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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 TEAS Working Group Daniele Ceccarelli (Ed) 2 Internet Draft Ericsson 3 Intended status: Informational Young Lee (Ed) 4 Expires: November 2016 Huawei 6 April 14, 2016 8 Framework for Abstraction and Control of Traffic Engineered Networks 10 draft-ceccarelli-teas-actn-framework-02 12 Status of this Memo 14 This Internet-Draft is submitted to IETF in full conformance with 15 the provisions of BCP 78 and BCP 79. 17 Internet-Drafts are working documents of the Internet Engineering 18 Task Force (IETF), its areas, and its working groups. Note that 19 other groups may also distribute working documents as Internet- 20 Drafts. 22 Internet-Drafts are draft documents valid for a maximum of six 23 months and may be updated, replaced, or obsoleted by other documents 24 at any time. It is inappropriate to use Internet-Drafts as 25 reference material or to cite them other than as "work in progress." 27 The list of current Internet-Drafts can be accessed at 28 http://www.ietf.org/ietf/1id-abstracts.txt 30 The list of Internet-Draft Shadow Directories can be accessed at 31 http://www.ietf.org/shadow.html. 33 This Internet-Draft will expire on October 14, 2015. 35 Copyright Notice 37 Copyright (c) 2016 IETF Trust and the persons identified as the 38 document authors. All rights reserved. 40 This document is subject to BCP 78 and the IETF Trust's Legal 41 Provisions Relating to IETF Documents 42 (http://trustee.ietf.org/license-info) in effect on the date of 43 publication of this document. Please review these documents 44 carefully, as they describe your rights and restrictions with 45 respect to this document. Code Components extracted from this 46 document must include Simplified BSD License text as described in 47 Section 4.e of the Trust Legal Provisions and are provided without 48 warranty as described in the Simplified BSD License. 50 Abstract 52 Traffic Engineered networks have a variety of mechanisms to 53 facilitate the 54 separation of the data plane and control plane. They also have a 55 range of management and provisioning protocols to configure and 56 activate network resources. These mechanisms represent key 57 technologies for enabling flexible and dynamic networking. 59 Abstraction of network resources is a technique that can be applied 60 to a single network domain or across multiple domains to create a 61 single virtualized network that is under the control of a network 62 operator or the customer of the operator that actually owns 63 the network resources. 65 This draft provides a framework for Abstraction and Control of 66 Traffic Engineered Networks (ACTN). 68 Table of Contents 70 1. Introduction................................................. 3 71 1.1. Terminology............................................. 5 72 2. Business Model of ACTN....................................... 7 73 2.1. Customers............................................... 7 74 2.2. Service Providers....................................... 9 75 2.3. Network Providers...................................... 11 76 3. ACTN architecture........................................... 11 77 3.1. Customer Network Controller............................ 14 78 3.2. Multi Domain Service Coordinator....................... 15 79 3.3. Physical Network Controller............................ 16 80 3.4. ACTN interfaces........................................ 17 81 4. VN creation process......................................... 19 82 5. Access Points and Virtual Network Access Points............. 20 83 5.1. Dual homing scenario................................... 22 84 6. End point selection & mobility.............................. 23 85 6.1. End point selection & mobility......................... 23 86 6.2. Preplanned end point migration......................... 24 87 6.3. On the fly end point migration......................... 25 89 7. Security.................................................... 25 90 8. References.................................................. 25 91 8.1. Informative References................................. 25 92 9. Contributors................................................ 28 93 Authors' Addresses............................................. 28 95 1. Introduction 97 Traffic Engineered networks have a variety of mechanisms to 98 facilitate separation of data plane and control plane including 99 distributed signaling for path setup and protection, centralized 100 path computation for planning and traffic engineering, and a range 101 of management and provisioning protocols to configure and activate 102 network resources. These mechanisms represent key technologies for 103 enabling flexible and dynamic networking. 105 The term Traffic Engineered Network in this draft refers to any 106 connection-oriented network that has the ability of dynamic 107 provisioning, abstracting and orchestrating network resource to the 108 network's clients. Some examples of networks that are in scope of 109 this definition are optical networks, MPLS Transport Profile (MPLS- 110 TP), MPLS Traffic Engineering (MPLS-TE), and other emerging 111 technologies with connection-oriented behavior. 113 One of the main drivers for Software Defined Networking (SDN) is a 114 decoupling of the network control plane from the data plane. This 115 separation of the control plane from the data plane has been already 116 achieved with the development of MPLS/GMPLS [GMPLS] and PCE [PCE] 117 for TE-based transport networks. One of the advantages of SDN is its 118 logically centralized control regime that allows a global view of 119 the underlying network under its control. Centralized control in SDN 120 helps improve network resources utilization compared with 121 distributed network control. For TE-based transport network control, 122 PCE is essentially equivalent to a logically centralized control for 123 path computation function. 125 Two key aspects that need to be solved by SDN are: 127 . Network and service abstraction: Detach the network and service 128 control from underlying technology and help customer express 129 the network as desired by business needs. 131 . Coordination of resources across multiple domains and multiple 132 layers to provide end-to-end services regardless of whether the 133 domains use SDN or not. 135 As networks evolve, the need to provide resource and service 136 abstraction has emerged as a key requirement for operators; this 137 implies in effect the virtualization of network resources so that 138 the network is "sliced" for different tenants shown as a dedicated 139 portion of the network resources 141 Particular attention needs to be paid to the multi-domain case, where 142 Abstraction and Control of Traffic Engineered Networks (ACTN) can 143 facilitate virtual network operation via the creation of a single 144 virtualized network or a seamless service. This supports operators in 145 viewing and controlling different domains (at any dimension: applied 146 technology, administrative zones, or vendor-specific technology 147 islands) as a single virtualized network. 149 Network virtualization refers to allowing the customers of network 150 operators (see Section 2.1) to utilize a certain amount of network 151 resources as if they own them and thus control their allocated 152 resources with higher layer or application processes that enables 153 the resources to be used in the most optimal way. More flexible, 154 dynamic customer control capabilities are added to the traditional 155 VPN along with a customer specific virtual network view. Customers 156 control a view of virtual network resources, specifically allocated 157 to each one of them. This view is called an abstracted network 158 topology. Such a view may be specific to a specific service, the set 159 of consumed resources or to a particular customer. Customer 160 controller of the virtual network is envisioned to support a 161 plethora of distinct applications. This means that there may be a 162 further level of virtualization that provides a view of resources in 163 the customer's virtual network for use by an individual application. 165 The framework described in this draft is named Abstraction and 166 Control of Traffic Engineered Network (ACTN) and facilitates: 168 - Abstraction of the underlying network resources to higher-layer 169 applications and customers [TE-INFO]. 171 - Virtualization of particular underlying resources, whose 172 selection criterion is the allocation of those resources to a 173 particular customer, application or service. [ONF-ARCH] 175 - Slicing infrastructure to connect multiple customers to meet 176 specific customer's service requirements. 178 - Creation of a virtualized environment allowing operators to 179 view and control multi-domain networks into a single 180 virtualized network; 182 - Possibility of providing a customer with virtualized network or 183 services (totally hiding the network). 185 - A virtualization/mapping network function that adapts customer 186 requests to the virtual resources (allocated to them) to the 187 supporting physical network control and performs the necessary 188 mapping, translation, isolation and security/policy 189 enforcement, etc.; This function is often referred to as 190 orchestration. 192 - The presentation of the networks as a virtualized topology to 193 the customers via open and programmable interfaces. This allows 194 for the recursion of controllers in a customer-provider 195 relationship. 197 1.1. Terminology 199 The following terms are used in this document. Some of them are 200 newly defined, some others reference existing definition: 201 - Node: A node is a topological entity describing the "opaque" 202 forwarding aspect of the topological component which represents 203 the opportunity to enable forwarding between points at the edge 204 of the node. It provides the context for instructing the 205 formation, adjustment and removal of the forwarding. A node, in 206 a VN network, can be represented by single physical entity or 207 by a group of nodes moving from physical to virtual network. 209 - Link: A link is a topological entity describing the effective 210 adjacency between two or more forwarding entities, such as two 211 or more nodes. In its basic form (i.e., point-to-point Link) it 212 associates an edge point of a node with an equivalent edge 213 point on another node. Links in virtual network is in fact 214 connectivity, realized by bandwidth engineering between any two 215 nodes meeting certain criteria, for example, redundancy, 216 protection, latency, not tied to any technology specific 217 characteristics like timeslots or wavelengths. The link can be 218 dynamic, realized by a service in underlay, or static. 220 - PNC domain: A PNC domain includes all the resources under the 221 control of a single PNC. It can be composed by different 222 routing domains, administrative domains and different layers. 223 The interconnection between PNC domains can be a link or a 224 node. 226 border 227 ------- link ------- 228 ( )---------( ) 229 - - - - 230 ( PNC )+---+( PNC ) 231 ( Domain X ) ( Domain Y ) 232 ( )+---+( ) 233 - - border- - 234 ( ) node ( ) 235 ------- ------- 237 Figure 1 : PNC domain borders 239 - Virtual Network: A Virtual Network (VN) is a customer view of the 240 transport network. It is composed by a set of physical 241 resources sliced in the provider network and presented to the 242 customer as a set of abstract resources i.e. virtual nodes and 243 virtual links. Depending on the agreement between customer and 244 provider a VN can be just represented by: 246 o How the end points can be connected with given SLA 247 attributes(e.g., re satisfying the customer's objectives) 248 o A pre-configured set of physical resources 249 o Or as outcome of a dynamic request from customer. 251 In the first case the VN can be seen at customer level as an 252 e2e connectivity that can be formed by recursive aggregation of 253 lower layers tunnels within the provider domain. 254 When the VN is pre-configured, it is provided after a static 255 negotiation between customer and provider while in the third 256 case VN can be dynamically created, deleted, or modified in 257 response to requests from the customer. This implies dynamic 258 changes of network resources reserved for the customer. 259 In the second and third case , once that customer has obtained 260 his VN, can act upon the virtual network resources to perform 261 connection management (set-up/release/modify connections). 263 - Abstract Topology: Every lower controller in the provider 264 network, when is representing its network topology to an higher 265 layer, it may want to hide details of the actual network 266 topology. In such case, an abstract topology may be used for 267 this purpose. Abstract topology enhances scalability for the 268 MDSC to operate multi-domain networks 270 - Access link: A link between a customer node and a provider 271 node. 273 - Inter domain link: A link between domains managed by different 274 PNCs. The MDSC is in charge of managing inter-domain links. 276 - Border node: A node whose interfaces belong to different 277 domains. It may be managed by different PNCs or by the MDSC. 279 - Access Point (AP): An access point is defined on an access 280 link. It is used to keep confidentiality between the customer 281 and the provider. It is an identifier shared between the 282 customer and the provider, used to map the end points of the 283 border node in the provider NW. The AP can be used by the 284 customer when requesting connectivity service to the provider. 285 A number of parameters, e.g. available bandwidth, need to be 286 associated to the AP to qualify it. 288 - VN Access Point (VNAP): A VNAP is defined within an AP as part 289 of a given VN and is used to identify the portion of the AP, 290 and hence of the access link) dedicated to a given VN. 292 2. Business Model of ACTN 294 The Virtual Private Network (VPN) [RFC4026] and Overlay Network (ON) 295 models [RFC4208] are built on the premise that one single network 296 provider provides all virtual private or overlay networks to its 297 customers. These models are simple to operate but have some 298 disadvantages in accommodating the increasing need for flexible and 299 dynamic network virtualization capabilities. 301 The ACTN model is built upon entities that reflect the current 302 landscape of network virtualization environments. There are three 303 key entities in the ACTN model [ACTN-PS]: 305 - Customers 306 - Service Providers 307 - Network Providers 309 2.1. Customers 311 Within the ACTN framework, different types of customers may be taken 312 into account depending on the type of their resource needs, on their 313 number and type of access. As example, it is possible to group them 314 into two main categories: 316 Basic Customer: Basic customers include fixed residential users, 317 mobile users and small enterprises. Usually the number of basic 318 customers is high; they require small amounts of resources and are 319 characterized by steady requests (relatively time invariant). A 320 typical request for a basic customer is for a bundle of voice 321 services and internet access. Moreover basic customers do not modify 322 their services themselves; if a service change is needed, it is 323 performed by the provider as proxy and they generally have very few 324 dedicated resources (subscriber drop), with everything else shared 325 on the basis of some SLA, which is usually best-efforts. 327 Advanced Customer: Advanced customers typically include enterprises, 328 governments and utilities. Such customers can ask for both point to 329 point and multipoint connectivity with high resource demand 330 significantly varying in time and from customer to customer. This is 331 one of the reasons why a bundled service offering is not enough and 332 it is desirable to provide each of them with a customized virtual 333 network service. 335 Advanced customers may own dedicated virtual resources, or share 336 resources. They may also have the ability to modify their service 337 parameters within the scope of their virtualized environments. 339 As customers are geographically spread over multiple network 340 provider domains, they have to interface multiple providers and may 341 have to support multiple virtual network services with different 342 underlying objectives set by the network providers. To enable these 343 customers to support flexible and dynamic applications they need to 344 control their allocated virtual network resources in a dynamic 345 fashion, and that means that they need an abstracted view of the 346 topology that spans all of the network providers. 348 ACTN's primary focus is Advanced Customers. 350 Customers of a given service provider can in turn offer a service to 351 other customers in a recursive way. An example of recursiveness with 352 2 service providers is shown below. 354 - Customer (of service B) 355 - Customer (of service A) & Service Provider (of service B) 356 - Service Provider (of service A) 357 - Network Provider 359 +------------------------------------------------------------+ --- 360 | | ^ 361 | Customer (of service B)| . 362 | +--------------------------------------------------------+ | B 363 | | | |--- . 364 | |Customer (of service A) & Service Provider(of service B)| | ^ . 365 | | +---------------------------------------------------+ | | . . 366 | | | | | | . . 367 | | | Service Provider (of service A)| | | A . 368 | | |+------------------------------------------+ | | | . . 369 | | || | | | | . . 370 | | || Network provider| | | | v v 371 | | |+------------------------------------------+ | | |------ 372 | | +---------------------------------------------------+ | | 373 | +--------------------------------------------------------+ | 374 +------------------------------------------------------------+ 376 Figure 2 : Service Recursiveness. 378 2.2. Service Providers 380 Service providers are the providers of virtual network services to 381 their customers. Service providers may or may not own physical 382 network resources. When a service provider is the same as the 383 network provider, this is similar to traditional VPN models. This 384 model works well when the customer maintains a single interface with 385 a single provider. When customer location spans across multiple 386 independent network provider domains, then it becomes hard to 387 facilitate the creation of end-to-end virtual network services with 388 this model. 390 A more interesting case arises when network providers only provide 391 infrastructure while service providers directly interface their 392 customers. In this case, service providers themselves are customers 393 of the network infrastructure providers. One service provider may 394 need to keep multiple independent network providers as its end-users 395 span geographically across multiple network provider domains as 396 shown in Figure 2 where Service Provider A uses resources from 397 Network Provider A and Network Provider B to offer a virtualized 398 network to its customer. 400 Customer X -----------------------------------X 402 Service Provider A X -----------------------------------X 404 Network Provider B X-----------------X 406 Network Provider A X------------------X 408 Figure 3 : A service Provider as Customer of Two Network Providers. 410 The ACTN network model is predicated upon this three tier model and 411 is summarized in Figure 3: 413 +----------------------+ 414 | customer | 415 +----------------------+ 416 | 417 | /\ Service/Customer specific 418 | || Abstract Topology 419 | || 420 +----------------------+ E2E abstract 421 | Service Provider | topology creation 422 +----------------------+ 423 / | \ 424 / | \ Network Topology 425 / | \ (raw or abstract) 426 / | \ 427 +------------------+ +------------------+ +------------------+ 428 |Network Provider 1| |Network Provider 2| |Network Provider 3| 429 +------------------+ +------------------+ +------------------+ 431 Figure 4 : Three tier model. 433 There can be multiple types of service providers. 435 . Data Center providers: can be viewed as a service provider type 436 as they own and operate data center resources to various WAN 437 customers, they can lease physical network resources from 438 network providers. 439 . Internet Service Providers (ISP): can be a service provider of 440 internet services to their customers while leasing physical 441 network resources from network providers. 442 . Mobile Virtual Network Operators (MVNO): provide mobile 443 services to their end-users without owning the physical network 444 infrastructure. 446 2.3. Network Providers 448 Network Providers are the infrastructure providers that own the 449 physical network resources and provide network resources to their 450 customers. The layered model proposed by this draft separates the 451 concerns of network providers and customers, with service providers 452 acting as aggregators of customer requests. 454 3. ACTN architecture 456 This section provides a high-level control and interface model of 457 ACTN. 459 The ACTN architecture, while being aligned with the ONF SDN 460 architecture [ONF-ARCH], is presenting a 3-tiers reference model. It 461 allows for hierarchy and recursiveness not only of SDN controllers 462 but also of traditionally controlled domains. It defines three types 463 of controllers depending on the functionalities they implement. The 464 main functionalities that are identified are: 466 . Multi domain coordination function: With the definition of 467 domain being "everything that is under the control of the same 468 controller",it is needed to have a control entity that oversees 469 the specific aspects of the different domains and to build a 470 single abstracted end-to-end network topology in order to 471 coordinate end-to-end path computation and path/service 472 provisioning. 474 . Virtualization/Abstraction function: To provide an abstracted 475 view of the underlying network resources towards customer, 476 being it the client or a higher level controller entity. It 477 includes computation of customer resource requests into virtual 478 network paths based on the global network-wide abstracted 479 topology and the creation of an abstracted view of network 480 slices allocated to each customer, according to customer- 481 specific virtual network objective functions, and to the 482 customer traffic profile. 484 . Customer mapping function: In charge of mapping customer VN 485 setup commands into network provisioning requests to the 486 Physical Network Controller (PNC) according to business OSS/NMS 487 provisioned static or dynamic policy. Moreover it provides 488 mapping and translation of customer virtual network slices into 489 physical network resources 491 . Virtual service coordination: Virtual service coordination 492 function in ACTN incorporates customer service-related 493 knowledge into the virtual network operations in order to 494 seamlessly operate virtual networks while meeting customer's 495 service requirements. 497 The virtual services that are coordinated under ACTN can be split 498 into two categories: 500 . Service-aware Connectivity Services: This category includes all 501 the network service operations used to provide connectivity 502 between customer end-points while meeting policies and service 503 related constraints. The data model for this category would 504 include topology entities such as virtual nodes, virtual links, 505 adaptation and termination points and service-related entities 506 such as policies and service related constraints. (See Section 507 4.2.2) 509 . Network Function Virtualization Services: These kinds of 510 services are usually setup in NFV (e.g. cloud) providers and 511 require connectivity between a customer site and the NFV 512 provider site (e.g. a data center). These VNF services may 513 include a security function like firewall, a traffic optimizer, 514 the provisioning of storage or computation capacity. In these 515 cases the customer does not care whether the service is 516 implemented in a given data center or another. This allows the 517 network provider divert customer requests where most suitable. 518 This is also known as "end points mobility" case. (See Section 519 4.2.3) 521 The types of controller defined are shown in Figure 4 below and are 522 the following: 524 . CNC - Customer Network Controller 525 . MDSC - Multi Domain Service Coordinator 526 . PNC - Physical Network Controller 528 VPN customer NW Mobile Customer ISP NW service Customer 529 | | | 530 +-------+ +-------+ +-------+ 531 | CNC-A | | CNC-B | | CNC-C | 532 +-------+ +-------+ +-------+ 533 \ | / 534 ----------- |CMI I/F -------------- 535 \ | / 536 +-----------------------+ 537 | MDSC | 538 +-----------------------+ 539 / | \ 540 ------------- |MPI I/F ------------- 541 / | \ 542 +-------+ +-------+ +-------+ 543 | PNC | | PNC | | PNC | 544 +-------+ +-------+ +-------+ 545 | GMPLS / | / \ 546 | trigger / | / \ 547 -------- ---- +-----+ +-----+ \ 548 ( ) ( ) | PNC | | PCE | \ 549 - - ( Phys ) +-----+ +-----+ ----- 550 ( GMPLS ) (Netw) | / ( ) 551 ( Physical ) ---- | / ( Phys. ) 552 ( Network ) ----- ----- ( Net ) 553 - - ( ) ( ) ----- 554 ( ) ( Phys. ) ( Phys ) 555 -------- ( Net ) ( Net ) 556 ----- ----- 558 Figure 5 : ACTN Control Hierarchy 560 3.1. Customer Network Controller 562 A Virtual Network Service is instantiated by the Customer Network 563 Controller via the CMI (CNC-MDSC Interface). As the Customer Network 564 Controller directly interfaces the applications, it understands 565 multiple application requirements and their service needs. It is 566 assumed that the Customer Network Controller and the MDSC have a 567 common knowledge on the end-point interfaces based on their business 568 negotiation prior to service instantiation. End-point interfaces 569 refer to customer-network physical interfaces that connect customer 570 premise equipment to network provider equipment. 572 In addition to abstract networks, ACTN allows to provide the CNC 573 with services. Example of services include connectivity between one 574 of the customer's end points with a given set of resources in a data 575 center from the service provider. 577 3.2. Multi Domain Service Coordinator 579 The MDSC (Multi Domain Service Coordinator) sits between the CNC 580 (the one issuing connectivity requests) and the PNCs (Physical 581 Network Controllersr - the ones managing the physical network 582 resources). The MDSC can be collocated with the PNC, especially in 583 those cases where the service provider and the network provider are 584 the same entity. 586 The internal system architecture and building blocks of the MDSC are 587 out of the scope of ACTN. Some examples can be found in the 588 Application Based Network Operations (ABNO) architecture [ABNO] and 589 the ONF SDN architecture [ONF-ARCH]. 591 The MDSC is the only building block of the architecture that is able 592 to implement all the four ACTN main functionalities, i.e. multi 593 domain coordination function, virtualization/abstraction function, 594 customer mapping function and virtual service coordination. The key 595 point of the MDSC and the whole ACTN framework is detaching the 596 network and service control from underlying technology and help 597 customer express the network as desired by business needs. The MDSC 598 envelopes the instantiation of right technology and network control 599 to meet business criteria. In essence it controls and manages the 600 primitives to achieve functionalities as desired by CNC 601 A hierarchy of MDSCs can be foreseen for scalability and 602 administrative choices. 604 +-------+ +-------+ +-------+ 605 | CNC-A | | CNC-B | | CNC-C | 606 +-------+ +-------+ +-------+ 607 \ | / 608 ---------- | ---------- 609 \ | / 610 +-----------------------+ 611 | MDSC | 612 +-----------------------+ 613 / | \ 614 ---------- | ----------- 615 / | \ 616 +----------+ +----------+ +--------+ 617 | MDSC | | MDSC | | MDSC | 618 +----------+ +----------+ +--------+ 619 | / | / \ 620 | / | / \ 621 +-----+ +-----+ +-----+ +-----+ +-----+ 622 | PNC | | PNC | | PNC | | PNC | | PNC | 623 +-----+ +-----+ +-----+ +-----+ +-----+ 625 Figure 6 : Controller recursiveness 627 A key requirement for allowing recursion of MDSCs is that a single 628 interface needs to be defined both for the north and the south 629 bounds. 630 In order to allow for multi-domain coordination a 1:N relationship 631 must be allowed between MDSCs and between MDSCs and PNCs (i.e. 1 632 parent MDSC and N child MDSC or 1 MDSC and N PNCs). In addition to 633 that it could be possible to have also a M:1 relationship between 634 MDSC and PNC to allow for network resource partitioning/sharing 635 among different customers not necessarily connected to the same MDSC 636 (e.g. different service providers). 638 3.3. Physical Network Controller 640 The Physical Network Controller is the one in charge of configuring 641 the network elements, monitoring the physical topology of the 642 network and passing it, either raw or abstracted, to the MDSC. 644 The internal architecture of the PNC, his building blocks and the 645 way it controls its domain, are out of the scope of ACTN. Some 646 examples can be found in the Application Based Network Operations 647 (ABNO) architecture [ABNO] and the ONF SDN architecture [ONF-ARCH] 648 The PNC, in addition to being in charge of controlling the physical 649 network, is able to implement two of the four ACTN main 650 functionalities: multi domain coordination function and 651 virtualization/abstraction function 652 A hierarchy of PNCs can be foreseen for scalability and 653 administrative choices. 655 3.4. ACTN interfaces 657 To allow virtualization and multi domain coordination, the network 658 has to provide open, programmable interfaces, in which customer 659 applications can create, replace and modify virtual network 660 resources and services in an interactive, flexible and dynamic 661 fashion while having no impact on other customers. Direct customer 662 control of transport network elements and virtualized services is 663 not perceived as a viable proposition for transport network 664 providers due to security and policy concerns among other reasons. 665 In addition, as discussed in the previous section, the network 666 control plane for transport networks has been separated from data 667 plane and as such it is not viable for the customer to directly 668 interface with transport network elements. 670 Figure 5 depicts a high-level control and interface architecture for 671 ACTN. A number of key ACTN interfaces exist for deployment and 672 operation of ACTN-based networks. These are highlighted in Figure 5 673 (ACTN Interfaces) below: 675 .-------------- 676 ------------- | 677 | Application |-- 678 ------------- 679 ^ 680 | I/F A -------- 681 v ( ) 682 -------------- - - 683 | Customer | ( Customer ) 684 | Network |--------->( Network ) 685 | Controller | ( ) 686 -------------- - - 687 ^ ( ) 688 | I/F B -------- 689 v 690 -------------- 691 | MultiDomain | 692 | Service | 693 | Coordinator| -------- 694 -------------- ( ) 695 ^ - - 696 | I/F C ( Physical ) 697 v ( Network ) 698 --------------- ( ) -------- 699 | |<----> - - ( ) 700 -------------- | ( ) - - 701 | Physical |-- -------- ( Physical ) 702 | Network |<---------------------->( Network ) 703 | Controller | I/F D ( ) 704 -------------- - - 705 ( ) 706 -------- 708 Figure 7 : ACTN Interfaces 710 The interfaces and functions are described below: 712 . Interface A: A north-bound interface (NBI) that will 713 communicate the service request or application demand. A 714 request will include specific service properties, including: 715 services, topology, bandwidth and constraint information. 717 . Interface B: The CNC-MDSC Interface (CMI) is an interface 718 between a Customer Network Controller and a Multi Service 719 Domain Controller. It requests the creation of the network 720 resources, topology or services for the applications. The 721 Virtual Network Controller may also report potential network 722 topology availability if queried for current capability from 723 the Customer Network Controller. 725 . Interface C: The MDSC-PNC Interface (MPI) is an interface 726 between a Multi Domain Service Coordinator and a Physical 727 Network Controller. It communicates the creation request, if 728 required, of new connectivity of bandwidth changes in the 729 physical network, via the PNC. In multi-domain environments, 730 the MDSC needs to establish multiple MPIs, one for each PNC, as 731 there are multiple PNCs responsible for its domain control. 733 . Interface D: The provisioning interface for creating forwarding 734 state in the physical network, requested via the Physical 735 Network Controller. 737 The interfaces within the ACTN scope are B and C. 739 4. VN creation process 741 The provider can present to the customer different level of network 742 abstraction, spanning from one extreme (say "black") where nothing 743 is shown, just the APs, to the other extreme (say "white") where a 744 slice of the network is shown to the customer. There are shades of 745 gray in between where a number of abstract links and nodes can be 746 shown. 748 The VN creation is composed by two phases: Negotiation and 749 Implementation. 751 Negotiation: In the case of grey/white topology abstraction, there 752 is an a priori phase in which the customer agrees with the provider 753 on the type of topology to be shown, e.q. 10 virtual links and 5 754 virtual nodes with a given interconnectivity. This is something that 755 is assumed to be preconfigured by the operator off-line, what is 756 online is the capability of modifying/deleting something (e.g. a 757 virtual link). In the case of "black" abstraction this negotiation 758 phase does not happen, in the sense that the customer can only see 759 the APs of the network. 761 Implementation: In the case of black topology abstraction, the 762 customers can ask for connectivity with given constraints/SLA 763 between the APs and LSPs/tunnels are created by the provider to 764 satisfy the request. What the customer sees is only that his CEs are 765 connected with a given SLA. In the case of grey/white topology the 766 customer creates his own LSPs accordingly to the topology that was 767 presented to him. 769 5. Access Points and Virtual Network Access Points 771 In order not to share unwanted topological information between the 772 customer domain and provider domain, a new entity is defined and 773 associated to an access link, the Access Point (AP). See the 774 definition of AP in Section 1.1. 776 A customer node will use APs as the end points for the request of 777 VNs. 779 A number of parameters need to be associated to the APs. Such 780 parameters need to include at least: the maximum reservable 781 bandwidth on the link, the available bandwidth and the link 782 characteristics (e.g. switching capability, type of mapping). 784 Editor note: it is not appropriate to define link characteristics 785 like bandwidth against a point (AP). A solution needs to be found. 787 ------------- 788 ( ) 789 - - 790 +---+ X ( ) Z +---+ 791 |CE1|---+----( )---+---|CE2| 792 +---+ | ( ) | +---+ 793 AP1 - - AP2 794 ( ) 795 ------------- 797 Figure 8 : APs definition customer view 799 Let's take as example a scenario in which CE1 is connected to the 800 network via a 10Gb link and CE2 via a 40Gb link. Before the creation 801 of any VN between AP1 and AP2 the customer view can be summarized as 802 follows: 804 +-----+----------+-------------+----------+ 805 |AP id| MaxResBw | AvailableBw | CE,port | 806 +-----+----------+-------------+----------+ 807 | AP1 | 10Gb | 10Gb |CE1,portX | 808 +-----+----------+-------------+----------+ 809 | AP2 | 40Gb | 40Gb |CE2,portZ | 810 +-----+----------+-------------+----------+ 812 Table 1: AP - customer view 814 On the other side what the provider sees is: 816 ------- ------- 817 ( ) ( ) 818 - - - - 819 W (+---+ ) ( +---+) Y 820 -+---( |PE1| Dom.X )----( Dom.Y |PE2| )---+- 821 | (+---+ ) ( +---+) | 822 AP1 - - - - AP2 823 ( ) ( ) 824 ------- ------- 826 Figure 9 : Provider view of the AP 828 Which in the example above ends up in a summarization as follows: 830 +-----+----------+-------------+----------+ 831 |AP id| MaxResBw | AvailableBw | PE,port | 832 +-----+----------+-------------+----------+ 833 | AP1 | 10Gb | 10Gb |PE1,portW | 834 +-----+----------+-------------+----------+ 835 | AP2 | 40Gb | 40Gb |PE2,portY | 836 +-----+----------+-------------+----------+ 838 Table 2: AP - provider view 840 The second entity that needs to be defined is a structure within the 841 AP that is linked to a VN and that is used to allow for different VN 842 to be provided starting from the same AP. It also allows reserving 843 the bandwidth for the VN on the access link. Such entity is called 844 Virtual Network Access Point. For each virtual network is defined on 845 an AP, a different VNAP is created. 847 In the simple scenario depicted above we suppose to create two 848 virtual networks. The first one has with VN identifier 9 between AP1 849 and AP2 with and bandwidth of 1Gbps, while the second one with VN id 850 5, again between AP1 and AP2 and bandwidth 2Gbps. 852 The customer view would evolve as follows: 854 +---------+----------+-------------+----------+ 855 |AP/VNAPid| MaxResBw | AvailableBw | PE,port | 856 +---------+----------+-------------+----------+ 857 |AP1 | 10Gbps | 7Gbps |PE1,portW | 858 | -VNAP1.9| 1Gbps | N.A. | | 859 | -VNAP1.5| 2Gbps | N.A | | 860 +---------+----------+-------------+----------+ 861 |AP2 | 40Gb | 37Gb |PE2,portY | 862 | -VNAP2.9| 1Gbps | N.A. | | 863 | -VNAP2.5| 2Gbps | N.A | | 864 +---------+----------+-------------+----------+ 866 Table 3: AP and VNAP - provider view after VN creation 868 5.1. Dual homing scenario 870 Often there is a dual homing relationship between a CE and a pair of 871 PE. This case needs to be supported also by the definition of VN, AP 872 and VNAP. Suppose to have CE1 connected to two different PE in the 873 operator domain via AP1 and AP2 and the customer needing 5Gbps of 874 bandwidth between CE1 and CE2. 876 AP1 -------------- AP3 877 -------(PE1) (PE3) ------- 878 W / - - \X 879 +---+ / ( ) \ +---+ 880 |CE1| ( ) |CE2| 881 +---+ \ ( ) / +---+ 882 Y \ - - /Z 883 -------(PE2) (PE4) ------- 884 AP2 -------------- AP4 886 Figure 10 : Dual homing scenario 888 In this case the customer will request for a VN between AP1, AP2 and 889 AP3 specifying a dual homing relationship between AP1 and AP2. As a 890 consequence no traffic will be flowing between AP1 and AP2. The dual 891 homing relationship would then be mapped against the VNAPs (since 892 other independent VNs might have AP1 and AP2 as end points). 894 The customer view would be as follows: 896 +---------+----------+-------------+----------+-----------+ 897 |AP/VNAPid| MaxResBw | AvailableBw | CE,port |Dual Homing| 898 +---------+----------+-------------+----------+-----------+ 899 |AP1 | 10Gbps | 5Gbps |CE1,portW | | 900 | -VNAP1.9| 5Gbps | N.A. | | VNAP2.9 | 901 +---------+----------+-------------+----------+-----------+ 902 |AP2 | 40Gbps | 35Gbps |CE1,portY | | 903 | -VNAP2.9| 5Gbps | N.A. | | VNAP1.9 | 904 +---------+----------+-------------+----------+-----------+ 905 |AP3 | 40Gbps | 35Gbps |CE2,portZ | | 906 | -VNAP3.9| 5Gbps | N.A. | | NONE | 907 +---------+----------+-------------+----------+-----------+ 909 Table 4: Dual homing - customer view after VN creation 911 6. End point selection & mobility 913 Virtual networks could be used as the infrastructure to connect a 914 number of sites of a customer among them or to provide connectivity 915 between customer sites and virtualized network functions (VNF) like 916 for example virtualized firewall, vBNG, storage, computational 917 functions. 919 6.1. End point selection & mobility 921 A VNF could be deployed in different places (e.g. data centers A, B 922 or C in figure below) but the VNF provider (=ACTN customer) doesn't 923 know which is the best site where to install the VNF from a network 924 point of view (e.g. latency). For example it is possible to compute 925 the path minimizing the delay between AP1 and AP2, but the customer 926 doesn't know a priori if the path with minimum delay is towards A, B 927 or C. 929 ------- ------- 930 ( ) ( ) 931 - - - - 932 +---+ ( ) ( ) +----+ 933 |CE1|---+----( Domain X )----( Domain Y )---+---|DC-A| 934 +---+ | ( ) ( ) | +----+ 935 AP1 - - - - AP2 936 ( ) ( ) 937 ---+--- ---+--- 938 AP3 | AP4 | 939 +----+ +----+ 940 |DC-B| |DC-C| 941 +----+ +----+ 943 Figure 11 : End point selection 945 In this case the VNF provider (=ACTN customer) should be allowed to 946 ask for a VN between AP1 and a set of end points. The list of end 947 points is provided by the VNF provider. When the end point is 948 identified the connectivity can be instantiated and a notification 949 can be sent to the VNF provider for the instantiation of the VNF. 951 6.2. Preplanned end point migration 953 A premium SLA for VNF service provisioning consists on the offering 954 of a protected VNF instantiated on two or more sites and with a hot 955 stand-by protection mechanism. In this case the VN should be 956 provided so to switch from one end point to another upon a trigger 957 from the VNF provider or an automatic failure detection mechanism. 958 An example is provided in figure below where the request from the 959 VNF provider is for connectivity with given constraint and 960 resiliency between CE1 and a VNF with primary installation in DC-A 961 and a protection in DC-C. 963 ------- ------- 964 ( ) ( ) 965 - - __ - - 966 +---+ ( ) ( ) +----+ 967 |CE1|---+----( Domain X )----( Domain Y )---+---|DC-A| 968 +---+ | ( ) ( ) | +----+ 969 AP1 - - - - AP2 | 970 ( ) ( ) | 971 ---+--- ---+--- | 972 AP3 | AP4 | HOT STANDBY 973 +----+ | 974 |DC-C|<------------- 975 +----+ 977 Figure 12 : Preplanned endpoint migration 979 6.3. On the fly end point migration 981 The one the fly end point migration concept is very similar to the 982 end point selection one. The idea is to give the provider not only 983 the list of sites where the VNF can be installed, but also a 984 mechanism to notify changes in the network that have impacts on the 985 SLA. After an handshake with the customer controller/applications, 986 the bandwidth in network would be moved accordingly with the moving 987 of the VNFs. 989 7. Security 991 TBD 993 8. References 995 8.1. Informative References 997 [PCE] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path 998 Computation Element (PCE)-Based Architecture", IETF RFC 999 4655, August 2006. 1001 [RFC4026] L. Andersson, T. Madsen, "Provider Provisioned Virtual 1002 Private Network (VPN) Terminology", RFC 4026, March 2005. 1004 [RFC4208] G. Swallow, J. Drake, H.Ishimatsu, Y. Rekhter, 1005 "Generalized Multiprotocol Label Switching (GMPLS) User- 1006 Network Interface (UNI): Resource ReserVation Protocol- 1007 Traffic Engineering (RSVP-TE) Support for the Overlay 1008 Model", RFC 4208, October 2005. 1010 [PCE-S] Crabbe, E, et. al., "PCEP extension for stateful 1011 PCE",draft-ietf-pce-stateful-pce, work in progress. 1013 [GMPLS] Manning, E., et al., "Generalized Multi-Protocol Label 1014 Switching (GMPLS) Architecture", RFC 3945, October 2004. 1016 [NFV-AF] "Network Functions Virtualization (NFV); Architectural 1017 Framework", ETSI GS NFV 002 v1.1.1, October 2013. 1019 [ACTN-PS] Y. Lee, D. King, M. Boucadair, R. Jing, L. Contreras 1020 Murillo, "Problem Statement for Abstraction and Control of 1021 Transport Networks", draft-leeking-actn-problem-statement, 1022 work in progress. 1024 [ONF] Open Networking Foundation, "OpenFlow Switch Specification 1025 Version 1.4.0 (Wire Protocol 0x05)", October 2013. 1027 [TE-INFO] A. Farrel, Editor, "Problem Statement and Architecture for 1028 Information Exchange Between Interconnected Traffic 1029 Engineered Networks", draft-ietf-teas-interconnected-te- 1030 info-exchange, work in progress. 1032 [ABNO] King, D., and Farrel, A., "A PCE-based Architecture for 1033 Application-based Network Operations", draft-farrkingel- 1034 pce-abno-architecture, work in progress. 1036 [ACTN-Info] Y. Lee, S. Belotti, D. Dhody, "Information Model for 1037 Abstraction and Control of Transport Networks", draft- 1038 leebelotti-teas-actn-info, work in progress. 1040 [Cheng] W. Cheng, et. al., "ACTN Use-cases for Packet Transport 1041 Networks in Mobile Backhaul Networks", draft-cheng-actn- 1042 ptn-requirements, work in progress. 1044 [Dhody] D. Dhody, et. al., "Packet Optical Integration (POI) Use 1045 Cases for Abstraction and Control of Transport Networks 1046 (ACTN)", draft-dhody-actn-poi-use-case, work in progress. 1048 [Fang] L. Fang, "ACTN Use Case for Multi-domain Data Center 1049 Interconnect", draft-fang-actn-multidomain-dci, work in 1050 progress. 1052 [Klee] K. Lee, H. Lee, R. Vilata, V. Lopez, "ACTN Use-case for On- 1053 demand E2E Connectivity Services in Multiple Vendor Domain 1054 Transport Networks", draft-klee-actn-connectivity-multi- 1055 vendor-domains, work in progress. 1057 [Kumaki] K. Kumaki, T. Miyasaka, "ACTN : Use case for Multi Tenant 1058 VNO ", draft-kumaki-actn-multitenant-vno, work in 1059 progress. 1061 [Lopez] D. Lopez (Ed), "ACTN Use-case for Virtual Network Operation 1062 for Multiple Domains in a Single Operator Network", draft- 1063 lopez-actn-vno-multidomains, work in progress. 1065 [Shin] J. Shin, R. Hwang, J. Lee, "ACTN Use-case for Mobile Virtual 1066 Network Operation for Multiple Domains in a Single 1067 Operator Network", draft-shin-actn-mvno-multi-domain, work 1068 in progress. 1070 [Xu] Y. Xu, et. al., "Use Cases and Requirements of Dynamic Service 1071 Control based on Performance Monitoring in ACTN 1072 Architecture", draft-xu-actn-perf-dynamic-service-control, 1073 work in progress. 1075 9. Contributors 1077 Authors' Addresses 1079 Daniele Ceccarelli (Editor) 1080 Ericsson 1081 Torshamnsgatan,48 1082 Stockholm, Sweden 1083 Email: daniele.ceccarelli@ericsson.com 1085 Young Lee (Editor) 1086 Huawei Technologies 1087 5340 Legacy Drive 1088 Plano, TX 75023, USA 1089 Phone: (469)277-5838 1090 Email: leeyoung@huawei.com 1092 Luyuan Fang 1093 Email: luyuanf@gmail.com 1095 Diego Lopez 1096 Telefonica I+D 1097 Don Ramon de la Cruz, 82 1098 28006 Madrid, Spain 1099 Email: diego@tid.es 1101 Sergio Belotti 1102 Alcatel Lucent 1103 Via Trento, 30 1104 Vimercate, Italy 1105 Email: sergio.belotti@alcatel-lucent.com 1107 Daniel King 1108 Lancaster University 1109 Email: d.king@lancaster.ac.uk 1111 Dhruv Dhoddy 1112 Huawei Technologies 1113 dhruv.ietf@gmail.com 1115 Gert Grammel 1116 Juniper Networks 1117 ggrammel@juniper.net