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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 (September 11, 2018) is 2055 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: March 15, 2019 Chosun University 6 T. Ahn 7 Korea Telecom 8 S. Hares 9 Huawei 10 D. Lopez 11 Telefonica I+D 12 September 11, 2018 14 Applicability of Interfaces to Network Security Functions to Network- 15 Based Security Services 16 draft-ietf-i2nsf-applicability-05 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 March 15, 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 . . . . . . . . . . . . . . . . . . . . . . . 3 62 4. Time-dependent Web Access Control Service . . . . . . . . . . 5 63 5. I2NSF Framework with SFC . . . . . . . . . . . . . . . . . . 6 64 6. I2NSF Framework with SDN . . . . . . . . . . . . . . . . . . 9 65 6.1. Firewall: Centralized Firewall System . . . . . . . . . . 11 66 6.2. Deep Packet Inspection: Centralized VoIP/VoLTE Security 67 System . . . . . . . . . . . . . . . . . . . . . . . . . 12 68 6.3. Attack Mitigation: Centralized DDoS-attack Mitigation 69 System . . . . . . . . . . . . . . . . . . . . . . . . . 14 70 7. I2NSF Framework with NFV . . . . . . . . . . . . . . . . . . 16 71 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18 72 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 73 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 18 74 11. Informative References . . . . . . . . . . . . . . . . . . . 19 75 Appendix A. Changes from draft-ietf-i2nsf-applicability-04 . . . 22 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22 78 1. Introduction 80 Interface to Network Security Functions (I2NSF) defines 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 Network 84 Functions Virtualization (NFV) environment [ETSI-NFV] by utilizing 85 the capabilities of such products and the virtualization of security 86 functions in the NFV platform. In the I2NSF framework, each NSF 87 initially registers the profile of its own capabilities into the 88 system in order for themselves to be available in the system. In 89 addition, the Security Controller is validated by the I2NSF Client 90 (also called I2NSF User) that the user is employing, so that the user 91 can request security services through the Security Controller. 93 This document illustrates the applicability of the I2NSF framework 94 with four different scenarios: (i) the enforcement of time-dependent 95 web access control; (ii) the application of I2NSF to a Service 96 Function Chaining (SFC) environment [RFC7665]; (iii) the integration 97 of the I2NSF framework with Software-Defined Networking (SDN) 98 [RFC7149] to provide different security functionality such as 99 firewalls [opsawg-firewalls], Deep Packet Inspection (DPI), and 100 Distributed Denial of Service (DDoS) attack mitigation; (iv) the use 101 of NFV as supporting technology. The implementation of I2NSF in 102 these scenarios has allowed us to verify the applicability and 103 effectiveness of the I2NSF framework for a variety of use cases. 105 2. Terminology 107 This document uses the terminology described in [RFC7149], 108 [ITU-T.Y.3300], [ONF-OpenFlow], [ONF-SDN-Architecture], 109 [ITU-T.X.1252], [ITU-T.X.800], [RFC8329], [i2nsf-terminology], 110 [consumer-facing-inf-im], [consumer-facing-inf-dm], 111 [i2nsf-nsf-cap-im], [nsf-facing-inf-dm], [registration-inf-dm], and 112 [nsf-triggered-steering]. In addition, the following terms are 113 defined below: 115 o Software-Defined Networking (SDN): A set of techniques that 116 enables to directly program, orchestrate, control, and manage 117 network resources, which facilitates the design, delivery and 118 operation of network services in a dynamic and scalable manner 119 [ITU-T.Y.3300]. 121 o Firewall: A service function at the junction of two network 122 segments that inspects every packet that attempts to cross the 123 boundary. It also rejects any packet that does not satisfy 124 certain criteria for, for example, disallowed port numbers or IP 125 addresses. 127 o Centralized Firewall System: A centralized firewall that can 128 establish and distribute policy rules into network resources for 129 efficient firewall management. 131 o Centralized VoIP Security System: A centralized security system 132 that handles the security functions required for VoIP and VoLTE 133 services. 135 o Centralized DDoS-attack Mitigation System: A centralized mitigator 136 that can establish and distribute access control policy rules into 137 network resources for efficient DDoS-attack mitigation. 139 3. I2NSF Framework 141 This section summarizes the I2NSF framework as defined in [RFC8329]. 142 As shown in Figure 1, an I2NSF User can use security functions by 143 delivering high-level security policies, which specify security 144 requirements that the I2NSF user wants to enforce, to the Security 145 Controller via the Consumer-Facing Interface 146 [consumer-facing-inf-im][consumer-facing-inf-dm]. 148 The Security Controller receives and analyzes the high-level security 149 policies from an I2NSF User, and identifies what types of security 150 capabilities are required to meet these high-level security policies. 151 The Security Controller then identifies NSFs that have the required 152 security capabilities, and generates low-level security policies for 153 each of the NSFs so that the high-level security policies are 154 eventually enforced by those NSFs [policy-translation]. Finally, the 155 Security Controller sends the generated low-level security policies 156 to the NSFs [i2nsf-nsf-cap-im][nsf-facing-inf-dm]. 158 The Security Controller requests NSFs to perform low-level security 159 services via the NSF-Facing Interface. The developers (or vendors) 160 inform the Security Controller of the capabilities of the NSFs 161 through the I2NSF Registration Interface [registration-inf-dm] for 162 registering (or deregistering) the corresponding NSFs. 164 The Consumer-Facing Interface between an I2NSF User and the Security 165 Controller can be implemented using, for example, RESTCONF [RFC8040]. 166 Data models specified by YANG [RFC6020] describe high-level security 167 policies to be specified by an I2NSF User. The data model defined in 168 [consumer-facing-inf-dm] can be used for the I2NSF Consumer-Facing 169 Interface. 171 +------------+ 172 | I2NSF User | 173 +------------+ 174 ^ 175 | Consumer-Facing Interface 176 v 177 +-------------------+ Registration +-----------------------+ 178 |Security Controller|<-------------------->|Developer's Mgmt System| 179 +-------------------+ Interface +-----------------------+ 180 ^ 181 | NSF-Facing Interface 182 v 183 +----------------+ +---------------+ +-----------------------+ 184 | NSF-1 |-| NSF-2 |...| NSF-n | 185 | (Firewall) | | (Web Filter) | |(DDoS-Attack Mitigator)| 186 +----------------+ +---------------+ +-----------------------+ 188 Figure 1: I2NSF Framework 190 The NSF-Facing Interface between the Security Controller and NSFs can 191 be implemented using NETCONF [RFC6241]. YANG data models describe 192 low-level security policies for the sake of NSFs, which are 193 translated from the high-level security policies by the Security 194 Controller. The data model defined in [nsf-facing-inf-dm] can be 195 used for the I2NSF NSF-Facing Interface. 197 The Registration Interface between the Security Controller and the 198 Developer's Management System can be implemented by RESTCONF 199 [RFC8040]. The data model defined in [registration-inf-dm] can be 200 used for the I2NSF Registration Interface. 202 Also, the I2NSF framework can enforce multiple chained NSFs for the 203 low-level security policies by means of SFC techniques for the I2NSF 204 architecture described in [nsf-triggered-steering]. 206 The following sections describe different security service scenarios 207 illustrating the applicability of the I2NSF framework. 209 4. Time-dependent Web Access Control Service 211 This service scenario assumes that an enterprise network 212 administrator wants to control the staff members' access to a 213 particular Interner service (e.g., Example.com) during business 214 hours. The following is an example high-level security policy rule 215 that the administrator requests: Block the staff members' access to 216 Example.com from 9 AM to 6 PM. The administrator sends this high- 217 level security policy to the Security Controller, then the Security 218 Controller identifies required security capabilities, e.g., IP 219 address and port number inspection capabilities and URL inspection 220 capability. In this scenario, it is assumed that the IP address and 221 port number inspection capabilities are required to check whether a 222 received packet is an HTTP packet from a staff member. The URL 223 inspection capability is required to check whether the target URL of 224 a received packet is in the Example.com domain or not. 226 The Security Controller maintains the security capabilities of each 227 NSF running in the I2NSF system, which have been reported by the 228 Developer's Management System via the Registation interface. Based 229 on this information, the Security Controller identifies NSFs that can 230 perform the IP address and port number inspection and URL inspection 231 [policy-translation]. In this scenario, it is assumed that an NSF of 232 firewall has the IP address and port number inspection capabilities 233 and an NSF of web filter has URL inspection capability. 235 The Security Controller generates low-level security rules for the 236 NSFs to perform IP address and port number inspection, URL 237 inspection, and time checking. Specifically, the Security Controller 238 may interoperate with an access control server in the enterprise 239 network in order to retrieve the information (e.g., IP address in 240 use, company identifier (ID), and role) of each employee that is 241 currently using the network. Based on the retrieved information, the 242 Security Controller generates low-level security rules to check 243 whether the source IP address of a received packet matches any one 244 being used by a staff member. In addition, the low-level security 245 rules should be able to determine that a received packet is of HTTP 246 protocol. The low-level security rules for web filter checks that 247 the target URL field of a received packet is equal to Example.com. 248 Finally, the Security Controller sends the low-level security rules 249 of the IP address and port number inspection to the NSF of firewall 250 and the low-level rules for URL inspection to the NSF of web filter. 252 The following describes how the time-dependent web access control 253 service is enforced by the NSFs of firewall and web filter. 255 1. A staff member tries to access Example.com during business hours, 256 e.g., 10 AM. 258 2. The packet is forwarded from the staff member's device to the 259 firewall, and the firewall checks the source IP address and port 260 number. Now the firewall identifies the received packet is an 261 HTTP packet from the staff member. 263 3. The firewall triggers the web filter to further inspect the 264 packet, and the packet is forwarded from the firewall to the web 265 filter. SFC technology can be utilized to support such packet 266 forwarding in the I2NSF framework [nsf-triggered-steering]. 268 4. The web filter checks the target URL field of the received 269 packet, and realizes the packet is toward Example.com. The web 270 filter then checks that the current time is in business hours. 271 If so, the web filter drops the packet, and consequently the 272 staff member's access to Example.com during business hours is 273 blocked. 275 5. I2NSF Framework with SFC 277 In the I2NSF architecture, an NSF can trigger an advanced security 278 action (e.g., DPI or DDoS attack mitigation) on a packet based on the 279 result of its own security inspection of the packet. For example, a 280 firewall triggers further inspection of a suspicious packet with DPI. 281 For this advanced security action to be fulfilled, the suspicious 282 packet should be forwarded from the current NSF to the successor NSF. 283 SFC [RFC7665] is a technology that enables this advanced security 284 action by steering a packet with multiple service functions (e.g., 285 NSFs), and this technology can be utilized by the I2NSF architecture 286 to support the advanced security action. 288 SFC generally requires classifiers and service function forwarders 289 (SFFs); classifiers are responsible for determining which service 290 function path (SFP) (i.e., an ordered sequence of service functions) 291 a given packet should pass through, according to pre-configured 292 classification rules, and SFFs perform forwarding the given packet to 293 the next service function (e.g., NSF) on the SFP of the packet by 294 referring to their forwarding tables. In the I2NSF architecture with 295 SFC, the Security Controller can take responsibilities of generating 296 classification rules for classifiers and forwarding tables for SFFs. 297 By analyzing high-level security policies from I2NSF users, the 298 Security Controller can construct SFPs that are required to meet the 299 high-level security policies, generates classification rules of the 300 SFPs, and then configures classifiers with the classification rules 301 over NSF-Facing Interface so that relevant traffic packets can follow 302 the SFPs. Also, based on the global view of NSF instances available 303 in the system, the Security Controller constructs forwarding tables, 304 which are required for SFFs to forward a given packet to the next NSF 305 over the SFP, and configures SFFs with those forwarding tables over 306 NSF-Facing Interface. 308 +------------+ 309 | I2NSF User | 310 +------------+ 311 ^ 312 | Consumer-Facing Interface 313 v 314 +-------------------+ Registration +-----------------------+ 315 |Security Controller|<-------------------->|Developer's Mgmt System| 316 +-------------------+ Interface +-----------------------+ 317 ^ ^ 318 | | NSF-Facing Interface 319 | |------------------------- 320 | | 321 | NSF-Facing Interface | 322 +-+-+-v-+-+-+-+-+-+ +------v-------+ 323 | +-----------+ | ------>| NSF-1 | 324 | |Classifier | | | | (Firewall) | 325 | +-----------+ | | +--------------+ 326 | +-----+ |<-----| +--------------+ 327 | | SFF | | |----->| NSF-2 | 328 | +-----+ | | | (DPI) | 329 +-+-+-+-+-+-+-+-+-+ | +--------------+ 330 | . 331 | . 332 | . 333 | +-----------------------+ 334 ------>| NSF-n | 335 |(DDoS-Attack Mitigator)| 336 +-----------------------+ 338 Figure 2: An I2NSF Framework with SFC 340 To trigger an advanced security action in the I2NSF architecture, the 341 current NSF appends a metadata describing the security capability 342 required for the advanced action to the suspicious packet and sends 343 the packet to the classifier. Based on the metadata information, the 344 classifier searches an SFP which includes an NSF with the required 345 security capability, changes the SFP-related information (e.g., 346 service path identifier and service index [RFC8300]) of the packet 347 with the new SFP that has been found, and then forwards the packet to 348 the SFF. When receiving the packet, the SFF checks the SFP-related 349 information such as the service path identifier and service index 350 contained in the packet and forwards the packet to the next NSF on 351 the SFP of the packet, according to its forwarding table. 353 6. I2NSF Framework with SDN 355 This section describes an I2NSF framework with SDN for I2NSF 356 applicability and use cases, such as firewall, deep packet 357 inspection, and DDoS-attack mitigation functions. SDN enables some 358 packet filtering rules to be enforced in network forwarding elements 359 (e.g., switch) by controlling their packet forwarding rules. By 360 taking advantage of this capability of SDN, it is possible to 361 optimize the process of security service enforcement in the I2NSF 362 system. 364 Figure 3 shows an I2NSF framework [RFC8329] with SDN networks to 365 support network-based security services. In this system, the 366 enforcement of security policy rules is divided into the SDN 367 forwarding elements (e.g., switch) and NSFs. Especially, SDN 368 forwarding elements enforce simple packet filtering rules that can be 369 translated into their packet forwarding rules, whereas NSFs enforce 370 NSF-related security rules requiring the security capabilities of the 371 NSFs. For this purpose, the Security Controller instructs the SDN 372 Controller via NSF-Facing Interface so that SDN forwarding elements 373 can perform the required security services with flow tables under the 374 supervision of the SDN Controller. 376 As an example, let us consider two different types of security rules: 377 Rule A is a simple packet fltering rule that checks only the IP 378 address and port number of a given packet, whereas rule B is a time- 379 consuming packet inspection rule for analyzing whether an attached 380 file being transmitted over a flow of packets contains malware. Rule 381 A can be translated into packet forwarding rules of SDN forwarding 382 elements and thus be enforced by these elements. In contrast, rule B 383 cannot be enforced by forwarding elements, but it has to be enforced 384 by NSFs with anti-malware capability. Specifically, a flow of 385 packets is forwarded to and reassembled by an NSF to reconstruct the 386 attached file stored in the flow of packets. The NSF then analyzes 387 the file to check the existence of malware. If the file contains 388 malware, the NSF drops the packets. 390 In an I2NSF framework with SDN, the Security Controller can analyze 391 given security policy rules and automatically determine which of the 392 given security policy rules should be enforced by SDN forwarding 393 elements and which should be enforced by NSFs. If some of the given 394 rules requires security capabilities that can be provided by SDN 395 forwarding elements, then the Security Controller instructs the SDN 396 Controller via NSF-Facing Interface so that SDN forwarding elements 397 can enforce those security policy rules with flow tables under the 398 supervision of the SDN Controller. Or if some rules require security 399 capabilities that cannot be provided by SDN forwarding elements but 400 by NSFs, then the Security Controller instructs relevant NSFs to 401 enforce those rules. 403 +------------+ 404 | I2NSF User | 405 +------------+ 406 ^ 407 | Consumer-Facing Interface 408 v 409 +-------------------+ Registration +-----------------------+ 410 |Security Controller|<-------------------->|Developer's Mgmt System| 411 +-------------------+ Interface +-----------------------+ 412 ^ ^ 413 | | NSF-Facing Interface 414 | v 415 | +----------------+ +---------------+ +-----------------------+ 416 | | NSF-1 |-| NSF-2 |...| NSF-n | 417 | | (Firewall) | | (DPI) | |(DDoS-Attack Mitigator)| 418 | +----------------+ +---------------+ +-----------------------+ 419 | ^ 420 | | 421 | v 422 | +--------+ 423 | | SFF | 424 | +--------+ 425 | ^ 426 | | 427 | V SDN Network 428 +--|----------------------------------------------------------------+ 429 | V NSF-Facing Interface | 430 | +----------------+ | 431 | | SDN Controller | | 432 | +----------------+ | 433 | ^ | 434 | | SDN Southbound Interface | 435 | v | 436 | +--------+ +--------+ +--------+ +--------+ | 437 | |Switch 1|-|Switch 2|-|Switch 3|......|Switch m| | 438 | +--------+ +--------+ +--------+ +--------+ | 439 +-------------------------------------------------------------------+ 441 Figure 3: An I2NSF Framework with SDN Network 443 The following subsections introduce three use cases for cloud-based 444 security services: (i) firewall system, (ii) deep packet inspection 445 system, and (iii) attack mitigation system. [RFC8192] 447 6.1. Firewall: Centralized Firewall System 449 A centralized network firewall can manage each network resource and 450 apply common rules to individual network elements (e.g., switch). 451 The centralized network firewall controls each forwarding element, 452 and firewall rules can be added or deleted dynamically. 454 The procedure of firewall operations in this system is as follows: 456 1. A switch forwards an unknown flow's packet to one of the SDN 457 Controllers. 459 2. The SDN Controller forwards the unknown flow's packet to an 460 appropriate security service application, such as the Firewall. 462 3. The Firewall analyzes, typically, the headers and contents of the 463 packet. 465 4. If the Firewall regards the packet as a malicious one with a 466 suspicious pattern, it reports the malicious packet to the SDN 467 Controller. 469 5. The SDN Controller installs new rules (e.g., drop packets with 470 the suspicious pattern) into underlying switches. 472 6. The suspected packets are dropped by these switches. 474 Existing SDN protocols can be used through standard interfaces 475 between the firewall application and switches 476 [RFC7149][ITU-T.Y.3300][ONF-OpenFlow] [ONF-SDN-Architecture]. 478 Legacy firewalls have some challenges such as the expensive cost, 479 performance, management of access control, establishment of policy, 480 and packet-based access mechanism. The proposed framework can 481 resolve the challenges through the above centralized firewall system 482 based on SDN as follows: 484 o Cost: The cost of adding firewalls to network resources such as 485 routers, gateways, and switches is substantial due to the reason 486 that we need to add firewall on each network resource. To solve 487 this, each network resource can be managed centrally such that a 488 single firewall is manipulated by a centralized server. 490 o Performance: The performance of firewalls is often slower than the 491 link speed of network interfaces. Every network resource for 492 firewall needs to check firewall rules according to network 493 conditions. Firewalls can be adaptively deployed among network 494 switches, depending on network conditions in the framework. 496 o The management of access control: Since there may be hundreds of 497 network resources in a network, the dynamic management of access 498 control for security services like firewall is a challenge. In 499 the framework, firewall rules can be dynamically added for new 500 malware. 502 o The establishment of policy: Policy should be established for each 503 network resource. However, it is difficult to describe what flows 504 are permitted or denied for firewall within a specific 505 organization network under management. Thus, a centralized view 506 is helpful to determine security policies for such a network. 508 o Packet-based access mechanism: Packet-based access mechanism is 509 not enough for firewall in practice since the basic unit of access 510 control is usually users or applications. Therefore, application 511 level rules can be defined and added to the firewall system 512 through the centralized server. 514 6.2. Deep Packet Inspection: Centralized VoIP/VoLTE Security System 516 A centralized VoIP/VoLTE security system can monitor each VoIP/VoLTE 517 flow and manage VoIP/VoLTE security rules, according to the 518 configuration of a VoIP/VoLTE security service called VoIP Intrusion 519 Prevention System (IPS). This centralized VoIP/VoLTE security system 520 controls each switch for the VoIP/VoLTE call flow management by 521 manipulating the rules that can be added, deleted or modified 522 dynamically. 524 The centralized VoIP/VoLTE security system can cooperate with a 525 network firewall to realize VoIP/VoLTE security service. 526 Specifically, a network firewall performs basic security checks of an 527 unknown flow's packet observed by a switch. If the network firewall 528 detects that the packet is an unknown VoIP call flow's packet that 529 exhibits some suspicious patterns, then it triggers the VoIP/VoLTE 530 security system for more specialized security analysis of the 531 suspicious VoIP call packet. 533 The procedure of VoIP/VoLTE security operations in this system is as 534 follows: 536 1. A switch forwards an unknown flow's packet to the SDN Controller, 537 and the SDN Controller further forwards the unknown flow's packet 538 to the Firewall for basic security inspection. 540 2. The Firewall analyzes the header fields of the packet, and 541 figures out that this is an unknown VoIP call flow's signal 542 packet (e.g., SIP packet) of a suspicious pattern. 544 3. The Firewall triggers an appropriate security service function, 545 such as VoIP IPS, for detailed security analysis of the 546 suspicious signal packet. That is, the firewall sends the packet 547 to the Service Function Forwarder (SFF) in the I2NSF framework 548 [nsf-triggered-steering], as shown in Figure 3. The SFF forwards 549 the suspicious signal packet to the VoIP IPS. 551 4. The VoIP IPS analyzes the headers and contents of the signal 552 packet, such as calling number and session description headers 553 [RFC4566]. 555 5. If, for example, the VoIP IPS regards the packet as a spoofed 556 packet by hackers or a scanning packet searching for VoIP/VoLTE 557 devices, it drops the packet. In addition, the VoIP IPS requests 558 the SDN Controller to block that packet and the subsequent 559 packets that have the same call-id. 561 6. The SDN Controller installs new rules (e.g., drop packets) into 562 underlying switches. 564 7. The illegal packets are dropped by these switches. 566 Existing SDN protocols can be used through standard interfaces 567 between the VoIP IPS application and switches [RFC7149][ITU-T.Y.3300] 568 [ONF-OpenFlow][ONF-SDN-Architecture]. 570 Legacy hardware based VoIP IPS has some challenges, such as 571 provisioning time, the granularity of security, expensive cost, and 572 the establishment of policy. The I2NSF framework can resolve the 573 challenges through the above centralized VoIP/VoLTE security system 574 based on SDN as follows: 576 o Provisioning: The provisioning time of setting up a legacy VoIP 577 IPS to network is substantial because it takes from some hours to 578 some days. By managing the network resources centrally, VoIP IPS 579 can provide more agility in provisioning both virtual and physical 580 network resources from a central location. 582 o The granularity of security: The security rules of a legacy VoIP 583 IPS are compounded considering the granularity of security. The 584 proposed framework can provide more granular security by 585 centralizing security control into a switch controller. The VoIP 586 IPS can effectively manage security rules throughout the network. 588 o Cost: The cost of adding VoIP IPS to network resources, such as 589 routers, gateways, and switches is substantial due to the reason 590 that we need to add VoIP IPS on each network resource. To solve 591 this, each network resource can be managed centrally such that a 592 single VoIP IPS is manipulated by a centralized server. 594 o The establishment of policy: Policy should be established for each 595 network resource. However, it is difficult to describe what flows 596 are permitted or denied for VoIP IPS within a specific 597 organization network under management. Thus, a centralized view 598 is helpful to determine security policies for such a network. 600 6.3. Attack Mitigation: Centralized DDoS-attack Mitigation System 602 A centralized DDoS-attack mitigation can manage each network resource 603 and manipulate rules to each switch through a common server for DDoS- 604 attack mitigation (called DDoS-attack Mitigator). The centralized 605 DDoS-attack mitigation system defends servers against DDoS attacks 606 outside the private network, that is, from public networks. 608 Servers are categorized into stateless servers (e.g., DNS servers) 609 and stateful servers (e.g., web servers). For DDoS-attack 610 mitigation, traffic flows in switches are dynamically configured by 611 traffic flow forwarding path management according to the category of 612 servers [AVANT-GUARD]. Such a managenent should consider the load 613 balance among the switches for the defense against DDoS attacks. 615 The procedure of DDoS-attack mitigation operations in this system is 616 as follows: 618 1. A Switch periodically reports an inter-arrival pattern of a 619 flow's packets to one of the SDN Controllers. 621 2. The SDN Controller forwards the flow's inter-arrival pattern to 622 an appropriate security service application, such as DDoS-attack 623 Mitigator. 625 3. The DDoS-attack Mitigator analyzes the reported pattern for the 626 flow. 628 4. If the DDoS-attack Mitigator regards the pattern as a DDoS 629 attack, it computes a packet dropping probability corresponding 630 to suspiciousness level and reports this DDoS-attack flow to the 631 SDN Controller. 633 5. The SDN Controller installs new rules into switches (e.g., 634 forward packets with the suspicious inter-arrival pattern with a 635 dropping probability). 637 6. The suspicious flow's packets are randomly dropped by switches 638 with the dropping probability. 640 For the above centralized DDoS-attack mitigation system, the existing 641 SDN protocols can be used through standard interfaces between the 642 DDoS-attack mitigator application and switches [RFC7149] 643 [ITU-T.Y.3300][ONF-OpenFlow][ONF-SDN-Architecture]. 645 The centralized DDoS-attack mitigation system has challenges similar 646 to the centralized firewall system. The proposed framework can 647 resolve the challenges through the above centralized DDoS-attack 648 mitigation system based on SDN as follows: 650 o Cost: The cost of adding DDoS-attack mitigators to network 651 resources such as routers, gateways, and switches is substantial 652 due to the reason that we need to add DDoS-attack mitigator on 653 each network resource. To solve this, each network resource can 654 be managed centrally such that a single DDoS-attack mitigator is 655 manipulated by a centralized server. 657 o Performance: The performance of DDoS-attack mitigators is often 658 slower than the link speed of network interfaces. The checking of 659 DDoS attacks may reduce the performance of the network interfaces. 660 DDoS-attack mitigators can be adaptively deployed among network 661 switches, depending on network conditions in the framework. 663 o The management of network resources: Since there may be hundreds 664 of network resources in an administered network, the dynamic 665 management of network resources for performance (e.g., load 666 balancing) is a challenge for DDoS-attack mitigation. In the 667 framework, as dynamic network resource management, traffic flow 668 forwarding path management can handle the load balancing of 669 network switches [AVANT-GUARD]. With this management, the current 670 and near-future workload can be spread among the network switches 671 for DDoS-attack mitigation. In addition, DDoS-attack mitigation 672 rules can be dynamically added for new DDoS attacks. 674 o The establishment of policy: Policy should be established for each 675 network resource. However, it is difficult to describe what flows 676 are permitted or denied for new DDoS-attacks (e.g., DNS reflection 677 attack) within a specific organization network under management. 678 Thus, a centralized view is helpful to determine security policies 679 for such a network. 681 So far this section has described the procedure and impact of the 682 three use cases for network-based security services using the I2NSF 683 framework with SDN networks. To support these use cases in the 684 proposed data-driven security service framework, YANG data models 685 described in [consumer-facing-inf-dm], [nsf-facing-inf-dm], and 686 [registration-inf-dm] can be used as Consumer-Facing Interface, NSF- 687 Facing Interface, and Registration Interface, respectively, along 688 with RESTCONF [RFC8040] and NETCONF [RFC6241]. 690 7. I2NSF Framework with NFV 692 This section discusses the implementation of the I2NSF framework 693 using Network Functions Virtualization (NFV). 695 +--------------------+ 696 +-------------------------------------------+ | ---------------- | 697 | I2NSF User (OSS/BSS) | | | NFV | | 698 +------+------------------------------------+ | | Orchestrator +-+ | 699 | Consumer-Facing Interface | -----+---------- | | 700 +------|------------------------------------+ | | | | 701 | -----+---------- (a) ----------------- | | | | | 702 | | Security |-------| Developer's | | | | | | 703 | |Controller(EM)| |Mgmt System(EM)| | | | | | 704 | -----+---------- ----------------- | | ----+----- | | 705 | | NSF-Facing Interface | | | | | | 706 | ----+----- ----+----- ----+----- | | | VNFM(s)| | | 707 | |NSF(VNF)| |NSF(VNF)| |NSF(VNF)| +-(b)-+ | | | 708 | ----+----- ----+----- ----+----- | | ----+----- | | 709 | | | | | | | | | 710 +------|-------------|-------------|--------+ | | | | 711 | | | | | | | 712 +------+-------------+-------------+--------+ | | | | 713 | NFV Infrastructure (NFVI) | | | | | 714 | ----------- ----------- ----------- | | | | | 715 | | Virtual | | Virtual | | Virtual | | | | | | 716 | | Compute | | Storage | | Network | | | | | | 717 | ----------- ----------- ----------- | | ----+----- | | 718 | +---------------------------------------+ | | | | | | 719 | | Virtualization Layer | +-----+ VIM(s) +------+ | 720 | +---------------------------------------+ | | | | | 721 | +---------------------------------------+ | | ---------- | 722 | | ----------- ----------- ----------- | | | | 723 | | | Compute | | Storage | | Network | | | | | 724 | | | Hardware| | Hardware| | Hardware| | | | | 725 | | ----------- ----------- ----------- | | | | 726 | | Hardware Resources | | | NFV Management | 727 | +---------------------------------------+ | | and Orchestration | 728 +-------------------------------------------+ +--------------------+ 729 (a) = Registration Interface 730 (b) = Ve-Vnfm Interface 732 Figure 4: I2NSF Framework Implementation with respect to the NFV 733 Reference Architectural Framework 735 NFV is a promising technology for improving the elasticity and 736 efficiency of network resource utilization. In NFV environments, 737 NSFs can be deployed in the forms of software-based virtual instances 738 rather than physical appliances. Virtualizing NSFs makes it possible 739 to rapidly and flexibly respond to the amount of service requests by 740 dynamically increasing or decreasing the number of NSF instances. 741 Moreover, NFV technology facilitates flexibly including or excluding 742 NSFs from multiple security solution vendors according to the changes 743 on security requirements. In order to take advantages of the NFV 744 technology, the I2NSF framework can be implemented on top of an NFV 745 infrastructure as show in Figure 4. 747 Figure 4 shows an I2NSF framework implementation based on the NFV 748 reference architecture that the European Telecommunications Standards 749 Institute (ETSI) defines [ETSI-NFV]. The NSFs are deployed as 750 virtual network functions (VNFs) in Figure 4. The Developer's 751 Management System (DMS) in the I2NSF framework is responsible for 752 registering capability information of NSFs into the Security 753 Controller. Those NSFs are created or removed by a virtual network 754 functions manager (VNFM) in the NFV architecture that performs the 755 life-cycle management of VNFs. The Security Controller controls and 756 monitors the configurations (e.g., function parameters and security 757 policy rules) of VNFs. Both the DMS and Security Controller can be 758 implemented as the Element Managements (EMs) in the NFV architecture. 759 Finally, the I2NSF User can be implemented as OSS/BSS (Operational 760 Support Systems/Business Support Systems) in the NFV architecture 761 that provides interfaces for users in the NFV system. 763 The operation procedure in the I2NSF framework based on the NFV 764 architecture is as follows: 766 1. The VNFM has a set of virtual machine (VM) images of NSFs, and 767 each VM image can be used to create an NSF instance that provides 768 a set of security capabilities. The DMS initially registers a 769 mapping table of the ID of each VM image and the set of 770 capabilities that can be provided by an NSF instance created from 771 the VM image into the Security Controller. 773 2. If the Security Controller does not have any instantiated NSF 774 that has the set of capabilities required to meet the security 775 requirements from users, it searches the mapping table 776 (registered by the DMS) for the VM image ID corresponding to the 777 required set of capabilities. 779 3. The Security Controller requests the DMS to instantiate an NSF 780 with the VM image ID via VNFM. 782 4. When receiving the instantiation request, the VNFM first asks the 783 NFV orchestrator for the permission required to create the NSF 784 instance, requests the VIM to allocate resources for the NSF 785 instance, and finally creates the NSF instance based on the 786 allocated resources. 788 5. Once the NSF instance has been created by the VNFM, the DMS 789 performs the initial configurations of the NSF instance and then 790 notifies the Security Controller of the NSF instance. 792 6. After being notified of the created NSF instance, the Security 793 Controller delivers low-level security policy rules to the NSF 794 instance for policy enforcement. 796 We can conclude that the I2NSF framework can be implemented based on 797 the NFV architecture framework. Note that the registration of the 798 capabilities of NSFs is performed through the Registration Interface 799 and the lifecycle management for NSFs (VNFs) is performed through the 800 Ve-Vnfm interface between the DMS and VNFM, as shown in Figure 4. 801 More details about the I2NSF framework based on the NFV reference 802 architecture are described in [i2nsf-nfv-architecture]. 804 8. Security Considerations 806 The same security considerations for the I2NSF framework [RFC8329] 807 are applicable to this document. 809 This document shares all the security issues of SDN that are 810 specified in the "Security Considerations" section of [ITU-T.Y.3300]. 812 9. Acknowledgments 814 This work was supported by Institute for Information & communications 815 Technology Promotion (IITP) grant funded by the Korea government 816 (MSIP) (No.R-20160222-002755, Cloud based Security Intelligence 817 Technology Development for the Customized Security Service 818 Provisioning). 820 10. Contributors 822 I2NSF is a group effort. I2NSF has had a number of contributing 823 authors. The following are considered co-authors: 825 o Hyoungshick Kim (Sungkyunkwan University) 827 o Jinyong Tim Kim (Sungkyunkwan University) 829 o Hyunsik Yang (Soongsil University) 830 o Younghan Kim (Soongsil University) 832 o Jung-Soo Park (ETRI) 834 o Se-Hui Lee (Korea Telecom) 836 o Mohamed Boucadair (Orange) 838 11. Informative References 840 [AVANT-GUARD] 841 Shin, S., Yegneswaran, V., Porras, P., and G. Gu, "AVANT- 842 GUARD: Scalable and Vigilant Switch Flow Management in 843 Software-Defined Networks", ACM CCS, November 2013. 845 [consumer-facing-inf-dm] 846 Jeong, J., Kim, E., Ahn, T., Kumar, R., and S. Hares, 847 "I2NSF Consumer-Facing Interface YANG Data Model", draft- 848 ietf-i2nsf-consumer-facing-interface-dm-01 (work in 849 progress), July 2018. 851 [consumer-facing-inf-im] 852 Kumar, R., Lohiya, A., Qi, D., Bitar, N., Palislamovic, 853 S., Xia, L., and J. Jeong, "Information Model for 854 Consumer-Facing Interface to Security Controller", draft- 855 kumar-i2nsf-client-facing-interface-im-07 (work in 856 progress), July 2018. 858 [ETSI-NFV] 859 ETSI GS NFV 002 V1.1.1, "Network Functions Virtualization 860 (NFV); Architectural Framework", October 2013. 862 [i2nsf-nfv-architecture] 863 Yang, H. and Y. Kim, "I2NSF on the NFV Reference 864 Architecture", draft-yang-i2nsf-nfv-architecture-02 (work 865 in progress), June 2018. 867 [i2nsf-nsf-cap-im] 868 Xia, L., Strassner, J., Basile, C., and D. Lopez, 869 "Information Model of NSFs Capabilities", draft-ietf- 870 i2nsf-capability-02 (work in progress), July 2018. 872 [i2nsf-terminology] 873 Hares, S., Strassner, J., Lopez, D., Xia, L., and H. 874 Birkholz, "Interface to Network Security Functions (I2NSF) 875 Terminology", draft-ietf-i2nsf-terminology-06 (work in 876 progress), July 2018. 878 [ITU-T.X.1252] 879 Recommendation ITU-T X.1252, "Baseline Identity Management 880 Terms and Definitions", April 2010. 882 [ITU-T.X.800] 883 Recommendation ITU-T X.800, "Security Architecture for 884 Open Systems Interconnection for CCITT Applications", 885 March 1991. 887 [ITU-T.Y.3300] 888 Recommendation ITU-T Y.3300, "Framework of Software- 889 Defined Networking", June 2014. 891 [nsf-facing-inf-dm] 892 Kim, J., Jeong, J., Park, J., Hares, S., and Q. Lin, 893 "I2NSF Network Security Function-Facing Interface YANG 894 Data Model", draft-ietf-i2nsf-nsf-facing-interface-data- 895 model-01 (work in progress), July 2018. 897 [nsf-triggered-steering] 898 Hyun, S., Jeong, J., Park, J., and S. Hares, "Service 899 Function Chaining-Enabled I2NSF Architecture", draft-hyun- 900 i2nsf-nsf-triggered-steering-06 (work in progress), July 901 2018. 903 [ONF-OpenFlow] 904 ONF, "OpenFlow Switch Specification (Version 1.4.0)", 905 October 2013. 907 [ONF-SDN-Architecture] 908 ONF, "SDN Architecture", June 2014. 910 [opsawg-firewalls] 911 Baker, F. and P. Hoffman, "On Firewalls in Internet 912 Security", draft-ietf-opsawg-firewalls-01 (work in 913 progress), October 2012. 915 [policy-translation] 916 Yang, J., Jeong, J., and J. Kim, "Security Policy 917 Translation in Interface to Network Security Functions", 918 draft-yang-i2nsf-security-policy-translation-01 (work in 919 progress), July 2018. 921 [registration-inf-dm] 922 Hyun, S., Jeong, J., Roh, T., Wi, S., and J. Park, "I2NSF 923 Registration Interface YANG Data Model", draft-hyun-i2nsf- 924 registration-dm-06 (work in progress), July 2018. 926 [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session 927 Description Protocol", RFC 4566, July 2006. 929 [RFC6020] Bjorklund, M., "YANG - A Data Modeling Language for the 930 Network Configuration Protocol (NETCONF)", RFC 6020, 931 October 2010. 933 [RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A. 934 Bierman, "Network Configuration Protocol (NETCONF)", 935 RFC 6241, June 2011. 937 [RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined 938 Networking: A Perspective from within a Service Provider 939 Environment", RFC 7149, March 2014. 941 [RFC7665] Halpern, J. and C. Pignataro, "Service Function Chaining 942 (SFC) Architecture", RFC 7665, October 2015. 944 [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF 945 Protocol", RFC 8040, January 2017. 947 [RFC8192] Hares, S., Lopez, D., Zarny, M., Jacquenet, C., Kumar, R., 948 and J. Jeong, "Interface to Network Security Functions 949 (I2NSF): Problem Statement and Use Cases", RFC 8192, July 950 2017. 952 [RFC8300] Quinn, P., Elzur, U., and C. Pignataro, "Network Service 953 Header (NSH)", RFC 8300, January 2018. 955 [RFC8329] Lopez, D., Lopez, E., Dunbar, L., Strassner, J., and R. 956 Kumar, "Framework for Interface to Network Security 957 Functions", RFC 8329, February 2018. 959 Appendix A. Changes from draft-ietf-i2nsf-applicability-04 961 The following changes have been made from draft-ietf-i2nsf- 962 applicability-04: 964 o A more precise description of the basic I2NSF flows is provided. 966 o The structure of the document makes each discussed use case be an 967 applicability statement according to the applied technology, such 968 as SFC, SDN, and NFV. 970 o In Section 6, Switch Controller is replaced by SDN Controller for 971 the terminology consistency in SDN standards. Switch is replaced 972 by forwarding element as a general term. 974 Authors' Addresses 976 Jaehoon Paul Jeong 977 Department of Software 978 Sungkyunkwan University 979 2066 Seobu-Ro, Jangan-Gu 980 Suwon, Gyeonggi-Do 16419 981 Republic of Korea 983 Phone: +82 31 299 4957 984 Fax: +82 31 290 7996 985 EMail: pauljeong@skku.edu 986 URI: http://iotlab.skku.edu/people-jaehoon-jeong.php 988 Sangwon Hyun 989 Department of Computer Engineering 990 Chosun University 991 309 Pilmun-daero, Dong-Gu 992 Gwangju 61452 993 Republic of Korea 995 Phone: +82 62 230 7473 996 EMail: shyun@chosun.ac.kr 997 Tae-Jin Ahn 998 Korea Telecom 999 70 Yuseong-Ro, Yuseong-Gu 1000 Daejeon 305-811 1001 Republic of Korea 1003 Phone: +82 42 870 8409 1004 EMail: taejin.ahn@kt.com 1006 Susan Hares 1007 Huawei 1008 7453 Hickory Hill 1009 Saline, MI 48176 1010 USA 1012 Phone: +1-734-604-0332 1013 EMail: shares@ndzh.com 1015 Diego R. Lopez 1016 Telefonica I+D 1017 Jose Manuel Lara, 9 1018 Seville 41013 1019 Spain 1021 Phone: +34 682 051 091 1022 EMail: diego.r.lopez@telefonica.com