idnits 2.17.1 draft-browne-sfc-nsh-kpi-stamp-05.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** There is 1 instance of too long lines in the document, the longest one being 2 characters in excess of 72. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (August 27, 2018) is 2062 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- == Unused Reference: 'RFC5226' is defined on line 1072, but no explicit reference was found in the text -- Obsolete informational reference (is this intentional?): RFC 5226 (Obsoleted by RFC 8126) Summary: 1 error (**), 0 flaws (~~), 2 warnings (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Network Working Group R. Browne 2 Internet Draft A. Chilikin 3 Intended status: Informational Intel 4 Expires: February 2019 T. Mizrahi 5 Marvell 6 August 27, 2018 8 A Key Performance Indicators (KPI) 9 Stamping for the Network Service Header (NSH) 10 draft-browne-sfc-nsh-kpi-stamp-05 12 Abstract 14 This document describes an experimenal method of carrying Key 15 Performance Indicators (KPIs) using the Network Service Header (NSH). 16 This method may be used, for example, to monitor latency and QoS 17 marking to identify problems on some links or service functions. 19 Status of this Memo 21 This Internet-Draft is submitted to IETF in full conformance with the 22 provisions of BCP 78 and BCP 79. 24 Internet-Drafts are working documents of the Internet Engineering 25 Task Force (IETF), its areas, and its working groups. Note that 26 other groups may also distribute working documents as Internet- 27 Drafts. 29 Internet-Drafts are draft documents valid for a maximum of six months 30 and may be updated, replaced, or obsoleted by other documents at any 31 time. It is inappropriate to use Internet-Drafts as reference 32 material or to cite them other than as "work in progress." 34 The list of current Internet-Drafts can be accessed at 35 http://www.ietf.org/ietf/1id-abstracts.txt. 37 The list of Internet-Draft Shadow Directories can be accessed at 38 http://www.ietf.org/shadow.html. 40 This Internet-Draft will expire on February 27, 2019. 42 Copyright Notice 44 Copyright (c) 2018 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (http://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction...................................................2 60 2. Terminology....................................................3 61 2.1. Requirement Language......................................3 62 2.2. Definition of Terms.......................................3 63 2.2.1. Terms Defined in this Document.......................4 64 2.3. Abbreviations.............................................4 65 3. NSH KPI Stamping: An Overview..................................6 66 3.1. Prerequisites.............................................7 67 3.2. Operation................................................10 68 3.2.1. Flow Selection......................................10 69 3.2.2. SCP Interface.......................................10 70 3.3. Performance Considerations...............................11 71 4. NSH KPI-stamping Encapsulation................................12 72 4.1. KPI-stamping Extended Encapsulation......................13 73 4.1.1. NSH Timestamping Encapsulation (Extended Mode)......15 74 4.1.2. NSH QoS-stamping Encapsulation (Extended Mode)......17 75 4.2. KPI-stamping Encapsulation (Detection Mode)..............20 76 5. Hybrid Models.................................................22 77 5.1. Targeted VNF Stamp.......................................23 78 6. Fragmentation Considerations..................................23 79 7. Security Considerations.......................................24 80 8. IANA Considerations...........................................25 81 9. Contributors..................................................25 82 10. Acknowledgments..............................................25 83 11. References...................................................26 84 11.1. Normative References....................................26 85 11.2. Informative References..................................26 87 1. Introduction 89 Network Service Header (NSH), as defined by [RFC8300], specifies a 90 method for steering the traffic among an order set of Service 91 Functions (SFs) using an extensible service header. This allows for 92 flexibility and programmability in the forwarding plane to invoke the 93 appropriate SFs for specific flows. 95 NSH promises a compelling vista of operational flexibility. However, 96 many service providers are concerned about service and configuration 97 visibility. This concern increases when considering that many service 98 providers wish to run their networks seamlessly in 'hybrid' mode, 99 whereby they wish to mix physical and virtual SFs and run services 100 seamlessly between the two domains. 102 This document describes a generic method to monitor and debug service 103 function chains in terms of latency and QoS marking of the flows 104 within a service function chain. Thus, it is possible to detect and 105 debug performance issues and to detect and debug QoS 106 misconfigurations on the chain. 108 The method described in the document is compliant with hybrid 109 architectures in which Virtual Network Functions (VNFs) and Physical 110 Network Functions (PNFs) are freely mixed in the service function 111 chain. This method also provides flexibility to monitor the 112 performance and configuration of an entire chain or part thereof as 113 desired. This method is extensible to monitoring other KPIs. Please 114 refer to [RFC7665] for an architectural context for this document. 116 The method described in this document is not an OAM protocol such as 117 [Y.1731] or [Y.1564]. As such it does not define new OAM packet types 118 or operation. Rather it monitors the service function chain 119 performance and configuration for subscriber payloads and indicates 120 subscriber QoE rather than out-of-band infrastructure metrics. This 121 document differs from to [I-D.ippm.ioam] in the sense that it is 122 specifically tied to NSH operation and not generic in nature. 124 2. Terminology 126 2.1. Requirement Language 128 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 129 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 130 document are to be interpreted as described in [RFC2119]. 132 2.2. Definition of Terms 134 This section presents the main terms used in this document. This 135 document makes use of the terms defined in [RFC7665] and [RFC8300]. 137 2.2.1. Terms Defined in this Document 139 First Stamping Node (FSN): The first node along a service function 140 chain that stamps packets using KPI stamping. The FSN matches each 141 packet with a Stamping Controller flow based on a stamping 142 classification criterion such as transport 5-tuple coordiantes, but 143 not limited to. 145 Last Stamping Node (LSN): The last node along a service function 146 chain that stamps packets using KPI stamping. The LSN reads all the 147 metadata and exports it to a system performance statistics agent or 148 repository. The LSN should use the NSH Service Index (SI) to indicate 149 if a SF was at the end of the chain. The LSN changes the Service Path 150 Identifier (SPI) in order that the network underlay forwards the 151 metadata back directly to the KPI database (KPIDB). 153 Key Performance Indicator Database (KPIDB): denotes the external 154 storage of metadata for reporting, trend analysis, etc. 156 KPI-stamping: The insertion of latency-related and/or QoS-related 157 information into a packet using NSH metadata. 159 Flow ID: The Flow ID is a unique 16 bit identifier written into the 160 header by the classifier. This allows 65536 flows to be concurrently 161 stamped on any given NSH service chain (SPI). 163 QoS-stamping: The insertion of QoS-related information into a packet 164 using NSH metadata. 166 Stamping Controller (SC): The SC is the central logic that decides 167 what packets to stamp and how. The SC instructs the classifier on how 168 to build the NSH. 170 Stamp Control Plane (SCP): the control plane between the FSN and the 171 SC. 173 2.3. Abbreviations 175 DEI Drop Eligible Indicator 177 DSCP Differentiated Services Code Point 179 FSN First Stamping Node 181 KPI Key Performance Indicator 183 KPIDB Key Performance Indicator Database 184 LSN Last Stamping Node 186 MD Metadata 188 NFV Network Function Virtualization 190 NFVI-PoP NFV Infrastructure Point of Presence 192 NIC Network Interface Card 194 NSH Network Service Header 196 OAM Operations, Administration, and Maintenance 198 PCP Priority Code Point 200 PNF Physical Network Function 202 PNFN Physical Network Function Node 204 QoE Quality of Experience 206 QoS Quality of Service 208 QS QoS Stamp 210 RSP Rendered Service Path 212 SC Stamping Controller 214 SCL Service Classifier 216 SCP Stamp Control Plane 218 SI Service Index 220 SF Service Function 222 SFC Service Function Chain 224 SFN Service Function Node 226 SFP Service Function Path 228 SSI Stamp Service Index 230 TC Traffic Class 231 TS Timestamp 233 VLAN Virtual Local Area Network 235 VNF Virtual Network Function 237 vSwitch Virtual Switch 239 3. NSH KPI Stamping: An Overview 241 A typical KPI stamping architecture is presented in Figure 1. 243 Stamping 244 Controller 245 | KPIDB 246 | SCP Interface | 247 ,---. ,---. ,---. ,---. 248 / \ / \ / \ / \ 249 ( SCL )-------->( SF1 )--------->( SF2 )--------->( SFN ) 250 \ FSN / \ / \ / \ LSN / 251 `---' `---' `---' `---' 252 Figure 1: Logical roles in NSH KPI Stamping 254 The Stamping Controller (SC) will most probably be part of the SFC 255 controller, but it is described separately in this document for 256 clarity. 258 The SC is responsible for initiating start/stop stamp requests to the 259 SCL or First Stamp Node (FSN), and also for distributing NSH stamping 260 policy into the service chain via the Stamping Control Plane (SCP) 261 interface. 263 The FSN will typically be part of the SCL, but again is called out as 264 separate logical entity for clarity. 266 The FSN is responsible for marking NSH MD fields which tells upstream 267 nodes how to behave in terms of stamping at SF ingress, egress or 268 both, or ignoring the stamp NSH metadata completely. 270 The FSN also writes the Reference Time value, a (possibly inaccurate) 271 estimate of the current time-of-day, into the header, allowing the 272 {SPI:Flow ID} performance to be compared to previous samples for 273 offline analysis. 275 The FSN should return an error to the SC if not synchronized to the 276 current time-of-day and forward the packet along the service-chain 277 unchanged. The code and format of the error is specific to the 278 protocol used between the FSN and SC; these considerations are out of 279 scope. 281 SF1 and SF2 stamp the packets as dictated by the FSN and process the 282 payload as per normal. 284 Note 1: The exact location of the stamp creation may not be in 285 the SF itself, as discussed in Section 3.3. 287 Note 2: Special cases exist where some of the SFs are 288 NSH-unaware. This is covered in Section 5. 290 The Last Stamp Node (LSN) should strip the entire NSH header and 291 forward the raw packet to the IP next hop as per [RFC8300]. The LSN 292 also exports NSH stamp information to the KPI Database (KPIDB) for 293 offline analysis; the LSN may either export the stamping information 294 of all packets, or a subset based on packet sampling. 296 In fully virtualized environments the LSN is likely to be co-located 297 with the SF that decrements the NSH Service Index (SI) to zero. 298 Corner cases exist whereby this is not the case and is covered in 299 Section 5. 301 3.1. Prerequisites 303 Timestamping presents a set of prerequisites not required to QoS- 304 Stamp. In order to guarantee metadata accuracy, all servers hosting 305 VNFs should be synchronized from a centralized stable clock. As it is 306 assumed that PNFs do not timestamp (as this would involve a software 307 change and probable throughput performance impact) there is no need 308 for them to synchronize. There are two possible levels of 309 synchronization: 311 Level A: Low accuracy time-of-day synchronization, based on 312 NTP [RFC5905]. 314 Level B: High accuracy synchronization (typically on the order of 315 microseconds), based on [IEEE1588]. 317 Each SF SHOULD have a level A synchronization, and MAY have a level B 318 synchronization. 320 Level A requires each platform (including the Stamp Controller) to 321 synchronize its system real-time-clock to an NTP server. This is used 322 to mark the metadata in the chain, using the field 323 in the NSH KPI-stamp header (Section 4.2). This timestamp is inserted 324 to the NSH by the first SF in the chain. NTP accuracy can vary by 325 several milliseconds between locations. This is not an issue as the 326 Reference Time is merely being used as a time-of-day reference 327 inserted into the KPIDB for performance monitoring and metadata 328 retrieval. 330 Level B synchronization requires each platform to be synchronized to 331 a Primary Reference Clock (PRC) using the Precision Time Protocol 332 [IEEE1588]. A platform MAY also use Synchronous Ethernet ([G.8261], 333 [G.8262], [G.8264]), allowing more accurate frequency 334 synchronization. 336 If an SF is not synchronized at the moment of timestamping, it should 337 indicate its synchronization status in the NSH. This is described in 338 more detail in Section 4. 340 By synchronizing the network in this way, the timestamping operation 341 is independent of the current Rendered Service Path (RSP). Indeed the 342 timestamp metadata can indicate where a chain has been moved due to a 343 resource starvation event as indicated in Figure 2, between VNF 3 and 344 VNF 4 at time B. 346 Delay 347 | v 348 | v 349 | x 350 | x x = reference time A 351 | xv v = reference time B 352 | xv 353 | xv 354 |______|______|______|______|______|_____ 355 VNF1 VNF2 VNF3 VNF4 VNF5 357 Figure 2: Flow performance in a service chain 359 For QoS-stamping it is desired that the SCL or FSN be synchronized in 360 order to provide reference time for offline analysis, but this is not 361 a hard requirement (they may be in holdover or free-run state, for 362 example). Other SFs in the service chain do not need to be 363 synchronized for QoS-stamping operation as described below. 365 QoS-stamping can be used to check consistency of configuration across 366 the entire chain or part thereof. By adding all potential layer 2 and 367 layer 3 QoS fields into a QoS sum at SF ingress or egress, this 368 allows quick identification of QoS mismatches across multiple L2/L3 369 fields which otherwise is a manual, expert-led consuming process. 371 | 372 | 373 | xy 374 | xy x = ingress QoS sum 375 | xv v = egress QoS sum 376 | xv y = egress QoS sum miss 377 | xv 378 |______|______|______|______|______|_____ 379 SF1 SF2 SF3 SF4 SF5 381 Figure 3: Flow QoS Consistency in a service chain 383 Referring to Figure 3, x, v, and y are notional sum values of the QoS 384 marking configuration of the flow within a given chain. As the 385 encapsulation of the flow can change from hop to hop in terms of VLAN 386 header(s), MPLS labels, DSCP(s) these values are used to compare 387 consistency of configuration from for example payload DSCP through 388 overlay and underlay QoS settings in VLAN IEEE 802.1Q bits, MPLS bits 389 and infrastructure DSCPs. 391 Figure 3 indicates that at SF4 in the chain, the egress QoS marking 392 is inconsistent. That is, the ingress QoS settings do not match the 393 egress. The method described here will indicate which QoS field(s) is 394 inconsistent, and whether this is ingress (whereby the underlay has 395 incorrectly marked and queued the packet) or egress (where the SF has 396 incorrectly marked and queued the packet. 398 Note that the SC must be aware of when a SF remarks QoS fields 399 deliberately and thus does not flag an issue for desired behavior. 401 3.2. Operation 403 KPI-stamping detection mode uses MD type 2 defined in [RFC8300]. This 404 involves the SFC classifier stamping the flow at chain ingress, and 405 no subsequent stamps being applied, rather each SF upstream can 406 compare its local condition with the ingress value and take 407 appropriate action. Therefore detection mode is very efficient in 408 terms of header size that does not grow after the classification. 409 This is further explained in Section 4.1. 411 3.2.1. Flow Selection 413 The SC should maintain a list of flows within each service chain to 414 be monitored. This flow table should be in the format 'SPI:FlowID'. 415 The SC should map these pairs to unique values presented as Flow IDs 416 per service chain within the NSH TLV specified in this document. The 417 SC should instruct the FSN to initiate timestamping on flow table 418 match. The SC may also tell the classifier the duration of the 419 timestamping operation, either by a number of packets in the flow or 420 by a time duration. 422 In this way the system can monitor the performance of the all en- 423 route traffic, or an individual subscriber in a chain, or just a 424 specific application or a QoS class that is used in the network. 426 The SC should write the list of monitored flows into the KPIDB for 427 correlation of performance and configuration data. Thus, when the 428 KPIDB receives data from the LSN it understands to which flow the 429 data pertains. 431 The association of source IP to subscriber identity is outside the 432 scope of this document and will vary by network application. For 433 example, the method of association of a source IP to IMSI will be 434 different to how a CPE with NAT function may be chained in an 435 enterprise NFV application. 437 3.2.2. SCP Interface 439 A Stamp Control Plane (SCP) interface is required between the SC and 440 the FSN or classifier. This interface is used to: 442 o Query the SFC classifier for a list of active chains and flows. 444 o Communicate which chains and flows to stamp. This can be a 445 specific {SPI:Flow ID} combination or include wildcards for 446 monitoring subscribers across multiple chains or multiple flows 447 within one chain. 449 o Instruct how the stamp should be applied (ingress, egress, both 450 or specific). 452 o Indicate when to stop stamping, either after a certain number 453 of packets or duration. 455 Typically SCP timestamps flows for a certain duration for trend 456 analysis, but only stamps one packet of each QoS class in a chain 457 periodically (perhaps once per day or after a network change). 458 Therefore, timestamping is generally applied to a much larger set of 459 packets than QoS-stamping. 461 Exact specification of SCP is for further study. 463 3.3. Performance Considerations 465 This document does not mandate a specific stamping implementation 466 method, and thus NSH KPI stamping can either be performed by hardware 467 mechanisms, or by software. 469 If software-based stamping is used, applying and operating on the 470 stamps themselves incur an additional small delay in the service 471 chain. However, it can be assumed that these additional delays are 472 all relative for the flow in question. This is only pertinent for 473 timestamping mode, and not for QoS-stamping mode. Thus, whist the 474 absolute timestamps may not be fully accurate for normal non- 475 timestamped traffic they can be assumed to be relative. 477 It is assumed that the method described in this document would only 478 operate on a small percentage of user flows. 480 The service provider may choose a flexible policy in the SC to 481 timestamp a selection of user-plane every minute for example to 482 highlight any performance issues. Alternatively, the LSN may 483 selectively export a subset of the KPI-stamps it receives, based on a 484 predefined sampling method. Of course the SC can stress test an 485 individual flow or chain should a deeper analysis be required. We can 486 expect that this type of deep analysis has an impact on the 487 performance of the chain itself whilst under investigation. The 488 impact will be dependent on vendor implementation and outside the 489 scope of this document. 491 For QoS-stamping the method described here is even less intrusive, as 492 typically multiple packets in a flow are QoS stamped periodically 493 (perhaps once per day) check one packet in a chain per QoS class. 495 4. NSH KPI-stamping Encapsulation 497 KPI stamping uses NSH MD type 0x2 for detection of anomalies and 498 extended mode for root cause analysis of KPI violations. These are 499 further explained in this section. 501 The generic NSH MD type 2 TLV for KPI Stamping is shown below. 503 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 1 504 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 505 |Ver|O|U| TTL | Length |U|U|U|U|Type=2 | Next Protocol | 506 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 507 | Service Path Identifier | Service Index | 508 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 509 | Metadata Class=0xfff6 | Type |U| Length | 510 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 511 | Variable-length KPI Metadata header and TLV(s) | 512 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 513 Figure 4: Generic NSH KPI Encapsulation 515 Relevant fields in header that the FSN must implement: 517 o The O bit must not be set. 519 o The MD type must be set to 0x2 521 o The MD Class must be set to 0xfff6. 523 o The Type field may have one of the following values; the 524 content of "KPI metadata" depends on the type value: 526 o Type = 0x01 Det: Detection 528 o Type = 0x02 TS: Timestamp Extended 529 o Type = 0x03 QoS: QoS-stamp Extended 531 The Type field determines the type of KPI-stamping format. The 532 supported formats are presented in the following subsections. 534 4.1. KPI-stamping Extended Encapsulation 536 The generic NSH MD type 2 KPI-stamping header extended mode is shown 537 in Figure 6. This is the format for performance monitoring of service 538 chain issues with respect to QoS configuration and latency. 540 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 1 541 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 542 |Ver|O|U| TTL | Length |U|U|U|U|Type=2 | Next Protocol | 543 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 544 | Service Path Identifier | Service Index | 545 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 546 | Metadata Class=0xfff6 | Type |U| Length | 547 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 548 | Variable Length KPI Configuration Header | 549 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 550 | Variable Length KPI Value (LSN) | 551 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 552 \ \ 553 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 554 | Variable Length KPI Value (FSN) | 555 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 556 Figure 5: Generic KPI Encapsulation (Extended Mode) 558 As mentioned above, two types are defined under the experimental MD 559 class to indicate extended KPI MD: a timestamp type and a QoS-stamp 560 type. 562 The KPI Encapsulation Configuration Header format is shown below. 564 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 565 |K|K|T|K|K|K|K|K| Stamping SI | Flow ID | 566 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 567 | Reference Time | 568 | | 569 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 570 Figure 6: KPI Encapsulation Configuration Header 572 The bits marked as 'K' are reserved for specific KPI type use and 573 described in the corresponding subsections below. 575 The T bit should be set if Reference Time follows KPI Encapsulation 576 Configuration Header. 578 Stamping Service Index (Stamping SI) contains the Service Index used 579 for KPI stamping and described in the corresponding subsections 580 below. 582 The Flow ID is a unique 16 bit identifier written into the header by 583 the classifier. This allows 65536 flows to be concurrently stamped on 584 any given NSH service chain (SPI). Flow IDs are not written by 585 subsequent SFs in the chain. The FSN may export monitored flow IDs to 586 the KPIDB for correlation. 588 Reference Time is the wall clock of the FSN, and may be used for 589 historical comparison of SC performance. If the FSN is not Level A 590 synchronized (see Section 3.1) it should inform the SC over the SCP 591 interface. The Reference Time is represented in 64-bit NTP format 592 [RFC5905] presented in Figure 8: 594 0 1 2 3 595 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 1 596 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 597 | Seconds | 598 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 599 | Fraction | 600 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 601 Figure 7: NTP [RFC5905] 64-bit Timestamp Format 603 4.1.1. NSH Timestamping Encapsulation (Extended Mode) 605 The NSH timestamping extended encapsulation is shown below. 607 0 1 2 3 608 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 1 609 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 610 |Ver|O|C|U|U|U|U|U|U| Length |U|U|U|U|Type=2 | NextProto | 611 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 612 | Service Path ID | Service Index | 613 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 614 | MD Class=0xfff6 | Type=TS(2) |R| Len | 615 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 616 |I|E|T|U|U|U|SSI| Stamping SI | Flow ID | 617 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 618 | Reference Time (T bit is set) | 619 | | 620 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 621 |I|E|U|U|U| SYN | Stamping SI | Unassigned | 622 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 623 | Ingress Timestamp (I bit is set)(LSN) | 624 | | 625 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 626 | Egress Timestamp (E bit is set)(LSN) | 627 | | 628 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 629 . . 630 . . 631 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 632 |I|E|U|U|U| SYN | Stamping SI | Unassigned | 633 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 634 | Ingress Timestamp (I bit is set) (FSN) | 635 | | 636 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 637 | Egress Timestamp (E bit is set) (FSN) | 638 | | 639 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 640 Figure 8: NSH Timestamp Encapsulation (Extended Mode) 642 The FSN KPI-stamp metadata starts with Stamping Configuration Header. 643 This header contains the I, E, T bits and Stamp Service Index (SSI). 645 The I bit should be set if Ingress stamp is requested. 647 The E bit should be set if Egress stamp is requested. 649 SSI field must be set to one of the following values: 651 o 0x0 KPI-stamp mode, no Service index specified in the Stamp 652 Service Index field. 654 o 0x1 KPI-stamp Hybrid mode is selected, Stamp Service Index 655 contains LSN Service index. This is used when PNFs or NSH-unaware 656 SFs are used at the tail of the chain. If SSI=0x1, then the value 657 in the type field informs the chain which SF should act as the 658 LSN. 660 o 0x2 KPI-stamp Specific mode is selected, Stamp Service Index 661 contains the targeted Service Index. In this case the Stamp 662 Service Index field indicates which SF is to be stamped. Both 663 ingress and egress stamps are performed when the SI=SSI on the 664 chain. For timestamping mode, the FSN will also apply the 665 Reference Time and Ingress Timestamp. This will indicate the delay 666 along the entire service chain to the targeted SF. This method may 667 also be used as a light implementation to monitor end-to-end 668 service chain performance whereby the targeted SF is the LSN. This 669 is not applicable to QoSStamping mode. 671 Each stamping Node adds stamping metadata which consist of Stamping 672 Reporting Header and timestamps. 674 The E bit should be set if Egress stamp is reported. 676 The I bit should be set if Ingress stamp is reported. 678 With respect to timestamping mode, the SYN bits are an indication of 679 the synchronization status of the node performing the timestamp and 680 must be set to one of the following values: 682 o In Synch: 0x00 684 o In holdover: 0x01 686 o In free run: 0x02 688 o Out of Synch: 0x03 689 If the platform hosting the SF is out of synch or in free run no 690 timestamp is applied by the node (but other timestamp MD is applied) 691 and the packet is processed normally. 693 If FSN is out of synch or in free run timestamp request rejected and 694 not propagated though the chain. The FSN should inform the SC in such 695 an event over the SCP interface. 697 The outer service index value is copied into the stamp metadata as 698 Stamping SI to help cater for hybrid chains that are a mix of VNFs 699 and PNFs or through NSH-unaware SFs. Thus, if a flow transits through 700 a PNF or an NSH-unaware node the delta in the inner service index 701 between timestamps will indicate this. 703 The Ingress Timestamp and Egress Timestamp are represented in 64-bit 704 NTP format. The corresponding bits (I and E) reported in the Stamping 705 Reporting Header of the node's metadata. 707 Timestamps are represented in 64-bit NTP [RFC5905] format, which is 708 one of the recommended formats of [TS]. 710 4.1.2. NSH QoS-stamping Encapsulation (Extended Mode) 712 Packets have a variable QoS stack. That is for example the same 713 payload IP can have a very different stack in the access part of the 714 network to the core. This is most apparent in mobile networks where 715 for example in an access circuit we would have 2 layers of 716 infrastructure IP header (DSCP) - one transport-based and the other 717 IPsec-based, in addition to multiple MPLS and VLAN tags. The same 718 packet as it leaves the PDN Gateway Gi egress interface may be very 719 much simplified in terms of overhead and related QoS fields. 721 Because of this variability we need to build extra meaning into the 722 QoS headers - they are not for example all PTP timestamps of a fixed 723 length as in the case of timestamping, rather they are variable 724 lengths and types. Also they can be changed on the underlay at any 725 time without knowledge by the SFC system. Therefore each SF must be 726 able to ascertain and record its ingress and egress QoS configuration 727 on the fly. 729 The suggested QoS type, lengths are as below. The type is 4 bits 730 long. 732 QoS Type(QT)Value Length Comment 734 IVLAN 0x01 4 Bits Ingress VLAN (PCP + DEI) 736 EVLAN 0x02 4 Bits Egress VLAN 738 IQINQ 0x03 8 Bits Ingress QinQ (2x PCP+DEI) 740 EQINQ 0x04 8 Bits Egress QinQ 742 IMPLS 0x05 3 Bits Ingress Label 744 EMPLS 0x06 3 Bits Egress Label 746 IMPLS 0x07 6 Bits 2 Ingress Labels (2x EXP) 748 EMPLS 0x08 6 Bits 2 Egress Labels 750 IDSCP 0x09 8 Bits Ingress DSCP 752 EDSCP 0x0A 8 Bits Egress DSCP 754 For stacked headers such as MPLS and 802.1ad, we extract the QoS 755 relevant data from the header and insert into one QoS value in order to 756 be more efficient on packet size. Thus for MPLS, we represent both EXP 757 fields in one QoS value, and both 802.1p priority and drop precedence in 758 one QoS value as indicated above. 760 0 1 2 3 761 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 1 762 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 763 |Ver|O|C|U|U|U|U|U|U| Length |U|U|U|U|Type=2 | NextProto=0x0 | 764 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 765 | Service Path ID | Service Index | 766 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 767 | MD Class= 0xfff6 |C| Type=QoS(3) |R| Len | 768 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 769 |U|U|T|U|U|U|SSI| Stamping SI | Flow ID | 770 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 771 | Reference Time (T bit is set) | 772 | | 773 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 774 |U|U|U|U|U|U|U|U| Stamping SI | Unassigned | 775 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 776 | QT | QoS Value |U|U|U|E| QT | QoS Value |U|U|U|E| 777 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 778 . . 779 . . 780 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 781 |U|U|U|U|U|U|U|U| Stamping SI | Unassigned | 782 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| 783 | QT | QoS Value |U|U|U|E| QT | QoS Value |U|U|U|E| 784 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 785 Figure 9: NSH QoS Configuration Encapsulation (Extended Mode) 787 The encapsulation in Figure 10 is very similar to that detailed in 788 Section 4.1 with the following exceptions: 790 - I and E bits are not required as we wish to examine the full QoS 791 stack at ingress and egress at every SF. 793 - Syn status bits are not required. 795 - The QT (QoS Type) and QoS value are as outlined in the table 796 above. 798 - The E bit at the tail of each QoS context field indicates if this 799 is the last egress QoS-stamp for a given SF. This should coincide 800 with SI=0 at the LSN, whereby the packet is truncated and the NSH 801 MD sent to the KPIDB and the subscriber raw IP packet forwarded to 802 the underlay next hop. 804 Note: It is possible to compress the frame structure to better 805 utilize the header, but this would come at the expense of crossing 806 byte boundaries. For ease of implementation, and that QoS-stamping is 807 applied on an extremely small subset of user plane traffic, we 808 believe the above structure is a pragmatic compromise between header 809 efficiency and ease of implementation. 811 4.2. KPI-stamping Encapsulation (Detection Mode) 813 The format of the NSH MD type 2 KPI-stamping TLV (detection mode) is 814 shown in Figure 11. 816 This TLV is used for KPI anomaly detection. Upon detecting a problem 817 or an anomaly it will be possible to enable the use of KPI-stamping 818 extended encapsulations, which will provide more detailed analysis. 820 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 1 821 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 822 |Ver|O|U| TTL | Length |U|U|U|U|Type=2 | Next Protocol | 823 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 824 | Service Path Identifier | Service Index | 825 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 826 |Metadata Class=0xfff6 | Type=Det(1) |U| Length | 827 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 828 | KPI Type | Stamping SI | Flow ID | 829 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 830 | Threshold KPI Value | 831 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 832 | Ingress KPI-stamp | 833 | | 834 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 835 Figure 10: Generic NSH KPI Encapsulation (Detection Mode) 837 The following fields are defined in the KPI TSD metadata: 839 o KPI Type: determines the type of KPI-stamp that is included in 840 this metadata field. 841 If a receiver along the path does not understand the KPI Type it 842 will pass the packet transparently and not drop. 843 The supported values of the KPI Type are: 844 0x0 Timestamp 845 0x1 QoS-stamp 847 o Threshold KPI Value: In the first header the SFC classifier may 848 program a KPI threshold value. This is a value that when exceeded, 849 requires the SF to insert the current SI value into the SI field. 850 The KPI type is the type of KPI stamp inserted into the header as 851 per section 9. 853 o Stamping SI: Service Identifier of the SF when the Threshold 854 above is exceeded. 856 o Flow ID: The flow ID is inserted into the header by the SFC 857 classifier in order to correlate flow data in the KPIDB for 858 offline analysis. 860 o Ingress KPI-stamp: The last 8 octets are reserved for the KPI- 861 stamp. This is the KPI value at the chain ingress at the SFC 862 classifier. Depending on the KPI Type, the KPI-stamp either 863 includes a timestamp or a QoS-stamp. 864 If the KPI Type is Timestamp, then the Ingress KPI-stamp field 865 contains a timestamp in 64-bit NTP timestamp format. If the KPI 866 Type is QoS-stamp, then the format of the 64-bit Ingress KPI-stamp 867 is as follows. 869 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 1 870 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 871 | QT | QoS Value | Unassigned | 872 +-+-+-+-+-+-+-+-+-+-+-+-+ + 873 | | 874 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 875 Figure 11: QoS-stamp Format (Detection Mode) 877 As an example operation, say we are using KPI type 0x01 (timestamp) 878 when a service function (SFn) receives the packet it can compare 879 current local timestamp (it first checks that it is synchronized to 880 network PRC) with chain ingress timestamp to calculate the latency in 881 the chain. If this value exceeds the timestamp threshold, it then 882 inserts its SI and returns the NSH to the KPIDB. This effectively 883 tells the system that at SFn the packet violated the KPI threshold. 884 Please refer to figure 9 for timestamp format. 886 When this occurs the SFC control plane system would then invoke the 887 KPI extended mode, which uses a more sophisticated (and intrusive) 888 method to isolate KPI violation root cause as described below. 890 Note: Whilst detection mode is a valuable tool for latency actions, 891 the authors feel that it is not justified to build the logic into the 892 KPI system for QoS configuration. As QoS-stamping is done 893 infrequently and on a tiny percentage of user plane, it is more 894 practical to use extended mode only for service chain QoS 895 verification. 897 5. Hybrid Models 899 A hybrid chain may be defined as a chain whereby there is a mix of 900 NSH-aware and NSH-unaware SFs. 902 Example 1. PNF in the middle 904 Stamp 905 Controller 906 | KPIDB 907 | SCP Interface | 908 ,---. ,---. ,---. ,---. 909 / \ / \ / \ / \ 910 ( SCL )-------->( SF1 )--------->( SF2 )--------->( SFN ) 911 \ FSN / \ / \ PNF1/ \ LSN / 912 `---' `---' `---' `---' 913 Figure 12: Hybrid chain with PNF in middle 915 In this example the FSN begins operation and sets the SI to 3, SF1 916 decrements this to 2 and passes the packet to an SFC proxy (not 917 shown). 919 The SFC proxy strips the NSH and passes to the PNF. On receipt back 920 from the PNF, the proxy decrements the SI and passes the packet onto 921 the LSN with a SI=1. 923 After the LSN processes the traffic it knows it is the last node on 924 the chain from the SI value and exports the entire NSH and all 925 metadata to the KPIDB. The payload is forwarded to the next hop on 926 the underlay minus the NSH. The TS information packet may be given a 927 new SPI to act as a homing tag to transport the timestamp data back 928 to the KPIDB. 930 Example 2. PNF at the end 932 Stamp 933 Controller 934 | KPIDB 935 | SCP Interface | 936 ,---. ,---. ,---. ,---. 937 / \ / \ / \ / \ 938 ( SCL )-------->( SF1 )--------->( SF2 )--------->( PNFN ) 939 \ FSN / \ / \ LSN / \ / 940 `---' `---' `---' `---' 941 Figure 13: Hybrid Chain with PNF at end 943 In this example the FSN begins operation and sets the SI to 3, the 944 SSI field set to 0x1, and the type to 1. Thus, when SF2 receives the 945 packet with SI=1, it understands that it is expected to take on the 946 role of the LSN as it is the last NSH-aware node in the chain. 948 5.1. Targeted VNF Stamp 950 For the majority of flows within the service chain, stamps (ingress, 951 egress or both) will be carried out at each hop until the SI 952 decrements to zero and the NSH and Stamp MD is exported to the KPIDB. 953 There may exist however the need to just test a particular VNF 954 (perhaps after a scale out operation, software upgrade or underlay 955 change for example). In this case the FSN should mark the NSH as 956 follows: 958 SSI field is set to 0x2. Type is set to the expected SI at the SF in 959 question. When outer SI is equal to the SSI, stamps are applied at SF 960 ingress and egress, and the NSH and MD are exported to the KPIDB. 962 6. Fragmentation Considerations 964 The method described in this document does not support fragmentation. 965 The SC should return an error should a stamping request from an 966 external system exceed MTU limits and require fragmentation. 968 Depending on the length of the payload and the type of KPI-stamp and 969 chain length, this will vary for each packet. 971 In most service provider architectures we would expect a SI << 10, 972 and that may include some PNFs in the chain which do not add 973 overhead. Thus for typical IMIX packet sizes we expect to able to 974 perform timestamping on the vast majority of flows without 975 fragmenting. Thus the classifier can have a simple rule to only allow 976 KPI-stamping on packet sizes less than 1200 bytes for example. 978 7. Security Considerations 980 The security considerations of NSH in general are discussed in 981 [RFC8300]. 983 The use of in-band timestamping, as defined in this document, can be 984 used as a means for network reconnaissance. By passively 985 eavesdropping to timestamped traffic, an attacker can gather 986 information about network delays and performance bottlenecks. 988 The NSH timestamp is intended to be used by various applications to 989 monitor the network performance and to detect anomalies. Thus, a man- 990 in-the-middle attacker can maliciously modify timestamps in order to 991 attack applications that use the timestamp values. For example, an 992 attacker could manipulate the SFC classifier operation, such that it 993 forwards traffic through 'better' behaving chains. Furthermore, if 994 timestamping is performed on a fraction of the traffic, an attacker 995 can selectively induce synthetic delay only to timestamped packets, 996 causing systematic error in the measurements. 998 Similarly, if an attacker can modify QoS stamps, erroneous values may 999 be imported into the KPIDB, resulting is further misconfiguration and 1000 subscriber QoE impairment. 1002 An attacker that gains access to the SCP can enable time and QoS- 1003 stamping for all subscriber flows, thereby causing performance 1004 bottlenecks, fragmentation, or outages. 1006 As discussed in previous sections, NSH timestamping relies on an 1007 underlying time synchronization protocol. Thus, by attacking the time 1008 protocol an attack can potentially compromise the integrity of the 1009 NSH timestamp. A detailed discussion about the threats against time 1010 protocols and how to mitigate them is presented in [RFC7384]. 1012 8. IANA Considerations 1014 IANA is requested allocate (register) new TLV types under the 1015 experimental MD class value 0xfff6: 1017 o Type = 0x01: Detection 1019 o Type = 0x02: Timestamp Extended 1021 o Type = 0x03: QoS-stamp Extended 1023 9. Contributors 1025 This document originated as draft-browne-sfc-nsh-timestamp-00 and had 1026 the following co-authors and contributors. We would like to thank and 1027 recognize them and their contributions. 1029 Yoram Moses 1031 Technion 1033 moses@ee.technion.ac.il 1035 Brendan Ryan 1037 Intel Corporation 1039 brendan.ryan@intel.com 1041 10. Acknowledgments 1043 This document was prepared using 2-Word-v2.0.template.dot. 1045 The authors would like to thank Ramki Krishnan and Anoop Ghanwani 1046 from Dell for their comments on this document. The authors also 1047 gratefully acknowledge Mohamed Boucadair for the thorough review and 1048 helpful comments. 1050 11. References 1052 11.1. Normative References 1054 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1055 Requirement Levels", BCP 14, RFC 2119, March 1997. 1057 [RFC7665] Halpern, J., Ed., and C. Pignataro, Ed., "Service 1058 Function Chaining (SFC) Architecture", RFC 7665, DOI 1059 10.17487/RFC7665, October 2015, . 1062 [RFC8300] Quinn, P., Elzur, U., Pignataro, C., "Network Service 1063 Header (NSH)", RFC 8300, 2018. 1065 11.2. Informative References 1067 [IEEE1588] IEEE TC 9 Instrumentation and Measurement Society, 1068 "1588 IEEE Standard for a Precision Clock 1069 Synchronization Protocol for Networked Measurement and 1070 Control Systems Version 2", IEEE Standard, 2008. 1072 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing 1073 an IANA Considerations Section in RFCs", BCP 26, RFC 1074 5226, May 2008. 1076 [RFC5905] Mills, D., Martin, J., Burbank, J., Kasch, W., 1077 "Network Time Protocol Version 4: Protocol and 1078 Algorithms Specification", RFC 5905, June 2010. 1080 [RFC7384] Mizrahi, T., "Security Requirements of Time Protocols 1081 in Packet Switched Networks", RFC 7384, October 2014. 1083 [TS] Mizrahi, T., Fabini, J., and A. Morton, "Guidelines 1084 for Defining Packet Timestamps", draft-ietf-ntp- 1085 packet-timestamps (work in progress), 2018. 1087 [Y.1731] ITU-T Recommendation G.8013/Y.1731, "OAM Functions and 1088 Mechanisms for Ethernet-based Networks", August 2015. 1090 [Y.1564] ITU-T Recommendation Y.1564, "Ethernet service 1091 activation test methodology", March 2011. 1093 [G.8261] ITU-T Recommendation G.8261/Y.1361, "Timing and 1094 synchronization aspects in packet networks", August 1095 2013. 1097 [G.8262] ITU-T Recommendation G.8262/Y.1362, "Timing 1098 characteristics of a synchronous Ethernet equipment 1099 slave clock", January 2015. 1101 [G.8264] ITU-T Recommendation G.8264/Y.1364, "Distribution of 1102 timing information through packet networks", May 2014. 1104 [I-D.ippm.ioam] 1106 Brockners, Bhandari et al. "Data Fields for In-situ OAM" 1107 draft-ietf-ippm-ioam-data-03 (work in progress), June 1108 2018 1110 Authors' Addresses 1112 Rory Browne 1113 Intel 1114 Dromore House 1115 Shannon 1116 Co.Clare 1117 Ireland 1119 Email: rory.browne@intel.com 1121 Andrey Chilikin 1122 Intel 1123 Dromore House 1124 Shannon 1125 Co.Clare 1126 Ireland 1128 Email: andrey.chilikin@intel.com 1130 Tal Mizrahi 1131 Marvell 1132 6 Hamada St. 1133 Yokneam, 2066721 Israel 1135 Email: tal.mizrahi.phd@gmail.com