Internet Engineering Task Force (IETF) D. Ceccarelli, Ed.
Request for Comments: 8453 Ericsson
Category: Informational Y. Lee, Ed.
ISSN: 2070-1721 Huawei
August 2018
Internet Engineering Task Force (IETF) D. Ceccarelli, Ed.
Request for Comments: 8453 Ericsson
Category: Informational Y. Lee, Ed.
ISSN: 2070-1721 Huawei
August 2018
Framework for Abstraction and Control of TE Networks (ACTN)
TE网络的抽象和控制框架（ACTN）
Abstract
摘要
Traffic Engineered (TE) networks have a variety of mechanisms to facilitate the separation of the data plane and control plane. They also have a range of management and provisioning protocols to configure and activate network resources. These mechanisms represent key technologies for enabling flexible and dynamic networking. The term "Traffic Engineered network" refers to a network that uses any connection-oriented technology under the control of a distributed or centralized control plane to support dynamic provisioning of end-to-end connectivity.
流量工程（TE）网络有多种机制来促进数据平面和控制平面的分离。他们还拥有一系列管理和供应协议来配置和激活网络资源。这些机制代表了实现灵活和动态网络的关键技术。术语“流量工程网络”是指在分布式或集中控制平面的控制下，使用任何面向连接的技术来支持端到端连接的动态供应的网络。
Abstraction of network resources is a technique that can be applied to a single network domain or across multiple domains to create a single virtualized network that is under the control of a network operator or the customer of the operator that actually owns the network resources.
网络资源抽象是一种技术，可应用于单个网络域或跨多个域，以创建一个由网络运营商或实际拥有网络资源的运营商客户控制的单一虚拟化网络。
This document provides a framework for Abstraction and Control of TE Networks (ACTN) to support virtual network services and connectivity services.
本文档提供了TE网络（ACTN）的抽象和控制框架，以支持虚拟网络服务和连接服务。
Status of This Memo
关于下段备忘
This document is not an Internet Standards Track specification; it is published for informational purposes.
本文件不是互联网标准跟踪规范；它是为了提供信息而发布的。
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Not all documents approved by the IESG are candidates for any level of Internet Standard; see Section 2 of RFC 7841.
本文件是互联网工程任务组（IETF）的产品。它代表了IETF社区的共识。它已经接受了公众审查，并已被互联网工程指导小组（IESG）批准出版。并非IESG批准的所有文件都适用于任何级别的互联网标准；见RFC 7841第2节。
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8453.
有关本文件当前状态、任何勘误表以及如何提供反馈的信息，请访问https://www.rfc-editor.org/info/rfc8453.
Copyright Notice
版权公告
Copyright (c) 2018 IETF Trust and the persons identified as the document authors. All rights reserved.
版权所有（c）2018 IETF信托基金和确定为文件作者的人员。版权所有。
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://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.
本文件受BCP 78和IETF信托有关IETF文件的法律规定的约束(https://trustee.ietf.org/license-info)自本文件出版之日起生效。请仔细阅读这些文件，因为它们描述了您对本文件的权利和限制。从本文件中提取的代码组件必须包括信托法律条款第4.e节中所述的简化BSD许可证文本，并提供简化BSD许可证中所述的无担保。
Table of Contents
目录
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. VNS Model of ACTN . . . . . . . . . . . . . . . . . . . . 7
2.2.1. Customers . . . . . . . . . . . . . . . . . . . . . . 9
2.2.2. Service Providers . . . . . . . . . . . . . . . . . . 9
2.2.3. Network Operators . . . . . . . . . . . . . . . . . . 10
3. ACTN Base Architecture . . . . . . . . . . . . . . . . . . . 10
3.1. Customer Network Controller . . . . . . . . . . . . . . . 12
3.2. Multi-Domain Service Coordinator . . . . . . . . . . . . 13
3.3. Provisioning Network Controller . . . . . . . . . . . . . 13
3.4. ACTN Interfaces . . . . . . . . . . . . . . . . . . . . . 14
4. Advanced ACTN Architectures . . . . . . . . . . . . . . . . . 15
4.1. MDSC Hierarchy . . . . . . . . . . . . . . . . . . . . . 15
4.2. Functional Split of MDSC Functions in Orchestrators . . . 16
5. Topology Abstraction Methods . . . . . . . . . . . . . . . . 18
5.1. Abstraction Factors . . . . . . . . . . . . . . . . . . . 18
5.2. Abstraction Types . . . . . . . . . . . . . . . . . . . . 19
5.2.1. Native/White Topology . . . . . . . . . . . . . . . . 19
5.2.2. Black Topology . . . . . . . . . . . . . . . . . . . 19
5.2.3. Grey Topology . . . . . . . . . . . . . . . . . . . . 20
5.3. Methods of Building Grey Topologies . . . . . . . . . . . 21
5.3.1. Automatic Generation of Abstract Topology by
Configuration . . . . . . . . . . . . . . . . . . . . 22
5.3.2. On-Demand Generation of Supplementary Topology via
Path Compute Request/Reply . . . . . . . . . . . . . 22
5.4. Hierarchical Topology Abstraction Example . . . . . . . . 23
5.5. VN Recursion with Network Layers . . . . . . . . . . . . 25
6. Access Points and Virtual Network Access Points . . . . . . . 28
6.1. Dual-Homing Scenario . . . . . . . . . . . . . . . . . . 30
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. VNS Model of ACTN . . . . . . . . . . . . . . . . . . . . 7
2.2.1. Customers . . . . . . . . . . . . . . . . . . . . . . 9
2.2.2. Service Providers . . . . . . . . . . . . . . . . . . 9
2.2.3. Network Operators . . . . . . . . . . . . . . . . . . 10
3. ACTN Base Architecture . . . . . . . . . . . . . . . . . . . 10
3.1. Customer Network Controller . . . . . . . . . . . . . . . 12
3.2. Multi-Domain Service Coordinator . . . . . . . . . . . . 13
3.3. Provisioning Network Controller . . . . . . . . . . . . . 13
3.4. ACTN Interfaces . . . . . . . . . . . . . . . . . . . . . 14
4. Advanced ACTN Architectures . . . . . . . . . . . . . . . . . 15
4.1. MDSC Hierarchy . . . . . . . . . . . . . . . . . . . . . 15
4.2. Functional Split of MDSC Functions in Orchestrators . . . 16
5. Topology Abstraction Methods . . . . . . . . . . . . . . . . 18
5.1. Abstraction Factors . . . . . . . . . . . . . . . . . . . 18
5.2. Abstraction Types . . . . . . . . . . . . . . . . . . . . 19
5.2.1. Native/White Topology . . . . . . . . . . . . . . . . 19
5.2.2. Black Topology . . . . . . . . . . . . . . . . . . . 19
5.2.3. Grey Topology . . . . . . . . . . . . . . . . . . . . 20
5.3. Methods of Building Grey Topologies . . . . . . . . . . . 21
5.3.1. Automatic Generation of Abstract Topology by
Configuration . . . . . . . . . . . . . . . . . . . . 22
5.3.2. On-Demand Generation of Supplementary Topology via
Path Compute Request/Reply . . . . . . . . . . . . . 22
5.4. Hierarchical Topology Abstraction Example . . . . . . . . 23
5.5. VN Recursion with Network Layers . . . . . . . . . . . . 25
6. Access Points and Virtual Network Access Points . . . . . . . 28
6.1. Dual-Homing Scenario . . . . . . . . . . . . . . . . . . 30
7. Advanced ACTN Application: Multi-Destination Service . . . . . 31
7.1. Preplanned Endpoint Migration . . . . . . . . . . . . . . 32
7.2. On-the-Fly Endpoint Migration . . . . . . . . . . . . . . 33
8. Manageability Considerations . . . . . . . . . . . . . . . . 33
8.1. Policy . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.2. Policy Applied to the Customer Network Controller . . . . 34
8.3. Policy Applied to the Multi-Domain Service Coordinator . 35
8.4. Policy Applied to the Provisioning Network Controller . . 35
9. Security Considerations . . . . . . . . . . . . . . . . . . . 36
9.1. CNC-MDSC Interface (CMI) . . . . . . . . . . . . . . . . 37
9.2. MDSC-PNC Interface (MPI) . . . . . . . . . . . . . . . . 37
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37
11. Informative References . . . . . . . . . . . . . . . . . . . 38
Appendix A. Example of MDSC and PNC Functions Integrated in a
Service/Network Orchestrator . . . . . . . . . . . . 40
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42
7. Advanced ACTN Application: Multi-Destination Service . . . . . 31
7.1. Preplanned Endpoint Migration . . . . . . . . . . . . . . 32
7.2. On-the-Fly Endpoint Migration . . . . . . . . . . . . . . 33
8. Manageability Considerations . . . . . . . . . . . . . . . . 33
8.1. Policy . . . . . . . . . . . . . . . . . . . . . . . . . 34
8.2. Policy Applied to the Customer Network Controller . . . . 34
8.3. Policy Applied to the Multi-Domain Service Coordinator . 35
8.4. Policy Applied to the Provisioning Network Controller . . 35
9. Security Considerations . . . . . . . . . . . . . . . . . . . 36
9.1. CNC-MDSC Interface (CMI) . . . . . . . . . . . . . . . . 37
9.2. MDSC-PNC Interface (MPI) . . . . . . . . . . . . . . . . 37
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 37
11. Informative References . . . . . . . . . . . . . . . . . . . 38
Appendix A. Example of MDSC and PNC Functions Integrated in a
Service/Network Orchestrator . . . . . . . . . . . . 40
Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 42
The term "Traffic Engineered network" refers to a network that uses any connection-oriented technology under the control of a distributed or centralized control plane to support dynamic provisioning of end-to-end connectivity. TE networks have a variety of mechanisms to facilitate the separation of data planes and control planes 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. Some examples of networks that are in scope of this definition are optical, MPLS Transport Profile (MPLS-TP) [RFC5654], and MPLS-TE networks [RFC2702].
术语“流量工程网络”是指在分布式或集中控制平面的控制下，使用任何面向连接的技术来支持端到端连接的动态供应的网络。TE网络具有多种机制来促进数据平面和控制平面的分离，包括用于路径设置和保护的分布式信令、用于规划和流量工程的集中式路径计算，以及用于配置和激活网络资源的一系列管理和供应协议。这些机制代表了实现灵活和动态网络的关键技术。本定义范围内的一些网络示例包括光纤、MPLS传输配置文件（MPLS-TP）[RFC5654]和MPLS-TE网络[RFC2702]。
One of the main drivers for Software-Defined Networking (SDN) [RFC7149] is a decoupling of the network control plane from the data plane. This separation has been achieved for TE networks with the development of MPLS/GMPLS [RFC3945] and the Path Computation Element (PCE) [RFC4655]. One of the advantages of SDN is its logically centralized control regime that allows a global view of the underlying networks. Centralized control in SDN helps improve network resource utilization compared with distributed network control. For TE-based networks, a PCE may serve as a logically centralized path computation function.
软件定义网络（SDN）[RFC7149]的主要驱动因素之一是网络控制平面与数据平面的解耦。随着MPLS/GMPLS[RFC3945]和路径计算元件（PCE）[RFC4655]的开发，TE网络实现了这种分离。SDN的优点之一是其逻辑集中的控制机制，允许对底层网络进行全局查看。与分布式网络控制相比，SDN中的集中控制有助于提高网络资源利用率。对于基于TE的网络，PCE可以用作逻辑上集中的路径计算功能。
This document describes a set of management and control functions used to operate one or more TE networks to construct virtual networks that can be presented to customers and that are built from abstractions of the underlying TE networks. For example, a link in
本文档描述了一组管理和控制功能，用于操作一个或多个TE网络，以构建虚拟网络，该虚拟网络可呈现给客户，并根据基础TE网络的抽象构建。例如，中的链接
the customer's network is constructed from a path or collection of paths in the underlying networks. We call this set of functions "Abstraction and Control of TE Networks" or "ACTN".
客户的网络是由底层网络中的一条或多条路径构成的。我们将这组函数称为“TE网络的抽象和控制”或“ACTN”。
Three key aspects that need to be solved by SDN are:
SDN需要解决的三个关键方面是：
o Separation of service requests from service delivery so that the configuration and operation of a network is transparent from the point of view of the customer but it remains responsive to the customer's services and business needs.
o 将服务请求与服务交付分离，以便从客户的角度来看，网络的配置和操作是透明的，但它仍能响应客户的服务和业务需求。
o Network abstraction: As described in [RFC7926], abstraction is the process of applying policy to a set of information about a TE network to produce selective information that represents the potential ability to connect across the network. The process of abstraction presents the connectivity graph in a way that is independent of the underlying network technologies, capabilities, and topology so that the graph can be used to plan and deliver network services in a uniform way
o 网络抽象：如[RFC7926]所述，抽象是将策略应用于一组关于TE网络的信息的过程，以产生表示跨网络连接的潜在能力的选择性信息。抽象过程以一种独立于底层网络技术、能力和拓扑的方式呈现连接图，以便可以使用该图以统一的方式规划和交付网络服务
o Coordination of resources across multiple independent networks and multiple technology layers to provide end-to-end services regardless of whether or not the networks use SDN.
o 跨多个独立网络和多个技术层协调资源，以提供端到端服务，而不管网络是否使用SDN。
As networks evolve, the need to provide support for distinct services, separated service orchestration, and resource abstraction have emerged as key requirements for operators. In order to support multiple customers each with its own view of and control of the server network, a network operator needs to partition (or "slice") or manage sharing of the network resources. Network slices can be assigned to each customer for guaranteed usage, which is a step further than shared use of common network resources.
随着网络的发展，为不同的服务、分离的服务编排和资源抽象提供支持的需求已经成为运营商的关键需求。为了支持多个客户，每个客户都有自己的服务器网络视图和控制权，网络运营商需要对网络资源进行分区（或“切片”）或管理共享。网络片可以分配给每个客户以保证使用，这比共享使用公共网络资源更进一步。
Furthermore, each network represented to a customer can be built from virtualization of the underlying networks so that, for example, a link in the customer's network is constructed from a path or collection of paths in the underlying network.
此外，可以通过基础网络的虚拟化来构建表示给客户的每个网络，以便例如，从基础网络中的路径或路径集合来构建客户网络中的链路。
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) and presenting virtualized networks to their customers.
ACTN可以通过创建单个虚拟化网络或无缝服务来促进虚拟网络操作。这支持运营商查看和控制不同的域（在任何维度：应用技术、管理区域或特定于供应商的技术孤岛），并向客户展示虚拟化网络。
The ACTN framework described in this document facilitates:
本文件中描述的ACTN框架有助于：
o Abstraction of the underlying network resources to higher-layer applications and customers [RFC7926].
o 将底层网络资源抽象到更高层的应用程序和客户[RFC7926]。
o Virtualization of particular underlying resources, whose selection criterion is the allocation of those resources to a particular customer, application, or service [ONF-ARCH].
o 特定底层资源的虚拟化，其选择标准是将这些资源分配给特定客户、应用程序或服务[ONF-ARCH]。
o TE Network slicing of infrastructure to meet specific customers' service requirements.
o 对基础设施进行网络分层，以满足特定客户的服务要求。
o Creation of an abstract environment allowing operators to view and control multi-domain networks as a single abstract network.
o 创建一个抽象环境，允许运营商将多域网络作为单个抽象网络进行查看和控制。
o The presentation to customers of networks as a virtual network via open and programmable interfaces.
o 通过开放和可编程接口向客户展示作为虚拟网络的网络。
The following terms are used in this document. Some of them are newly defined, some others reference existing definitions:
本文件中使用了以下术语。其中一些是新定义的，另一些引用现有定义：
Domain: A domain as defined by [RFC4655] is "any collection of network elements within a common sphere of address management or path computation responsibility". Specifically, within this document we mean a part of an operator's network that is under common management (i.e., under shared operational management using the same instances of a tool and the same policies). Network elements will often be grouped into domains based on technology types, vendor profiles, and geographic proximity.
域：[RFC4655]定义的域是“地址管理或路径计算责任的公共范围内的任何网络元素集合”。具体而言，在本文件中，我们指的是处于共同管理下的运营商网络的一部分（即，在使用相同工具实例和相同策略的共享运营管理下）。网络元素通常会根据技术类型、供应商概况和地理位置的接近程度分为多个域。
Abstraction: This process is defined in [RFC7926].
抽象：此过程在[RFC7926]中定义。
TE Network Slicing: In the context of ACTN, a TE network slice is a collection of resources that is used to establish a logically dedicated virtual network over one or more TE networks. TE network slicing allows a network operator to provide dedicated virtual networks for applications/customers over a common network infrastructure. The logically dedicated resources are a part of the larger common network infrastructures that are shared among various TE network slice instances, which are the end-to-end realization of TE network slicing, consisting of the combination of physically or logically dedicated resources.
TE网络切片：在ACTN的上下文中，TE网络切片是用于在一个或多个TE网络上建立逻辑专用虚拟网络的资源集合。TE网络切片允许网络运营商通过公共网络基础设施为应用程序/客户提供专用虚拟网络。逻辑专用资源是在各种TE网络切片实例之间共享的大型公共网络基础设施的一部分，这些实例是TE网络切片的端到端实现，由物理或逻辑专用资源的组合组成。
Node: A node is a vertex on the graph representation of a TE topology. In a physical network topology, a node corresponds to a physical network element (NE) such as a router. In an abstract network topology, a node (sometimes called an "abstract node") is a representation as a single vertex of one or more physical NEs and their connecting physical connections. The concept of a node represents the ability to connect from any access to the node (a link end) to any other access to that node, although "limited cross-connect capabilities" may also be defined to restrict this functionality. Network abstraction may be applied recursively, so a node in one topology may be created by applying abstraction to the nodes in the underlying topology.
节点：节点是TE拓扑图表示形式上的顶点。在物理网络拓扑中，节点对应于物理网络元件（NE），例如路由器。在抽象网络拓扑中，节点（有时称为“抽象节点”）表示为一个或多个物理网元及其连接物理连接的单个顶点。节点的概念表示从对节点的任何访问（链路端）连接到对该节点的任何其他访问的能力，尽管也可以定义“有限的交叉连接能力”来限制该功能。可以递归地应用网络抽象，因此可以通过对底层拓扑中的节点应用抽象来创建一个拓扑中的节点。
Link: A link is an edge on the graph representation of a TE topology. Two nodes connected by a link are said to be "adjacent" in the TE topology. In a physical network topology, a link corresponds to a physical connection. In an abstract network topology, a link (sometimes called an "abstract link") is a representation of the potential to connect a pair of points with certain TE parameters (see [RFC7926] for details). Network abstraction may be applied recursively, so a link in one topology may be created by applying abstraction to the links in the underlying topology.
链接：链接是TE拓扑的图形表示上的边。通过链路连接的两个节点在TE拓扑中称为“相邻”。在物理网络拓扑中，链路对应于物理连接。在抽象网络拓扑中，链路（有时称为“抽象链路”）表示连接具有特定TE参数的一对点的可能性（详情请参见[RFC7926]）。可以递归地应用网络抽象，因此可以通过对底层拓扑中的链路应用抽象来创建一个拓扑中的链路。
Abstract Topology: The topology of abstract nodes and abstract links presented through the process of abstraction by a lower-layer network for use by a higher-layer network.
抽象拓扑：抽象节点和抽象链接的拓扑，通过较低层网络的抽象过程呈现，供较高层网络使用。
Virtual Network (VN): A VN is a network provided by a service provider to a customer for the customer to use in any way it wants as though it was a physical network. There are two views of a VN as follows:
虚拟网络（VN）：VN是由服务提供商向客户提供的一个网络，供客户以其想要的任何方式使用，就像它是一个物理网络一样。VN有两个视图，如下所示：
o The VN can be abstracted as a set of edge-to-edge links (a Type 1 VN). Each link is referred as a "VN member" and is formed as an end-to-end tunnel across the underlying networks. Such tunnels may be constructed by recursive slicing or abstraction of paths in the underlying networks and can encompass edge points of the customer's network, access links, intra-domain paths, and inter-domain links.
o VN可以抽象为一组边到边链接（类型1 VN）。每个链路被称为“VN成员”，并形成为跨底层网络的端到端隧道。这种隧道可以通过递归切片或对底层网络中的路径进行抽象来构建，并且可以包含客户网络的边缘点、接入链路、域内路径和域间链路。
o The VN can also be abstracted as a topology of virtual nodes and virtual links (a Type 2 VN). The operator needs to map the VN to actual resource assignment, which is known as "virtual network embedding". The nodes in this case include physical endpoints, border nodes, and internal nodes as well as
o VN也可以抽象为虚拟节点和虚拟链路的拓扑（类型2 VN）。运营商需要将VN映射到实际的资源分配，这被称为“虚拟网络嵌入”。本例中的节点包括物理端点、边界节点、内部节点以及
abstracted nodes. Similarly, the links include physical access links, inter-domain links, and intra-domain links as well as abstract links.
抽象节点。类似地，链路包括物理访问链路、域间链路、域内链路以及抽象链路。
Clearly, a Type 1 VN is a special case of a Type 2 VN.
显然，1型VN是2型VN的特例。
Access link: A link between a customer node and an operator node.
访问链接：客户节点和运营商节点之间的链接。
Inter-domain link: A link between domains under distinct management administration.
域间链接：在不同管理下的域之间的链接。
Access Point (AP): An AP is a logical identifier shared between the customer and the operator used to identify an access link. The AP is used by the customer when requesting a Virtual Network Service (VNS). Note that the term "TE Link Termination Point" defined in [TE-TOPO] describes the endpoints of links, while an AP is a common identifier for the link itself.
接入点（AP）：AP是客户和运营商之间共享的逻辑标识符，用于标识接入链路。客户在请求虚拟网络服务（VNS）时使用AP。注意，[TE-TOPO]中定义的术语“TE链路终止点”描述链路的端点，而AP是链路本身的公共标识符。
VN Access Point (VNAP): A VNAP is the binding between an AP and a given VN.
VN访问点（VNAP）：VNAP是AP和给定VN之间的绑定。
Server Network: As defined in [RFC7926], a server network is a network that provides connectivity for another network (the Client Network) in a client-server relationship.
服务器网络：如[RFC7926]中所定义，服务器网络是为客户机-服务器关系中的另一个网络（客户机网络）提供连接的网络。
A Virtual Network Service (VNS) is the service agreement between a customer and operator to provide a VN. When a VN is a simple connectivity between two points, the difference between VNS and connectivity service becomes blurred. There are three types of VNSs defined in this document.
虚拟网络服务（VNS）是客户和运营商之间提供虚拟网络的服务协议。当VN是两点之间的简单连接时，VN和连接服务之间的区别变得模糊。本文档中定义了三种类型的VNS。
o Type 1 VNS refers to a VNS in which the customer is allowed to create and operate a Type 1 VN.
o 类型1 VNS指允许客户创建和操作类型1 VN的VNS。
o Type 2a and 2b VNS refer to VNSs in which the customer is allowed to create and operates a Type 2 VN. With a Type 2a VNS, the VN is statically created at service configuration time, and the customer is not allowed to change the topology (e.g., by adding or deleting abstract nodes and links). A Type 2b VNS is the same as a Type 2a VNS except that the customer is allowed to make dynamic changes to the initial topology created at service configuration time.
o 2a型和2b型VN是指允许客户创建和操作2型VN的VNS。对于2a型VN，VN是在服务配置时静态创建的，不允许客户更改拓扑（例如，通过添加或删除抽象节点和链接）。2b型VNS与2a型VNS相同，只是允许客户对服务配置时创建的初始拓扑进行动态更改。
VN Operations are functions that a customer can exercise on a VN depending on the agreement between the customer and the operator.
VN操作是客户可以根据客户和运营商之间的协议在VN上执行的功能。
o VN Creation allows a customer to request the instantiation of a VN. This could be through offline preconfiguration or through dynamic requests specifying attributes to a Service Level Agreement (SLA) to satisfy the customer's objectives.
o VN创建允许客户请求VN的实例化。这可以通过离线预配置或通过动态请求指定服务级别协议（SLA）的属性来满足客户的目标。
o Dynamic Operations allow a customer to modify or delete the VN. The customer can further act upon the virtual network to create/modify/delete virtual links and nodes. These changes will result in subsequent tunnel management in the operator's networks.
o 动态操作允许客户修改或删除VN。客户可以进一步操作虚拟网络以创建/修改/删除虚拟链路和节点。这些变化将导致运营商网络中的后续隧道管理。
There are three key entities in the ACTN VNS model:
ACTN VNS模型中有三个关键实体：
o Customers o Service Providers o Network Operators
o 客户、服务提供商、网络运营商
These entities are related in a three tier model as shown in Figure 1.
这些实体在三层模型中是相关的，如图1所示。
+----------------------+
| Customer |
+----------------------+
|
VNS || | /\ VNS
Request || | || Reply
\/ | ||
+----------------------+
| Service Provider |
+----------------------+
/ | \
/ | \
/ | \
/ | \
+------------------+ +------------------+ +------------------+
|Network Operator 1| |Network Operator 2| |Network Operator 3|
+------------------+ +------------------+ +------------------+
+----------------------+
| Customer |
+----------------------+
|
VNS || | /\ VNS
Request || | || Reply
\/ | ||
+----------------------+
| Service Provider |
+----------------------+
/ | \
/ | \
/ | \
/ | \
+------------------+ +------------------+ +------------------+
|Network Operator 1| |Network Operator 2| |Network Operator 3|
+------------------+ +------------------+ +------------------+
Figure 1: The Three-Tier Model
图1：三层模型
The commercial roles of these entities are described in the following sections.
这些实体的商业角色将在以下章节中描述。
Basic customers include fixed residential users, mobile users, and small enterprises. Each requires a small amount of resources and is characterized by steady requests (relatively time invariant). Basic customers do not modify their services themselves: if a service change is needed, it is performed by the provider as a proxy.
基本客户包括固定住宅用户、移动用户和小型企业。每个请求都需要少量资源，并且具有稳定的请求（相对时间不变）的特点。基本客户不会自行修改其服务：如果需要更改服务，则由提供商作为代理执行。
Advanced customers include enterprises and governments. Such customers ask for both point-to point and multipoint connectivity with high resource demands varying significantly in time. This is one of the reasons why a bundled service offering is not enough, and it is desirable to provide each advanced customer with a customized VNS. Advanced customers may also have the ability to modify their service parameters within the scope of their virtualized environments. The primary focus of ACTN is Advanced Customers.
先进客户包括企业和政府。这类客户要求点对点和多点连接，高资源需求随时间显著变化。这是捆绑服务不够的原因之一，最好为每个高级客户提供定制的VNS。高级客户还可以在其虚拟化环境的范围内修改其服务参数。ACTN的主要关注点是高级客户。
As customers are geographically spread over multiple network operator domains, they have to interface to multiple operators and may have to support multiple virtual network services with different underlying objectives set by the network operators. To enable these customers to support flexible and dynamic applications, they need to control their allocated virtual network resources in a dynamic fashion; that means that they need a view of the topology that spans all of the network operators. Customers of a given service provider can, in turn, offer a service to other customers in a recursive way.
由于客户在地理上分布在多个网络运营商域，因此他们必须与多个运营商建立接口，并且可能必须支持多个虚拟网络服务，网络运营商设定了不同的基本目标。为了使这些客户能够支持灵活和动态的应用程序，他们需要以动态方式控制分配的虚拟网络资源；这意味着他们需要一个覆盖所有网络运营商的拓扑视图。给定服务提供商的客户可以反过来以递归方式向其他客户提供服务。
In the scope of ACTN, service providers deliver VNSs to their customers. Service providers may or may not own physical network resources (i.e., may or may not be network operators as described in Section 2.2.3). When a service provider is the same as the network operator, the case is similar to existing VPN models applied to a single operator (although it may be hard to use this approach when the customer spans multiple independent network operator domains).
在ACTN范围内，服务提供商向其客户提供VNS。服务提供商可能拥有也可能不拥有物理网络资源（即，可能是也可能不是第2.2.3节所述的网络运营商）。当服务提供商与网络运营商相同时，情况类似于应用于单个运营商的现有VPN模型（尽管当客户跨越多个独立的网络运营商域时，可能很难使用这种方法）。
When network operators supply only infrastructure, while distinct service providers interface with the customers, the service providers are themselves customers of the network infrastructure operators. One service provider may need to keep multiple independent network operators because its end users span geographically across multiple network operator domains. In some cases, a service provider is also a network operator when it owns network infrastructure on which service is provided.
当网络运营商只提供基础设施，而不同的服务提供商与客户交互时，服务提供商本身就是网络基础设施运营商的客户。一个服务提供商可能需要保留多个独立的网络运营商，因为其最终用户在地理上跨越多个网络运营商域。在某些情况下，当服务提供商拥有提供服务的网络基础设施时，它也是网络运营商。
Network operators are the infrastructure operators that provision the network resources and provide network resources to their customers. The layered model described in this architecture separates the concerns of network operators and customers, with service providers acting as aggregators of customer requests.
网络运营商是提供网络资源并向其客户提供网络资源的基础设施运营商。该体系结构中描述的分层模型分离了网络运营商和客户的关注点，服务提供商充当客户请求的聚合器。
This section provides a high-level model of ACTN, showing the interfaces and the flow of control between components.
本节提供了ACTN的高级模型，显示了组件之间的接口和控制流。
The ACTN architecture is based on a three-tier reference model and allows for hierarchy and recursion. The main functionalities within an ACTN system are:
ACTN体系结构基于三层参考模型，并允许分层和递归。ACTN系统内的主要功能包括：
o Multi-domain coordination: This function oversees the specific aspects of different domains and builds a single abstracted end-to-end network topology in order to coordinate end-to-end path computation and path/service provisioning. Domain sequence path calculation/determination is also a part of this function.
o 多域协调：此功能监督不同域的特定方面，并构建单个抽象的端到端网络拓扑，以协调端到端路径计算和路径/服务供应。域序列路径计算/确定也是此功能的一部分。
o Abstraction: This function provides an abstracted view of the underlying network resources for use by the customer -- a customer may be the client or a higher-level controller entity. This function includes network path computation based on customer-service-connectivity request constraints, path computation based on the global network-wide abstracted topology, and the creation of an abstracted view of network resources allocated to each customer. These operations depend on customer-specific network objective functions and customer traffic profiles.
o 抽象：此函数提供底层网络资源的抽象视图供客户使用——客户可以是客户机或更高级别的控制器实体。此功能包括基于客户服务连接性请求约束的网络路径计算、基于全局网络范围抽象拓扑的路径计算，以及创建分配给每个客户的网络资源的抽象视图。这些操作取决于特定于客户的网络目标函数和客户流量配置文件。
o Customer mapping/translation: This function is to map customer requests/commands into network provisioning requests that can be sent from the Multi-Domain Service Coordinator (MDSC) to the Provisioning Network Controller (PNC) according to business policies provisioned statically or dynamically at the Operations Support System (OSS) / Network Management System (NMS). Specifically, it provides mapping and translation of a customer's service request into a set of parameters that are specific to a network type and technology such that network configuration process is made possible.
o 客户映射/转换：此功能用于将客户请求/命令映射为网络配置请求，这些请求可以根据在操作支持系统（OSS）静态或动态配置的业务策略从多域服务协调器（MDSC）发送到配置网络控制器（PNC）/网络管理系统（NMS）。具体而言，它将客户的服务请求映射并转换为一组特定于网络类型和技术的参数，从而使网络配置过程成为可能。
o Virtual service coordination: This function translates information that is customer service related into virtual network service operations in order to seamlessly operate virtual networks while meeting a customer's service requirements. In the context of
o 虚拟服务协调：此功能将与客户服务相关的信息转换为虚拟网络服务操作，以便在满足客户服务需求的同时无缝操作虚拟网络。在
ACTN, service/virtual service coordination includes a number of service orchestration functions such as multi-destination load-balancing and guarantees of service quality. It also includes notifications for service fault and performance degradation and so forth.
服务/虚拟服务协调包括许多服务编排功能，如多目标负载平衡和服务质量保证。它还包括服务故障和性能下降等通知。
The base ACTN architecture defines three controller types and the corresponding interfaces between these controllers. The following types of controller are shown in Figure 2:
基本ACTN体系结构定义了三种控制器类型以及这些控制器之间的相应接口。图2显示了以下类型的控制器：
o CNC - Customer Network Controller o MDSC - Multi-Domain Service Coordinator o PNC - Provisioning Network Controller
o CNC-客户网络控制器o MDSC-多域服务协调员o PNC-供应网络控制器
Figure 2 also shows the following interfaces
图2还显示了以下接口
o CMI - CNC-MDSC Interface o MPI - MDSC-PNC Interface o SBI - Southbound Interface
o CMI-CNC-MDSC接口o MPI-MDSC-PNC接口o SBI-南行接口
+---------+ +---------+ +---------+
| CNC | | CNC | | CNC |
+---------+ +---------+ +---------+
\ | /
\ | /
Boundary ========\==================|=====================/=======
between \ | /
Customer & ----------- | CMI --------------
Network Operator \ | /
+---------------+
| MDSC |
+---------------+
/ | \
------------ | MPI -------------
/ | \
+-------+ +-------+ +-------+
| PNC | | PNC | | PNC |
+-------+ +-------+ +-------+
| SBI / | / \
| / | SBI SBI / \
--------- ----- | / \
( ) ( ) | / \
- Control - ( Phys. ) | / -----
( Plane ) ( Net ) | / ( )
( Physical ) ----- | / ( Phys. )
( Network ) ----- ----- ( Net )
- - ( ) ( ) -----
( ) ( Phys. ) ( Phys. )
--------- ( Net ) ( Net )
----- -----
+---------+ +---------+ +---------+
| CNC | | CNC | | CNC |
+---------+ +---------+ +---------+
\ | /
\ | /
Boundary ========\==================|=====================/=======
between \ | /
Customer & ----------- | CMI --------------
Network Operator \ | /
+---------------+
| MDSC |
+---------------+
/ | \
------------ | MPI -------------
/ | \
+-------+ +-------+ +-------+
| PNC | | PNC | | PNC |
+-------+ +-------+ +-------+
| SBI / | / \
| / | SBI SBI / \
--------- ----- | / \
( ) ( ) | / \
- Control - ( Phys. ) | / -----
( Plane ) ( Net ) | / ( )
( Physical ) ----- | / ( Phys. )
( Network ) ----- ----- ( Net )
- - ( ) ( ) -----
( ) ( Phys. ) ( Phys. )
--------- ( Net ) ( Net )
----- -----
Figure 2: ACTN Base Architecture
图2:ACTN基础架构
Note that this is a functional architecture: an implementation and deployment might collocate one or more of the functional components. Figure 2 shows a case where the service provider is also a network operator.
请注意，这是一个功能架构：实现和部署可能会将一个或多个功能组件并置。图2显示了服务提供商也是网络运营商的情况。
A Customer Network Controller (CNC) is responsible for communicating a customer's VNS requirements to the network operator over the CNC-MDSC Interface (CMI). It has knowledge of the endpoints associated with the VNS (expressed as APs), the service policy, and other QoS information related to the service.
客户网络控制器（CNC）负责通过CNC-MDSC接口（CMI）向网络运营商传达客户的VNS要求。它了解与VN（表示为AP）关联的端点、服务策略以及与服务相关的其他QoS信息。
As the CNC directly interfaces with the applications, it understands multiple application requirements and their service needs. The capability of a CNC beyond its CMI role is outside the scope of ACTN and may be implemented in different ways. For example, the CNC may, in fact, be a controller or part of a controller in the customer's domain, or the CNC functionality could also be implemented as part of a service provider's portal.
由于CNC直接与应用程序接口，它了解多种应用程序需求及其服务需求。CNC超出其CMI角色的能力不在ACTN的范围内，可以以不同的方式实现。例如，CNC实际上可以是客户域中的控制器或控制器的一部分，或者CNC功能也可以作为服务提供商门户的一部分实现。
A Multi-Domain Service Coordinator (MDSC) is a functional block that implements all of the ACTN functions listed in Section 3 and described further in Section 4.2. Two functions of the MDSC, namely, multi-domain coordination and virtualization/abstraction are referred to as network-related functions; whereas the other two functions, namely, customer mapping/translation and virtual service coordination, are referred to as service-related functions. The MDSC sits at the center of the ACTN model between the CNC that issues connectivity requests and the Provisioning Network Controllers (PNCs) that manage the network resources. The key point of the MDSC (and of the whole ACTN framework) is detaching the network and service control from underlying technology to help the customer express the network as desired by business needs. The MDSC envelopes the instantiation of the right technology and network control to meet business criteria. In essence, it controls and manages the primitives to achieve functionalities as desired by the CNC.
多域服务协调器（MDSC）是一个功能块，它实现了第3节中列出的所有ACTN功能，并在第4.2节中作了进一步描述。MDSC的两个功能，即多域协调和虚拟化/抽象被称为网络相关功能；而其他两个功能，即客户映射/翻译和虚拟服务协调，则称为服务相关功能。MDSC位于ACTN模型的中心，位于发出连接请求的CNC和管理网络资源的供应网络控制器（PNC）之间。MDSC（以及整个ACTN框架）的关键点是将网络和服务控制与底层技术分离，以帮助客户根据业务需求表达网络。MDSC封装了正确技术和网络控制的实例，以满足业务标准。本质上，它控制和管理原语，以实现CNC所需的功能。
In order to allow for multi-domain coordination, a 1:N relationship must be allowed between MDSCs and PNCs.
为了允许多域协调，MDSC和PNC之间必须允许1:N关系。
In addition to that, it could also be possible to have an M:1 relationship between MDSCs and PNCs to allow for network-resource partitioning/sharing among different customers that are not necessarily connected to the same MDSC (e.g., different service providers) but that are all using the resources of a common network infrastructure operator.
除此之外，还可以在MDSC和PNC之间建立M:1关系，以允许不同客户之间的网络资源分区/共享，这些客户不一定连接到同一MDSC（例如，不同的服务提供商），但都使用公共网络基础设施运营商的资源。
The Provisioning Network Controller (PNC) oversees configuring the network elements, monitoring the topology (physical or virtual) of the network, and collecting information about the topology (either raw or abstracted).
供应网络控制器（PNC）监督配置网元、监控网络拓扑（物理或虚拟）以及收集拓扑信息（原始或抽象）。
The PNC functions can be implemented as part of an SDN domain controller, a Network Management System (NMS), an Element Management System (EMS), an active PCE-based controller [RFC8283], or any other means to dynamically control a set of nodes that implements a
PNC功能可以作为SDN域控制器、网络管理系统（NMS）、元素管理系统（EMS）、基于活动PCE的控制器[RFC8283]的一部分来实现，或者可以作为动态控制一组节点的任何其他方式来实现
northbound interface from the standpoint of the nodes (which is out of the scope of this document). A PNC domain includes all the resources under the control of a single PNC. It can be composed of different routing domains and administrative domains, and the resources may come from different layers. The interconnection between PNC domains is illustrated in Figure 3.
从节点的角度来看，北向接口（不在本文档范围内）。PNC域包括单个PNC控制下的所有资源。它可以由不同的路由域和管理域组成，资源可能来自不同的层。PNC域之间的互连如图3所示。
_______ _______
_( )_ _( )_
_( )_ _( )_
( ) Border ( )
( PNC ------ Link ------ PNC )
( Domain X |Border|========|Border| Domain Y )
( | Node | | Node | )
( ------ ------ )
(_ _) (_ _)
(_ _) (_ _)
(_______) (_______)
_______ _______
_( )_ _( )_
_( )_ _( )_
( ) Border ( )
( PNC ------ Link ------ PNC )
( Domain X |Border|========|Border| Domain Y )
( | Node | | Node | )
( ------ ------ )
(_ _) (_ _)
(_ _) (_ _)
(_______) (_______)
Figure 3: PNC Domain Borders
图3:PNC域边界
Direct customer control of transport network elements and virtualized services is not a viable proposition for network operators due to security and policy concerns. Therefore, the network has to provide open, programmable interfaces, through which customer applications can create, replace, and modify virtual network resources and services in an interactive, flexible, and dynamic fashion.
由于安全和政策方面的考虑，对于网络运营商来说，直接由客户控制传输网络元件和虚拟化服务不是一个可行的方案。因此，网络必须提供开放、可编程的接口，通过这些接口，客户应用程序可以以交互、灵活和动态的方式创建、替换和修改虚拟网络资源和服务。
Three interfaces exist in the ACTN architecture as shown in Figure 2.
ACTN体系结构中存在三个接口，如图2所示。
o CMI: The CNC-MDSC Interface (CMI) is an interface between a CNC and an MDSC. The CMI is a business boundary between customer and network operator. It is used to request a VNS for an application. All service-related information is conveyed over this interface (such as the VNS type, topology, bandwidth, and service constraints). Most of the information over this interface is agnostic of the technology used by network operators, but there are some cases (e.g., access link configuration) where it is necessary to specify technology-specific details.
o CMI:CNC-MDSC接口（CMI）是CNC和MDSC之间的接口。CMI是客户和网络运营商之间的业务边界。它用于为应用程序请求VNS。所有与服务相关的信息都通过该接口传输（例如VNS类型、拓扑、带宽和服务约束）。此接口上的大多数信息与网络运营商使用的技术无关，但在某些情况下（例如，访问链路配置），有必要指定特定于技术的详细信息。
o MPI: The MDSC-PNC Interface (MPI) is an interface between an MDSC and a PNC. It communicates requests for new connectivity or for bandwidth changes in the physical network. In multi-domain environments, the MDSC needs to communicate with multiple PNCs,
o MPI:MDSC-PNC接口（MPI）是MDSC和PNC之间的接口。它传递对物理网络中新连接或带宽更改的请求。在多域环境中，MDSC需要与多个PNC通信，
each responsible for control of a domain. The MPI presents an abstracted topology to the MDSC hiding technology-specific aspects of the network and hiding topology according to policy.
每个人负责控制一个域。MPI为MDSC隐藏技术提供了一个抽象的拓扑，隐藏网络的特定方面，并根据策略隐藏拓扑。
o SBI: The Southbound Interface (SBI) is out of scope of ACTN. Many different SBIs have been defined for different environments, technologies, standards organizations, and vendors. It is shown in Figure 3 for reference reason only.
o SBI：南行接口（SBI）不在ACTN范围内。针对不同的环境、技术、标准组织和供应商定义了许多不同的SBI。图3所示仅供参考。
This section describes advanced configurations of the ACTN architecture.
本节介绍ACTN体系结构的高级配置。
A hierarchy of MDSCs can be foreseen for many reasons, among which are scalability, administrative choices, or putting together different layers and technologies in the network. In the case where there is a hierarchy of MDSCs, we introduce the terms "higher-level MDSC" (MDSC-H) and "lower-level MDSC" (MDSC-L). The interface between them is a recursion of the MPI. An implementation of an MDSC-H makes provisioning requests as normal using the MPI, but an MDSC-L must be able to receive requests as normal at the CMI and also at the MPI. The hierarchy of MDSCs can be seen in Figure 4.
由于许多原因，可以预见MDSC的层次结构，其中包括可伸缩性、管理选择或将不同的层和技术组合在一起。在存在MDSC层次结构的情况下，我们引入术语“高级MDSC”（MDSC-H）和“低级MDSC”（MDSC-L）。它们之间的接口是MPI的递归。MDSC-H的实现使用MPI使资源调配请求正常，但MDSC-L必须能够在CMI和MPI上正常接收请求。MDSC的层次结构如图4所示。
Another implementation choice could foresee the usage of an MDSC-L for all the PNCs related to a given technology (e.g., Internet Protocol (IP) / Multiprotocol Label Switching (MPLS)) and a different MDSC-L for the PNCs related to another technology (e.g., Optical Transport Network (OTN) / Wavelength Division Multiplexing (WDM)) and an MDSC-H to coordinate them.
另一个实现选择可以预见对与给定技术（例如，因特网协议（IP）/多协议标签交换（MPLS））相关的所有pnc使用MDSC-L，并对与另一技术（例如，光传输网络（OTN）/波分复用（WDM））相关的pnc使用不同的MDSC-L和一个MDSC-H来协调它们。
+--------+
| CNC |
+--------+
| +-----+
| CMI | CNC |
+----------+ +-----+
-------| MDSC-H |---- |
| +----------+ | | CMI
MPI | MPI | |
| | |
+---------+ +---------+
| MDSC-L | | MDSC-L |
+---------+ +---------+
MPI | | | |
| | | |
----- ----- ----- -----
| PNC | | PNC | | PNC | | PNC |
----- ----- ----- -----
+--------+
| CNC |
+--------+
| +-----+
| CMI | CNC |
+----------+ +-----+
-------| MDSC-H |---- |
| +----------+ | | CMI
MPI | MPI | |
| | |
+---------+ +---------+
| MDSC-L | | MDSC-L |
+---------+ +---------+
MPI | | | |
| | | |
----- ----- ----- -----
| PNC | | PNC | | PNC | | PNC |
----- ----- ----- -----
Figure 4: MDSC Hierarchy
图4:MDSC层次结构
The hierarchy of MDSC can be recursive, where an MDSC-H is, in turn, an MDSC-L to a higher-level MDSC-H.
MDSC的层次结构可以是递归的，其中MDSC-H是从MDSC-L到更高级别的MDSC-H。
An implementation choice could separate the MDSC functions into two groups: one group for service-related functions and the other for network-related functions. This enables the implementation of a service orchestrator that provides the service-related functions of the MDSC and a network orchestrator that provides the network-related functions of the MDSC. This split is consistent with the YANG service model architecture described in [RFC8309]. Figure 5 depicts this and shows how the ACTN interfaces may map to YANG data models.
实现选项可以将MDSC功能分为两组：一组用于服务相关功能，另一组用于网络相关功能。这允许实现提供MDSC的服务相关功能的服务编排器和提供MDSC的网络相关功能的网络编排器。此拆分与[RFC8309]中描述的YANG服务模型体系结构一致。图5描述了这一点，并显示了ACTN接口如何映射到数据模型。
+--------------------+
| Customer |
| +-----+ |
| | CNC | |
| +-----+ |
+--------------------+
CMI | Customer Service Model
|
+---------------------------------------+
| Service |
********|*********************** Orchestrator |
* MDSC | +-----------------+ * |
* | | Service-related | * |
* | | Functions | * |
* | +-----------------+ * |
* +----------------------*----------------+
* * | Service Delivery
* * | Model
* +----------------------*----------------+
* | * Network |
* | +-----------------+ * Orchestrator |
* | | Network-related | * |
* | | Functions | * |
* | +-----------------+ * |
********|*********************** |
+---------------------------------------+
MPI | Network Configuration
| Model
+------------------------+
| Domain |
| +------+ Controller |
| | PNC | |
| +------+ |
+------------------------+
SBI | Device Configuration
| Model
+--------+
| Device |
+--------+
+--------------------+
| Customer |
| +-----+ |
| | CNC | |
| +-----+ |
+--------------------+
CMI | Customer Service Model
|
+---------------------------------------+
| Service |
********|*********************** Orchestrator |
* MDSC | +-----------------+ * |
* | | Service-related | * |
* | | Functions | * |
* | +-----------------+ * |
* +----------------------*----------------+
* * | Service Delivery
* * | Model
* +----------------------*----------------+
* | * Network |
* | +-----------------+ * Orchestrator |
* | | Network-related | * |
* | | Functions | * |
* | +-----------------+ * |
********|*********************** |
+---------------------------------------+
MPI | Network Configuration
| Model
+------------------------+
| Domain |
| +------+ Controller |
| | PNC | |
| +------+ |
+------------------------+
SBI | Device Configuration
| Model
+--------+
| Device |
+--------+
Figure 5: ACTN Architecture in the Context of the YANG Service Models
图5：服务模型上下文中的ACTN体系结构
Topology abstraction is described in [RFC7926]. This section discusses topology abstraction factors, types, and their context in the ACTN architecture.
[RFC7926]中描述了拓扑抽象。本节讨论ACTN体系结构中的拓扑抽象因素、类型及其上下文。
Abstraction in ACTN is performed by the PNC when presenting available topology to the MDSC, or by an MDSC-L when presenting topology to an MDSC-H. This function is different from the creation of a VN (and particularly a Type 2 VN) that is not abstraction but construction of virtual resources.
ACTN中的抽象由PNC在向MDSC呈现可用拓扑时执行，或由MDSC-L在向MDSC-H呈现拓扑时执行。此功能不同于创建不是抽象而是构建虚拟资源的VN（尤其是类型2 VN）。
As discussed in [RFC7926], abstraction is tied with the policy of the networks. For instance, per an operational policy, the PNC would not provide any technology-specific details (e.g., optical parameters for Wavelength Switched Optical Network (WSON) in the abstract topology it provides to the MDSC. Similarly, the policy of the networks may determine the abstraction type as described in Section 5.2.
正如[RFC7926]中所讨论的，抽象和网络的策略相联系。例如，根据运营政策，PNC不会在其提供给MDSC的抽象拓扑中提供任何特定于技术的细节（例如，波长交换光网络（WSON）的光学参数）。类似地，网络政策可能会确定第5.2节所述的抽象类型。
There are many factors that may impact the choice of abstraction:
有许多因素可能会影响抽象的选择：
o Abstraction depends on the nature of the underlying domain networks. For instance, packet networks may be abstracted with fine granularity while abstraction of optical networks depends on the switching units (such as wavelengths) and the end-to-end continuity and cross-connect limitations within the network.
o 抽象取决于底层域网络的性质。例如，分组网络可以细粒度抽象，而光网络的抽象取决于交换单元（例如波长）以及网络内的端到端连续性和交叉连接限制。
o Abstraction also depends on the capability of the PNCs. As abstraction requires hiding details of the underlying network resources, the PNC's capability to run algorithms impacts the feasibility of abstraction. Some PNCs may not have the ability to abstract native topology while other PNCs may have the ability to use sophisticated algorithms.
o 抽象还取决于PNC的能力。由于抽象需要隐藏底层网络资源的细节，PNC运行算法的能力会影响抽象的可行性。一些PNC可能没有能力抽象本机拓扑，而其他PNC可能有能力使用复杂的算法。
o Abstraction is a tool that can improve scalability. Where the native network resource information is of a large size, there is a specific scaling benefit to abstraction.
o 抽象是一种可以提高可伸缩性的工具。当本机网络资源信息较大时，抽象具有特定的扩展优势。
o The proper abstraction level may depend on the frequency of topology updates and vice versa.
o 适当的抽象级别可能取决于拓扑更新的频率，反之亦然。
o The nature of the MDSC's support for technology-specific parameters impacts the degree/level of abstraction. If the MDSC is not capable of handling such parameters, then a higher level of abstraction is needed.
o MDSC对特定于技术的参数的支持的性质会影响抽象的程度/级别。如果MDSC无法处理此类参数，则需要更高级别的抽象。
o In some cases, the PNC is required to hide key internal topological data from the MDSC. Such confidentiality can be achieved through abstraction.
o 在某些情况下，需要PNC对MDSC隐藏关键内部拓扑数据。这种保密性可以通过抽象实现。
This section defines the following three types of topology abstraction:
本节定义了以下三种类型的拓扑抽象：
o Native/White Topology (Section 5.2.1) o Black Topology (Section 5.2.2) o Grey Topology (Section 5.2.3)
o 本地/白色拓扑（第5.2.1节）o黑色拓扑（第5.2.2节）o灰色拓扑（第5.2.3节）
This is a case where the PNC provides the actual network topology to the MDSC without any hiding or filtering of information, i.e., no abstraction is performed. In this case, the MDSC has the full knowledge of the underlying network topology and can operate on it directly.
在这种情况下，PNC向MDSC提供实际网络拓扑，而不隐藏或过滤信息，即不执行抽象。在这种情况下，MDSC完全了解底层网络拓扑，可以直接对其进行操作。
A black topology replaces a full network with a minimal representation of the edge-to-edge topology without disclosing any node internal connectivity information. The entire domain network may be abstracted as a single abstract node with the network's access/egress links appearing as the ports to the abstract node and the implication that any port can be "cross-connected" to any other. Figure 6 depicts a native topology with the corresponding black topology with one virtual node and inter-domain links. In this case, the MDSC has to make a provisioning request to the PNCs to establish the port-to-port connection. If there is a large number of interconnected domains, this abstraction method may impose a heavy coordination load at the MDSC level in order to find an optimal end-to-end path since the abstraction hides so much information that it is not possible to determine whether an end-to-end path is feasible without asking each PNC to set up each path fragment. For this reason, the MPI might need to be enhanced to allow the PNCs to be queried for the practicality and characteristics of paths across the abstract node.
黑色拓扑用边到边拓扑的最小表示形式替换完整网络，而不公开任何节点内部连接信息。整个域网络可以抽象为单个抽象节点，网络的访问/出口链路显示为抽象节点的端口，并且暗示任何端口可以“交叉连接”到任何其他端口。图6描述了一个本机拓扑，其对应的黑色拓扑具有一个虚拟节点和域间链路。在这种情况下，MDSC必须向PNC发出配置请求，以建立端口到端口的连接。如果存在大量相互连接的域，这种抽象方法可能会在MDSC级别施加沉重的协调负载，以便找到最佳的端到端路径，因为抽象隐藏了太多的信息，以至于不要求每个PNC设置每个路径片段就无法确定端到端路径是否可行。因此，可能需要增强MPI，以允许查询PNC以了解抽象节点上路径的实用性和特性。
.....................................
: PNC Domain :
: +--+ +--+ +--+ +--+ :
------+ +-----+ +-----+ +-----+ +------
: ++-+ ++-+ +-++ +-++ :
: | | | | :
: | | | | :
: | | | | :
: | | | | :
: ++-+ ++-+ +-++ +-++ :
------+ +-----+ +-----+ +-----+ +------
: +--+ +--+ +--+ +--+ :
:....................................
.....................................
: PNC Domain :
: +--+ +--+ +--+ +--+ :
------+ +-----+ +-----+ +-----+ +------
: ++-+ ++-+ +-++ +-++ :
: | | | | :
: | | | | :
: | | | | :
: | | | | :
: ++-+ ++-+ +-++ +-++ :
------+ +-----+ +-----+ +-----+ +------
: +--+ +--+ +--+ +--+ :
:....................................
+----------+
---+ +---
| Abstract |
| Node |
---+ +---
+----------+
+----------+
---+ +---
| Abstract |
| Node |
---+ +---
+----------+
Figure 6: Native Topology with Corresponding Black Topology Expressed as an Abstract Node
图6：本机拓扑，对应的黑色拓扑表示为抽象节点
A grey topology represents a compromise between black and white topologies from a granularity point of view. In this case, the PNC exposes an abstract topology containing all PNC domain border nodes and an abstraction of the connectivity between those border nodes. This abstraction may contain either physical or abstract nodes/links.
灰色拓扑表示从粒度角度看黑白拓扑之间的折衷。在这种情况下，PNC公开了一个包含所有PNC域边界节点的抽象拓扑以及这些边界节点之间的连接的抽象。此抽象可能包含物理或抽象节点/链接。
Two types of grey topology are identified:
确定了两种灰色拓扑：
o In a type A grey topology, border nodes are connected by a full mesh of TE links (see Figure 7).
o 在a型灰色拓扑中，边界节点通过TE链接的完整网格连接（见图7）。
o In a type B grey topology, border nodes are connected over a more-detailed network comprising internal abstract nodes and abstracted links. This mode of abstraction supplies the MDSC with more information about the internals of the PNC domain and allows it to make more informed choices about how to route connectivity over the underlying network.
o 在B型灰色拓扑中，边界节点通过更详细的网络连接，该网络包括内部抽象节点和抽象链接。这种抽象模式为MDSC提供了有关PNC域内部的更多信息，并允许它对如何在底层网络上路由连接做出更明智的选择。
.....................................
: PNC Domain :
: +--+ +--+ +--+ +--+ :
------+ +-----+ +-----+ +-----+ +------
: ++-+ ++-+ +-++ +-++ :
: | | | | :
: | | | | :
: | | | | :
: | | | | :
: ++-+ ++-+ +-++ +-++ :
------+ +-----+ +-----+ +-----+ +------
: +--+ +--+ +--+ +--+ :
:....................................
.....................................
: PNC Domain :
: +--+ +--+ +--+ +--+ :
------+ +-----+ +-----+ +-----+ +------
: ++-+ ++-+ +-++ +-++ :
: | | | | :
: | | | | :
: | | | | :
: | | | | :
: ++-+ ++-+ +-++ +-++ :
------+ +-----+ +-----+ +-----+ +------
: +--+ +--+ +--+ +--+ :
:....................................
....................
: Abstract Network :
: :
: +--+ +--+ :
-------+ +----+ +-------
: ++-+ +-++ :
: | \ / | :
: | \/ | :
: | /\ | :
....................
: Abstract Network :
: :
: +--+ +--+ :
-------+ +----+ +-------
: ++-+ +-++ :
: | \ / | :
: | \/ | :
: | /\ | :
: | / \ | :
: ++-+ +-++ :
-------+ +----+ +-------
: +--+ +--+ :
:..................:
: | / \ | :
: ++-+ +-++ :
-------+ +----+ +-------
: +--+ +--+ :
:..................:
Figure 7: Native Topology with Corresponding Grey Topology
图7：具有相应灰色拓扑的本机拓扑
This section discusses two different methods of building a grey topology:
本节讨论构建灰色拓扑的两种不同方法：
o Automatic generation of abstract topology by configuration (Section 5.3.1)
o 通过配置自动生成抽象拓扑（第5.3.1节）
o On-demand generation of supplementary topology via path computation request/reply (Section 5.3.2)
o 通过路径计算请求/回复按需生成补充拓扑（第5.3.2节）
Automatic generation is based on the abstraction/summarization of the whole domain by the PNC and its advertisement on the MPI. The level of abstraction can be decided based on PNC configuration parameters (e.g., "provide the potential connectivity between any PE and any ASBR in an MPLS-TE network").
自动生成是基于PNC对整个领域的抽象/总结及其在MPI上的广告。可根据PNC配置参数确定抽象级别（例如，“提供MPLS-TE网络中任何PE和任何ASBR之间的潜在连接”）。
Note that the configuration parameters for this abstract topology can include available bandwidth, latency, or any combination of defined parameters. How to generate such information is beyond the scope of this document.
请注意，此抽象拓扑的配置参数可以包括可用带宽、延迟或任何已定义参数的组合。如何生成此类信息超出了本文档的范围。
This abstract topology may need to be periodically or incrementally updated when there is a change in the underlying network or the use of the network resources that make connectivity more or less available.
当基础网络或网络资源的使用发生变化，使连接或多或少可用时，可能需要定期或增量更新此抽象拓扑。
5.3.2. On-Demand Generation of Supplementary Topology via Path Compute Request/Reply
5.3.2. 通过路径计算请求/应答按需生成补充拓扑
While abstract topology is generated and updated automatically by configuration as explained in Section 5.3.1, additional supplementary topology may be obtained by the MDSC via a path compute request/reply mechanism.
虽然抽象拓扑由配置自动生成和更新，如第5.3.1节所述，但MDSC可通过路径计算请求/应答机制获得额外的补充拓扑。
The abstract topology advertisements from PNCs give the MDSC the border node/link information for each domain. Under this scenario, when the MDSC needs to create a new VN, the MDSC can issue path computation requests to PNCs with constraints matching the VN request as described in [ACTN-YANG]. An example is provided in Figure 8, where the MDSC is creating a P2P VN between AP1 and AP2. The MDSC could use two different inter-domain links to get from domain X to domain Y, but in order to choose the best end-to-end path, it needs to know what domain X and Y can offer in terms of connectivity and constraints between the PE nodes and the border nodes.
来自PNC的抽象拓扑播发为MDSC提供每个域的边界节点/链路信息。在这种情况下，当MDSC需要创建新的VN时，MDSC可以向PNC发出路径计算请求，其约束与[ACTN-YANG]中所述的VN请求相匹配。图8提供了一个示例，其中MDSC正在AP1和AP2之间创建一个P2P VN。MDSC可以使用两个不同的域间链路从域X到域Y，但为了选择最佳的端到端路径，它需要知道域X和Y在PE节点和边界节点之间的连接和约束方面可以提供什么。
------- --------
( ) ( )
- BrdrX.1------- BrdrY.1 -
(+---+ ) ( +---+)
-+---( |PE1| Dom.X ) ( Dom.Y |PE2| )---+-
| (+---+ ) ( +---+) |
AP1 - BrdrX.2------- BrdrY.2 - AP2
( ) ( )
------- --------
------- --------
( ) ( )
- BrdrX.1------- BrdrY.1 -
(+---+ ) ( +---+)
-+---( |PE1| Dom.X ) ( Dom.Y |PE2| )---+-
| (+---+ ) ( +---+) |
AP1 - BrdrX.2------- BrdrY.2 - AP2
( ) ( )
------- --------
Figure 8: A Multi-Domain Example
图8：一个多域示例
The MDSC issues a path computation request to PNC.X asking for potential connectivity between PE1 and border node BrdrX.1 and between PE1 and BrdrX.2 with related objective functions and TE metric constraints. A similar request for connectivity from the border nodes in domain Y to PE2 will be issued to PNC.Y. The MDSC merges the results to compute the optimal end-to-end path including the inter-domain links. The MDSC can use the result of this computation to request the PNCs to provision the underlying networks, and the MDSC can then use the end-to-end path as a virtual link in the VN it delivers to the customer.
MDSC向PNC.X发出路径计算请求，请求PE1和边界节点BrdrX.1之间以及PE1和BrdrX.2之间具有相关目标函数和TE度量约束的潜在连接。将向PNC.Y发出从域Y中的边界节点到PE2的类似连接请求。MDSC合并结果以计算最佳端到端路径，包括域间链路。MDSC可以使用此计算的结果请求PNC提供底层网络，然后MDSC可以使用端到端路径作为其交付给客户的VN中的虚拟链路。
This section illustrates how topology abstraction operates in different levels of a hierarchy of MDSCs as shown in Figure 9.
本节说明了拓扑抽象如何在MDSC层次结构的不同层次上运行，如图9所示。
+-----+
| CNC | CNC wants to create a VN
+-----+ between CE A and CE B
|
|
+-----------------------+
| MDSC-H |
+-----------------------+
/ \
/ \
+---------+ +---------+
| MDSC-L1 | | MDSC-L2 |
+---------+ +---------+
/ \ / \
/ \ / \
+----+ +----+ +----+ +----+
CE A o----|PNC1| |PNC2| |PNC3| |PNC4|----o CE B
+----+ +----+ +----+ +----+
+-----+
| CNC | CNC wants to create a VN
+-----+ between CE A and CE B
|
|
+-----------------------+
| MDSC-H |
+-----------------------+
/ \
/ \
+---------+ +---------+
| MDSC-L1 | | MDSC-L2 |
+---------+ +---------+
/ \ / \
/ \ / \
+----+ +----+ +----+ +----+
CE A o----|PNC1| |PNC2| |PNC3| |PNC4|----o CE B
+----+ +----+ +----+ +----+
Virtual Network Delivered to CNC
向CNC交付虚拟网络
CE A o==============o CE B
CE A o==============o CE B
Topology operated on by MDSC-H
由MDSC-H操作的拓扑
CE A o----o==o==o===o----o CE B
CE A o----o==o==o===o----o CE B
Topology operated on by MDSC-L1 Topology operated on by MDSC-L2
_ _ _ _
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
CE A o--(o---o)==(o---o)==Dom.3 Dom.2==(o---o)==(o---o)--o CE B
( ) ( ) ( ) ( )
(_) (_) (_) (_)
Topology operated on by MDSC-L1 Topology operated on by MDSC-L2
_ _ _ _
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
CE A o--(o---o)==(o---o)==Dom.3 Dom.2==(o---o)==(o---o)--o CE B
( ) ( ) ( ) ( )
(_) (_) (_) (_)
Actual Topology
___ ___ ___ ___
( ) ( ) ( ) ( )
( o ) ( o ) ( o--o) ( o )
( / \ ) ( |\ ) ( | | ) ( / \ )
CE A o---(o-o---o-o)==(o-o-o-o-o)==(o--o--o-o)==(o-o-o-o-o)---o CE B
( \ / ) ( | |/ ) ( | | ) ( \ / )
( o ) (o-o ) ( o--o) ( o )
(___) (___) (___) (___)
Actual Topology
___ ___ ___ ___
( ) ( ) ( ) ( )
( o ) ( o ) ( o--o) ( o )
( / \ ) ( |\ ) ( | | ) ( / \ )
CE A o---(o-o---o-o)==(o-o-o-o-o)==(o--o--o-o)==(o-o-o-o-o)---o CE B
( \ / ) ( | |/ ) ( | | ) ( \ / )
( o ) (o-o ) ( o--o) ( o )
(___) (___) (___) (___)
Domain 1 Domain 2 Domain 3 Domain 4
域1域2域3域4
Where
o is a node
--- is a link
=== is a border link
Where
o is a node
--- is a link
=== is a border link
Figure 9: Illustration of Hierarchical Topology Abstraction
图9：分层拓扑抽象的说明
In the example depicted in Figure 9, there are four domains under control of PNCs: PNC1, PNC2, PNC3, and PNC4. MDSC-L1 controls PNC1 and PNC2, while MDSC-L2 controls PNC3 and PNC4. Each of the PNCs provides a grey topology abstraction that presents only border nodes and links across and outside the domain. The abstract topology MDSC-L1 that operates is a combination of the two topologies from PNC1 and PNC2. Likewise, the abstract topology that MDSC-L2 operates is shown in Figure 9. Both MDSC-L1 and MDSC-L2 provide a black topology abstraction to MDSC-H in which each PNC domain is presented as a single virtual node. MDSC-H combines these two topologies to create the abstraction topology on which it operates. MDSC-H sees the whole four domain networks as four virtual nodes connected via virtual links.
在图9所示的示例中，有四个域受PNC控制：PNC1、PNC2、PNC3和PNC4。MDSC-L1控制PNC1和PNC2，而MDSC-L2控制PNC3和PNC4。每个PNC都提供了灰色拓扑抽象，仅表示域内外的边界节点和链接。运行的抽象拓扑MDSC-L1是来自PNC1和PNC2的两种拓扑的组合。同样，MDSC-L2操作的抽象拓扑如图9所示。MDSC-L1和MDSC-L2都为MDSC-H提供了一个黑色拓扑抽象，其中每个PNC域都表示为一个虚拟节点。MDSC-H将这两种拓扑结合起来，以创建其操作的抽象拓扑。MDSC-H将整个四域网络视为通过虚拟链路连接的四个虚拟节点。
In some cases, the VN supplied to a customer may be built using resources from different technology layers operated by different operators. For example, one operator may run a packet TE network and use optical connectivity provided by another operator.
在某些情况下，提供给客户的VN可以使用来自不同运营商操作的不同技术层的资源来构建。例如，一个运营商可以运行分组TE网络并使用由另一个运营商提供的光连接。
As shown in Figure 10, a customer asks for end-to-end connectivity between CE A and CE B, a virtual network. The customer's CNC makes a request to Operator 1's MDSC. The MDSC works out which network resources need to be configured and sends instructions to the appropriate PNCs. However, the link between Q and R is a virtual link supplied by Operator 2: Operator 1 is a customer of Operator 2.
如图10所示，客户要求在虚拟网络CE a和CE B之间建立端到端连接。客户的CNC向操作员1的MDSC发出请求。MDSC确定需要配置哪些网络资源，并向相应的PNC发送指令。然而，Q和R之间的链路是由运营商2提供的虚拟链路：运营商1是运营商2的客户。
To support this, Operator 1 has a CNC that communicates with Operator 2's MDSC. Note that Operator 1's CNC in Figure 10 is a functional component that does not dictate implementation: it may be embedded in a PNC.
为了支持这一点，操作员1有一个与操作员2的MDSC通信的CNC。请注意，图10中操作员1的CNC是一个功能组件，它不指定实现：它可以嵌入到PNC中。
Virtual CE A o===============================o CE B
Network
Virtual CE A o===============================o CE B
Network
----- CNC wants to create a VN
Customer | CNC | between CE A and CE B
-----
:
***********************************************
:
Operator 1 ---------------------------
| MDSC |
---------------------------
: : :
: : :
----- ------------- -----
| PNC | | PNC | | PNC |
----- ------------- -----
: : : : :
Higher v v : v v
Layer CE A o---P-----Q===========R-----S---o CE B
Network | : |
| : |
| ----- |
| | CNC | |
| ----- |
| : |
***********************************************
| : |
Operator 2 | ------ |
| | MDSC | |
| ------ |
| : |
| ------- |
| | PNC | |
| ------- |
\ : : : /
Lower \v v v/
Layer X--Y--Z
Network
----- CNC wants to create a VN
Customer | CNC | between CE A and CE B
-----
:
***********************************************
:
Operator 1 ---------------------------
| MDSC |
---------------------------
: : :
: : :
----- ------------- -----
| PNC | | PNC | | PNC |
----- ------------- -----
: : : : :
Higher v v : v v
Layer CE A o---P-----Q===========R-----S---o CE B
Network | : |
| : |
| ----- |
| | CNC | |
| ----- |
| : |
***********************************************
| : |
Operator 2 | ------ |
| | MDSC | |
| ------ |
| : |
| ------- |
| | PNC | |
| ------- |
\ : : : /
Lower \v v v/
Layer X--Y--Z
Network
Where
哪里
--- is a link
=== is a virtual link
--- is a link
=== is a virtual link
Figure 10: VN Recursion with Network Layers
图10：网络层的VN递归
In order to map identification of connections between the customer's sites and the TE networks and to scope the connectivity requested in the VNS, the CNC and the MDSC refer to the connections using the Access Point (AP) construct as shown in Figure 11.
为了映射客户站点和TE网络之间的连接标识，并确定VNS中请求的连接范围，CNC和MDSC使用接入点（AP）结构参考连接，如图11所示。
-------------
( )
- -
+---+ X ( ) Z +---+
|CE1|---+----( )---+---|CE2|
+---+ | ( ) | +---+
AP1 - - AP2
( )
-------------
-------------
( )
- -
+---+ X ( ) Z +---+
|CE1|---+----( )---+---|CE2|
+---+ | ( ) | +---+
AP1 - - AP2
( )
-------------
Figure 11: Customer View of APs
图11:APs的客户视图
Let's take as an example a scenario shown in Figure 11. CE1 is connected to the network via a 10 Gbps link and CE2 via a 40 Gbps link. Before the creation of any VN between AP1 and AP2, the customer view can be summarized as shown in Figure 12.
让我们以图11所示的场景为例。CE1通过10 Gbps链路连接到网络，CE2通过40 Gbps链路连接到网络。在创建AP1和AP2之间的任何VN之前，可以总结customer视图，如图12所示。
+----------+------------------------+
| Endpoint | Access Link Bandwidth |
+-----+----------+----------+-------------+
|AP id| CE,port | MaxResBw | AvailableBw |
+-----+----------+----------+-------------+
| AP1 |CE1,portX | 10 Gbps | 10 Gbps |
+-----+----------+----------+-------------+
| AP2 |CE2,portZ | 40 Gbps | 40 Gbps |
+-----+----------+----------+-------------+
+----------+------------------------+
| Endpoint | Access Link Bandwidth |
+-----+----------+----------+-------------+
|AP id| CE,port | MaxResBw | AvailableBw |
+-----+----------+----------+-------------+
| AP1 |CE1,portX | 10 Gbps | 10 Gbps |
+-----+----------+----------+-------------+
| AP2 |CE2,portZ | 40 Gbps | 40 Gbps |
+-----+----------+----------+-------------+
Figure 12: AP - Customer View
图12:AP-客户视图
On the other hand, what the operator sees is shown in Figure 13
另一方面，操作员看到的如图13所示
------- -------
( ) ( )
- - - -
W (+---+ ) ( +---+) Y
-+---( |PE1| Dom.X )----( Dom.Y |PE2| )---+-
| (+---+ ) ( +---+) |
AP1 - - - - AP2
( ) ( )
------- -------
------- -------
( ) ( )
- - - -
W (+---+ ) ( +---+) Y
-+---( |PE1| Dom.X )----( Dom.Y |PE2| )---+-
| (+---+ ) ( +---+) |
AP1 - - - - AP2
( ) ( )
------- -------
Figure 13: Operator View of the AP
图13：AP的操作员视图
which results in a summarization as shown in Figure 14.
这将导致如图14所示的总结。
+----------+------------------------+
| Endpoint | Access Link Bandwidth |
+-----+----------+----------+-------------+
|AP id| PE,port | MaxResBw | AvailableBw |
+-----+----------+----------+-------------+
| AP1 |PE1,portW | 10 Gbps | 10 Gbps |
+-----+----------+----------+-------------+
| AP2 |PE2,portY | 40 Gbps | 40 Gbps |
+-----+----------+----------+-------------+
+----------+------------------------+
| Endpoint | Access Link Bandwidth |
+-----+----------+----------+-------------+
|AP id| PE,port | MaxResBw | AvailableBw |
+-----+----------+----------+-------------+
| AP1 |PE1,portW | 10 Gbps | 10 Gbps |
+-----+----------+----------+-------------+
| AP2 |PE2,portY | 40 Gbps | 40 Gbps |
+-----+----------+----------+-------------+
Figure 14: AP - Operator View
图14：AP-操作员视图
A Virtual Network Access Point (VNAP) needs to be defined as binding between an AP and a VN. It is used to allow different VNs to start from the same AP. It also allows for traffic engineering on the access and/or inter-domain links (e.g., keeping track of bandwidth allocation). A different VNAP is created on an AP for each VN.
虚拟网络接入点（VNAP）需要定义为AP和VN之间的绑定。它用于允许不同的VN从同一AP启动。它还允许在访问和/或域间链路上进行流量工程（例如，跟踪带宽分配）。在AP上为每个VN创建不同的VNAP。
In this simple scenario, we suppose we want to create two virtual networks: the first with VN identifier 9 between AP1 and AP2 with bandwidth of 1 Gbps and the second with VN identifier 5, again between AP1 and AP2 and with bandwidth 2 Gbps.
在这个简单的场景中，我们假设要创建两个虚拟网络：第一个虚拟网络在AP1和AP2之间的VN标识符为9，带宽为1 Gbps；第二个虚拟网络在AP1和AP2之间的VN标识符为5，带宽为2 Gbps。
The operator view would evolve as shown in Figure 15.
operator视图的演变如图15所示。
+----------+------------------------+
| Endpoint | Access Link/VNAP Bw |
+---------+----------+----------+-------------+
|AP/VNAPid| PE,port | MaxResBw | AvailableBw |
+---------+----------+----------+-------------+
|AP1 |PE1,portW | 10 Gbps | 7 Gbps |
| -VNAP1.9| | 1 Gbps | N.A. |
| -VNAP1.5| | 2 Gbps | N.A |
+---------+----------+----------+-------------+
|AP2 |PE2,portY | 4 0Gbps | 37 Gbps |
| -VNAP2.9| | 1 Gbps | N.A. |
| -VNAP2.5| | 2 Gbps | N.A |
+---------+----------+----------+-------------+
+----------+------------------------+
| Endpoint | Access Link/VNAP Bw |
+---------+----------+----------+-------------+
|AP/VNAPid| PE,port | MaxResBw | AvailableBw |
+---------+----------+----------+-------------+
|AP1 |PE1,portW | 10 Gbps | 7 Gbps |
| -VNAP1.9| | 1 Gbps | N.A. |
| -VNAP1.5| | 2 Gbps | N.A |
+---------+----------+----------+-------------+
|AP2 |PE2,portY | 4 0Gbps | 37 Gbps |
| -VNAP2.9| | 1 Gbps | N.A. |
| -VNAP2.5| | 2 Gbps | N.A |
+---------+----------+----------+-------------+
Figure 15: AP and VNAP - Operator View after VNS Creation
图15:AP和VNAP-创建VNS后的操作员视图
Often there is a dual-homing relationship between a CE and a pair of PEs. This case needs to be supported by the definition of VN, APs, and VNAPs. Suppose CE1 connected to two different PEs in the operator domain via AP1 and AP2 and that the customer needs 5 Gbps of bandwidth between CE1 and CE2. This is shown in Figure 16.
CE和一对PE之间通常存在双重归位关系。这种情况需要VN、APs和VNAP的定义来支持。假设CE1通过AP1和AP2连接到运营商域中的两个不同PE，并且客户需要CE1和CE2之间的5 Gbps带宽。如图16所示。
____________
AP1 ( ) AP3
-------(PE1) (PE3)-------
W / ( ) \ X
+---+/ ( ) \+---+
|CE1| ( ) |CE2|
+---+\ ( ) /+---+
Y \ ( ) / Z
-------(PE2) (PE4)-------
AP2 (____________)
____________
AP1 ( ) AP3
-------(PE1) (PE3)-------
W / ( ) \ X
+---+/ ( ) \+---+
|CE1| ( ) |CE2|
+---+\ ( ) /+---+
Y \ ( ) / Z
-------(PE2) (PE4)-------
AP2 (____________)
Figure 16: Dual-Homing Scenario
图16：双归宿场景
In this case, the customer will request a VN between AP1, AP2, and AP3 specifying a dual-homing relationship between AP1 and AP2. As a consequence, no traffic will flow between AP1 and AP2. The dual-homing relationship would then be mapped against the VNAPs (since other independent VNs might have AP1 and AP2 as endpoints).
在这种情况下，客户将请求AP1、AP2和AP3之间的VN，指定AP1和AP2之间的双归宿关系。因此，AP1和AP2之间不会有交通流。然后将双归宿关系映射到VNAP（因为其他独立的VN可能有AP1和AP2作为端点）。
The customer view would be shown in Figure 17.
customer视图如图17所示。
+----------+------------------------+
| Endpoint | Access Link/VNAP Bw |
+---------+----------+----------+-------------+-----------+
|AP/VNAPid| CE,port | MaxResBw | AvailableBw |Dual Homing|
+---------+----------+----------+-------------+-----------+
|AP1 |CE1,portW | 10 Gbps | 5 Gbps | |
| -VNAP1.9| | 5 Gbps | N.A. | VNAP2.9 |
+---------+----------+----------+-------------+-----------+
|AP2 |CE1,portY | 40 Gbps | 35 Gbps | |
| -VNAP2.9| | 5 Gbps | N.A. | VNAP1.9 |
+---------+----------+----------+-------------+-----------+
|AP3 |CE2,portX | 50 Gbps | 45 Gbps | |
| -VNAP3.9| | 5 Gbps | N.A. | NONE |
+---------+----------+----------+-------------+-----------+
+----------+------------------------+
| Endpoint | Access Link/VNAP Bw |
+---------+----------+----------+-------------+-----------+
|AP/VNAPid| CE,port | MaxResBw | AvailableBw |Dual Homing|
+---------+----------+----------+-------------+-----------+
|AP1 |CE1,portW | 10 Gbps | 5 Gbps | |
| -VNAP1.9| | 5 Gbps | N.A. | VNAP2.9 |
+---------+----------+----------+-------------+-----------+
|AP2 |CE1,portY | 40 Gbps | 35 Gbps | |
| -VNAP2.9| | 5 Gbps | N.A. | VNAP1.9 |
+---------+----------+----------+-------------+-----------+
|AP3 |CE2,portX | 50 Gbps | 45 Gbps | |
| -VNAP3.9| | 5 Gbps | N.A. | NONE |
+---------+----------+----------+-------------+-----------+
Figure 17: Dual-Homing -- Customer View after VN Creation
图17：双重归宿——VN创建后的客户视图
A more-advanced application of ACTN is the case of data center (DC) selection, where the customer requires the DC selection to be based on the network status; this is referred to as "Multi-Destination Service" in [ACTN-REQ]. In terms of ACTN, a CNC could request a VNS between a set of source APs and destination APs and leave it up to the network (MDSC) to decide which source and destination APs to be used to set up the VNS. The candidate list of source and destination APs is decided by a CNC (or an entity outside of ACTN) based on certain factors that are outside the scope of ACTN.
ACTN更高级的应用是数据中心（DC）选择，客户要求DC选择基于网络状态；这在[ACTN-REQ]中称为“多目的地服务”。就ACTN而言，CNC可以请求一组源AP和目标AP之间的VNS，并由网络（MDSC）决定使用哪个源AP和目标AP来设置VNS。源AP和目标AP的候选列表由CNC（或ACTN之外的实体）根据ACTN范围之外的某些因素确定。
Based on the AP selection as determined and returned by the network (MDSC), the CNC (or an entity outside of ACTN) should further take care of any subsequent actions such as orchestration or service setup requirements. These further actions are outside the scope of ACTN.
根据网络（MDSC）确定并返回的AP选择，CNC（或ACTN之外的实体）应进一步处理任何后续操作，如编排或服务设置要求。这些进一步行动不属于ACTN的范围。
Consider a case as shown in Figure 18, where three DCs are available, but the customer requires the DC selection to be based on the network status and the connectivity service setup between the AP1 (CE1) and one of the destination APs (AP2 (DC-A), AP3 (DC-B), and AP4 (DC-C)). The MDSC (in coordination with PNCs) would select the best destination AP based on the constraints, optimization criteria, policies, etc., and set up the connectivity service (virtual network).
考虑如图18所示的情况，其中三个DCS可用，但是客户要求DC选择基于网络状态和AP1（CE1）和目的地AP之一（AP2（DC-A）、AP3（DC-B）和AP4（DC-C））之间的连接服务设置。MDSC（与PNC协调）将根据约束、优化标准、策略等选择最佳目的地AP，并设置连接服务（虚拟网络）。
------- -------
( ) ( )
- - - -
+---+ ( ) ( ) +----+
|CE1|---+---( Domain X )----( Domain Y )---+---|DC-A|
+---+ | ( ) ( ) | +----+
AP1 - - - - AP2
( ) ( )
---+--- ---+---
| |
AP3-+ AP4-+
| |
+----+ +----+
|DC-B| |DC-C|
+----+ +----+
------- -------
( ) ( )
- - - -
+---+ ( ) ( ) +----+
|CE1|---+---( Domain X )----( Domain Y )---+---|DC-A|
+---+ | ( ) ( ) | +----+
AP1 - - - - AP2
( ) ( )
---+--- ---+---
| |
AP3-+ AP4-+
| |
+----+ +----+
|DC-B| |DC-C|
+----+ +----+
Figure 18: Endpoint Selection Based on Network Status
图18：基于网络状态的端点选择
Furthermore, in the case of DC selection, a customer could request a backup DC to be selected, such that in case of failure, another DC site could provide hot stand-by protection. As shown in Figure 19, DC-C is selected as a backup for DC-A. Thus, the VN should be set up by the MDSC to include primary connectivity between AP1 (CE1) and AP2 (DC-A) as well as protection connectivity between AP1 (CE1) and AP4 (DC-C).
此外，在选择DC的情况下，客户可以请求选择备用DC，以便在发生故障时，另一个DC站点可以提供热备用保护。如图19所示，选择DC-C作为DC-a的备份。因此，MDSC应设置VN，以包括AP1（CE1）和AP2（DC-a）之间的主要连接以及AP1（CE1）和AP4（DC-C）之间的保护连接。
------- -------
( ) ( )
- - __ - -
+---+ ( ) ( ) +----+
|CE1|---+----( Domain X )----( Domain Y )---+---|DC-A|
+---+ | ( ) ( ) | +----+
AP1 - - - - AP2 |
( ) ( ) |
---+--- ---+--- |
| | |
AP3-| AP4-| HOT STANDBY
| | |
+----+ +----+ |
|DC-D| |DC-C|<-------------
+----+ +----+
------- -------
( ) ( )
- - __ - -
+---+ ( ) ( ) +----+
|CE1|---+----( Domain X )----( Domain Y )---+---|DC-A|
+---+ | ( ) ( ) | +----+
AP1 - - - - AP2 |
( ) ( ) |
---+--- ---+--- |
| | |
AP3-| AP4-| HOT STANDBY
| | |
+----+ +----+ |
|DC-D| |DC-C|<-------------
+----+ +----+
Figure 19: Preplanned Endpoint Migration
图19：预先计划的端点迁移
Compared to preplanned endpoint migration, on-the-fly endpoint selection is dynamic in that the migration is not preplanned but decided based on network condition. Under this scenario, the MDSC would monitor the network (based on the VN SLA) and notify the CNC in the case where some other destination AP would be a better choice based on the network parameters. The CNC should instruct the MDSC when it is suitable to update the VN with the new AP if it is required.
与预先计划的端点迁移相比，动态端点选择是动态的，因为迁移不是预先计划的，而是根据网络条件决定的。在这种情况下，MDSC将监控网络（基于VN SLA），并在根据网络参数选择其他目的地AP时通知CNC。如果需要，CNC应指示MDSC何时适合使用新AP更新VN。
The objective of ACTN is to manage traffic engineered resources and provide a set of mechanisms to allow customers to request virtual connectivity across server-network resources. ACTN supports multiple customers, each with its own view of and control of a virtual network built on the server network; the network operator will need to partition (or "slice") their network resources, and manage the resources accordingly.
ACTN的目标是管理流量工程资源，并提供一组机制，允许客户请求跨服务器网络资源的虚拟连接。ACTN支持多个客户，每个客户都有自己对构建在服务器网络上的虚拟网络的视图和控制；网络运营商将需要对其网络资源进行分区（或“切片”），并相应地管理这些资源。
The ACTN platform will, itself, need to support the request, response, and reservations of client- and network-layer connectivity. It will also need to provide performance monitoring and control of TE resources. The management requirements may be categorized as follows:
ACTN平台本身需要支持客户端和网络层连接的请求、响应和保留。它还需要对TE资源进行性能监控。管理要求可分为以下几类：
o Management of external ACTN protocols o Management of internal ACTN interfaces/protocols o Management and monitoring of ACTN components o Configuration of policy to be applied across the ACTN system
o 管理外部ACTN协议o管理内部ACTN接口/协议o管理和监控ACTN组件o配置要在整个ACTN系统中应用的策略
The ACTN framework and interfaces are defined to enable traffic engineering for virtual network services and connectivity services. Network operators may have other Operations, Administration, and Maintenance (OAM) tasks for service fulfillment, optimization, and assurance beyond traffic engineering. The realization of OAM beyond abstraction and control of TE networks is not discussed in this document.
ACTN框架和接口的定义是为了实现虚拟网络服务和连接服务的流量工程。除了流量工程之外，网络运营商还可以执行其他操作、管理和维护（OAM）任务，以实现服务、优化和保证。本文不讨论TE网络抽象和控制之外的OAM实现。
Policy is an important aspect of ACTN control and management. Policies are used via the components and interfaces, during deployment of the service, to ensure that the service is compliant with agreed-upon policy factors and variations (often described in SLAs); these include, but are not limited to connectivity, bandwidth, geographical transit, technology selection, security, resilience, and economic cost.
政策是ACTN控制和管理的一个重要方面。在服务部署期间，通过组件和接口使用策略，以确保服务符合商定的策略因素和变化（通常在SLA中描述）；这些因素包括但不限于连通性、带宽、地理传输、技术选择、安全性、恢复力和经济成本。
Depending on the deployment of the ACTN architecture, some policies may have local or global significance. That is, certain policies may be ACTN component specific in scope, while others may have broader scope and interact with multiple ACTN components. Two examples are provided below:
根据ACTN体系结构的部署，某些策略可能具有本地或全局意义。也就是说，某些策略的作用域可能特定于ACTN组件，而其他策略的作用域可能更广，并与多个ACTN组件交互。下面提供了两个例子：
o A local policy might limit the number, type, size, and scheduling of virtual network services a customer may request via its CNC. This type of policy would be implemented locally on the MDSC.
o 本地策略可能会限制客户可能通过其CNC请求的虚拟网络服务的数量、类型、大小和调度。此类政策将在MDSC本地实施。
o A global policy might constrain certain customer types (or specific customer applications) only to use certain MDSCs and be restricted to physical network types managed by the PNCs. A global policy agent would govern these types of policies.
o 全局策略可能仅将某些客户类型（或特定客户应用程序）限制为使用某些MDSC，并限制为PNC管理的物理网络类型。全局策略代理将管理这些类型的策略。
The objective of this section is to discuss the applicability of ACTN policy: requirements, components, interfaces, and examples. This section provides an analysis and does not mandate a specific method for enforcing policy, or the type of policy agent that would be responsible for propagating policies across the ACTN components. It does highlight examples of how policy may be applied in the context of ACTN, but it is expected further discussion in an applicability or solution-specific document, will be required.
本节的目的是讨论ACTN策略的适用性：需求、组件、接口和示例。本节提供了一个分析，并不要求强制执行策略的特定方法，也不要求指定负责跨ACTN组件传播策略的策略代理的类型。它确实突出了政策如何在ACTN环境中应用的示例，但预计需要在适用性或解决方案特定文档中进行进一步讨论。
A virtual network service for a customer application will be requested by the CNC. The request will reflect the application requirements and specific service needs, including bandwidth, traffic type and survivability. Furthermore, application access and type of virtual network service requested by the CNC, will be need adhere to specific access control policies.
CNC将请求客户应用程序的虚拟网络服务。请求将反映应用程序需求和特定服务需求，包括带宽、流量类型和生存能力。此外，CNC要求的应用程序访问和虚拟网络服务类型需要遵守特定的访问控制政策。
A key objective of the MDSC is to support the customer's expression of the application connectivity request via its CNC as a set of desired business needs; therefore, policy will play an important role.
MDSC的一个关键目标是支持客户通过其CNC将应用程序连接请求表达为一组期望的业务需求；因此，政策将发挥重要作用。
Once authorized, the virtual network service will be instantiated via the CNC-MDSC Interface (CMI); it will reflect the customer application and connectivity requirements and specific service-transport needs. The CNC and the MDSC components will have agreed-upon connectivity endpoints; use of these endpoints should be defined as a policy expression when setting up or augmenting virtual network services. Ensuring that permissible endpoints are defined for CNCs and applications will require the MDSC to maintain a registry of permissible connection points for CNCs and application types.
一旦授权，虚拟网络服务将通过CNC-MDSC接口（CMI）实例化；它将反映客户的应用程序和连接要求以及特定的服务传输需求。CNC和MDSC组件将商定连接端点；在设置或扩充虚拟网络服务时，应将这些端点的使用定义为策略表达式。确保为CNC和应用程序定义了允许的端点，将要求MDSC维护CNC和应用程序类型的允许连接点注册表。
Conflicts may occur when virtual network service optimization criteria are in competition. For example, to meet objectives for service reachability, a request may require an interconnection point between multiple physical networks; however, this might break a confidentially policy requirement of a specific type of end-to-end service. Thus, an MDSC may have to balance a number of the constraints on a service request and between different requested services. It may also have to balance requested services with operational norms for the underlying physical networks. This balancing may be resolved using configured policy and using hard and soft policy constraints.
当虚拟网络服务优化标准处于竞争状态时，可能会发生冲突。例如，为了满足服务可达性的目标，请求可能需要多个物理网络之间的互连点；但是，这可能会打破特定类型的端到端服务的保密策略要求。所以，MDSC可能必须平衡服务请求上的许多约束以及不同请求的服务之间的约束。它可能还必须平衡所请求的服务与底层物理网络的操作规范。这种平衡可以使用配置的策略以及硬策略和软策略约束来解决。
The PNC is responsible for configuring the network elements, monitoring physical network resources, and exposing connectivity (direct or abstracted) to the MDSC. Therefore, it is expected that policy will dictate what connectivity information will be exchanged on the MPI.
PNC负责配置网元、监控物理网络资源，并向MDSC公开连接（直接或抽象）。因此，预期策略将规定在MPI上交换哪些连接信息。
Policy interactions may arise when a PNC determines that it cannot compute a requested path from the MDSC, or notices that (per a locally configured policy) the network is low on resources (for example, the capacity on key links became exhausted). In either case, the PNC will be required to notify the MDSC, which may (again per policy) act to construct a virtual network service across another physical network topology.
当PNC确定无法计算来自MDSC的请求路径，或注意到（根据本地配置的策略）网络资源不足（例如，关键链路上的容量耗尽）时，可能会出现策略交互。在任何一种情况下，PNC都需要通知MDSC，MDSC可能（同样根据策略）通过另一个物理网络拓扑构造虚拟网络服务。
Furthermore, additional forms of policy-based resource management will be required to provide VNS performance, security, and resilience guarantees. This will likely be implemented via a local policy agent and additional protocol methods.
此外，还需要其他形式的基于策略的资源管理，以提供VNS性能、安全性和恢复力保证。这可能通过本地策略代理和其他协议方法实现。
The ACTN framework described in this document defines key components and interfaces for managed TE networks. Securing the request and control of resources, confidentiality of the information, and availability of function should all be critical security considerations when deploying and operating ACTN platforms.
本文档中描述的ACTN框架定义了托管TE网络的关键组件和接口。在部署和操作ACTN平台时，确保资源的请求和控制、信息的机密性以及功能的可用性都应该是关键的安全考虑因素。
Several distributed ACTN functional components are required, and implementations should consider encrypting data that flows between components, especially when they are implemented at remote nodes, regardless of whether these data flows are on external or internal network interfaces.
需要几个分布式的ACTN功能组件，并且实现应该考虑对组件之间流动的数据进行加密，特别是当它们在远程节点上实现时，而不管这些数据流是在外部网络还是内部网络接口上。
The ACTN security discussion is further split into two specific categories described in the following subsections:
ACTN安全讨论进一步分为以下小节中描述的两个特定类别：
o Interface between the Customer Network Controller and Multi-Domain Service Coordinator (MDSC), CNC-MDSC Interface (CMI)
o 客户网络控制器和多域服务协调器（MDSC）之间的接口，CNC-MDSC接口（CMI）
o Interface between the Multi-Domain Service Coordinator and Provisioning Network Controller (PNC), MDSC-PNC Interface (MPI)
o 多域服务协调器和供应网络控制器（PNC）之间的接口，MDSC-PNC接口（MPI）
From a security and reliability perspective, ACTN may encounter many risks such as malicious attack and rogue elements attempting to connect to various ACTN components. Furthermore, some ACTN components represent a single point of failure and threat vector and must also manage policy conflicts and eavesdropping of communication between different ACTN components.
从安全性和可靠性的角度来看，ACTN可能会遇到许多风险，例如恶意攻击和试图连接到各种ACTN组件的恶意元素。此外，一些ACTN组件代表单点故障和威胁向量，还必须管理不同ACTN组件之间的策略冲突和通信窃听。
The conclusion is that all protocols used to realize the ACTN framework should have rich security features, and customer, application and network data should be stored in encrypted data stores. Additional security risks may still exist. Therefore, discussion and applicability of specific security functions and protocols will be better described in documents that are use case and environment specific.
结论是，用于实现ACTN框架的所有协议都应该具有丰富的安全特性，客户、应用程序和网络数据应该存储在加密的数据存储中。其他安全风险可能仍然存在。因此，特定安全功能和协议的讨论和适用性将在特定于用例和环境的文档中得到更好的描述。
Data stored by the MDSC will reveal details of the virtual network services and which CNC and customer/application is consuming the resource. Therefore, the data stored must be considered a candidate for encryption.
MDSC存储的数据将显示虚拟网络服务的详细信息，以及CNC和客户/应用程序正在消耗的资源。因此，必须将存储的数据视为加密的候选数据。
CNC Access rights to an MDSC must be managed. The MDSC must allocate resources properly, and methods to prevent policy conflicts, resource waste, and denial-of-service attacks on the MDSC by rogue CNCs should also be considered.
必须管理MDSC的CNC访问权限。MDSC必须正确分配资源，还应考虑防止恶意CNC对MDSC的策略冲突、资源浪费和拒绝服务攻击的方法。
The CMI will likely be an external protocol interface. Suitable authentication and authorization of each CNC connecting to the MDSC will be required; especially, as these are likely to be implemented by different organizations and on separate functional nodes. Use of the AAA-based mechanisms would also provide role-based authorization methods so that only authorized CNC's may access the different functions of the MDSC.
CMI可能是一个外部协议接口。需要对连接到MDSC的每个CNC进行适当的认证和授权；特别是，因为这些可能由不同的组织在不同的功能节点上实施。使用基于AAA的机制还将提供基于角色的授权方法，以便只有经过授权的CNC才能访问MDSC的不同功能。
Where the MDSC must interact with multiple (distributed) PNCs, a PKI-based mechanism is suggested, such as building a TLS or HTTPS connection between the MDSC and PNCs, to ensure trust between the physical network layer control components and the MDSC. Trust anchors for the PKI can be configured to use a smaller (and potentially non-intersecting) set of trusted Certificate Authorities (CAs) than in the Web PKI.
当MDSC必须与多个（分布式）PNC交互时，建议使用基于PKI的机制，例如在MDSC和PNC之间建立TLS或HTTPS连接，以确保物理网络层控制组件和MDSC之间的信任。PKI的信任锚可以配置为使用比Web PKI更小（并且可能不相交）的可信证书颁发机构（CA）集。
Which MDSC the PNC exports topology information to, and the level of detail (full or abstracted), should also be authenticated, and specific access restrictions and topology views should be configurable and/or policy based.
PNC将拓扑信息导出到哪个MDSC以及详细程度（完整或抽象）也应经过身份验证，并且特定的访问限制和拓扑视图应可配置和/或基于策略。
This document has no IANA actions.
本文档没有IANA操作。
[ACTN-REQ] Lee, Y., Ceccarelli, D., Miyasaka, T., Shin, J., and K. Lee, "Requirements for Abstraction and Control of TE Networks", Work in Progress, draft-ietf-teas-actn-requirements-09, March 2018.
[ACTN-REQ]Lee，Y.，Ceccarelli，D.，Miyasaka，T.，Shin，J.，和K.Lee，“TE网络的抽象和控制要求”，在建工程，草案-ietf-teas-ACTN-Requirements-092018年3月。
[ACTN-YANG] Lee, Y., Dhody, D., Ceccarelli, D., Bryskin, I., Yoon, B., Wu, Q., and P. Park, "A Yang Data Model for ACTN VN Operation", Work in Progress, draft-ietf-teas-actn-vn-yang-01, June 2018.
[ACTN-YANG]Lee，Y.，Dhody，D.，Ceccarelli，D.，Bryskin，I.，Yoon，B.，Wu，Q.，和P.Park，“ACTN VN运行的杨数据模型”，正在进行中的工作，草案-ietf-teas-ACTN-VN-YANG-012018年6月。
[ONF-ARCH] Open Networking Foundation, "SDN Architecture", Issue 1.1, ONF TR-521, June 2016.
开放网络基础，“SDN架构”，发行1.1，ONF TR 521，2016年6月。
[RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J. McManus, "Requirements for Traffic Engineering Over MPLS", RFC 2702, DOI 10.17487/RFC2702, September 1999, <https://www.rfc-editor.org/info/rfc2702>.
[RFC2702]Awduche，D.，Malcolm，J.，Agogbua，J.，O'Dell，M.，和J.McManus，“MPLS上的流量工程要求”，RFC 2702，DOI 10.17487/RFC2702，1999年9月<https://www.rfc-editor.org/info/rfc2702>.
[RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Architecture", RFC 3945, DOI 10.17487/RFC3945, October 2004, <https://www.rfc-editor.org/info/rfc3945>.
[RFC3945]Mannie，E.，Ed.“通用多协议标签交换（GMPLS）体系结构”，RFC 3945，DOI 10.17487/RFC3945，2004年10月<https://www.rfc-editor.org/info/rfc3945>.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, DOI 10.17487/RFC4655, August 2006, <https://www.rfc-editor.org/info/rfc4655>.
[RFC4655]Farrel，A.，Vasseur，J.，和J.Ash，“基于路径计算元素（PCE）的体系结构”，RFC 4655，DOI 10.17487/RFC4655，2006年8月<https://www.rfc-editor.org/info/rfc4655>.
[RFC5654] Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed., Sprecher, N., and S. Ueno, "Requirements of an MPLS Transport Profile", RFC 5654, DOI 10.17487/RFC5654, September 2009, <https://www.rfc-editor.org/info/rfc5654>.
[RFC5654]Niven Jenkins，B.，Ed.，Brungard，D.，Ed.，Betts，M.，Ed.，Sprecher，N.，和S.Ueno，“MPLS传输配置文件的要求”，RFC 5654，DOI 10.17487/RFC5654，2009年9月<https://www.rfc-editor.org/info/rfc5654>.
[RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined Networking: A Perspective from within a Service Provider Environment", RFC 7149, DOI 10.17487/RFC7149, March 2014, <https://www.rfc-editor.org/info/rfc7149>.
[RFC7149]Boucadair，M.和C.Jacquenet，“软件定义的网络：服务提供商环境中的视角”，RFC 7149，DOI 10.17487/RFC7149，2014年3月<https://www.rfc-editor.org/info/rfc7149>.
[RFC7926] Farrel, A., Ed., Drake, J., Bitar, N., Swallow, G., Ceccarelli, D., and X. Zhang, "Problem Statement and Architecture for Information Exchange between Interconnected Traffic-Engineered Networks", BCP 206, RFC 7926, DOI 10.17487/RFC7926, July 2016, <https://www.rfc-editor.org/info/rfc7926>.
[RFC7926]Farrel，A.，Ed.，Drake，J.，Bitar，N.，Swallow，G.，Ceccarelli，D.，和X.Zhang，“互联流量工程网络之间信息交换的问题陈述和体系结构”，BCP 206，RFC 7926，DOI 10.17487/RFC7926，2016年7月<https://www.rfc-editor.org/info/rfc7926>.
[RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An Architecture for Use of PCE and the PCE Communication Protocol (PCEP) in a Network with Central Control", RFC 8283, DOI 10.17487/RFC8283, December 2017, <https://www.rfc-editor.org/info/rfc8283>.
[RFC8283]Farrel，A.，Ed.，Zhao，Q.，Ed.，Li，Z.，和C.Zhou，“在具有中央控制的网络中使用PCE和PCE通信协议（PCEP）的体系结构”，RFC 8283，DOI 10.17487/RFC8283，2017年12月<https://www.rfc-editor.org/info/rfc8283>.
[RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018, <https://www.rfc-editor.org/info/rfc8309>.
[RFC8309]Wu，Q.，Liu，W.，和A.Farrel，“解释服务模型”，RFC 8309，DOI 10.17487/RFC8309，2018年1月<https://www.rfc-editor.org/info/rfc8309>.
[TE-TOPO] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and O. Dios, "YANG Data Model for Traffic Engineering (TE) Topologies", Work in Progress, draft-ietf-teas-yang-te-topo-18, June 2018.
[TE-TOPO]Liu，X.，Bryskin，I.，Beeram，V.，Saad，T.，Shah，H.，和O.Dios，“交通工程（TE）拓扑的YANG数据模型”，正在进行的工作，草案-ietf-teas-YANG-TE-TOPO-18，2018年6月。
Appendix A. Example of MDSC and PNC Functions Integrated in a Service/ Network Orchestrator
附录A.服务/网络编排器中集成的MDSC和PNC功能示例
This section provides an example of a possible deployment scenario, in which Service/Network Orchestrator can include the PNC functionalities for domain 2 and the MDSC functionalities.
本节提供了一个可能的部署场景示例，其中服务/网络编排器可以包括域2的PNC功能和MDSC功能。
Customer
+-------------------------------+
| +-----+ |
| | CNC | |
| +-----+ |
+-------|-----------------------+
|
Service/Network | CMI
Orchestrator |
+-------|------------------------+
| +------+ MPI +------+ |
| | MDSC |---------| PNC2 | |
| +------+ +------+ |
+-------|------------------|-----+
| MPI |
Domain Controller | |
+-------|-----+ |
| +-----+ | | SBI
| |PNC1 | | |
| +-----+ | |
+-------|-----+ |
v SBI v
------- -------
( ) ( )
- - - -
( ) ( )
( Domain 1 )----( Domain 2 )
( ) ( )
- - - -
( ) ( )
------- -------
Customer
+-------------------------------+
| +-----+ |
| | CNC | |
| +-----+ |
+-------|-----------------------+
|
Service/Network | CMI
Orchestrator |
+-------|------------------------+
| +------+ MPI +------+ |
| | MDSC |---------| PNC2 | |
| +------+ +------+ |
+-------|------------------|-----+
| MPI |
Domain Controller | |
+-------|-----+ |
| +-----+ | | SBI
| |PNC1 | | |
| +-----+ | |
+-------|-----+ |
v SBI v
------- -------
( ) ( )
- - - -
( ) ( )
( Domain 1 )----( Domain 2 )
( ) ( )
- - - -
( ) ( )
------- -------
Contributors
贡献者
Adrian Farrel Old Dog Consulting Email: adrian@olddog.co.uk
Adrian Farrel老狗咨询电子邮件：adrian@olddog.co.uk
Italo Busi Huawei Email: Italo.Busi@huawei.com
Italo Busi华为电子邮件：Italo。Busi@huawei.com
Khuzema Pithewan Peloton Technology Email: khuzemap@gmail.com
Khuzema Pithewan Peloton技术电子邮件：khuzemap@gmail.com
Michael Scharf Nokia Email: michael.scharf@nokia.com
Michael Scharf诺基亚电子邮件：Michael。scharf@nokia.com
Luyuan Fang eBay Email: luyuanf@gmail.com
陆元芳易趣邮箱：luyuanf@gmail.com
Diego Lopez Telefonica I+D Don Ramon de la Cruz, 82 28006 Madrid Spain Email: diego@tid.es
Diego Lopez Telefonica I+D Don Ramon de la Cruz，82 28006马德里西班牙电子邮件：diego@tid.es
Sergio Belotti Nokia Via Trento, 30 Vimercate Italy Email: sergio.belotti@nokia.com
Sergio Belotti诺基亚Via Trento，30 Vimercate Italy电子邮件：Sergio。belotti@nokia.com
Daniel King Lancaster University Email: d.king@lancaster.ac.uk
丹尼尔·金·兰开斯特大学电子邮件：d。king@lancaster.ac.uk
Dhruv Dhody Huawei Technologies Divyashree Techno Park, Whitefield Bangalore, Karnataka 560066 India Email: dhruv.ietf@gmail.com
Dhruv Dhody华为技术部门位于卡纳塔克邦班加罗尔怀特菲尔德科技园，邮编560066，印度电子邮件：Dhruv。ietf@gmail.com
Gert Grammel Juniper Networks Email: ggrammel@juniper.net
Gert Grammel Juniper Networks电子邮件：ggrammel@juniper.net
Authors' Addresses
作者地址
Daniele Ceccarelli (editor) Ericsson Torshamnsgatan, 48 Stockholm Sweden
Daniele Ceccarelli（编辑）Ericsson Torshamnsgatan，48岁，瑞典斯德哥尔摩
Email: daniele.ceccarelli@ericsson.com
Email: daniele.ceccarelli@ericsson.com
Young Lee (editor) Huawei Technologies 5340 Legacy Drive Plano, TX 75023 United States of America
Young Lee（编辑）华为技术5340 Legacy Drive Plano，德克萨斯州75023美利坚合众国
Email: leeyoung@huawei.com
Email: leeyoung@huawei.com