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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-04) exists of draft-boucadair-dots-multihoming-03 == Outdated reference: A later version (-22) exists of draft-ietf-dots-requirements-14 Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DOTS R. Dobbins 3 Internet-Draft Arbor Networks 4 Intended status: Informational D. Migault 5 Expires: January 18, 2019 Ericsson 6 S. Fouant 8 R. Moskowitz 9 HTT Consulting 10 N. Teague 11 Verisign 12 L. Xia 13 Huawei 14 K. Nishizuka 15 NTT Communications 16 July 17, 2018 18 Use cases for DDoS Open Threat Signaling 19 draft-ietf-dots-use-cases-14 21 Abstract 23 The DDoS Open Threat Signaling (DOTS) effort is intended to provide 24 protocols to facilitate interoperability across disparate DDoS 25 mitigation solutions. This document presents use cases which 26 describe the interactions expected between the DOTS components as 27 well as DOTS messaging exchanges. These use cases are meant to 28 identify the interacting DOTS components, how they collaborate and 29 what are the typical information to be exchanged. 31 Status of This Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at https://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on January 18, 2019. 48 Copyright Notice 50 Copyright (c) 2018 IETF Trust and the persons identified as the 51 document authors. All rights reserved. 53 This document is subject to BCP 78 and the IETF Trust's Legal 54 Provisions Relating to IETF Documents 55 (https://trustee.ietf.org/license-info) in effect on the date of 56 publication of this document. Please review these documents 57 carefully, as they describe your rights and restrictions with respect 58 to this document. Code Components extracted from this document must 59 include Simplified BSD License text as described in Section 4.e of 60 the Trust Legal Provisions and are provided without warranty as 61 described in the Simplified BSD License. 63 Table of Contents 65 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 66 2. Terminology and Acronyms . . . . . . . . . . . . . . . . . . 3 67 3. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3 68 3.1. Upstream DDoS Mitigation by an Upstream Internet Transit 69 Provider . . . . . . . . . . . . . . . . . . . . . . . . 3 70 3.2. DDoS Mitigation by a Third Party DDoS Mitigation Service 71 Provider . . . . . . . . . . . . . . . . . . . . . . . . 7 72 3.3. DDoS Orchestration . . . . . . . . . . . . . . . . . . . 9 73 4. Security Considerations . . . . . . . . . . . . . . . . . . . 12 74 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 75 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 12 76 7. Informative References . . . . . . . . . . . . . . . . . . . 13 77 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13 79 1. Introduction 81 At the time of writing, distributed denial-of-service (DDoS) attack 82 mitigation solutions are largely based upon siloed, proprietary 83 communications schemes with vendor lock-in as a side-effect. This 84 can result in the configuration, provisioning, operation, and 85 activation of these solutions being a highly manual and often time- 86 consuming process. Additionally, coordinating multiple DDoS 87 mitigation solutions simultaneously is fraught with both technical 88 and process-related hurdles. This greatly increases operational 89 complexity which, in turn, can degrade the efficacy of mitigations. 91 The DDoS Open Threat Signaling (DOTS) effort is intended to specify 92 protocols that facilitate interoperability between diverse DDoS 93 mitigation solutions and ensure greater integration in term of 94 mitigation requests and attack characterization patterns. As DDoS 95 solutions are broadly heterogeneous among vendors, the primary goal 96 of DOTS is to provide high-level interaction amongst differing DDoS 97 solutions, such as initiating, terminating DDoS mitigation assistance 98 or requesting the status of a DDoS mitigation. 100 This document provides use cases to provide inputs for the design of 101 the DOTS protocol(s). The use cases are not exhaustive and future 102 use cases are expected to emerge as DOTS is adopted and evolves. 104 2. Terminology and Acronyms 106 This document makes use of the same terminology and definitions as 107 [I-D.ietf-dots-requirements]. In addition it uses the terms defined 108 below: 110 o DDoS Mitigation Service Provider: designates the administrative 111 entity providing the DDoS Mitigation Service. 113 o DDoS Mitigation System (DMS): A system that performs DDoS 114 mitigation. The DDoS Mitigation System may be composed by a 115 cluster of hardware and/or software resources, but could also 116 involve an orchestrator that may take decisions such as 117 outsourcing partial or more of the mitigation to another DDoS 118 Mitigation System. 120 o DDoS Mitigation Service: designates a DDoS mitigation service 121 provided to a customer and which is scoped to mitigate DDoS 122 attacks. Services usually involve Service Level Agreement (SLA) 123 that have to be met. It is the responsibility of the service 124 provider to instantiate the DDoS Mitigation System to meet these 125 SLAs. 127 o DDoS Mitigation: The action performed by the DDoS Mitigation 128 System. 130 o Internet Transit Provider (ITP): designates the entity that 131 delivers the traffic to the network. It can be an Internet 132 Service Provider (ISP), or an upstream entity delivering the 133 traffic to the ISP. 135 3. Use Cases 137 3.1. Upstream DDoS Mitigation by an Upstream Internet Transit Provider 139 This use case describes how an enterprise or a residential customer 140 network may take advantage of a pre-existing relation with its 141 Internet Transit Provider (ITP) in order to mitigate a DDoS attack 142 targeting its network. To improve the clarity of our purpose, the 143 targeted network will be designated as enterprise network, but the 144 same scenario applies to any downstream network, including 145 residential network and cloud hosting network. As the ITP provides 146 connectivity to the enterprise network, it is already on the path of 147 the inbound or outbound traffic of the enterprise network and well 148 aware of the networking parameters associated to the enterprise 149 network connectivity. This eases both the configuration and the 150 instantiation of a DDoS Mitigation Service. This section considers 151 two kind of DDoS Mitigation Service between an enterprise network and 152 an ITP: 154 o The upstream ITP may instantiate a DDoS Mitigation System (DMS) 155 upon receiving a request from the enterprise network. This 156 typically corresponds to the case when the enterprise network is 157 under attack. 159 o On the other hand, the ITP may identify an enterprise network as 160 the source of an attack and send a mitigation request to the 161 enterprise DMS to mitigate this at the source. 163 In the first scenario, as depicted in Figure 1, an enterprise network 164 with self-hosted Internet-facing properties such as Web servers, 165 authoritative DNS servers, and VoIP servers has a DMS deployed to 166 protect those servers and applications from DDoS attacks. In 167 addition to on-premise DDoS defense capability, enterprises have 168 contracted with their ITP for DDoS Mitigation Services which threaten 169 to overwhelm their WAN link(s) bandwidth. 171 +------------------+ +------------------+ 172 | Enterprise | | Upstream | 173 | Network | | Internet Transit | 174 | | | Provider | 175 | +--------+ | | DDoS Attack 176 | | DDoS | | <================================= 177 | | Target | | <================================= 178 | +--------+ | | +------------+ | 179 | | +-------->| DDoS | | 180 | | | |S | Mitigation | | 181 | | | | | System | | 182 | | | | +------------+ | 183 | | | | | 184 | | | | | 185 | | | | | 186 | +------------+ | | | | 187 | | DDoS |<---+ | | 188 | | Mitigation |C | | | 189 | | System | | | | 190 | +------------+ | | | 191 +------------------+ +------------------+ 193 * C is for DOTS client functionality 194 * S is for DOTS server functionality 196 Figure 1: Upstream Internet Transit Provider DDoS Mitigation 198 The enterprise DMS is configured such that if the incoming Internet 199 traffic volume exceeds 50% of the provisioned upstream Internet WAN 200 link capacity, the DMS will request DDoS mitigation assistance from 201 the upstream transit provider. 203 The requests to trigger, manage, and finalize a DDoS Mitigation 204 between the enterprise DMS and the ITP is performed using DOTS. The 205 enterprise DMS implements a DOTS client while the ITP implements a 206 DOTS server which is integrated with their DMS. 208 When the enterprise DMS detects an inbound DDoS attack targeting its 209 resources ( e.g. servers, hosts or applications), it immediately 210 begins a DDoS Mitigation. 212 During the course of the attack, the inbound traffic volume exceeds 213 the 50% threshold; the DMS DOTS client signals the DOTS server on the 214 upstream ITP to initiate DDoS Mitigation. The DOTS server signals 215 the DOTS client that it can serve this request, and mitigation is 216 initiated on the ITP network by the ITP DMS. 218 Over the course of the attack, the DOTS server of the ITP 219 periodically informs the DOTS client on the enterprise DMS mitigation 220 status, statistics related to DDoS attack traffic mitigation, and 221 related information. Once the DDoS attack has ended, or decreased to 222 the certain level that the DOTS client can handle by itself, the DOTS 223 server signals the enterprise DMS DOTS client that the attack has 224 subsided. 226 The enterprise DMS then requests the ITP to terminate the DDoS 227 Mitigation. The DOTS server on the ITP receives this request and 228 once the mitigation has ended, confirms the end of upstream DDoS 229 Mitigation to the enterprise DMS DOTS client. 231 The following is an overview of the DOTS communication model for this 232 use-case: 234 o (a) A DDoS attack is initiated against resources of a network 235 organization which has deployed a DOTS-capable DMS - typically a 236 DOTS client. 238 o (b) The enterprise DMS detects, classifies, and begins the DDoS 239 Mitigation. 241 o (c) The enterprise DMS determines that its capacity and/or 242 capability to mitigate the DDoS attack is insufficient, and sends 243 via its DOTS client a DOTS DDoS Mitigation request to one or more 244 DOTS servers residing on the upstream ITP. 246 o (d) The DOTS server which receives the DOTS Mitigation request 247 determines that it has been configured to honor requests from the 248 requesting DOTS client, and honored its DDoS Mitigation by 249 orchestrating its DMS. 251 o (e) While the DDoS Mitigation is active, DOTS server regularly 252 transmits DOTS DDoS Mitigation status updates to the DOTS client. 254 o (f) Informed by the DOTS server status update that the attack has 255 ended or subsided, the DOTS client transmits a DOTS DDoS 256 Mitigation termination request to the DOTS server. 258 o (g) The DOTS server terminates DDoS Mitigation, and sends the 259 notification to the DOTS client. 261 Note that communications between the enterprise DOTS client and the 262 upstream ITP DOTS Server may take place in-band within the main 263 Internet WAN link between the enterprise and the ITP; out-of-band via 264 a separate, dedicated wireline network link utilized solely for DOTS 265 signaling; or out-of-band via some other form of network connectivity 266 such as a third-party wireless 4G network connectivity. 268 Note also that a DOTS client that sends a DOTS Mitigation request may 269 be also triggered by a network admin that manually confirms the 270 request to the upstream ITP, in which case the request may be sent 271 from an application such as a web browser or a dedicated mobile 272 application. 274 Note also that when the enterprise is multihomed and connected to 275 multiple upstream ITPs, each ITP is only able to provide a DDoS 276 Mitigation Service for the traffic it transits. As a result, the 277 enterprise network may require to coordinate the various DDoS 278 Mitigation Services associated to each link. More multi-homing 279 considerations are discussed in [I-D.boucadair-dots-multihoming]. 281 3.2. DDoS Mitigation by a Third Party DDoS Mitigation Service Provider 283 This use case differs from the previous use case described in 284 Section 3.1 in that the DDoS Mitigation Service is not provided by an 285 upstream ITP. In other words, as represented in Figure 2, the 286 traffic is not forwarded through the DDoS Mitigation Service Provider 287 by default. In order to steer the traffic to the DDoS Mitigation 288 Service Provider, some network configuration changes are required. 289 As such, this use case likely to match large enterprises or large 290 data centers, but not exclusively. Another typical scenario for this 291 use case is the relation between DDoS Mitigation Service Providers 292 forming an overlay of DMS. When a DDoS Mitigation Service Provider 293 mitigating a DDoS attack reaches it resources capacities, it may 294 chose to delegate the DDoS Mitigation to another DDoS Mitigation 295 Service Provider. 297 +------------------+ +------------------+ 298 | Enterprise | | Upstream | 299 | Network | | Internet Transit | 300 | | | Provider | 301 | +--------+ | | DDoS Attack 302 | | DDoS | | <================================= 303 | | Target | | <================================= 304 | +--------+ | +----------------------------+ 305 | | | | | | 306 | | | +------------------+ | 307 | | | | 308 | | | +------------------+ | 309 | | | | DDoS Mitigation | | 310 | | | | Service Provider | | 311 | | | | | | 312 | +------------+ | | | +------------+ | | 313 | | DDoS |<---+ | | DDoS |<----+ 314 | | Mitigation |C | | | Mitigation |S | 315 | | System | | | | System | | 316 | +------------+ | | +------------+ | 317 +------------------+ +------------------+ 319 * C is for DOTS client functionality 320 * S is for DOTS server functionality 322 Figure 2: DDoS Mitigation between an Enterprise Network and Third 323 Party DDoS Mitigation Service Provider 325 In this scenario, an Enterprise Network has entered into a pre- 326 arranged DDoS mitigation assistance agreement with one or more other 327 DDoS Mitigation Service Providers in order to ensure that sufficient 328 DDoS mitigation capacity and/or capabilities may be activated in the 329 event that a given DDoS attack threatens to overwhelm the ability of 330 a given DMS to mitigate the attack on its own. 332 The pre-arrangement typically includes the agreement on the 333 mechanisms used to redirect the traffic to the DDoS Mitigation 334 Service Provider, as well as the mechanism to re-inject the traffic 335 back to the Enterprise Network. Redirection to the DDoS Mitigation 336 Service Provider typically involves BGP prefix announcement or DNS 337 redirection, while re-injection of the scrubbed traffic to the 338 enterprise network may be performed via tunneling mechanisms such as 339 GRE for example. These exact mechanisms used for traffic steering 340 are out of scope. 342 +------------------+ +------------------+ 343 | Enterprise | | Upstream | 344 | Network | | Internet Transit | 345 | | | Provider | 346 | +--------+ | | DDoS Attack 347 | | DDoS | |<----------------+ | ++==== 348 | | Target | | Mitigated | | || ++= 349 | +--------+ | | | | || || 350 | | | | | || || 351 | | +--------|---------+ || || 352 | | | || || 353 | | +--------|---------+ || || 354 | | | DDoS Mitigation | || || 355 | | | Service Provider | || || 356 | | | | | || || 357 | +------------+ | | +------------+ | || || 358 | | DDoS |<------------>| DDoS | | || || 359 | | mitigation |C | |S | mitigation |<===++ || 360 | | system | | | | system |<======++ 361 | +------------+ | | +------------+ | 362 +------------------+ +------------------+ 364 * C is for DOTS client functionality 365 * S is for DOTS server functionality 367 Figure 3: Redirection to a DDoS Mitigation Service Provider 369 When the Enterprise Network is under attack or at least is reaching 370 its capacity or ability to mitigate a given DDoS attack traffic, the 371 DOTS client sends a DOTS request to the DDoS Mitigation Service 372 Provider to initiate network traffic diversion - as represented in 373 Figure 3 - and DDoS mitigation activities. Ongoing attack and 374 mitigation status messages may be passed between the Enterprise 375 Network and the DDoS Mitigation Service Provider. If the DDoS attack 376 has stopped or the severity of the attack has subsided, the DOTS 377 client can request the DDoS Mitigation Service Provider to stop the 378 DDoS Mitigation. 380 3.3. DDoS Orchestration 382 In this use case, one or more DDoS telemetry systems or monitoring 383 devices monitor a network - typically an ISP network, an Enterprise 384 network, or a data center. Upon detection of a DDoS attack, these 385 DDoS telemetry systems alert an orchestrator in charge of 386 coordinating the various DMS within the domain. The DDoS telemetry 387 systems may be configured to provide required information, such as a 388 preliminary analysis of the observation to the orchestrator. 390 The orchestrator analyses the various information it receives from 391 DDoS telemetry system, and elaborates one or multiple DDoS mitigation 392 strategies. In some case, a manual confirmation or selection may 393 also be required to choose a proposed strategy or to initiate a DDoS 394 Mitigation. The DDoS Mitigation may consist of multiple steps such 395 as configuring the network, or updating already instantiated DDoS 396 mitigation functions. In some cases, some specific DDoS mitigation 397 functions must be instantiated and properly ordered. Eventually, the 398 coordination of the mitigation may involve external DDoS resources 399 such as a transit provider or a DDoS Mitigation Service Provider. 401 The communication used to trigger a DDoS Mitigation between the DDoS 402 telemetry and monitoring systems and the orchestrator is performed 403 using DOTS. The DDoS telemetry system implements a DOTS client while 404 the orchestrator implements a DOTS server. 406 The communication between a network administrator and the 407 orchestrator is also performed using DOTS. The network administrator 408 via its web interfaces implements a DOTS client, while the 409 Orchestrator implements a DOTS server. 411 The communication between the orchestrator and the DDoS mitigation 412 systems is performed using DOTS. The orchestrator implements a DOTS 413 Client while the DDoS mitigation systems implement a DOTS Server. 415 The configuration aspects of each DDoS mitigation system, as well as 416 the instantiations of DDoS mitigation functions or network 417 configuration is not part of DOTS. Similarly, the discovery of 418 available DDoS mitigation functions is not part of DOTS; and as such 419 is out of scope. 421 +----------+ 422 | network |C (Enterprise Network) 423 | adminis |<-+ 424 | trator | | 425 +----------+ | 426 | 427 +----------+ | S+--------------+ +-----------+ 428 |telemetry/| +->| |C S| DDoS |+ 429 |monitoring|<--->| Orchestrator |<--->| mitigation|| 430 |systems |C S| |<-+ | systems || 431 +----------+ +--------------+C | +-----------+| 432 | +----------+ 433 -----------------------------------|----------------- 434 | 435 | 436 (Internet Transit Provider) | 437 | +-----------+ 438 | S| DDoS | 439 +->| mitigation| 440 | systems | 441 +-----------+ 442 * C is for DOTS client functionality 443 * S is for DOTS server functionality 445 Figure 4: DDoS Orchestration 447 The DDoS telemetry systems monitor various network traffic and 448 perform some measurement tasks. 450 These systems are configured so that when an event or some 451 measurement indicators reach a predefined level to send DOTS 452 mitigation request to the orchestrator. The DOTS mitigation request 453 may be associated with some optional mitigation hints to let the 454 orchestrator know what has triggered the request. 456 Upon receipt of the DOTS mitigation request from the DDoS telemetry 457 system, the orchestrator responds with an acknowledgment, to avoid 458 retransmission of the request for mitigation. The orchestrator may 459 begin collecting additional fined grain and specific information from 460 various DDoS telemetry systems in order to correlate the measurements 461 and provide an analysis of the event. Eventually, the orchestrator 462 may ask additional information to the DDoS telemetry system, however, 463 the collection of these information is out of scope. 465 The orchestrator may be configured to start a DDoS Mitigation upon 466 approval from a network administrator. The analysis from the 467 orchestrator is reported to the network administrator via a web 468 interface. If the network administrator decides to start the 469 mitigation, the network administrator triggers the DDoS mitigation 470 request using the web interface of a DOTS client. This request is 471 expected to be associated with a context that provides sufficient 472 information to the orchestrator to infer the DDoS Mitigation to 473 elaborate and coordinate. 475 Upon receiving a request to mitigate a DDoS attack performed over a 476 target, the orchestrator, may evaluate the volumetry of the attack as 477 well as the value that represent the target. The orchestrator may 478 select the DDoS Mitigation Service Provider based on the attack 479 severity. It may also coordinate the DDoS Mitigation performed by 480 the DDoS Mitigation Service Provider with some other tasks such as 481 for example, moving the target to another network so new sessions 482 will not be impacted. When DDoS Mitigation is requested, the status 483 indicates the DDoS Mitigation is starting while not effective. The 484 DOTS client of the orchestrator will later be notified that the DDoS 485 Mitigation is effective. 487 Orchestration of the DDoS mitigation systems works similarly as 488 described in Section 3.1. The orchestrator indicates with its status 489 whether the DDoS Mitigation is effective. 491 When the DDoS attack has stopped, the orchestrator indicates to the 492 DDoS telemetry systems as well as to the network administrator the 493 end of the DDoS Mitigation. 495 4. Security Considerations 497 The document does not describe any protocol. 499 DOTS is at risk from three primary attacks: DOTS agent impersonation, 500 traffic injection, and signaling blocking. 502 Impersonation and traffic injection mitigation can be mitigated 503 through current secure communications best practices. 505 Additional details of DOTS security requirements can be found in 506 [I-D.ietf-dots-requirements]. 508 5. IANA Considerations 510 No IANA considerations exist for this document at this time. 512 6. Acknowledgments 514 The authors would like to thank among others Tirumaleswar Reddy; 515 Andrew Mortensen; Mohamed Boucadaire; Artyom Gavrichenkov; Jon 516 Shallow and the DOTS WG chairs, Roman Danyliw and Tobias Gondrom, for 517 their valuable feedback. 519 7. Informative References 521 [I-D.boucadair-dots-multihoming] 522 Boucadair, M. and T. Reddy, "Multi-homing Deployment 523 Considerations for Distributed-Denial-of-Service Open 524 Threat Signaling (DOTS)", draft-boucadair-dots- 525 multihoming-03 (work in progress), April 2018. 527 [I-D.ietf-dots-requirements] 528 Mortensen, A., Moskowitz, R., and T. Reddy, "Distributed 529 Denial of Service (DDoS) Open Threat Signaling 530 Requirements", draft-ietf-dots-requirements-14 (work in 531 progress), February 2018. 533 Authors' Addresses 535 Roland Dobbins 536 Arbor Networks 537 Singapore 539 EMail: rdobbins@arbor.net 541 Daniel Migault 542 Ericsson 543 8275 Trans Canada Route 544 Saint Laurent, QC 4S 0B6 545 Canada 547 EMail: daniel.migault@ericsson.com 549 Stefan Fouant 550 USA 552 EMail: stefan.fouant@copperriverit.com 554 Robert Moskowitz 555 HTT Consulting 556 Oak Park, MI 48237 557 USA 559 EMail: rgm@labs.htt-consult.com 560 Nik Teague 561 Verisign 562 12061 Bluemont Way 563 Reston, VA 20190 565 EMail: nteague@verisign.com 567 Liang Xia 568 Huawei 569 No. 101, Software Avenue, Yuhuatai District 570 Nanjing 571 China 573 EMail: Frank.xialiang@huawei.com 575 Kaname Nishizuka 576 NTT Communications 577 GranPark 16F 3-4-1 Shibaura, Minato-ku 578 Tokyo 108-8118 579 Japan 581 EMail: kaname@nttv6.jp