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Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (July 17, 2018) is 2110 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 4566 (Obsoleted by RFC 8866) Summary: 1 error (**), 0 flaws (~~), 1 warning (==), 2 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 I2NSF Working Group J. Jeong 3 Internet-Draft Sungkyunkwan University 4 Intended status: Informational S. Hyun 5 Expires: January 18, 2019 Chosun University 6 T. Ahn 7 Korea Telecom 8 S. Hares 9 Huawei 10 D. Lopez 11 Telefonica I+D 12 July 17, 2018 14 Applicability of Interfaces to Network Security Functions to Network- 15 Based Security Services 16 draft-ietf-i2nsf-applicability-04 18 Abstract 20 This document describes the applicability of Interface to Network 21 Security Functions (I2NSF) to network-based security services in 22 Network Functions Virtualization (NFV) environments, such as 23 firewall, deep packet inspection, or attack mitigation engines. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on January 18, 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 (https://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 3. I2NSF Framework . . . . . . . . . . . . . . . . . . . . . . . 4 62 3.1. Time-dependent Web Access Control Service . . . . . . . . 5 63 4. I2NSF Framework with SFC . . . . . . . . . . . . . . . . . . 7 64 5. I2NSF Framework with SDN . . . . . . . . . . . . . . . . . . 9 65 5.1. Firewall: Centralized Firewall System . . . . . . . . . . 11 66 5.2. Deep Packet Inspection: Centralized VoIP/VoLTE Security 67 System . . . . . . . . . . . . . . . . . . . . . . . . . 12 68 5.3. Attack Mitigation: Centralized DDoS-attack Mitigation 69 System . . . . . . . . . . . . . . . . . . . . . . . . . 14 70 6. I2NSF Framework with NFV . . . . . . . . . . . . . . . . . . 16 71 7. Security Considerations . . . . . . . . . . . . . . . . . . . 19 72 8. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19 73 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19 74 10. Informative References . . . . . . . . . . . . . . . . . . . 20 75 Appendix A. Changes from draft-ietf-i2nsf-applicability-03 . . . 23 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 78 1. Introduction 80 Interface to Network Security Functions (I2NSF) defined a framework 81 and interfaces for interacting with Network Security Functions 82 (NSFs). The I2NSF framework allows heterogeneous NSFs developed by 83 different security solution vendors to be used in the NFV environment 84 by utilizing the capabilities of such products and the virtualization 85 of security functions in the NFV platform. In the I2NSF framework, 86 each NSF initially registers the profile of its own capabilities into 87 the system in order for themselves to be available in the system. In 88 addition, the Security Controller registers itself to the I2NSF user 89 so that the user can request security services to the Security 90 Controller. 92 This document describes the applicability of I2NSF framework to 93 network-based security services with a use case of time-dependent web 94 access control. This document also describes integrating I2NSF 95 framework with Software-Defined Networking (SDN) technology for 96 efficient security services and use cases, such as firewall 98 [opsawg-firewalls], Deep Packet Inspection (DPI), and Distributed 99 Denial of Service (DDoS) attack mitigation. We implemented the I2NSF 100 framework based on SDN for these use cases, and the implementation 101 successfully verified the effectiveness of the I2NSF framework. 103 2. Terminology 105 This document uses the terminology described in [RFC7149], 106 [ITU-T.Y.3300], [ONF-OpenFlow], [ONF-SDN-Architecture], 107 [ITU-T.X.1252], [ITU-T.X.800], [RFC8329], [i2nsf-terminology], 108 [consumer-facing-inf-im], [consumer-facing-inf-dm], 109 [i2nsf-nsf-cap-im], [nsf-facing-inf-dm], [registration-inf-im], 110 [registration-inf-dm], and [nsf-triggered-steering]. In addition, 111 the following terms are defined below: 113 o Software-Defined Networking (SDN): A set of techniques that 114 enables to directly program, orchestrate, control, and manage 115 network resources, which facilitates the design, delivery and 116 operation of network services in a dynamic and scalable manner 117 [ITU-T.Y.3300]. 119 o Firewall: A service function at the junction of two network 120 segments that inspects every packet that attempts to cross the 121 boundary. It also rejects any packet that does not satisfy 122 certain criteria for, for example, disallowed port numbers or IP 123 addresses. 125 o Centralized Firewall System: A centralized firewall that can 126 establish and distribute policy rules into network resources for 127 efficient firewall management. These rules can be managed 128 dynamically by a centralized server for firewall. SDN can work as 129 a network-based firewall system through a standard interface 130 between an SDN switch and a firewall function as a vitual network 131 function (VNF). 133 o Centralized VoIP Security System: A centralized security system 134 that handles the security functions required for VoIP and VoLTE 135 services. SDN can work as a network-based security system through 136 a standard interface between an SDN switch and a VoIP/VoLTE 137 security function as a VNF. 139 o Centralized DDoS-attack Mitigation System: A centralized mitigator 140 that can establish and distribute access control policy rules into 141 network resources for efficient DDoS-attack mitigation. These 142 rules can be managed dynamically by a centralized server for DDoS- 143 attack mitigation. The SDN controller and switches can 144 cooperatively work as a network-based firewall system through a 145 standard interface between an SDN switch and a firewall function 146 as a VNF running in the SDN controller. 148 3. I2NSF Framework 150 This section describes an I2NSF framework and its use case. Figure 1 151 shows an I2NSF framework [RFC8329] to support network-based security 152 services. As shown in Figure 1, I2NSF User can use security 153 functions by delivering high-level security policies, which specify 154 security requirements the I2NSF user wants to enforce, to the 155 Security Controller via the Consumer-Facing Interface 156 [consumer-facing-inf-im][consumer-facing-inf-dm]. 158 The Security Controller receives and analyzes the high-level security 159 policies from an I2NSF User, and identifies what types of security 160 capabilities are required to meet these high-level security policies. 161 The Security Controller then identifies NSFs that have the required 162 security capabilities, and generates low-level security policies for 163 each of the NSFs so that the high-level security policies are 164 eventually enforced by those NSFs. Finally, the Security Controller 165 sends the generated low-level security policies to the NSFs 166 [i2nsf-nsf-cap-im][nsf-facing-inf-dm]. 168 The Security Controller requests NSFs to perform low-level security 169 services via the NSF-Facing Interface. The NSFs are enabled as 170 Virtual Network Functions (VNFs) on top of virtual machines through 171 Network Functions Virtualization (NFV) [ETSI-NFV]. In addition, the 172 Security Controller uses the I2NSF Registration Interface 173 [registration-inf-im][registration-inf-dm] to communicate with 174 Developer's Management System (called Developer's Mgmt System) for 175 registering (or deregistering) the developer's NSFs into (or from) 176 the NFV system using the I2NSF framework. 178 The Consumer-Facing Interface between an I2NSF User and the Security 179 Controller can be implemented using, for example, RESTCONF [RFC8040]. 180 Data models specified by YANG [RFC6020] describe high-level security 181 policies to be specified by an I2NSF User. The data model defined in 182 [consumer-facing-inf-dm] can be used for the I2NSF Consumer-Facing 183 Interface. 185 +------------+ 186 | I2NSF User | 187 +------------+ 188 ^ 189 | Consumer-Facing Interface 190 v 191 +-------------------+ Registration +-----------------------+ 192 |Security Controller|<-------------------->|Developer's Mgmt System| 193 +-------------------+ Interface +-----------------------+ 194 ^ 195 | NSF-Facing Interface 196 v 197 +----------------+ +---------------+ +-----------------------+ 198 | NSF-1 |-| NSF-2 |...| NSF-n | 199 | (Firewall) | | (Web Filter) | |(DDoS-Attack Mitigator)| 200 +----------------+ +---------------+ +-----------------------+ 202 Figure 1: I2NSF Framework 204 The NSF-Facing Interface between the Security Controller and NSFs can 205 be implemented using NETCONF [RFC6241]. YANG data models describe 206 low-level security policies for the sake of NSFs, which are 207 translated from the high-level security policies by the Security 208 Controller. The data model defined in [nsf-facing-inf-dm] can be 209 used for the I2NSF NSF-Facing Interface. 211 The Registration Interface between the Security Controller and the 212 Developer's Mgmt System can be implemented by RESTCONF [RFC8040]. 213 The data model defined in [registration-inf-dm] can be used for the 214 I2NSF Registration Interface. 216 Also, the I2NSF framework can enforce multiple chained NSFs for the 217 low-level security policies by means of service function chaining 218 (SFC) techniques for the I2NSF architecture described in 219 [nsf-triggered-steering]. 221 The following describes a security service scenario using the I2NSF 222 framework. 224 3.1. Time-dependent Web Access Control Service 226 This service scenario assumes that an enterprise network 227 administrator wants to control the staff members' access to Facebook 228 during business hours. The following is an example high-level 229 security policy rule that the administrator requests: Block the staff 230 members' access to Facebook from 9 am to 6 pm. The administrator 231 sends this high-level security policy to the security controller, 232 then the security controller identifies required secuity 233 capabilities, e.g., IP address and port number inspection 234 capabilities and URL inspection capability. In this scenario, it is 235 assumed that the IP address and port number inspection capabilities 236 are required to check whether a received packet is an HTTP packet 237 from a staff member. The URL inspection capability is required to 238 check whether the target URL of a received packet is facebook.com or 239 not. 241 The Security Controller maintains the security capabilities of each 242 NSF running in the I2NSF system, which have been reported by the 243 Developer's Management System via the Registation interface. Based 244 on this information, the Security Controller identifies NSFs that can 245 perform the IP address and port number inspection and URL inspection. 246 In this scenario, it is assumed that an NSF of firewall has the IP 247 address and port number inspection capabilities and an NSF of web 248 filter has URL inspection capability. 250 The Security Controller generates low-level security rules for the 251 NSFs to perform IP address and port number inspection, URL 252 inspection, and time checking. Specifically, the Security Controller 253 may interoperate with an access control server in the enterprise 254 network in order to retrieve the information (e.g., IP address in 255 use, company identifier (ID), and role) of each employee that is 256 currently using the network. Based on the retrieved information, the 257 Security Controller generates low-level security rules to check 258 whether the source IP address of a received packet matches any one 259 being used by a staff member. In addition, the low-level security 260 rules should be able to determine that a received packet is of HTTP 261 protocol. The low-level security rules for web filter checks that 262 the target URL field of a received packet is equal to facebook.com. 263 Finally, the Security Controller sends the low-level security rules 264 of the IP address and port number inspection to the NSF of firewall 265 and the low-level rules for URL inspection to the NSF of web filter. 267 The following describes how the time-dependent web access control 268 service is enforced by the NSFs of firewall and web filter. 270 1. A staff member tries to access Fackbook.com during business 271 hours, e.g., 10 am. 273 2. The packet is forwarded from the staff member's device to the 274 firewall, and the firewall checks the source IP address and port 275 number. Now the firewall identifies the received packet is an 276 HTTP packet from the staff member. 278 3. The firewall triggers the web filter to further inspect the 279 packet, and the packet is forwarded from the firewall to the web 280 filter. Service Function Chaining (SFC) technology can be 281 utilized to support such packet forwarding in the I2NSF framework 282 [nsf-triggered-steering]. 284 4. The web filter checks the target URL field of the received 285 packet, and realizes the packet is toward Facebook.com. The web 286 filter then checks that the current time is in business hours. 287 If so, the web filter drops the packet, and consequently the 288 staff member's access to Facebook during business hours is 289 blocked. 291 4. I2NSF Framework with SFC 293 In the I2NSF architecture, an NSF can trigger an advanced security 294 action (e.g., DPI and DDoS attack mitigation) on a packet based on 295 the result of its own security inspection of the packet. For 296 example, a firewall triggers further inspection of a suspicious 297 packet with DPI. For this advanced security action to be fulfilled, 298 the suspicious packet should be forwarded from the current NSF to the 299 successor NSF. Service Function Chaining (SFC) [RFC7665] is a 300 technology that enables this advanced security action by steering a 301 packet with multiple service functions (e.g., NSFs), and this 302 technology can be utilized by the I2NSF architecture to support the 303 advanced security action. 305 SFC generally requires classifiers and service function forwarders 306 (SFFs); classifiers are responsible for determining which service 307 function path (SFP) (i.e., an ordered sequence of service functions) 308 a given packet should pass through, according to pre-configured 309 classification rules, and SFFs perform forwarding the given packet to 310 the next service function (e.g., NSF) on the SFP of the packet by 311 referring to their forwarding tables. In the I2NSF architecture with 312 SFC, the Security Controller can take responsibilities of generating 313 classification rules for classifiers and forwarding tables for SFFs. 314 By analyzing high-level security policies from I2NSF users, the 315 Security Controller can construct SFPs that are required to meet the 316 high-level security policies, generates classification rules of the 317 SFPs, and then configures classifiers with the classification rules 318 over NSF-Facing Interface so that relevant traffic packets can follow 319 the SFPs. Also, based on the global view of NSF instances available 320 in the system, the Security Controller constructs forwarding tables, 321 which are required for SFFs to forward a given packet to the next NSF 322 over the SFP, and configures SFFs with those forwarding tables over 323 NSF-Facing Interface. 325 +------------+ 326 | I2NSF User | 327 +------------+ 328 ^ 329 | Consumer-Facing Interface 330 v 331 +-------------------+ Registration +-----------------------+ 332 |Security Controller|<-------------------->|Developer's Mgmt System| 333 +-------------------+ Interface +-----------------------+ 334 ^ ^ 335 | | NSF-Facing Interface 336 | |------------------------- 337 | | 338 | NSF-Facing Interface | 339 +-+-+-v-+-+-+-+-+-+ +------v-------+ 340 | +-----------+ | ------>| NSF-1 | 341 | |Classifier | | | | (Firewall) | 342 | +-----------+ | | +--------------+ 343 | +-----+ |<-----| +--------------+ 344 | | SFF | | |----->| NSF-2 | 345 | +-----+ | | | (DPI) | 346 +-+-+-+-+-+-+-+-+-+ | +--------------+ 347 | . 348 | . 349 | . 350 | +-----------------------+ 351 ------>| NSF-n | 352 |(DDoS-Attack Mitigator)| 353 +-----------------------+ 355 Figure 2: An I2NSF Framework with SFC 357 To trigger an advanced security action in the I2NSF architecture, the 358 current NSF appends a metadata describing the security capability 359 required for the advanced action to the suspicious packet and sends 360 the packet to the classifier. Based on the metadata information, the 361 classifier searches an SFP which includes an NSF with the required 362 security capability, changes the SFP-related information (e.g., 363 service path identifier and service index [RFC8300]) of the packet 364 with the new SFP that has been found, and then forwards the packet to 365 the SFF. When receiving the packet, the SFF checks the SFP-related 366 information such as the service path identifier and service index 367 contained in the packet and forwards the packet to the next NSF on 368 the SFP of the packet, according to its forwarding table. 370 5. I2NSF Framework with SDN 372 This section describes an I2NSF framework with SDN for I2NSF 373 applicability and use cases, such as firewall, deep packet 374 inspection, and DDoS-attack mitigation functions. SDN enables some 375 packet filtering rules to be enforced in the network switches by 376 controlling their packet forwarding rules. By taking advantage of 377 this capability of SDN, it is possible to optimize the process of 378 security service enforcement in the I2NSF system. 380 Figure 3 shows an I2NSF framework [RFC8329] with SDN networks to 381 support network-based security services. In this system, the 382 enforcement of security policy rules is divided into the SDN switches 383 and NSFs. Especially, SDN switches enforce simple packet filtering 384 rules that can be translated into their packet forwarding rules, 385 whereas NSFs enforce NSF-related security rules requiring the 386 security capabilities of the NSFs. For this purpose, the Security 387 Controller instructs the Switch Controller via NSF-Facing Interface 388 so that SDN switches can perform the required security services with 389 flow tables under the supervision of the Switch Controller (i.e., SDN 390 Controller). 392 As an example, let us consider two different types of security rules: 393 Rule A is a simple packet fltering rule that checks only the IP 394 address and port number of a given packet, whereas rule B is a time- 395 consuming packet inspection rule for analyzing whether an attached 396 file being transmitted over a flow of packets contains malware. Rule 397 A can be translated into packet forwarding rules of SDN switches and 398 thus be enforced by the switches. In contrast, rule B cannot be 399 enforced by switches, but it can be enforced by NSFs with anti- 400 malware capability. Specifically, a flow of packets is forwarded to 401 and reassembled by an NSF to reconstruct the attached file stored in 402 the flow of packets. The NSF then analyzes the file to check the 403 existence of malware. If the file contains malware, the NSF drops 404 the packets. 406 In an I2NSF framework with SDN, the Security Controller can analyze 407 given security policy rules and automatically determine which of the 408 given security policy rules should be enforced by SDN switches and 409 which should be enforced by NSFs. If some of the given rules 410 requires security capabilities that can be provided by SDN switches, 411 then the Security Controller instructs the Switch Controller via NSF- 412 Facing Interface so that SDN switches can enforce those security 413 policy rules with flow tables under the supervision of the Switch 414 Controller (i.e., SDN Controller). Or if some rules require security 415 capabilities that can be provided by not SDN switches but NSFs, then 416 the Security Controller instructs relevant NSFs to enforce those 417 rules. 419 +------------+ 420 | I2NSF User | 421 +------------+ 422 ^ 423 | Consumer-Facing Interface 424 v 425 +-------------------+ Registration +-----------------------+ 426 |Security Controller|<-------------------->|Developer's Mgmt System| 427 +-------------------+ Interface +-----------------------+ 428 ^ ^ 429 | | NSF-Facing Interface 430 | v 431 | +----------------+ +---------------+ +-----------------------+ 432 | | NSF-1 |-| NSF-2 |...| NSF-n | 433 | | (Firewall) | | (DPI) | |(DDoS-Attack Mitigator)| 434 | +----------------+ +---------------+ +-----------------------+ 435 | ^ 436 | | 437 | v 438 | +--------+ 439 | | SFF | 440 | +--------+ 441 | ^ 442 | | 443 | V SDN Network 444 +--|----------------------------------------------------------------+ 445 | V NSF-Facing Interface | 446 | +-----------------+ | 447 | |Switch Controller| | 448 | +-----------------+ | 449 | ^ | 450 | | SDN Southbound Interface | 451 | v | 452 | +--------+ +--------+ +--------+ +--------+ | 453 | |Switch 1|-|Switch 2|-|Switch 3|......|Switch m| | 454 | +--------+ +--------+ +--------+ +--------+ | 455 +-------------------------------------------------------------------+ 457 Figure 3: An I2NSF Framework with SDN Network 459 The following subsections introduce three use cases for cloud-based 460 security services: (i) firewall system, (ii) deep packet inspection 461 system, and (iii) attack mitigation system. [RFC8192] 463 5.1. Firewall: Centralized Firewall System 465 A centralized network firewall can manage each network resource and 466 firewall rules can be managed flexibly by a centralized server for 467 firewall (called Firewall). The centralized network firewall 468 controls each switch for the network resource management and the 469 firewall rules can be added or deleted dynamically. 471 The procedure of firewall operations in this system is as follows: 473 1. A switch forwards an unknown flow's packet to one of the Switch 474 Controllers. 476 2. The Switch Controller forwards the unknown flow's packet to an 477 appropriate security service application, such as the Firewall. 479 3. The Firewall analyzes, typically, the headers and contents of the 480 packet. 482 4. If the Firewall regards the packet as a malicious one with a 483 suspicious pattern, it reports the malicious packet to the Switch 484 Controller. 486 5. The Switch Controller installs new rules (e.g., drop packets with 487 the suspicious pattern) into underlying switches. 489 6. The suspected packets are dropped by these switches. 491 Existing SDN protocols can be used through standard interfaces 492 between the firewall application and switches 493 [RFC7149][ITU-T.Y.3300][ONF-OpenFlow] [ONF-SDN-Architecture]. 495 Legacy firewalls have some challenges such as the expensive cost, 496 performance, management of access control, establishment of policy, 497 and packet-based access mechanism. The proposed framework can 498 resolve the challenges through the above centralized firewall system 499 based on SDN as follows: 501 o Cost: The cost of adding firewalls to network resources such as 502 routers, gateways, and switches is substantial due to the reason 503 that we need to add firewall on each network resource. To solve 504 this, each network resource can be managed centrally such that a 505 single firewall is manipulated by a centralized server. 507 o Performance: The performance of firewalls is often slower than the 508 link speed of network interfaces. Every network resource for 509 firewall needs to check firewall rules according to network 510 conditions. Firewalls can be adaptively deployed among network 511 switches, depending on network conditions in the framework. 513 o The management of access control: Since there may be hundreds of 514 network resources in a network, the dynamic management of access 515 control for security services like firewall is a challenge. In 516 the framework, firewall rules can be dynamically added for new 517 malware. 519 o The establishment of policy: Policy should be established for each 520 network resource. However, it is difficult to describe what flows 521 are permitted or denied for firewall within a specific 522 organization network under management. Thus, a centralized view 523 is helpful to determine security policies for such a network. 525 o Packet-based access mechanism: Packet-based access mechanism is 526 not enough for firewall in practice since the basic unit of access 527 control is usually users or applications. Therefore, application 528 level rules can be defined and added to the firewall system 529 through the centralized server. 531 5.2. Deep Packet Inspection: Centralized VoIP/VoLTE Security System 533 A centralized VoIP/VoLTE security system can monitor each VoIP/VoLTE 534 flow and manage VoIP/VoLTE security rules controlled by a centralized 535 server for VoIP/VoLTE security service called VoIP Intrusion 536 Prevention System (IPS). The VoIP/VoLTE security system controls 537 each switch for the VoIP/VoLTE call flow management by manipulating 538 the rules that can be added, deleted or modified dynamically. 540 A centralized VoIP/VoLTE security system can cooperate with a network 541 firewall to realize VoIP/VoLTE security service. Specifically, a 542 network firewall performs basic security checks of an unknown flow's 543 packet observed by a switch. If the network firewall detects that 544 the packet is an unknown VoIP call flow's packet that exhibits some 545 suspicious patterns, then it triggers the VoIP/VoLTE security system 546 for more specialized security analysis of the suspicious VoIP call 547 packet. 549 The procedure of VoIP/VoLTE security operations in this system is as 550 follows: 552 1. A switch forwards an unknown flow's packet to the Switch 553 Controller, and the Switch Controller further forwards the 554 unknown flow's packet to the Firewall for basic security 555 inspection. 557 2. The Firewall analyzes the header fields of the packet, and 558 figures out that this is an unknown VoIP call flow's signal 559 packet (e.g., SIP packet) of a suspicious pattern. 561 3. The Firewall triggers an appropriate security service function, 562 such as VoIP IPS, for detailed security analysis of the 563 suspicious signal packet. That is, the firewall sends the packet 564 to the Service Function Forwarder (SFF) in the I2NSF framework 565 [nsf-triggered-steering], as shown in Figure 3. The SFF forwards 566 the suspicious signal packet to the VoIP IPS. 568 4. The VoIP IPS analyzes the headers and contents of the signal 569 packet, such as calling number and session description headers 570 [RFC4566]. 572 5. If, for example, the VoIP IPS regards the packet as a spoofed 573 packet by hackers or a scanning packet searching for VoIP/VoLTE 574 devices, it drops the packet. In addition, the VoIP IPS requests 575 the Switch Controller to block that packet and the subsequent 576 packets that have the same call-id. 578 6. The Switch Controller installs new rules (e.g., drop packets) 579 into underlying switches. 581 7. The illegal packets are dropped by these switches. 583 Existing SDN protocols can be used through standard interfaces 584 between the VoIP IPS application and switches [RFC7149][ITU-T.Y.3300] 585 [ONF-OpenFlow][ONF-SDN-Architecture]. 587 Legacy hardware based VoIP IPS has some challenges, such as 588 provisioning time, the granularity of security, expensive cost, and 589 the establishment of policy. The I2NSF framework can resolve the 590 challenges through the above centralized VoIP/VoLTE security system 591 based on SDN as follows: 593 o Provisioning: The provisioning time of setting up a legacy VoIP 594 IPS to network is substantial because it takes from some hours to 595 some days. By managing the network resources centrally, VoIP IPS 596 can provide more agility in provisioning both virtual and physical 597 network resources from a central location. 599 o The granularity of security: The security rules of a legacy VoIP 600 IPS are compounded considering the granularity of security. The 601 proposed framework can provide more granular security by 602 centralizing security control into a switch controller. The VoIP 603 IPS can effectively manage security rules throughout the network. 605 o Cost: The cost of adding VoIP IPS to network resources, such as 606 routers, gateways, and switches is substantial due to the reason 607 that we need to add VoIP IPS on each network resource. To solve 608 this, each network resource can be managed centrally such that a 609 single VoIP IPS is manipulated by a centralized server. 611 o The establishment of policy: Policy should be established for each 612 network resource. However, it is difficult to describe what flows 613 are permitted or denied for VoIP IPS within a specific 614 organization network under management. Thus, a centralized view 615 is helpful to determine security policies for such a network. 617 5.3. Attack Mitigation: Centralized DDoS-attack Mitigation System 619 A centralized DDoS-attack mitigation can manage each network resource 620 and manipulate rules to each switch through a centralized server for 621 DDoS-attack mitigation (called DDoS-attack Mitigator). The 622 centralized DDoS-attack mitigation system defends servers against 623 DDoS attacks outside private network, that is, from public network. 625 Servers are categorized into stateless servers (e.g., DNS servers) 626 and stateful servers (e.g., web servers). For DDoS-attack 627 mitigation, traffic flows in switches are dynamically configured by 628 traffic flow forwarding path management according to the category of 629 servers [AVANT-GUARD]. Such a managenent should consider the load 630 balance among the switches for the defense against DDoS attacks. 632 The procedure of DDoS-attack mitigation operations in this system is 633 as follows: 635 1. A Switch periodically reports an inter-arrival pattern of a 636 flow's packets to one of the Switch Controllers. 638 2. The Switch Controller forwards the flow's inter-arrival pattern 639 to an appropriate security service application, such as DDoS- 640 attack Mitigator. 642 3. The DDoS-attack Mitigator analyzes the reported pattern for the 643 flow. 645 4. If the DDoS-attack Mitigator regards the pattern as a DDoS 646 attack, it computes a packet dropping probability corresponding 647 to suspiciousness level and reports this DDoS-attack flow to 648 Switch Controller. 650 5. The Switch Controller installs new rules into switches (e.g., 651 forward packets with the suspicious inter-arrival pattern with a 652 dropping probability). 654 6. The suspicious flow's packets are randomly dropped by switches 655 with the dropping probability. 657 For the above centralized DDoS-attack mitigation system, the existing 658 SDN protocols can be used through standard interfaces between the 659 DDoS-attack mitigator application and switches [RFC7149] 660 [ITU-T.Y.3300][ONF-OpenFlow][ONF-SDN-Architecture]. 662 The centralized DDoS-attack mitigation system has challenges similar 663 to the centralized firewall system. The proposed framework can 664 resolve the challenges through the above centralized DDoS-attack 665 mitigation system based on SDN as follows: 667 o Cost: The cost of adding DDoS-attack mitigators to network 668 resources such as routers, gateways, and switches is substantial 669 due to the reason that we need to add DDoS-attack mitigator on 670 each network resource. To solve this, each network resource can 671 be managed centrally such that a single DDoS-attack mitigator is 672 manipulated by a centralized server. 674 o Performance: The performance of DDoS-attack mitigators is often 675 slower than the link speed of network interfaces. The checking of 676 DDoS attacks may reduce the performance of the network interfaces. 677 DDoS-attack mitigators can be adaptively deployed among network 678 switches, depending on network conditions in the framework. 680 o The management of network resources: Since there may be hundreds 681 of network resources in an administered network, the dynamic 682 management of network resources for performance (e.g., load 683 balancing) is a challenge for DDoS-attack mitigation. In the 684 framework, as dynamic network resource management, traffic flow 685 forwarding path management can handle the load balancing of 686 network switches [AVANT-GUARD]. With this management, the current 687 and near-future workload can be spread among the network switches 688 for DDoS-attack mitigation. In addition, DDoS-attack mitigation 689 rules can be dynamically added for new DDoS attacks. 691 o The establishment of policy: Policy should be established for each 692 network resource. However, it is difficult to describe what flows 693 are permitted or denied for new DDoS-attacks (e.g., DNS reflection 694 attack) within a specific organization network under management. 695 Thus, a centralized view is helpful to determine security policies 696 for such a network. 698 So far this document has described the procedure and impact of the 699 three use cases for network-based security services using the I2NSF 700 framework with SDN networks. To support these use cases in the 701 proposed data-driven security service framework, YANG data models 702 described in [consumer-facing-inf-dm], [nsf-facing-inf-dm], and 703 [registration-inf-dm] can be used as Consumer-Facing Interface, NSF- 704 Facing Interface, and Registration Interface, respectively, along 705 with RESTCONF [RFC8040] and NETCONF [RFC6241]. 707 6. I2NSF Framework with NFV 709 This section discusses the implementation of the I2NSF framework with 710 Network Functions Virtualization (called NFV). 712 +--------------------+ 713 +-------------------------------------------+ | ---------------- | 714 | I2NSF User (OSS/BSS) | | | NFV | | 715 +------+------------------------------------+ | | Orchestrator +-+ | 716 | Consumer-Facing Interface | -----+---------- | | 717 +------|------------------------------------+ | | | | 718 | -----+---------- (a) ----------------- | | | | | 719 | | Security |-------| Developer's | | | | | | 720 | |Controller(EM)| |Mgmt System(EM)| | | | | | 721 | -----+---------- ----------------- | | ----+----- | | 722 | | NSF-Facing Interface | | | | | | 723 | ----+----- ----+----- ----+----- | | | VNFM(s)| | | 724 | |NSF(VNF)| |NSF(VNF)| |NSF(VNF)| +-(b)-+ | | | 725 | ----+----- ----+----- ----+----- | | ----+----- | | 726 | | | | | | | | | 727 +------|-------------|-------------|--------+ | | | | 728 | | | | | | | 729 +------+-------------+-------------+--------+ | | | | 730 | NFV Infrastructure (NFVI) | | | | | 731 | ----------- ----------- ----------- | | | | | 732 | | Virtual | | Virtual | | Virtual | | | | | | 733 | | Compute | | Storage | | Network | | | | | | 734 | ----------- ----------- ----------- | | ----+----- | | 735 | +---------------------------------------+ | | | | | | 736 | | Virtualization Layer | +-----+ VIM(s) +------+ | 737 | +---------------------------------------+ | | | | | 738 | +---------------------------------------+ | | ---------- | 739 | | ----------- ----------- ----------- | | | | 740 | | | Compute | | Storage | | Network | | | | | 741 | | | Hardware| | Hardware| | Hardware| | | | | 742 | | ----------- ----------- ----------- | | | | 743 | | Hardware Resources | | | NFV Management | 744 | +---------------------------------------+ | | and Orchestration | 745 +-------------------------------------------+ +--------------------+ 746 (a) = Registration Interface 747 (b) = Ve-Vnfm Interface 749 Figure 4: I2NSF Framework Implementation in NFV Reference 750 Architectural Framework 752 NFV is a promising technology for improving the elasticity and 753 efficiency of network resource utilization. In NFV environments, 754 NSFs can be deployed in the forms of software-based virtual instances 755 rather than physical appliances. Virtualizing NSFs makes it possible 756 to rapidly and flexibly respond to the amount of service requests by 757 dynamically increasing or decreasing the number of NSF instances. 758 Moreover, NFV technology facilitates flexibly including or excluding 759 NSFs from multiple security solution vendors according to the changes 760 on security requirements. In order to take advantages of the NFV 761 technology, the I2NSF framework can be implemented on top of an NFV 762 infrastructure as show in Figure 4. 764 Figure 4 shows an I2NSF framework implementation based on the NFV 765 reference architecture that the European Telecommunications Standards 766 Institute (ETSI) defines [ETSI-NFV]. The NSFs are deployed as 767 virtual network functions (VNFs) in Figure 4. The Developer's 768 Management System (DMS) in the I2NSF framework is responsible for 769 registering capability information of NSFs into the Security 770 Controller. Those NSFs are created or removed by a virtual network 771 functions manager (VNFM) in the NFV architecture that performs the 772 life-cycle management of VNFs. The Security Controller controls and 773 monitors the configurations (e.g., function parameters and security 774 policy rules) of VNFs. Both the DMS and Security Controller can be 775 implemented as the Element Managements (EMs) in the NFV architecture. 776 Finally, the I2NSF User can be implemented as OSS/BSS (Operational 777 Support Systems/Business Support Systems) in the NFV architecture 778 that provides interfaces for users in the NFV system. 780 The operation procedure in the I2NSF framework based on the NFV 781 architecture is as follows: 783 1. The VNFM has a set of virtual machine (VM) images of NSFs, and 784 each VM image can be used to create an NSF instance that provides 785 a set of security capabilities. The DMS initially registers a 786 mapping table of the ID of each VM image and the set of 787 capabilities that can be provided by an NSF instance created from 788 the VM image into the Security Controller. 790 2. If the Security Controller does not have any instantiated NSF 791 that has the set of capabilities required to meet the security 792 requirements from users, it searches the mapping table 793 (registered by the DMS) for the VM image ID corresponding to the 794 required set of capabilities. 796 3. The Security Controller requests the DMS to instantiate an NSF 797 with the VM image ID via VNFM. 799 4. When receiving the instantiation request, the VNFM first asks the 800 NFV orchestrator for the permission required to create the NSF 801 instance, requests the VIM to allocate resources for the NSF 802 instance, and finally creates the NSF instance based on the 803 allocated resources. 805 5. Once the NSF instance has been created by the VNFM, the DMS 806 performs the initial configurations of the NSF instance and then 807 notifies the Security Controller of the NSF instance. 809 6. After being notified of the created NSF instance, the Security 810 Controller delivers low-level security policy rules to the NSF 811 instance for policy enforcement. 813 The I2NSF framework can be implemented based on the NFV architecture. 814 Note that the registration of the capabilities of NSFs is performed 815 through the Registration Interface and the life-cycle management for 816 NSFs (VNFs) is performed through the Ve-Vnfm interface between the 817 DMS and VNFM, as shown in Figure 4. More details about the I2NSF 818 framework based on the NFV reference architecture are described in 819 [i2nsf-nfv-architecture]. 821 7. Security Considerations 823 The I2NSF framework with SDN networks in this document is derived 824 from the I2NSF framework [RFC8329], so the security considerations of 825 the I2NSF framework should be included in this document. Therefore, 826 proper secure communication channels should be used the delivery of 827 control or management messages among the components in the proposed 828 framework. 830 This document shares all the security issues of SDN that are 831 specified in the "Security Considerations" section of [ITU-T.Y.3300]. 833 8. Acknowledgments 835 This work was supported by Institute for Information & communications 836 Technology Promotion (IITP) grant funded by the Korea government 837 (MSIP) (No.R-20160222-002755, Cloud based Security Intelligence 838 Technology Development for the Customized Security Service 839 Provisioning). 841 9. Contributors 843 I2NSF is a group effort. I2NSF has had a number of contributing 844 authors. The following are considered co-authors: 846 o Hyoungshick Kim (Sungkyunkwan University) 848 o Jinyong Tim Kim (Sungkyunkwan University) 850 o Hyunsik Yang (Soongsil University) 852 o Younghan Kim (Soongsil University) 854 o Jung-Soo Park (ETRI) 856 o Se-Hui Lee (Korea Telecom) 857 o Mohamed Boucadair (Orange) 859 10. Informative References 861 [AVANT-GUARD] 862 Shin, S., Yegneswaran, V., Porras, P., and G. Gu, "AVANT- 863 GUARD: Scalable and Vigilant Switch Flow Management in 864 Software-Defined Networks", ACM CCS, November 2013. 866 [consumer-facing-inf-dm] 867 Jeong, J., Kim, E., Ahn, T., Kumar, R., and S. Hares, 868 "I2NSF Consumer-Facing Interface YANG Data Model", draft- 869 ietf-i2nsf-consumer-facing-interface-dm-01 (work in 870 progress), July 2018. 872 [consumer-facing-inf-im] 873 Kumar, R., Lohiya, A., Qi, D., Bitar, N., Palislamovic, 874 S., Xia, L., and J. Jeong, "Information Model for 875 Consumer-Facing Interface to Security Controller", draft- 876 kumar-i2nsf-client-facing-interface-im-07 (work in 877 progress), July 2018. 879 [ETSI-NFV] 880 ETSI GS NFV 002 V1.1.1, "Network Functions Virtualization 881 (NFV); Architectural Framework", October 2013. 883 [i2nsf-nfv-architecture] 884 Yang, H. and Y. Kim, "I2NSF on the NFV Reference 885 Architecture", draft-yang-i2nsf-nfv-architecture-02 (work 886 in progress), June 2018. 888 [i2nsf-nsf-cap-im] 889 Xia, L., Strassner, J., Basile, C., and D. Lopez, 890 "Information Model of NSFs Capabilities", draft-ietf- 891 i2nsf-capability-02 (work in progress), July 2018. 893 [i2nsf-terminology] 894 Hares, S., Strassner, J., Lopez, D., Xia, L., and H. 895 Birkholz, "Interface to Network Security Functions (I2NSF) 896 Terminology", draft-ietf-i2nsf-terminology-06 (work in 897 progress), July 2018. 899 [ITU-T.X.1252] 900 Recommendation ITU-T X.1252, "Baseline Identity Management 901 Terms and Definitions", April 2010. 903 [ITU-T.X.800] 904 Recommendation ITU-T X.800, "Security Architecture for 905 Open Systems Interconnection for CCITT Applications", 906 March 1991. 908 [ITU-T.Y.3300] 909 Recommendation ITU-T Y.3300, "Framework of Software- 910 Defined Networking", June 2014. 912 [nsf-facing-inf-dm] 913 Kim, J., Jeong, J., Park, J., Hares, S., and Q. Lin, 914 "I2NSF Network Security Function-Facing Interface YANG 915 Data Model", draft-ietf-i2nsf-nsf-facing-interface-data- 916 model-01 (work in progress), July 2018. 918 [nsf-triggered-steering] 919 Hyun, S., Jeong, J., Park, J., and S. Hares, "Service 920 Function Chaining-Enabled I2NSF Architecture", draft-hyun- 921 i2nsf-nsf-triggered-steering-06 (work in progress), July 922 2018. 924 [ONF-OpenFlow] 925 ONF, "OpenFlow Switch Specification (Version 1.4.0)", 926 October 2013. 928 [ONF-SDN-Architecture] 929 ONF, "SDN Architecture", June 2014. 931 [opsawg-firewalls] 932 Baker, F. and P. Hoffman, "On Firewalls in Internet 933 Security", draft-ietf-opsawg-firewalls-01 (work in 934 progress), October 2012. 936 [registration-inf-dm] 937 Hyun, S., Jeong, J., Roh, T., Wi, S., and J. Park, "I2NSF 938 Registration Interface YANG Data Model", draft-hyun-i2nsf- 939 registration-dm-05 (work in progress), July 2018. 941 [registration-inf-im] 942 Hyun, S., Jeong, J., Roh, T., Wi, S., and J. Park, "I2NSF 943 Registration Interface Information Model", draft-hyun- 944 i2nsf-registration-interface-im-06 (work in progress), 945 July 2018. 947 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 948 Description Protocol", RFC 4566, July 2006. 950 [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the 951 Network Configuration Protocol (NETCONF)", RFC 6020, 952 October 2010. 954 [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. 955 Bierman, "Network Configuration Protocol (NETCONF)", 956 RFC 6241, June 2011. 958 [RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined 959 Networking: A Perspective from within a Service Provider 960 Environment", RFC 7149, March 2014. 962 [RFC7665] Halpern, J. and C. Pignataro, "Service Function Chaining 963 (SFC) Architecture", RFC 7665, October 2015. 965 [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF 966 Protocol", RFC 8040, January 2017. 968 [RFC8192] Hares, S., Lopez, D., Zarny, M., Jacquenet, C., Kumar, R., 969 and J. Jeong, "Interface to Network Security Functions 970 (I2NSF): Problem Statement and Use Cases", RFC 8192, July 971 2017. 973 [RFC8300] Quinn, P., Elzur, U., and C. Pignataro, "Network Service 974 Header (NSH)", RFC 8300, January 2018. 976 [RFC8329] Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R. 977 Kumar, "Framework for Interface to Network Security 978 Functions", RFC 8329, February 2018. 980 Appendix A. Changes from draft-ietf-i2nsf-applicability-03 982 The following changes have been made from draft-ietf-i2nsf- 983 applicability-03: 985 o In Section 4, NSF-Facing Interface is used between Security 986 Controller and Classifier (or SFF) in order to configure 987 Classifier (or SFF) for SFC-based NSF chaining. 989 o In Section 6, Developer's Management System is implemented as EM 990 rather than VNFM in the NFV reference architecture. 992 Authors' Addresses 994 Jaehoon Paul Jeong 995 Department of Software 996 Sungkyunkwan University 997 2066 Seobu-Ro, Jangan-Gu 998 Suwon, Gyeonggi-Do 16419 999 Republic of Korea 1001 Phone: +82 31 299 4957 1002 Fax: +82 31 290 7996 1003 EMail: pauljeong@skku.edu 1004 URI: http://iotlab.skku.edu/people-jaehoon-jeong.php 1006 Sangwon Hyun 1007 Department of Computer Engineering 1008 Chosun University 1009 309 Pilmun-daero, Dong-Gu 1010 Gwangju 61452 1011 Republic of Korea 1013 Phone: +82 62 230 7473 1014 EMail: shyun@chosun.ac.kr 1016 Tae-Jin Ahn 1017 Korea Telecom 1018 70 Yuseong-Ro, Yuseong-Gu 1019 Daejeon 305-811 1020 Republic of Korea 1022 Phone: +82 42 870 8409 1023 EMail: taejin.ahn@kt.com 1024 Susan Hares 1025 Huawei 1026 7453 Hickory Hill 1027 Saline, MI 48176 1028 USA 1030 Phone: +1-734-604-0332 1031 EMail: shares@ndzh.com 1033 Diego R. Lopez 1034 Telefonica I+D 1035 Jose Manuel Lara, 9 1036 Seville 41013 1037 Spain 1039 Phone: +34 682 051 091 1040 EMail: diego.r.lopez@telefonica.com