1113 (OWAMP) and the Two-Way Active Measurement Protocol 1114 (TWAMP)", RFC 8545, DOI 10.17487/RFC8545, March 2019, 1115 . 1117 [RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., 1118 Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header 1119 (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, 1120 . 1122 [I-D.ietf-spring-segment-routing-policy] 1123 Filsfils, C., Talaulikar, K., Voyer, D., Bogdanov, A., and 1124 P. Mattes, "Segment Routing Policy Architecture", draft- 1125 ietf-spring-segment-routing-policy-08 (work in progress), 1126 July 2020. 1128 [I-D.ietf-spring-sr-replication-segment] 1129 Voyer, D., Filsfils, C., Parekh, R., Bidgoli, H., and Z. 1130 Zhang, "SR Replication Segment for Multi-point Service 1131 Delivery", draft-ietf-spring-sr-replication-segment-00 1132 (work in progress), July 2020. 1134 [I-D.shen-spring-p2mp-transport-chain] 1135 Shen, Y., Zhang, Z., Parekh, R., Bidgoli, H., and Y. 1136 Kamite, "Point-to-Multipoint Transport Using Chain 1137 Replication in Segment Routing", draft-shen-spring-p2mp- 1138 transport-chain-02 (work in progress), April 2020. 1140 [I-D.ietf-pim-sr-p2mp-policy] 1141 Voyer, D., Filsfils, C., Parekh, R., Bidgoli, H., and Z. 1142 Zhang, "Segment Routing Point-to-Multipoint Policy", 1143 draft-ietf-pim-sr-p2mp-policy-00 (work in progress), July 1144 2020. 1146 [I-D.ietf-spring-mpls-path-segment] 1147 Cheng, W., Li, H., Chen, M., Gandhi, R., and R. Zigler, 1148 "Path Segment in MPLS Based Segment Routing Network", 1149 draft-ietf-spring-mpls-path-segment-02 (work in progress), 1150 February 2020. 1152 [I-D.ietf-spring-srv6-network-programming] 1153 Filsfils, C., Camarillo, P., Leddy, J., Voyer, D., 1154 Matsushima, S., and Z. Li, "SRv6 Network Programming", 1155 draft-ietf-spring-srv6-network-programming-16 (work in 1156 progress), June 2020. 1158 [BBF.TR-390] 1159 "Performance Measurement from IP Edge to Customer 1160 Equipment using TWAMP Light", BBF TR-390, May 2017. 1162 [I-D.gandhi-mpls-ioam-sr] 1163 Gandhi, R., Ali, Z., Filsfils, C., Brockners, F., Wen, B., 1164 and V. Kozak, "MPLS Data Plane Encapsulation for In-situ 1165 OAM Data", draft-gandhi-mpls-ioam-sr-02 (work in 1166 progress), March 2020. 1168 [I-D.ali-spring-ioam-srv6] 1169 Ali, Z., Gandhi, R., Filsfils, C., Brockners, F., Kumar, 1170 N., Pignataro, C., Li, C., Chen, M., and G. Dawra, 1171 "Segment Routing Header encapsulation for In-situ OAM 1172 Data", draft-ali-spring-ioam-srv6-02 (work in progress), 1173 November 2019. 1175 [I-D.ietf-pce-sr-bidir-path] 1176 Li, C., Chen, M., Cheng, W., Gandhi, R., and Q. Xiong, 1177 "PCEP Extensions for Associated Bidirectional Segment 1178 Routing (SR) Paths", draft-ietf-pce-sr-bidir-path-02 (work 1179 in progress), March 2020. 1181 [I-D.gandhi-spring-sr-enhanced-plm] 1182 Gandhi, R., Filsfils, C., Vaghamshi, N., Nagarajah, M., 1183 and R. Foote, "Enhanced Performance Delay and Liveness 1184 Monitoring in Segment Routing Networks", draft-gandhi- 1185 spring-sr-enhanced-plm-02 (work in progress), July 2020. 1187 Acknowledgments 1189 The authors would like to thank Thierry Couture for the discussions 1190 on the use-cases for Performance Measurement in Segment Routing. The 1191 authors would also like to thank Greg Mirsky for reviewing this 1192 document and providing useful comments and suggestions. Patrick 1193 Khordoc and Radu Valceanu, both from Cisco Systems have helped 1194 significantly improve the mechanisms defined in this document. The 1195 authors would like to acknowledge the earlier work on the loss 1196 measurement using TWAMP described in draft-xiao-ippm-twamp-ext- 1197 direct-loss. 1199 Authors' Addresses 1201 Rakesh Gandhi (editor) 1202 Cisco Systems, Inc. 1203 Canada 1205 Email: rgandhi@cisco.com 1207 Clarence Filsfils 1208 Cisco Systems, Inc. 1210 Email: cfilsfil@cisco.com 1212 Daniel Voyer 1213 Bell Canada 1215 Email: daniel.voyer@bell.ca 1217 Mach(Guoyi) Chen 1218 Huawei 1220 Email: mach.chen@huawei.com 1222 Bart Janssens 1223 Colt 1225 Email: Bart.Janssens@colt.net