[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 02 03 04 05 06 07

Network Working Group                                Daniele Ceccarelli
Internet Draft                                                 Ericsson

Intended status: Informational                              Luyuan Fang
Expires: June 2015                                            Microsoft

                                                              Young Lee
                                                                 Huawei

                                                            Diego Lopez
                                                             Telefonica

                                                          Sergio Belotti
                                                          Alcatel-Lucent

                                                             Daniel King
                                                    Lancaster University


                                                      December 15, 2014



      Framework for Abstraction and Control of Transport Networks

                  draft-ceccarelli-actn-framework-05.txt


Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with
   the provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six
   months and may be updated, replaced, or obsoleted by other documents
   at any time.  It is inappropriate to use Internet-Drafts as
   reference material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.




Ceccarelli, et al.      Expires June 15, 2015                  [Page 1]


Internet-Draft              ACTN Framework                December 2014


   This Internet-Draft will expire on June 15, 2015.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with
   respect to this document.  Code Components extracted from this
   document must include Simplified BSD License text as described in
   Section 4.e of the Trust Legal Provisions and are provided without
   warranty as described in the Simplified BSD License.

Abstract

   This draft provides a framework for abstraction and control of
   transport networks.


Table of Contents


   1. Introduction...................................................3
   2. Business Model of ACTN.........................................5
      2.1. Customers.................................................6
      2.2. Service Providers.........................................7
      2.3. Network Providers.........................................9
   3. ACTN architecture..............................................9
      3.1. Customer Network Controller..............................13
      3.2. Multi Domain Service Coordinator.........................13
      3.3. Physical Network Controller..............................14
      3.4. ACTN interfaces..........................................14
   4. ACTN Applicability............................................16
      4.1. ACTN Use cases Summary...................................17
      4.2. Work in Scope of ACTN....................................20
         -  Coordination of Multi-destination Service
         Requirement/Policy (Section 4.2.1).........................24
         -  Application Service Policy-aware Network Operation (section
         4.2.2).....................................................24
         -  Dynamic Service Control Policy Enforcement for
         Performance/Fault Management (Section 4.2.3)...............24




Ceccarelli, et al.       Expires June15,2015                   [Page 2]


Internet-Draft              ACTN Framework                December 2014


         -  Multi-Layer (Packet-Optical) Coordination for
         Protection/Restoration (Section 4.2.4).....................24
         4.2.1. Coordination of Multi-destination Service
         Requirement/Policy.........................................25
         4.2.2. Application Service Policy-aware Network Operation..27
         4.2.3. Dynamic Service Control Policy Enforcement for
         Performance and Fault Management...........................28
         4.2.4. Multi-Layer (Packet-Optical) Coordination for
         Protection/Restoration (TBD)...............................29
   5. ACTN interfaces requirements..................................29
   6. Security Considerations.......................................29
   7. IANA Considerations...........................................29
   8. References....................................................29
      8.1. Informative References...................................29
   Appendix A.......................................................30
   Contributors' Addresses..........................................30
   Authors' Addresses...............................................31
   9. Appendix I: Abstracted Topology Illustration..................32

1. Introduction

   Transport networks have a variety of mechanisms to facilitate
   separation of data plane and control plane including distributed
   signaling for path setup and protection, centralized path
   computation for planning and traffic engineering, and a range of
   management and provisioning protocols to configure and activate
   network resources. These mechanisms represent key technologies for
   enabling flexible and dynamic networking.

   Transport networks in this draft refer to a set of different type of
   connection-oriented networks, primarily Connection-Oriented Circuit
   Switched (CO-CS) networks and Connection-Oriented Packet Switched
   (CO-PS) networks. This implies that at least the following transport
   networks are in scope of the discussion of this draft: Layer 1(L1)
   and Layer 0 (L0) optical networks (e.g., Optical Transport Network
   (OTN), Optical Channel Data Unit (ODU), Optical Channel
   (OCh)/Wavelength Switched Optical Network (WSON)), Multi-Protocol
   Label Switching - Transport Profile (MPLS-TP), Multi-Protocol Label
   Switching - Traffic Engineering (MPLS-TE), as well as other emerging
   technologies with connection-oriented behavior. One of the
   characteristics of these network types is the ability of dynamic
   provisioning and traffic engineering such that resource guarantee
   can be provided to their clients.

   One of the main drivers for Software Defined Networking (SDN) is a
   decoupling of the network control plane from the data plane. This
   separation of the control plane from the data plane has been already


Ceccarelli, et al.       Expires June15,2015                   [Page 3]


Internet-Draft              ACTN Framework                December 2014


   achieved with the development of MPLS/GMPLS [GMPLS] and PCE [PCE]
   for TE-based transport networks. One of the advantages of SDN is its
   logically centralized control regime that allows a global view of
   the underlying network under its control. Centralized control in SDN
   helps improve network resources utilization from a distributed
   network control. For TE-based transport network control, PCE is
   essentially equivalent to a logically centralized control for path
   computation function.

   Two key aspects that need to be solved by SDN are:

     . Network and service abstraction
     . End to end coordination of multiple SDN and pre-SDN domains
        e.g. NMS, MPLS-TE or GMPLS.

   As transport networks evolve, the need to provide network and
   service abstraction has emerged as a key requirement for operators;
   this implies in effect the virtualization of network resources so
   that the network is "sliced" for different tenants shown as a
   dedicated portion of the network resources

   Particular attention needs to be paid to the multi-domain case,
   where Abstraction and Control of Transport Networks (ACTN) can
   facilitate virtual network operation via the creation of a single
   virtualized network or a seamless service. This supports operators
   in viewing and controlling different domains (at any dimension:
   applied technology, administrative zones, or vendor-specific
   technology islands) as a single virtualized network.

   Network virtualization, in general, refers to allowing the customers
   to utilize a certain amount of network resources as if they own them
   and thus control their allocated resources in a way most optimal
   with higher layer or application processes. This empowerment of
   customer control facilitates introduction of new services and
   applications as the customers are permitted to create, modify, and
   delete their virtual network services. More flexible, dynamic
   customer control capabilities are added to the traditional VPN along
   with a customer specific virtual network view. Customers control a
   view of virtual network resources, specifically allocated to each
   one of them. This view is called an abstracted network topology.
   Such a view may be specific to the set of consumed services as well
   as to a particular customer. As the Customer Network Controller is
   envisioned to support a plethora of distinct applications, there
   would be another level of virtualization from the customer to
   individual applications.




Ceccarelli, et al.       Expires June15,2015                   [Page 4]


Internet-Draft              ACTN Framework                December 2014


   The framework described in this draft is named Abstraction and
   Control of Transport Network (ACTN) and facilitates:

     - Abstraction of the underlying network resources to higher-layer
        applications and users (customers); abstraction for a specific
        application or customer is referred to as virtualization in the
        ONF SDN architecture. [ONF-ARCH]

     - Slicing infrastructure to connect multiple customers to meet
        specific customer's service requirements;

     - Creation of a virtualized environment allowing operators to
        view and control multi-subnet multi-technology networks into a
        single virtualized network;

     - Possibility of providing a customer with abstracted network or
        abstracted services (totally hiding the network).


     - A virtualization/mapping network function that adapts customer
        requests to the virtual resources (allocated to them) to the
        supporting physical network control and performs the necessary
        mapping, translation, isolation and security/policy
        enforcement, etc.; This function is often referred to as
        orchestration.

     - The multi-domain coordination of the underlying transport
        domains, presenting it as an abstracted topology to the
        customers via open and programmable interfaces. This allows for
        the recursion of controllers in a customer-provider
        relationship.

   The organization of this draft is as follows. Section 2 provides a
   discussion for a Business Model, Section 3 ACTN Architecture,
   Section 4 ACTN Applicability, and Section 5 ACTN Interface
   requirements.

2. Business Model of ACTN

   The traditional Virtual Private Network (VPN) and Overlay Network
   (ON) models are built on the premise that one single network
   provider provides all virtual private or overlay networks to its
   customers. This model is simple to operate but has some
   disadvantages in accommodating the increasing need for flexible and
   dynamic network virtualization capabilities.



Ceccarelli, et al.       Expires June15,2015                   [Page 5]


Internet-Draft              ACTN Framework                December 2014


   The ACTN model is built upon entities that reflect the current
   landscape of network virtualization environments. There are three
   key entities in the ACTN model [ACTN-PS]:

     - Customers
     - Service Providers
     - Network Providers


    2.1. Customers

   Within the ACTN framework, different types of customers may be taken
   into account depending on the type of their resource needs, on their
   number and type of access. As example, it is possible to group them
   into two main categories:

   Basic Customer: Basic customers include fixed residential users,
   mobile users and small enterprises. Usually the number of basic
   customers is high; they require small amounts of resources and are
   characterized by steady requests (relatively time invariant). A
   typical request for a basic customer is for a bundle of voice
   service and internet access. Moreover basic customers do not modify
   their services themselves; if a service change is needed, it is
   performed by the provider as proxy and they generally has very few
   dedicated resources (subscriber drop), with everything else shared
   on the basis of some SLA, which is usually best-efforts.

   Advanced Customer: Advanced customers typically include enterprises,
   governments and utilities. Such customers can ask for both point to
   point and multipoint connectivity with high resource demand
   significantly varying in time and from customer to customer. This is
   one of reasons why a bundled services offer is not enough but it is
   desirable to provide each of them with customized virtual network
   services. Advanced customers may own dedicated virtual resources, or
   share resources, but shared resources are likely to be governed by
   more complex SLA agreements; moreover they may have the ability to
   modify their service parameters directly (within the scope of their
   virtualized environments).As customers are geographically spread
   over multiple network provider domains, the necessary control and
   data interfaces to support such customer needs is no longer a single
   interface between the customer and one single network provider. With
   this premise, customers have to interface multiple providers to get
   their end-to-end network connectivity service and the associated
   topology information. Customers may have to support multiple virtual
   network services with different service objectives and QoS
   requirements. For flexible and dynamic applications, customers may
   want to control their allocated virtual network resources in a


Ceccarelli, et al.       Expires June15,2015                   [Page 6]


Internet-Draft              ACTN Framework                December 2014


   dynamic fashion. To allow that, customers should be given an
   abstracted view of topology on which they can perform the necessary
   control decisions and take the corresponding actions. ACTN's primary
   focus is Advanced Customers.

   Customers of a given service provider can in turn offer a service to
   other customers in a recursive way. An example of recursiveness with
   2 service providers is shown below.

     - Customer (of service B)
     - Customer (of service A) & Service Provider (of service B)
     - Service Provider (of service A)
     - Network Provider


   +-----------------------------------------------------------------+   ---
   |                                                                 |    ^
   |                                          Customer (of service B)|    .
   | +-------------------------------------------------------------+ |    B
   | |                                                             | |--- .
   | |     Customer (of service A) & Service Provider(of service B)| | ^  .
   | | +--------------------------------------------------------+  | | .  .
   | | |                                                        |  | | .  .
   | | |                         Service Provider (of service A)|  | | A  .
   | | |+-----------------------------------------------+       |  | | .  .
   | | ||                                               |       |  | | .  .
   | | ||                               Network provider|       |  | | v  v
   | | |+-----------------------------------------------+       |  | |------
   | | +--------------------------------------------------------+  | |
   | +-------------------------------------------------------------+ |
   +-----------------------------------------------------------------+


                     Figure 1: Network Recursiveness.



    2.2. Service Providers

   Service providers are the providers of virtual network services to
   their customers. Service providers may or may not own physical
   network resources. When a service provider is the same as the
   network provider, this is similar to traditional VPN models. This
   model works well when the customer maintains a single interface with
   a single provider.  When customer location spans across multiple
   independent network provider domains, then it becomes hard to



Ceccarelli, et al.       Expires June15,2015                   [Page 7]


Internet-Draft              ACTN Framework                December 2014


   facilitate the creation of end-to-end virtual network services with
   this model.

   A more interesting case arises when network providers only provide
   infrastructure while service providers directly interface their
   customers. In this case, service providers themselves are customers
   of the network infrastructure providers. One service provider may
   need to keep multiple independent network providers as its end-users
   span geographically across multiple network provider domains.



   Customer            X -----------------------------------X

   Service Provider A  X -----------------------------------X

   Network Provider B                     X-----------------X

   Network Provider A  X------------------X

   The ACTN network model is predicated upon this three tier model and
   is summarized in figure below:

                       +----------------------+
                       |       customer       |
                       +----------------------+
                                 |
                                 |   /\  Service/Customer specific
                                 |   ||  Abstract Topology
                                 |   ||
                       +----------------------+  E2E abstract
                       |  Service Provider    | topology creation
                       +----------------------+
                       /         |            \
                      /          |             \  Network Topology
                     /           |              \ (raw or abstract)
                    /            |               \
   +------------------+   +------------------+   +------------------+
   |Network Provider 1|   |Network Provider 2|   |Network Provider 3|
   +------------------+   +------------------+   +------------------+



                        Figure 2: Three tier model.


Ceccarelli, et al.       Expires June15,2015                   [Page 8]


Internet-Draft              ACTN Framework                December 2014




   There can be multiple types of service providers.

     . Data Center providers: can be viewed as a service provider type
        as they own and operate data center resources to various WAN
        clients, they can lease physical network resources from network
        providers.
     . Internet Service Providers (ISP): can be a service provider of
        internet services to their customers while leasing physical
        network resources from network providers.
     . Mobile Virtual Network Operators (MVNO): provide mobile
        services to their end-users without owning the physical network
        infrastructure.

   The network provider space is the one where recursiveness occurs. A
   customer-provider relationship between multiple service providers
   can be established leading to a hierarchical architecture of
   controllers within service provider network.


    2.3. Network Providers

   Network Providers are the infrastructure providers that own the
   physical network resources and provide network resources to their
   customers. The layered model proposed by this draft separates the
   concerns of network providers and customers, with service providers
   acting as aggregators of customer requests.

3. ACTN architecture

   This section provides a high-level control and interface model of
   ACTN.

   The ACTN architecture, while being aligned with the ONF SDN
   architecture [ONF-ARCH], is presenting a 3-tiers reference model. It
   allows for hierarchy and recursiveness not only of SDN controllers
   but also of traditionally controlled domains. It defines three types
   of controllers depending on the functionalities they implement. The
   main functionalities that are identified are:

     . Multi domain coordination function: With the definition of
        domain being "everything that is under the control of the same
        controller",it is needed to have a control entity that oversees
        the specific aspects of the different domains and to build a
        single abstracted end-to-end network topology in order to


Ceccarelli, et al.       Expires June15,2015                   [Page 9]


Internet-Draft              ACTN Framework                December 2014


        coordinate end-to-end path computation and path/service
        provisioning.

     . Virtualization/Abstraction function: To provide an abstracted
        view of the underlying network resources towards customer,
        being it the client or a higher level controller entity. It
        includes computation of customer resource requests into virtual
        network paths based on the global network-wide abstracted
        topology and the creation of an abstracted view of network
        slices allocated to each customer, according to customer-
        specific virtual network objective functions, and to the
        customer traffic profile.

     . Customer mapping function: In charge of mapping customer VN
        setup commands into network provisioning requests to the
        Physical Network Controller (PNC) according to business OSS/NMS
        provisioned static or dynamic policy. Moreover it provides
        mapping and translation of customer virtual network slices into
        physical network resources


     . Virtual service coordination: Virtual service coordination
        function in ACTN incorporates customer service-related
        knowledge into the virtual network operations in order to
        seamlessly operate virtual networks while meeting customer's
        service requirements.


         The functionality is covering two types of services:

         - Service-aware Connectivity Services: This category includes
           all the network service operations used to provide
           connectivity between customer end-points while meeting
           policies, service related constraints. The data model for
           this category would include topology entities such as
           virtual nodes, virtual links, adaptation and termination
           points and service-related entities such as policies and
           service related constraints.

         - Network Function Virtualization Services: These kinds of
           services are usually setup between customers' premises and
           service provider premises and are provided mostly by cloud
           providers or content delivery providers. The context may
           include, but not limited to a security function like
           firewall, a traffic optimizer, the provisioning of storage
           or computation capacity where the customer does not care
           whether the service is implemented in a given data center or


Ceccarelli, et al.       Expires June15,2015                  [Page 10]


Internet-Draft              ACTN Framework                December 2014


           another. These services may be hosted virtually by the
           provider or physically part of the network. This allows the
           service provider to hide his own resources (both network and
           data centers) and divert customer requests where most
           suitable. This is also known as "end points mobility" case
           and introduces new concepts of traffic and service
           provisioning and resiliency. (e.g. Virtual Machine
           mobility)."

         About the Customer service-related knowledge it includes:

         - VN Service Requirements: The end customer would have
           specific service requirements for the VN including the
           customer endpoints access profile as well as the E2E
           customer service objectives. The ACTN framework
           architectural "entities" would monitor the E2E service
           during the lifetime of VN by focusing on both the
           connectivity provided by the network as well as the customer
           service objectives. These E2E service requirements go beyond
           the VN service requirements and include customer
           infrastructure as well.

         - Application Service Policy: Apart for network connectivity,
           the customer may also require some policies for application
           specific features or services. The ACTN framework would take
           these application service policies and requirements into
           consideration while coordinating the virtual network
           operations, which require end customer connectivity for
           these advanced services.


   While the "types" of controller defined are shown in Figure 3 below
   and are the following:

     . CNC - Customer Network Controller
     . MDSC - Multi Domain Service Coordinator
     . PNC - Physical Network Controller












Ceccarelli, et al.       Expires June15,2015                  [Page 11]


Internet-Draft              ACTN Framework                December 2014


   VPN customer         NW Mobile Customer     ISP NW service Customer

       |                         |                           |

   +-------+                 +-------+                   +-------+

   | CNC-A |                 | CNC-B |                   | CNC-C |

   +-------+                 +-------+                   +-------+

         \___________            |             _____________/

                      \          |            /

                      +-----------------------+

                      |         MDSC          |

                      +-----------------------+

            ___________/          |          \_____________

           /                      |                         \

   +-------+                 +-------+                   +-------+

   |  PNC  |                 |  PNC  |                   |  PNC  |

   +-------+                 +-------+                   +-------+

        | GMPLS             /      |                      /    \
        | trigger          /       |                     /      \
       --------       __----      +-----+  __        +-----+     \
      (        )       (    )_    | PNC |__          | PCE |      \
      -        -      ( Phys )    +-----+            +-----+    -----
     (  GMPLS   )      (Netw)        |                /        (     )
    (  Physical  )      ----         |               /        ( Phys. )
     (  Network )                 -----        -----           ( Net )
      -        -                 (     )      (     )           -----
      (        )                ( Phys. )    ( Phys  )
       --------                  ( Net )      ( Net )
                                  -----        -----

                     Figure 3: ACTN Control Hierarchy





Ceccarelli, et al.       Expires June15,2015                  [Page 12]


Internet-Draft              ACTN Framework                December 2014


    3.1. Customer Network Controller

   A Virtual Network Service is instantiated by the Customer Network
   Controller via the CMI (CNC-MDSC Interface). As the Customer Network
   Controller directly interfaces the application stratum, it
   understands multiple application requirements and their service
   needs. It is assumed that the Customer Network Controller and the
   VNC have a common knowledge on the end-point interfaces based on
   their business negotiation prior to service instantiation. End-point
   interfaces refer to customer-network physical interfaces that
   connect customer premise equipment to network provider equipment.
   Figure 8 in Appendix shows an example physical network topology that
   supports multiple customers. In this example, customer A has three
   end-points A.1, A.2 and A.3. The interfaces between customers and
   transport networks are assumed to be 40G OTU links.

   In addition to abstract networks, ACTN allows to provide the CNC
   with services. Example of services include connectivity between one
   of the customer's end points with a given set of resources in a data
   center from the service provider.

    3.2. Multi Domain Service Coordinator

   The MSDC (Multi Domain Service Coordinator) sits between the CNC
   (the one issuing connectivity requests) and the PNCs (Physical
   Network Controllersr - the ones managing the physical network
   resources). The MSDC can be collocated with the PNC, especially in
   those cases where the service provider and the network provider are
   the same entity.

   The internal system architecture and building blocks of the MDSC are
   out of the scope of ACTN. Some examples can be found in the
   Application Based Network Operations (ABNO) architecture [ABNO] and
   the ONF SDN architecture [ONF-ARCH].

   The MDSC is the only building block of the architecture that is able
   to implement all the four ACTN main functionalities, i.e. multi
   domain coordination function, virtualization/abstraction function,
   customer mapping function and virtual service coordination.
   A hierarchy of MSDCs can be foreseen for scalability and
   administrative choices.







Ceccarelli, et al.       Expires June15,2015                  [Page 13]


Internet-Draft              ACTN Framework                December 2014


    3.3. Physical Network Controller

   The physical network controller is the one in charge of configuring
   the network elements, monitoring the physical topology of the
   network and passing it, either raw or abstracted, to the MDSC.

   The internal architecture of the PNC, his building blocks and the
   way it controls its domain, are out of the scope of ACTN. Some
   examples can be found in the Application Based Network Operations
   (ABNO) architecture [ABNO] and the ONF SDN architecture [ONF-ARCH]

   The PNC, in addition to being in charge of controlling the physical
   network, is able to implement two of the four ACTN main
   functionalities: multi domain coordination function and
   virtualization/abstraction function
   A hierarchy of PNCs can be foreseen for scalability and
   administrative choices.

    3.4. ACTN interfaces

   To allow virtualization and multi domain coordination, the network
   has to provide open, programmable interfaces, in which customer
   applications can create, replace and modify virtual network
   resources and services in an interactive, flexible and dynamic
   fashion while having no impact on other customers. Direct customer
   control of transport network elements and virtualized services is
   not perceived as a viable proposition for transport network
   providers due to security and policy concerns among other reasons.
   In addition, as discussed in the previous section, the network
   control plane for transport networks has been separated from data
   plane and as such it is not viable for the customer to directly
   interface with transport network elements.

   While the current network control plane is well suited for control
   of physical network resources via dynamic provisioning, path
   computation, etc., a multi service domain controller needs to be
   built on top of physical network controller to support network
   virtualization. On a high-level, virtual network control refers to a
   mediation layer that performs several functions:

   Figure 4 depicts a high-level control and interface architecture for
   ACTN. A number of key ACTN interfaces exist for deployment and
   operation of ACTN-based networks. These are highlighted in Figure 4
   (ACTN Interfaces) below:




Ceccarelli, et al.       Expires June15,2015                  [Page 14]


Internet-Draft              ACTN Framework                December 2014


                .--------------
               -------------   |
              | Application |--
               -------------
                       Figure 1                   ^

                     | I/F A                 --------
                     v                      (        )
                --------------             -          -
               | Customer     |           (  Customer  )
               |  Network     |--------->(    Network   )
               |   Controller |           (            )
                --------------             -          -
                     ^                      (        )
                     | I/F B                 --------
                     v                        ^    ^
                --------------                :    :
               | MultiDomain  |               :     .
               |  Service     |               :      .
               |   Coordinator|            --------   . I/F E
                --------------            (        )   .
                     ^                   -          -   .
                     | I/F C            (  Physical  )   .
                     v                 (    Network   )   .
                  ---------------       (            )     --------
                 |               |<----> -          -     (        )
                --------------   |        (        )     -         -
               | Physical     |--          --------     (  Physical  )
               |  Network     |<---------------------->(    Network   )
               |   Controller |         I/F D           (            )
                --------------                           -         -
                                                          (        )
                                                           --------


                         Figure 4: ACTN Interfaces

   The interfaces and functions are described below:

     - Interface A: A north-bound interface (NBI) that will
        communicate the service request or application demand. A
        request will include specific service properties, including:
        services, topology, bandwidth and constraint information.

     - Interface B: The CNC-MSDC Interface (CMI) is an interface
        between a Customer Network Controller and a Multi Service
        Domain Controller. It requests the creation of the network


Ceccarelli, et al.       Expires June15,2015                  [Page 15]


Internet-Draft              ACTN Framework                December 2014


        resources, topology or services for the applications. The
        Virtual Network Controller may also report potential network
        topology availability if queried for current capability from
        the Customer Network Controller.


     - Interface C: The MDSC-PNC Interface (MPI) is an interface
        between a Multi Domain Service Coordinator and a Physical
        Network Controller. It communicates the creation request, if
        required, of new connectivity of bandwidth changes in the
        physical network, via the PNC. In multi-domain environments,
        the MDSC needs to establish multiple MPIs, one for each PNC, as
        there are multiple PNCs responsible for its domain control.


     - Interface D: The provisioning interface for creating forwarding
        state in the physical network, requested via the Physical
        Network Controller.


     - Interface E: A mapping of physical resources to overlay
        resources.



   The interfaces within the ACTN scope are B and C.

4. ACTN Applicability

   This section provides a high-level applicability of ACTN based on a
   number of use-cases listed in the following:

  + draft-cheng-actn-ptn-requirements-00 (ACTN Use-cases for Packet
     Transport Networks in Mobile Backhaul Networks)

  + draft-dhody-actn-poi-use-case-03 (Packet Optical Integration (POI)
     Use Cases for Abstraction and Control of Transport Networks
     (ACTN))

  + draft-fang-actn-multidomain-dci-01 (ACTN Use Case for Multi-domain
     Data Center Interconnect)

  + draft-klee-actn-connectivity-multi-vendor-domains-03 (ACTN Use-
     case for On-demand E2E Connectivity Services in Multiple Vendor
     Domain Transport Networks)



Ceccarelli, et al.       Expires June15,2015                  [Page 16]


Internet-Draft              ACTN Framework                December 2014


  + draft-kumaki-actn-multitenant-vno-00 (ACTN : Use case for Multi
     Tenant VNO)

  + draft-lopez-actn-vno-multidomains-01 (ACTN Use-case for Virtual
     Network Operation for Multiple Domains in a Single Operator
     Network)

  + draft-shin-actn-mvno-multi-domain-00 (ACTN Use-case for Mobile
     Virtual Network Operation for Multiple Domains in a Single
     Operator Network)

  + draft-xu-actn-perf-dynamic-service-control-02 (Use Cases and
     Requirements of Dynamic Service Control based on Performance
     Monitoring in ACTN Architecture)

4.1. ACTN Use cases Summary

Listed below is a set of generalized requirements identified by each of
the aforementioned use-cases:

  + draft-cheng-actn-ptn-requirements-00

       - Faster End-to-End Enterprise Services Provisioning
       - Multi-layer coordination in L2/L3 Packet Transport Networks
       - Optimizing the network resources utilization (supporting
          various performances monitoring matrix, such as traffic flow
          statistics, packet delay, delay variation, throughput and
          packet-loss rate)
       - Virtual Networks Operations for multi-domain Packet Transport
          Networks

  + draft-dhody-actn-poi-use-case-03

       - Packet Optical Integration to support Traffic Planning,
          performance Monitoring, automated congestion management and
          Automatic Network Adjustments
       - Protection and Restoration Synergy in Packet Optical Multi-
          layer network.
       - Service Awareness and Coordination between Multiple Network
          Domains

  + draft-fang-actn-multidomain-dci-01

      + Multi-domain Data Center Interconnection to support VM
        Migration, Global Load Balancing, Disaster Recovery, On-demand
        Virtual Connection/Circuit Services



Ceccarelli, et al.       Expires June15,2015                  [Page 17]


Internet-Draft              ACTN Framework                December 2014


      + The interfaces between the Data Center Operation and each
        transport network domain should support standards-based
        abstraction with a common information/data model to support the
        following:
            - Network Query (Pull Model) from the Data Center
               Operation to each transport network domain to collect
               potential resource availability (e.g., BW availability,
               latency range, etc.) between a few data center
               locations.
            - Network Path Computation Request from the Data Center
               Operation to each transport network domain to estimate
               the path availability.
            - Network Virtual Connections/Circuits Request from the
               Data Center Operation to each transport domain to
               establish end-to-end virtual connections/circuits (with
               type, concurrency, duration, SLA.QoS parameters,
               protection.reroute policy options, policy constraints
               such as peering preference, etc.).
            - Network Virtual Connections/Circuits Modification
               Request

  + draft-klee-actn-connectivity-multi-vendor-domains-02

       - Two-stage path computation capability in a hierarchical
          control architecture (VNC-PNC) and  a hierarchical
          composition of integrated network views

       - Coordination of signal flow for E2E connections.

       - Abstraction of:

            - Inter-connection data between domains

            - Customer Endpoint data

            - The multiple levels/granularities of the abstraction of
               network resource (which is subject to policy and service
               need).

            - Any physical network constraints (such as SRLG, link
               distance, etc.) should be reflected in abstraction.

            - Domain preference and local policy (such as preferred
               peering point(s), preferred route, etc.), Domain network
               capability (e.g., support of push/pull model).

  + draft-kumaki-actn-multitenant-vno-00


Ceccarelli, et al.       Expires June15,2015                  [Page 18]


Internet-Draft              ACTN Framework                December 2014


       - On-demand Virtual Network Service Creation
       - Domain Control Plane/Routing Layer Separation
       - Independent service Operation for Virtual Services from
          control of other domains
       - Multiple service level support for each VN (e.g., bandwidth
          and latency for each VN service).
       - VN diversity/survivability should be met in physical network
          mapping.
       - VN confidentiality and sharing constraint should be supported.

  + draft-lopez-actn-vno-multidomains-01

       - Creation of a global abstraction of network topology: The VNO
          Coordinator assembles each domain level abstraction of
          network topology into a global abstraction of the end-to-
          endnetwork.
       - End-to-end connection lifecycle management
       - Invocation of path provisioning request to each domain
          (including optimization requests)
       - Invocation of path protection/reroute to the affected
          domain(s)
       - End-to-end network monitoring and fault management. This could
          imply potential KPIs and alarm correlation capabilities.
       - End-to-end accounting and generation of detailed records for
          resource usage
       - End-to-end policy enforcement

  + draft-shin-actn-mvno-multi-domain-00

       - Resource abstraction: operational mechanisms in mobile
          backhaul network to give the current network usage
          information for dynamic and elastic applications be
          provisioned dynamically with QoS guarantee.

       - Load balancing or for recovery, the selection of core DC
          location from edge constitutes a data center selection
          problem.

       - Multi-layer routing and optimization, coordination between
          these two layers.

  + draft-xu-actn-perf-dynamic-service-control-02

       - Dynamic Service Control Policy enforcement and Traffic/SLA
          Monitoring:



Ceccarelli, et al.       Expires June15,2015                  [Page 19]


Internet-Draft              ACTN Framework                December 2014


            - Customer service performance monitoring strategy,
               including the traffic monitoring object (the service
               need to be monitored)
            - monitoring parameters (e.g., transmitted and received
               bytes per unit time),
            - traffic monitoring cycle (e.g., 15 minutes, 24 hours),
            - threshold of traffic monitoring (e.g., high and low
               threshold), etc.

4.2. Work in Scope of ACTN

   This section provides a summary of use-cases in terms of two
   categories: (i) service-specific requirements; (ii) network-related
   requirements.

   Service-specific requirements listed below are uniquely applied to
   the work scope of ACTN. Service-specific requirements are related to
   virtual service coordination function defined in Section 3. These
   requirements are related to customer's VNs in terms of service
   policy associated with VNs such as service performance objectives,
   VN endpoint location information for certain required service-
   specific functions (e.g., security and others), VN survivability
   requirement, or dynamic service control policy, etc.

   Network-related requirements are related to virtual network
   operation function defined in Section 3. These requirements are
   related to multi-domain and multi-layer signaling, routing,
   protection/restoration and synergy, re-optimization/re-grooming,
   etc. These requirements are not inherently unique for the scope of
   ACTN but some of these requirements are in scope of ACTN, especially
   for coherent/seamless operation aspect of multiple controller
   hierarchy.

   The following table gives an overview of service-specific
   requirements and network-related requirements respectively for each
   ACTN use-case and identifies the work in scope of ACTN.











Ceccarelli, et al.       Expires June15,2015                  [Page 20]


Internet-Draft              ACTN Framework                December 2014


   Use case-1: Cheng

   Service-Specific requirements:

         - E2E service provisioning
         - Performance Monitoring, resource utilization, abstraction

   Network-related requirements:

         - Multi-layer (L2/L2.5) coordination
         - VNO for multi-domain transport networks

   ACTN work scope:

         - Dynamic multi-layer coordination based on utilization is in
           scope of ACTN
         - YANG for utilization abstraction

   +------------------------------------------------------------------+

   Use case-2: Dhody

   Service-Specific requirements:

         - Service-awareness/coordination between Packet and Optical

   Network-related requirements:

         - Packet/Optical performance monitoring
         - Protection/Restoration synergy

   ACTN work scope:

         - Performance related data model may be in scope of ACTN
         - Customer's VN survivability  policy enforcement for
           protection/restoration is unique to ACTN.

   +------------------------------------------------------------------+

   Use case-3: Fang

   Service-Specific requirements:

         - Dynamic VM migration (service), Global load balancing
           (utilization efficiency), Disaster recovery
         - Service-aware network query
         - Service Policy Enforcement


Ceccarelli, et al.       Expires June15,2015                  [Page 21]


Internet-Draft              ACTN Framework                December 2014


   Network-related requirements:

         - On-demand virtual circuit request
         - Network Path Connection request

   ACTN work scope:

         - Multi-destination service selection policy enforcement and
           its related primitives/information are unique to ACTN.
         - Service-aware network query and its data model can be
           extended by ACTN.

   +------------------------------------------------------------------+

   Use case-4: Klee

   Network-related requirements:

         - Two stage path computation
         - E2E signaling coordination
         - Abstraction of inter-domain info
         - Enforcement of network policy (peering, domain preference)
         - Network capability exchange (pull/push, abstraction level,
           etc.)

   ACTN work scope:

         - Multi-domain service policy coordination to network
           primitives is in scope of ACTN

   +------------------------------------------------------------------+

   Use case-5: Kumaki

   Service-Specific requirements:

         - On-demand VN creation
         - Multi-service level for VN
         - VN survivability /diversity/confidentiality

   ACTN work scope:

         - All of the service-specific lists in the left column is
           unique to ACTN.

   +------------------------------------------------------------------+



Ceccarelli, et al.       Expires June15,2015                  [Page 22]


Internet-Draft              ACTN Framework                December 2014


   Use case-6: Lopez

   Service-Specific requirements:

         - E2E accounting and resource usage data
         - E2E service policy enforcement

   Network-related requirements:

         - E2E connection management, path provisioning
         - E2E network monitoring and fault management

   ACTN work scope:

         - Escalation of performance/fault management data to CNC and
           the policy enforcement for this area is unique to ACTN.

   +------------------------------------------------------------------+

   Use case-7: Shin

   Service-Specific requirements:

         - Current network resource abstraction
         - Endpoint/DC dynamic selection (for VM migration)

   Network-related requirements:

         - LB for recovery
         - Multi-layer routing and optimization coordination

   ACTN work scope:

         - Multi-layer routing and optimization are related to VN's
           dynamic endpoint selection policy.

   +------------------------------------------------------------------+

   Use case-8: Xu

   Service-Specific requirements:

         - Dynamic service control policy enforcement
         - Dynamic service control

   Network-related requirements:



Ceccarelli, et al.       Expires June15,2015                  [Page 23]


Internet-Draft              ACTN Framework                December 2014


         - Traffic monitoring
         - SLA monitoring

   ACTN work scope:

         - Dynamic service control policy enforcement and its control
           primitives are in scope of ACTN
         - Data model to support traffic monitoring data is an
           extension of YANG model ACTN can extend.

   +------------------------------------------------------------------+

The subsequent sections provide some illustration of the ACTN's unique
work scope identified by the above analysis:

- Coordination of Multi-destination Service Requirement/Policy (Section
  4.2.1)

- Application Service Policy-aware Network Operation (section 4.2.2)

- Dynamic Service Control Policy Enforcement for Performance/Fault
  Management (Section 4.2.3)

- Multi-Layer (Packet-Optical) Coordination for Protection/Restoration
  (Section 4.2.4)
























Ceccarelli, et al.       Expires June15,2015                  [Page 24]


Internet-Draft              ACTN Framework                December 2014


4.2.1. Coordination of Multi-destination Service Requirement/Policy

                                  +----------------+
                                  |       CNC      |
                                  |   (Global DC   |
                                  |   Operation    |
                                  |    Control)    |
                                  +--------+-------+
                                           | |   Service Requirement/Policy:
                                           | |   - Endpoint/DC location info
                                           | |   - Endpoint/DC dynamic selection
                                           | |     policy (for VM migration, DR, LB)
                                           | v
                                 +---------+--------+
                                 |  Multi-domain    |  Service policy-driven
                                 |Service Controller|  dynamic DC selection
                                 +-----+---+---+----+
                                       |   |   |
                                       |   |   |
                       +---------------+   |   +----------------+
                       |                   |                    |
                +------+-----+       +-----+------+      +------+-----+
                |   PNC for  |       |  PNC for   |      |  PNC for   |
                | Transport  |       | Transport  |      | Transport  |
                | Network A  |       | Network B  |      | network C  |
                +------------+       +------------+      +------------+
                       |                    |                   |
         +---+      ------               ------              ------       +---+
         |DC1|--////      \\\\       ////      \\\\      ////      \\\\---+DC4|
         +---+ |              |     |              |    |              |  +---+
              |      TN A      +---+     TN B       +--+      TN C      |
               /              |     |              |    |              |
              / \\\\      ////     / \\\\      ////      \\\\      ////
        +---+/      ------        /      ------    \         ------ \
        |DC2|                    /                  \                \\+---+
        +---+                   /                    \                 \DC6|
                              +/--+                   \ +---+          +---+
                              |DC3|                    \|DC4|
                              +---+                     +---+


                                                          DR: Disaster Recovery
                                                          LB: Load Balancing

             Figure 5: Service Policy-driven Data Center Selection




Ceccarelli, et al.       Expires June15,2015                  [Page 25]


Internet-Draft              ACTN Framework                December 2014


   Figure 5 shows how VN service policies from the CNC are incorporated
   by the MDSC to support multi-destination applications. Multi-
   destination applications refer to applications in which the
   selection of the destination of a network path for a given source
   needs to be decided dynamically to support such applications.

   Data Center selection problems arise for VM mobility, disaster
   recovery and load balancing cases. VN's service policy plays an
   important role for virtual network operation. Service policy can be
   static or dynamic. Dynamic service policy for data center selection
   may be placed as a result of utilization of data center resources
   supporting VNs. The MSDC would then incorporate this information to
   meet the service objective of this application.




































Ceccarelli, et al.       Expires June15,2015                  [Page 26]


Internet-Draft              ACTN Framework                December 2014


4.2.2. Application Service Policy-aware Network Operation

                                  +----------------+
                                  |       CNC      |
                                  |   (Global DC   |
                                  |   Operation    |
                                  |    Control)    |
                                  +--------+-------+
                                           | |   Application Service Policy
                                           | |   - VNF requirement (e.g. security
                                           | |     function, etc.)
                                           | |   - Location profile for each VNF
                                           | v
                                 +---------+--------+
                                 |  Multi-domain    |   Dynamically select the
                                 |Service Controller|   network destination to meet
                                 +-----+---+---+----+   VNF requirement.
                                       |   |   |
                                       |   |   |
                       +---------------+   |   +----------------+
                       |                   |                    |
                +------+-----+       +-----+------+      +------+-----+
                |   PNC for  |       |  PNC for   |      |  PNC for   |
                | Transport  |       | Transport  |      | Transport  |
                | Network A  |       | Network B  |      | network C  |
                |            |       |            |      |            |
                +------------+       +------------+      +------------+
      {VNF b}          |                    |                   |
         +---+      ------               ------              ------       +---+
         |DC1|--////      \\\\       ////      \\\\      ////      \\\\---+DC4|
         +---+ |              |     |              |    |              |  +---+
              |      TN A      +---+     TN B       +--+      TN C      |  {VNF b,c}
               /              |     |              |    |              |
              / \\\\      ////     / \\\\      ////      \\\\      ////
        +---+/      ------        /      ------    \         ------ \
        |DC2|                    /                  \                \\+---+
        +---+                   /                    \                 \DC6|
          {VNF a}             +/--+                   \ +---+          +---+
                              |DC3|                    \|DC4|            {VNF a,b,c}
                              +---+                     +---+
                               {VNF a, b}               {VNF a, c}
         Figure 6: Application Service Policy-aware Network Operation

   This scenario is similar to the previous case in that the VN service
   policy for the application can be met by a set of multiple


Ceccarelli, et al.       Expires June15,2015                  [Page 27]


Internet-Draft              ACTN Framework                December 2014


   destinations that provide the required virtual network functions
   (VNF). Virtual network functions can be, for example, security
   functions required by the VN application. The VN service policy by
   the CNC would indicate the locations of a certain VNF that can be
   fulfilled. This policy information is critical in finding the
   optimal network path subject to this constraint. As VNFs can be
   dynamically moved across different DCs, this policy should be
   dynamically enforced from the CNC to the MDSC and the PNCs.


4.2.3. Dynamic Service Control Policy Enforcement for Performance and
     Fault Management

        +------------------------------------------------+
        |           Customer Network Controller          |
        +------------------------------------------------+
        1.Traffic|  /|\4.Traffic           | /|\
        Monitor& |   |  Monitor            |  | 8.Traffic
        Optimize |   |  Result   5.Service |  | modify &
        Policy   |   |             modify& |  | optimize
                \|/  |       optimize Req.\|/ | result
        +------------------------------------------------+
        |         Mult-domain Service Controller         |
        +------------------------------------------------+
        2. Path  |  /|\3.Traffic           |  |
        Monitor  |   | Monitor             |  |7.Path
        Request  |   | Result     6.Path   |  | modify &
                 |   |            modify&  |  | optimize
                \|/  |       optimize Req.\|/ | result
        +------------------------------------------------+
        |          Physical Network Controller           |
        +------------------------------------------------+

         Figure 7: Dynamic Service Control for Performance and Fault
                                 Management

   Figure 7 shows the flow of dynamic service control policy
   enforcement for performance and fault management initiated by
   customer per their VN. The feedback loop and filtering mechanism
   tailored for VNs performed by the MDSC differentiates this ACTN
   scope from traditional network management paradigm. VN level dynamic
   OAM data model is a building block to support this capability.






Ceccarelli, et al.       Expires June15,2015                  [Page 28]


Internet-Draft              ACTN Framework                December 2014


4.2.4. Multi-Layer (Packet-Optical) Coordination for
     Protection/Restoration (TBD)



5. ACTN interfaces requirements

   This section provides ACTN interface requirements for the two
   interfaces that are within the ACTN scope.

     . CMI: CNC-MDSC Interface
     . MPI: MDSC-PNC Interface



   TO BE FILLED

6. Security Considerations

   TBD

7. IANA Considerations

   TBD

8. References

    8.1. Informative References

   [PCE]     Farrel, A., Vasseur, J.-P., and J. Ash, "A Path
             Computation Element (PCE)-Based Architecture", IETF RFC
             4655, August 2006.



   [PCE-S]   Crabbe, E, et. al., "PCEP extension for stateful
             PCE",draft-ietf-pce-stateful-pce, work in progress.



   [GMPLS]   Manning, E., et al., "Generalized Multi-Protocol Label
             Switching (GMPLS) Architecture", RFC 3945, October 2004.



   [NFV-AF]  "Network Functions Virtualization (NFV); Architectural
             Framework", ETSI GS NFV 002 v1.1.1, October 2013.


Ceccarelli, et al.       Expires June15,2015                  [Page 29]


Internet-Draft              ACTN Framework                December 2014




   [ACTN-PS] Y. Lee, D. King, M. Boucadair, R. Jing, L. Contreras
             Murillo, "Problem Statement for Abstraction and Control of
             Transport Networks", draft-leeking-actn-problem-statement,
             work in progress.

   [ONF]     Open Networking Foundation, "OpenFlow Switch Specification
             Version 1.4.0 (Wire Protocol 0x05)", October 2013.



   [ABNO]    King, D., and Farrel, A., "A PCE-based Architecture for
             Application-based Network Operations", draft-farrkingel-
             pce-abno-architecture, work in progress.

   [VNM-OP]  Melo, M, et al. "Virtual Network Mapping - An Optimization
             Problem", Springer Berlin Heidelberg, January 2012.



Appendix A

Contributors' Addresses

   Dhruv Dhoddy
   Huawei Technologies
   dhruv.ietf@gmail.com





















Ceccarelli, et al.       Expires June15,2015                  [Page 30]


Internet-Draft              ACTN Framework                December 2014


Authors' Addresses

   Daniele Ceccarelli
   Ericsson
   Torshamnsgatan,48
   Stockholm, Sweden
   Email: daniele.ceccarelli@ericsson.com

   Luyuan Fang
   Email: luyuanf@gmail.com

   Young Lee
   Huawei Technologies
   5340 Legacy Drive
   Plano, TX 75023, USA
   Phone: (469)277-5838
   Email: leeyoung@huawei.com


   Diego Lopez
   Telefonica I+D
   Don Ramon de la Cruz, 82
   28006 Madrid, Spain
   Email: diego@tid.es

   Sergio Belotti
   Alcatel Lucent
   Via Trento, 30
   Vimercate, Italy
   Email: sergio.belotti@alcatel-lucent.com

   Daniel King
   Lancaster University
   Email: d.king@lancaster.ac.uk














Ceccarelli, et al.       Expires June15,2015                  [Page 31]


Internet-Draft              ACTN Framework                December 2014


9. Appendix I: Abstracted Topology Illustration

   There are two levels of abstracted topology that needs to be
   maintained and supported for ACTN. Customer-specific Abstracted
   Topology refers to the abstracted view of network resources
   allocated (shared or dedicated) to the customer. The granularity of
   this abstraction varies depending on the nature of customer
   applications. Figure 8 illustrates this.

   Figure 8 shows how three independent customers A, B and C provide
   its respective traffic demand matrix to the VNC. The physical
   network topology shown in Figure 6 is the provider's network
   topology generated by the PNC topology creation engine such as the
   link state database (LSDB) and Traffic Engineering DB (TEDB) based
   on control plane discovery function. This topology is internal to
   PNC and not available to customers. What is available to them is an
   abstracted network topology (a virtual network topology) based on
   the negotiated level of abstraction. This is a part of VNS
   instantiation between a client control and VNC.



             +------+           +------+          +------+
   A.1 ------o      o-----------o      o----------o      o------- A.2
   B.1 ------o   1  |           |   2  |          |   3  |
   C.1 ------o      o-----------o      o----------o      o------- B.2
             +-o--o-+           +-o--o-+          +-o--o-+
               |  |               |  |              |  |
               |  |               |  |              |  |
               |  |               |  |              |  |
               |  |             +-o--o-+          +-o--o-+
               |  `-------------o      o----------o      o------- B.3
               |                |   4  |          |   5  |
               `----------------o      o----------o      o------- C.3
                                +-o--o-+          +------+
                                  |  |
                                  |  |
                                C.2  A.3

       Traffic Matrix           Traffic Matrix           Traffic Matrix
       for Customer A           for Customer B           for Customer C

         A.1  A.2  A.3            B.1  B.2  B.3           C.1  C.2  C.3



Ceccarelli, et al.       Expires June15,2015                  [Page 32]


Internet-Draft              ACTN Framework                December 2014


    -------------------      ------------------       -----------------
    A.1  -    20G  20G       B.1  -    40G  40G       C.1 -    20G  20G
    A.2  20G   -   10G       B.2  40G   -   20G       C.2 20G   -   10G
    A.3  20G  10G   -        B.3  40G  20G   -        C.3 20G  10G   -


   Figure 8: Physical network topology shared with multiple customers

   Figure 9 depicts illustrative examples of different level of
   topology abstractions that can be provided by the VNC topology
   abstraction engine based on the physical topology base maintained by
   the PNC.  The level of topology abstraction is expressed in terms of
   the number of virtual nodes (VNs) and virtual links (VLs). For
   example, the abstracted topology for customer A shows there are 5
   VNEs and 10 VLs. This is by far the most detailed topology
   abstraction with a minimal link hiding compared to other abstracted
   topologies in Figure 7.

       (a)  Abstracted Topology for Customer A (5 VNEs and 10 VLs)

             +------+           +------+          +------+
   A.1 ------o      o-----------o      o----------o      o------- A.2
             |   1  |           |   2  |          |   3  |
             |      |           |      |          |      |
             +-o----+           +-o----+          +-o----+
               |                  |                 |
               |                  |                 |
               |                  |                 |
               |                +-o----+          +-o--o-+
               |                |      |          |      |
               |                |   4  |          |   5  |
               `----------------o      o----------o      |
                                +----o-+          +------+
                                     |
                                     |
                                    A.3


        (b)  Abstracted Topology for Customer B (3 VNEs and 6 VLs)

             +------+                             +------+
   B.1 ------o      o-----------------------------o      o------ B.2



Ceccarelli, et al.       Expires June15,2015                  [Page 33]


Internet-Draft              ACTN Framework                December 2014


             |   1  |                             |   3  |
             |      |                             |      |
             +-o----+                             +-o----+
                \                                    |
                 \                                   |
                  \                                  |
                   `-------------------              |
                                       `          +-o----+
                                        \         |      o------ B.3
                                         \        |   5  |
                                          `-------o      |
                                                  +------+




        (c)  Abstracted Topology for Customer C (1 VNE and 3 VLs)


             +-------------------------------------------+
             |                                           |
             |                                           |
   C.1 ------o                                           |
             |                                           |
             |                                           |
             |                                           |
             |                                           o--------C.3
             |                                           |
             +--------------------o----------------------+
                                  |
                                  |
                                  |
                                  |
                                 C.2


         Figure 9: Topology Abstraction Examples for Customers


   As different customers have different control/application needs,
   abstracted topologies for customers B and C, respectively show a
   much higher degree of abstraction. The level of abstraction is


Ceccarelli, et al.       Expires June15,2015                  [Page 34]


Internet-Draft              ACTN Framework                December 2014


   determined by the policy (e.g., the granularity level) placed for
   the customer and/or the path computation results by the PCE operated
   by the PNC. The more granular the abstraction topology is, the more
   control is given to the Customer Network Controller. If the Customer
   Network Controller has applications that require more granular
   control of virtual network resources, then the abstracted topology
   shown for customer A may be the right abstraction level for such
   controller. For instance, if the customer is a third-party virtual
   service broker/provider, then it would desire much more
   sophisticated control of virtual network resources to support
   different application needs. On the other hand, if the customer were
   only to support simple tunnel services to its applications, then the
   abstracted topology shown for customer C (one VNE and three VLs)
   would suffice.



































Ceccarelli, et al.       Expires June15,2015                  [Page 35]


Html markup produced by rfcmarkup 1.129b, available from https://tools.ietf.org/tools/rfcmarkup/