draft-ietf-teas-actn-framework-15.txt   rfc8453.txt 
TEAS Working Group Daniele Ceccarelli (Ed)
Internet Draft Ericsson
Intended status: Informational Young Lee (Ed)
Expires: November 28, 2018 Huawei
May 28, 2018 Internet Engineering Task Force (IETF) D. Ceccarelli, Ed.
Request for Comments: 8453 Ericsson
Framework for Abstraction and Control of Traffic Engineered Networks Category: Informational Y. Lee, Ed.
ISSN: 2070-1721 Huawei
August 2018
draft-ietf-teas-actn-framework-15 Framework for Abstraction and Control of TE Networks (ACTN)
Abstract Abstract
Traffic Engineered networks have a variety of mechanisms to Traffic Engineered (TE) networks have a variety of mechanisms to
facilitate the separation of the data plane and control plane. They facilitate the separation of the data plane and control plane. They
also have a range of management and provisioning protocols to also have a range of management and provisioning protocols to
configure and activate network resources. These mechanisms represent configure and activate network resources. These mechanisms represent
key technologies for enabling flexible and dynamic networking. The key technologies for enabling flexible and dynamic networking. The
term "Traffic Engineered network" refers to a network that uses any term "Traffic Engineered network" refers to a network that uses any
connection-oriented technology under the control of a distributed or connection-oriented technology under the control of a distributed or
centralized control plane to support dynamic provisioning of end-to- centralized control plane to support dynamic provisioning of end-to-
end connectivity. end connectivity.
Abstraction of network resources is a technique that can be applied Abstraction of network resources is a technique that can be applied
to a single network domain or across multiple domains to create a to a single network domain or across multiple domains to create a
single virtualized network that is under the control of a network single virtualized network that is under the control of a network
operator or the customer of the operator that actually owns operator or the customer of the operator that actually owns the
the network resources. network resources.
This document provides a framework for Abstraction and Control of
Traffic Engineered Networks (ACTN) to support virtual network
services and connectivity services.
Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with This document provides a framework for Abstraction and Control of TE
the provisions of BCP 78 and BCP 79. Networks (ACTN) to support virtual network services and connectivity
services.
Internet-Drafts are working documents of the Internet Engineering Status of This Memo
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six This document is not an Internet Standards Track specification; it is
months and may be updated, replaced, or obsoleted by other documents published for informational purposes.
at any time. It is inappropriate to use Internet-Drafts as
reference material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt
The list of Internet-Draft Shadow Directories can be accessed at This document is a product of the Internet Engineering Task Force
http://www.ietf.org/shadow.html. (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.
This Internet-Draft will expire on November 3, 2018. 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.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction...................................................3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview.......................................................4 2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Terminology...............................................5 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
2.2. VNS Model of ACTN.........................................7 2.2. VNS Model of ACTN . . . . . . . . . . . . . . . . . . . . 7
2.2.1. Customers............................................9 2.2.1. Customers . . . . . . . . . . . . . . . . . . . . . . 9
2.2.2. Service Providers...................................10 2.2.2. Service Providers . . . . . . . . . . . . . . . . . . 9
2.2.3. Network Operators...................................10 2.2.3. Network Operators . . . . . . . . . . . . . . . . . . 10
3. ACTN Base Architecture........................................10 3. ACTN Base Architecture . . . . . . . . . . . . . . . . . . . 10
3.1. Customer Network Controller..............................12 3.1. Customer Network Controller . . . . . . . . . . . . . . . 12
3.2. Multi-Domain Service Coordinator.........................13 3.2. Multi-Domain Service Coordinator . . . . . . . . . . . . 13
3.3. Provisioning Network Controller..........................13 3.3. Provisioning Network Controller . . . . . . . . . . . . . 13
3.4. ACTN Interfaces..........................................14 3.4. ACTN Interfaces . . . . . . . . . . . . . . . . . . . . . 14
4. Advanced ACTN Architectures...................................15 4. Advanced ACTN Architectures . . . . . . . . . . . . . . . . . 15
4.1. MDSC Hierarchy...........................................15 4.1. MDSC Hierarchy . . . . . . . . . . . . . . . . . . . . . 15
4.2. Functional Split of MDSC Functions in Orchestrators......16 4.2. Functional Split of MDSC Functions in Orchestrators . . . 16
5. Topology Abstraction Methods..................................17 5. Topology Abstraction Methods . . . . . . . . . . . . . . . . 18
5.1. Abstraction Factors......................................17 5.1. Abstraction Factors . . . . . . . . . . . . . . . . . . . 18
5.2. Abstraction Types........................................18 5.2. Abstraction Types . . . . . . . . . . . . . . . . . . . . 19
5.2.1. Native/White Topology...............................18 5.2.1. Native/White Topology . . . . . . . . . . . . . . . . 19
5.2.2. Black Topology......................................19 5.2.2. Black Topology . . . . . . . . . . . . . . . . . . . 19
5.2.3. Grey Topology.......................................20 5.2.3. Grey Topology . . . . . . . . . . . . . . . . . . . . 20
5.3. Methods of Building Grey Topologies......................21 5.3. Methods of Building Grey Topologies . . . . . . . . . . . 21
5.3.1. Automatic Generation of Abstract Topology by 5.3.1. Automatic Generation of Abstract Topology by
Configuration..............................................21 Configuration . . . . . . . . . . . . . . . . . . . . 22
5.3.2. On-demand Generation of Supplementary Topology via Path 5.3.2. On-Demand Generation of Supplementary Topology via
Compute Request/Reply......................................21 Path Compute Request/Reply . . . . . . . . . . . . . 22
5.4. Hierarchical Topology Abstraction Example................22 5.4. Hierarchical Topology Abstraction Example . . . . . . . . 23
5.5. VN Recursion with Network Layers.........................24 5.5. VN Recursion with Network Layers . . . . . . . . . . . . 25
6. Access Points and Virtual Network Access Points...............25 6. Access Points and Virtual Network Access Points . . . . . . . 28
6.1. Dual-Homing Scenario.....................................27 6.1. Dual-Homing Scenario . . . . . . . . . . . . . . . . . . 30
7. Advanced ACTN Application: Multi-Destination Service..........28
7.1. Pre-Planned End Point Migration..........................29
7.2. On the Fly End-Point Migration...........................30
8. Manageability Considerations..................................30
8.1. Policy...................................................31
8.2. Policy Applied to the Customer Network Controller........32
8.3. Policy Applied to the Multi-Domain Service Coordinator...32
8.4. Policy Applied to the Provisioning Network Controller....32
9. Security Considerations.......................................33
9.1. CNC-MDSC Interface (CMI).................................34
9.2. MDSC-PNC Interface (MPI).................................34
10. IANA Considerations..........................................34
11. References...................................................35
11.1. Informative References..................................35
12. Contributors.................................................36
Authors' Addresses...............................................37
APPENDIX A - Example of MDSC and PNC Functions Integrated in A
Service/Network Orchestrator.....................................37
1. Introduction 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
1. Introduction
The term "Traffic Engineered network" refers to a network that uses The term "Traffic Engineered network" refers to a network that uses
any connection-oriented technology under the control of a any connection-oriented technology under the control of a distributed
distributed or centralized control plane to support dynamic or centralized control plane to support dynamic provisioning of end-
provisioning of end-to-end connectivity. Traffic Engineered (TE) to-end connectivity. TE networks have a variety of mechanisms to
networks have a variety of mechanisms to facilitate the separation facilitate the separation of data planes and control planes including
of data plane and control plane including distributed signaling for distributed signaling for path setup and protection, centralized path
path setup and protection, centralized path computation for planning computation for planning and traffic engineering, and a range of
and traffic engineering, and a range of management and provisioning management and provisioning protocols to configure and activate
protocols to configure and activate network resources. These network resources. These mechanisms represent key technologies for
mechanisms represent key technologies for enabling flexible and enabling flexible and dynamic networking. Some examples of networks
dynamic networking. Some examples of networks that are in scope of that are in scope of this definition are optical, MPLS Transport
this definition are optical networks, Multiprotocol Label Switching Profile (MPLS-TP) [RFC5654], and MPLS-TE networks [RFC2702].
(MPLS) Transport Profile (MPLS-TP) networks [RFC5654], and MPLS-TE
networks [RFC2702].
One of the main drivers for Software Defined Networking (SDN) One of the main drivers for Software-Defined Networking (SDN)
[RFC7149] is a decoupling of the network control plane from the data [RFC7149] is a decoupling of the network control plane from the data
plane. This separation has been achieved for TE networks with the plane. This separation has been achieved for TE networks with the
development of MPLS/GMPLS [RFC3945] and the Path Computation Element development of MPLS/GMPLS [RFC3945] and the Path Computation Element
(PCE) [RFC4655]. One of the advantages of SDN is its logically (PCE) [RFC4655]. One of the advantages of SDN is its logically
centralized control regime that allows a global view of the centralized control regime that allows a global view of the
underlying networks. Centralized control in SDN helps improve underlying networks. Centralized control in SDN helps improve
network resource utilization compared with distributed network network resource utilization compared with distributed network
control. For TE-based networks, a PCE may serve as a logically control. For TE-based networks, a PCE may serve as a logically
centralized path computation function. centralized path computation function.
This document describes a set of management and control functions This document describes a set of management and control functions
used to operate one or more TE networks to construct virtual used to operate one or more TE networks to construct virtual networks
networks that can be presented to customers and that are built from that can be presented to customers and that are built from
abstractions of the underlying TE networks. For example, a link in abstractions of the underlying TE networks. For example, a link in
the customer's network is constructed from a path or collection of the customer's network is constructed from a path or collection of
paths in the underlying networks. We call this set of functions paths in the underlying networks. We call this set of functions
"Abstraction and Control of Traffic Engineered Networks" (ACTN). "Abstraction and Control of TE Networks" or "ACTN".
2. Overview 2. Overview
Three key aspects that need to be solved by SDN are: Three key aspects that need to be solved by SDN are:
. Separation of service requests from service delivery so that o Separation of service requests from service delivery so that the
the configuration and operation of a network is transparent configuration and operation of a network is transparent from the
from the point of view of the customer, but remains responsive point of view of the customer but it remains responsive to the
to the customer's services and business needs. customer's services and business needs.
. Network abstraction: As described in [RFC7926], abstraction is o Network abstraction: As described in [RFC7926], abstraction is the
the process of applying policy to a set of information about a process of applying policy to a set of information about a TE
TE network to produce selective information that represents the network to produce selective information that represents the
potential ability to connect across the network. The process potential ability to connect across the network. The process of
of abstraction presents the connectivity graph in a way that is abstraction presents the connectivity graph in a way that is
independent of the underlying network technologies, independent of the underlying network technologies, capabilities,
capabilities, and topology so that the graph can be used to and topology so that the graph can be used to plan and deliver
plan and deliver network services in a uniform way network services in a uniform way
. Coordination of resources across multiple independent networks o Coordination of resources across multiple independent networks and
and multiple technology layers to provide end-to-end services multiple technology layers to provide end-to-end services
regardless of whether the networks use SDN or not. regardless of whether or not the networks use SDN.
As networks evolve, the need to provide support for distinct As networks evolve, the need to provide support for distinct
services, separated service orchestration, and resource abstraction services, separated service orchestration, and resource abstraction
have emerged as key requirements for operators. In order to support have emerged as key requirements for operators. In order to support
multiple customers each with its own view of and control of the multiple customers each with its own view of and control of the
server network, a network operator needs to partition (or "slice") server network, a network operator needs to partition (or "slice") or
or manage sharing of the network resources. Network slices can be manage sharing of the network resources. Network slices can be
assigned to each customer for guaranteed usage which is a step assigned to each customer for guaranteed usage, which is a step
further than shared use of common network resources. further than shared use of common network resources.
Furthermore, each network represented to a customer can be built Furthermore, each network represented to a customer can be built from
from virtualization of the underlying networks so that, for example, virtualization of the underlying networks so that, for example, a
a link in the customer's network is constructed from a path or link in the customer's network is constructed from a path or
collection of paths in the underlying network. collection of paths in the underlying network.
ACTN can facilitate virtual network operation via the creation of a ACTN can facilitate virtual network operation via the creation of a
single virtualized network or a seamless service. This supports single virtualized network or a seamless service. This supports
operators in viewing and controlling different domains (at any operators in viewing and controlling different domains (at any
dimension: applied technology, administrative zones, or vendor- dimension: applied technology, administrative zones, or vendor-
specific technology islands) and presenting virtualized networks to specific technology islands) and presenting virtualized networks to
their customers. their customers.
The ACTN framework described in this document facilitates: The ACTN framework described in this document facilitates:
. Abstraction of the underlying network resources to higher-layer o Abstraction of the underlying network resources to higher-layer
applications and customers [RFC7926]. applications and customers [RFC7926].
. Virtualization of particular underlying resources, whose o Virtualization of particular underlying resources, whose selection
selection criterion is the allocation of those resources to a criterion is the allocation of those resources to a particular
particular customer, application, or service [ONF-ARCH]. customer, application, or service [ONF-ARCH].
. TE Network slicing of infrastructure to meet specific o TE Network slicing of infrastructure to meet specific customers'
customers' service requirements. service requirements.
. Creation of an abstract environment allowing operators to view o Creation of an abstract environment allowing operators to view and
and control multi-domain networks as a single abstract network. control multi-domain networks as a single abstract network.
. The presentation to customers of networks as a virtual network o The presentation to customers of networks as a virtual network via
via open and programmable interfaces. open and programmable interfaces.
2.1. Terminology 2.1. Terminology
The following terms are used in this document. Some of them are The following terms are used in this document. Some of them are
newly defined, some others reference existing definitions: newly defined, some others reference existing definitions:
. Domain: A domain [RFC4655] is any collection of network Domain: A domain as defined by [RFC4655] is "any collection of
elements within a common sphere of address management or path network elements within a common sphere of address management or
computation responsibility. Specifically within this document path computation responsibility". Specifically, within this
we mean a part of an operator's network that is under common document we mean a part of an operator's network that is under
management (i.e., under shared operational management using the common management (i.e., under shared operational management using
same instances of a tool and the same policies). Network the same instances of a tool and the same policies). Network
elements will often be grouped into domains based on technology elements will often be grouped into domains based on technology
types, vendor profiles, and geographic proximity. types, vendor profiles, and geographic proximity.
. Abstraction: This process is defined in [RFC7926]. Abstraction: This process is defined in [RFC7926].
. TE Network Slicing: In the context of ACTN, a TE network slice TE Network Slicing: In the context of ACTN, a TE network slice is a
is a collection of resources that is used to establish a collection of resources that is used to establish a logically
logically dedicated virtual network over one or more TE dedicated virtual network over one or more TE networks. TE
networks. TE network slicing allows a network operator to network slicing allows a network operator to provide dedicated
provide dedicated virtual networks for applications/customers virtual networks for applications/customers over a common network
over a common network infrastructure. The logically dedicated infrastructure. The logically dedicated resources are a part of
resources are a part of the larger common network the larger common network infrastructures that are shared among
infrastructures that are shared among various TE network slice various TE network slice instances, which are the end-to-end
instances which are the end-to-end realization of TE network realization of TE network slicing, consisting of the combination
slicing, consisting of the combination of physically or of physically or logically dedicated resources.
logically dedicated resources.
. Node: A node is a vertex on the graph representation of a TE Node: A node is a vertex on the graph representation of a TE
topology. In a physical network topology, a node corresponds topology. In a physical network topology, a node corresponds to a
to a physical network element (NE) such as a router. In an physical network element (NE) such as a router. In an abstract
abstract network topology, a node (sometimes called an abstract network topology, a node (sometimes called an "abstract node") is
node) is a representation as a single vertex of one or more a representation as a single vertex of one or more physical NEs
physical NEs and their connecting physical connections. The and their connecting physical connections. The concept of a node
concept of a node represents the ability to connect from any represents the ability to connect from any access to the node (a
access to the node (a link end) to any other access to that link end) to any other access to that node, although "limited
node, although "limited cross-connect capabilities" may also be cross-connect capabilities" may also be defined to restrict this
defined to restrict this functionality. Network abstraction functionality. Network abstraction may be applied recursively, so
may be applied recursively, so a node in one topology may be a node in one topology may be created by applying abstraction to
created by applying abstraction to the nodes in the underlying the nodes in the underlying topology.
topology.
. Link: A link is an edge on the graph representation of a TE Link: A link is an edge on the graph representation of a TE
topology. Two nodes connected by a link are said to be topology. Two nodes connected by a link are said to be "adjacent"
"adjacent" in the TE topology. In a physical network topology, in the TE topology. In a physical network topology, a link
a link corresponds to a physical connection. In an abstract corresponds to a physical connection. In an abstract network
network topology, a link (sometimes called an abstract link) is topology, a link (sometimes called an "abstract link") is a
a representation of the potential to connect a pair of points representation of the potential to connect a pair of points with
with certain TE parameters (see [RFC7926] for details). certain TE parameters (see [RFC7926] for details). Network
Network abstraction may be applied recursively, so a link in abstraction may be applied recursively, so a link in one topology
one topology may be created by applying abstraction to the may be created by applying abstraction to the links in the
links in the underlying topology. underlying topology.
. Abstract Topology: The topology of abstract nodes and abstract Abstract Topology: The topology of abstract nodes and abstract links
links presented through the process of abstraction by a lower presented through the process of abstraction by a lower-layer
layer network for use by a higher layer network. network for use by a higher-layer network.
. A Virtual Network (VN) is a network provided by a service 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 provider to a customer for the customer to use in any way it wants
wants as though it was a physical network. There are two views as though it was a physical network. There are two views of a VN
of a VN as follows: as follows:
a) The VN can be abstracted as a set of edge-to-edge links (a o The VN can be abstracted as a set of edge-to-edge links (a Type
Type 1 VN). Each link is referred as a VN member and is 1 VN). Each link is referred as a "VN member" and is formed as
formed as an end-to-end tunnel across the underlying an end-to-end tunnel across the underlying networks. Such
networks. Such tunnels may be constructed by recursive tunnels may be constructed by recursive slicing or abstraction
slicing or abstraction of paths in the underlying networks of paths in the underlying networks and can encompass edge
and can encompass edge points of the customer's network, points of the customer's network, access links, intra-domain
access links, intra-domain paths, and inter-domain links. paths, and inter-domain links.
b) The VN can also be abstracted as a topology of virtual nodes 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 and virtual links (a Type 2 VN). The operator needs to map the
the VN to actual resource assignment, which is known as VN to actual resource assignment, which is known as "virtual
virtual network embedding. The nodes in this case include network embedding". The nodes in this case include physical
physical end points, border nodes, and internal nodes as well endpoints, border nodes, and internal nodes as well as
as abstracted nodes. Similarly the links include physical abstracted nodes. Similarly, the links include physical access
access links, inter-domain links, and intra-domain links as links, inter-domain links, and intra-domain links as well as
well as abstract links. abstract links.
Clearly a Type 1 VN is a special case of a Type 2 VN. Clearly, a Type 1 VN is a special case of a Type 2 VN.
. Access link: A link between a customer node and a operator Access link: A link between a customer node and an operator node.
node.
. Inter-domain link: A link between domains under distinct Inter-domain link: A link between domains under distinct management
management administration. administration.
. Access Point (AP): An AP is a logical identifier shared between Access Point (AP): An AP is a logical identifier shared between the
the customer and the operator used to identify an access link. customer and the operator used to identify an access link. The AP
The AP is used by the customer when requesting a VNS. Note that is used by the customer when requesting a Virtual Network Service
the term "TE Link Termination Point" (LTP) defined in [TE-Topo] (VNS). Note that the term "TE Link Termination Point" defined in
describes the end points of links, while an AP is a common [TE-TOPO] describes the endpoints of links, while an AP is a
identifier for the link itself. common identifier for the link itself.
. VN Access Point (VNAP): A VNAP is the binding between an AP and VN Access Point (VNAP): A VNAP is the binding between an AP and a
a given VN. given VN.
. Server Network: As defined in [RFC7926], a server network is a Server Network: As defined in [RFC7926], a server network is a
network that provides connectivity for another network (the network that provides connectivity for another network (the Client
Client Network) in a client-server relationship. Network) in a client-server relationship.
2.2. VNS Model of ACTN 2.2. VNS Model of ACTN
A Virtual Network Service (VNS) is the service agreement between a A Virtual Network Service (VNS) is the service agreement between a
customer and operator to provide a VN. When a VN is a simple customer and operator to provide a VN. When a VN is a simple
connectivity between two points, the difference between VNS and connectivity between two points, the difference between VNS and
connectivity service becomes blurred. There are three types of VNS connectivity service becomes blurred. There are three types of VNSs
defined in this document. defined in this document.
o Type 1 VNS refers to a VNS in which the customer is allowed o Type 1 VNS refers to a VNS in which the customer is allowed to
to create and operate a Type 1 VN. create and operate a Type 1 VN.
o Type 2a and 2b VNS refer to VNSs in which the customer is o Type 2a and 2b VNS refer to VNSs in which the customer is allowed
allowed to create and operates a Type 2 VN. With a Type to create and operates a Type 2 VN. With a Type 2a VNS, the VN is
2a VNS, the VN is statically created at service statically created at service configuration time, and the customer
configuration time and the customer is not allowed to is not allowed to change the topology (e.g., by adding or deleting
change the topology (e.g., by adding or deleting abstract abstract nodes and links). A Type 2b VNS is the same as a Type 2a
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
VNS except that the customer is allowed to make dynamic the initial topology created at service configuration time.
changes to the initial topology created at service
configuration time.
VN Operations are functions that a customer can exercise on a VN VN Operations are functions that a customer can exercise on a VN
depending on the agreement between the customer and the operator. depending on the agreement between the customer and the operator.
o VN Creation allows a customer to request the instantiation o VN Creation allows a customer to request the instantiation of a
of a VN. This could be through off-line pre-configuration VN. This could be through offline preconfiguration or through
or through dynamic requests specifying attributes to a dynamic requests specifying attributes to a Service Level
Service Level Agreement (SLA) to satisfy the customer's Agreement (SLA) to satisfy the customer's objectives.
objectives.
o Dynamic Operations allow a customer to modify or delete the o Dynamic Operations allow a customer to modify or delete the VN.
VN. The customer can further act upon the virtual network The customer can further act upon the virtual network to
to create/modify/delete virtual links and nodes. These create/modify/delete virtual links and nodes. These changes will
changes will result in subsequent tunnel management in the result in subsequent tunnel management in the operator's networks.
operator's networks.
There are three key entities in the ACTN VNS model: There are three key entities in the ACTN VNS model:
- Customers o Customers
- Service Providers o Service Providers
- Network Operators o Network Operators
These entities are related in a three tier model as shown in Figure These entities are related in a three tier model as shown in
1. Figure 1.
+----------------------+ +----------------------+
| Customer | | Customer |
+----------------------+ +----------------------+
| |
VNS || | /\ VNS VNS || | /\ VNS
Request || | || Reply Request || | || Reply
\/ | || \/ | ||
+----------------------+ +----------------------+
| Service Provider | | Service Provider |
+----------------------+ +----------------------+
/ | \ / | \
/ | \ / | \
/ | \ / | \
/ | \ / | \
+------------------+ +------------------+ +------------------+ +------------------+ +------------------+ +------------------+
|Network Operator 1| |Network Operator 2| |Network Operator 3| |Network Operator 1| |Network Operator 2| |Network Operator 3|
+------------------+ +------------------+ +------------------+ +------------------+ +------------------+ +------------------+
Figure 1: The Three Tier Model. Figure 1: The Three-Tier Model
The commercial roles of these entities are described in the The commercial roles of these entities are described in the following
following sections. sections.
2.2.1. Customers 2.2.1. Customers
Basic customers include fixed residential users, mobile users, and Basic customers include fixed residential users, mobile users, and
small enterprises. Each requires a small amount of resources and is small enterprises. Each requires a small amount of resources and is
characterized by steady requests (relatively time invariant). Basic characterized by steady requests (relatively time invariant). Basic
customers do not modify their services themselves: if a service customers do not modify their services themselves: if a service
change is needed, it is performed by the provider as a proxy. change is needed, it is performed by the provider as a proxy.
Advanced customers include enterprises and governments. Such Advanced customers include enterprises and governments. Such
customers ask for both point-to point and multipoint connectivity customers ask for both point-to point and multipoint connectivity
with high resource demands varying significantly in time. This is with high resource demands varying significantly in time. This is
one of the reasons why a bundled service offering is not enough and one of the reasons why a bundled service offering is not enough, and
it is desirable to provide each advanced customer with a customized it is desirable to provide each advanced customer with a customized
virtual network service. Advanced customers may also have the VNS. Advanced customers may also have the ability to modify their
ability to modify their service parameters within the scope of their service parameters within the scope of their virtualized
virtualized environments. The primary focus of ACTN is Advanced environments. The primary focus of ACTN is Advanced Customers.
Customers.
As customers are geographically spread over multiple network As customers are geographically spread over multiple network operator
operator domains, they have to interface to multiple operators and domains, they have to interface to multiple operators and may have to
may have to support multiple virtual network services with different support multiple virtual network services with different underlying
underlying objectives set by the network operators. To enable these objectives set by the network operators. To enable these customers
customers to support flexible and dynamic applications they need to to support flexible and dynamic applications, they need to control
control their allocated virtual network resources in a dynamic their allocated virtual network resources in a dynamic fashion; that
fashion, and that means that they need a view of the topology that means that they need a view of the topology that spans all of the
spans all of the network operators. Customers of a given service network operators. Customers of a given service provider can, in
provider can in turn offer a service to other customers in a turn, offer a service to other customers in a recursive way.
recursive way.
2.2.2. Service Providers 2.2.2. Service Providers
In the scope of ACTN, service providers deliver VNSs to their In the scope of ACTN, service providers deliver VNSs to their
customers. Service providers may or may not own physical network customers. Service providers may or may not own physical network
resources (i.e., may or may not be network operators as described in 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 Section 2.2.3). When a service provider is the same as the network
operator, this is similar to existing VPN models applied to a single operator, the case is similar to existing VPN models applied to a
operator although it may be hard to use this approach when the single operator (although it may be hard to use this approach when
customer spans multiple independent network operator domains. the customer spans multiple independent network operator domains).
When network operators supply only infrastructure, while distinct When network operators supply only infrastructure, while distinct
service providers interface to the customers, the service providers service providers interface with the customers, the service providers
are themselves customers of the network infrastructure operators. are themselves customers of the network infrastructure operators.
One service provider may need to keep multiple independent network One service provider may need to keep multiple independent network
operators because its end-users span geographically across multiple operators because its end users span geographically across multiple
network operator domains. In some cases, service provider is also a network operator domains. In some cases, a service provider is also
network operator when it owns network infrastructure on which a network operator when it owns network infrastructure on which
service is provided. service is provided.
2.2.3. Network Operators 2.2.3. Network Operators
Network operators are the infrastructure operators that provision Network operators are the infrastructure operators that provision the
the network resources and provide network resources to their network resources and provide network resources to their customers.
customers. The layered model described in this architecture The layered model described in this architecture separates the
separates the concerns of network operators and customers, with concerns of network operators and customers, with service providers
service providers acting as aggregators of customer requests. acting as aggregators of customer requests.
3. ACTN Base Architecture 3. ACTN Base Architecture
This section provides a high-level model of ACTN showing the This section provides a high-level model of ACTN, showing the
interfaces and the flow of control between components. interfaces and the flow of control between components.
The ACTN architecture is based on a 3-tier reference model and The ACTN architecture is based on a three-tier reference model and
allows for hierarchy and recursion. The main functionalities within allows for hierarchy and recursion. The main functionalities within
an ACTN system are: an ACTN system are:
. Multi-domain coordination: This function oversees the specific o Multi-domain coordination: This function oversees the specific
aspects of different domains and builds a single abstracted aspects of different domains and builds a single abstracted end-
end-to-end network topology in order to coordinate end-to-end to-end network topology in order to coordinate end-to-end path
path computation and path/service provisioning. Domain computation and path/service provisioning. Domain sequence path
sequence path calculation/determination is also a part of this calculation/determination is also a part of this function.
function.
. Abstraction: This function provides an abstracted view of the o Abstraction: This function provides an abstracted view of the
underlying network resources for use by the customer - a underlying network resources for use by the customer -- a customer
customer may be the client or a higher level controller entity. may be the client or a higher-level controller entity. This
This function includes network path computation based on function includes network path computation based on customer-
customer service connectivity request constraints, path service-connectivity request constraints, path computation based
computation based on the global network-wide abstracted on the global network-wide abstracted topology, and the creation
topology, and the creation of an abstracted view of network of an abstracted view of network resources allocated to each
resources allocated to each customer. These operations depend customer. These operations depend on customer-specific network
on customer-specific network objective functions and customer objective functions and customer traffic profiles.
traffic profiles.
. Customer mapping/translation: This function is to map customer o Customer mapping/translation: This function is to map customer
requests/commands into network provisioning requests that can requests/commands into network provisioning requests that can be
be sent from the Multi-Domain Service Coordinator (MDSC) to the sent from the Multi-Domain Service Coordinator (MDSC) to the
Provisioning Network Controller (PNC) according to business Provisioning Network Controller (PNC) according to business
policies provisioned statically or dynamically at the Operations policies provisioned statically or dynamically at the Operations
Support System (OSS)/ Network Management System (NMS). Support System (OSS) / Network Management System (NMS).
Specifically, it provides mapping and translation of a Specifically, it provides mapping and translation of a customer's
customer's service request into a set of parameters that are service request into a set of parameters that are specific to a
specific to a network type and technology such that network network type and technology such that network configuration
configuration process is made possible. process is made possible.
. Virtual service coordination: This function translates customer o Virtual service coordination: This function translates information
service-related information into virtual network service that is customer service related into virtual network service
operations in order to seamlessly operate virtual networks operations in order to seamlessly operate virtual networks while
while meeting a customer's service requirements. In the meeting a customer's service requirements. In the context of
context of ACTN, service/virtual service coordination includes ACTN, service/virtual service coordination includes a number of
a number of service orchestration functions such as multi- service orchestration functions such as multi-destination load-
destination load balancing, guarantees of service quality, balancing and guarantees of service quality. It also includes
bandwidth and throughput. It also includes notifications for notifications for service fault and performance degradation and so
service fault and performance degradation and so forth. forth.
The base ACTN architecture defines three controller types and the The base ACTN architecture defines three controller types and the
corresponding interfaces between these controllers. The following corresponding interfaces between these controllers. The following
types of controller are shown in Figure 2: types of controller are shown in Figure 2:
. CNC - Customer Network Controller o CNC - Customer Network Controller
. MDSC - Multi-Domain Service Coordinator o MDSC - Multi-Domain Service Coordinator
. PNC - Provisioning Network Controller o PNC - Provisioning Network Controller
Figure 2 also shows the following interfaces:
. CMI - CNC-MDSC Interface Figure 2 also shows the following interfaces
. MPI - MDSC-PNC Interface
. SBI - Southbound Interface
o CMI - CNC-MDSC Interface
o MPI - MDSC-PNC Interface
o SBI - Southbound Interface
+---------+ +---------+ +---------+ +---------+ +---------+ +---------+
| CNC | | CNC | | CNC | | CNC | | CNC | | CNC |
+---------+ +---------+ +---------+ +---------+ +---------+ +---------+
\ | / \ | /
\ | / \ | /
Boundary ========\==================|=====================/======= Boundary ========\==================|=====================/=======
Between \ | / between \ | /
Customer & ----------- | CMI -------------- Customer & ----------- | CMI --------------
Network Operator \ | / Network Operator \ | /
+---------------+ +---------------+
| MDSC | | MDSC |
+---------------+ +---------------+
/ | \ / | \
------------ | MPI ------------- ------------ | MPI -------------
/ | \ / | \
+-------+ +-------+ +-------+ +-------+ +-------+ +-------+
| PNC | | PNC | | PNC | | PNC | | PNC | | PNC |
skipping to change at page 12, line 41 skipping to change at page 12, line 39
( Network ) ----- ----- ( Net ) ( Network ) ----- ----- ( Net )
- - ( ) ( ) ----- - - ( ) ( ) -----
( ) ( Phys. ) ( Phys. ) ( ) ( Phys. ) ( Phys. )
--------- ( Net ) ( Net ) --------- ( Net ) ( Net )
----- ----- ----- -----
Figure 2: ACTN Base Architecture Figure 2: ACTN Base Architecture
Note that this is a functional architecture: an implementation and Note that this is a functional architecture: an implementation and
deployment might collocate one or more of the functional components. deployment might collocate one or more of the functional components.
Figure 2 shows a case where service provider is also a network Figure 2 shows a case where the service provider is also a network
operator. operator.
3.1. Customer Network Controller 3.1. Customer Network Controller
A Customer Network Controller (CNC) is responsible for communicating A Customer Network Controller (CNC) is responsible for communicating
a customer's VNS requirements to the network operator over the CNC- a customer's VNS requirements to the network operator over the CNC-
MDSC Interface (CMI). It has knowledge of the end-points associated MDSC Interface (CMI). It has knowledge of the endpoints associated
with the VNS (expressed as APs), the service policy, and other QoS with the VNS (expressed as APs), the service policy, and other QoS
information related to the service. information related to the service.
As the Customer Network Controller directly interfaces to the As the CNC directly interfaces with the applications, it understands
applications, it understands multiple application requirements and multiple application requirements and their service needs. The
their service needs. The capability of a CNC beyond its CMI role is capability of a CNC beyond its CMI role is outside the scope of ACTN
outside the scope of ACTN and may be implemented in different ways. and may be implemented in different ways. For example, the CNC may,
For example, the CNC may in fact be a controller or part of a in fact, be a controller or part of a controller in the customer's
controller in the customer's domain, or the CNC functionality could domain, or the CNC functionality could also be implemented as part of
also be implemented as part of a service provider's portal. a service provider's portal.
3.2. Multi-Domain Service Coordinator 3.2. Multi-Domain Service Coordinator
A Multi-Domain Service Coordinator (MDSC) is a functional block that A Multi-Domain Service Coordinator (MDSC) is a functional block that
implements all of the ACTN functions listed in Section 3 and implements all of the ACTN functions listed in Section 3 and
described further in Section 4.2. Two functions of the MDSC, described further in Section 4.2. Two functions of the MDSC, namely,
namely, multi-domain coordination and virtualization/abstraction are multi-domain coordination and virtualization/abstraction are referred
referred to as network-related functions while the other two to as network-related functions; whereas the other two functions,
functions, namely, customer mapping/translation and virtual service namely, customer mapping/translation and virtual service
coordination are referred to as service-related functions. The MDSC coordination, are referred to as service-related functions. The MDSC
sits at the center of the ACTN model between the CNC that issues sits at the center of the ACTN model between the CNC that issues
connectivity requests and the Provisioning Network Controllers connectivity requests and the Provisioning Network Controllers (PNCs)
(PNCs) that manage the network resources. that manage the network resources. The key point of the MDSC (and of
The key point of the MDSC (and of the whole ACTN framework) is the whole ACTN framework) is detaching the network and service
detaching the network and service control from underlying technology control from underlying technology to help the customer express the
to help the customer express the network as desired by business network as desired by business needs. The MDSC envelopes the
needs. The MDSC envelopes the instantiation of the right technology instantiation of the right technology and network control to meet
and network control to meet business criteria. In essence it business criteria. In essence, it controls and manages the
controls and manages the primitives to achieve functionalities as primitives to achieve functionalities as desired by the CNC.
desired by the CNC.
In order to allow for multi-domain coordination a 1:N relationship In order to allow for multi-domain coordination, a 1:N relationship
must be allowed between MDSCs and PNCs. must be allowed between MDSCs and PNCs.
In addition to that, it could also be possible to have an M:1 In addition to that, it could also be possible to have an M:1
relationship between MDSCs and PNC to allow for network resource relationship between MDSCs and PNCs to allow for network-resource
partitioning/sharing among different customers not necessarily partitioning/sharing among different customers that are not
connected to the same MDSC (e.g., different service providers) but necessarily connected to the same MDSC (e.g., different service
all using the resources of a common network infrastructure operator. providers) but that are all using the resources of a common network
infrastructure operator.
3.3. Provisioning Network Controller 3.3. Provisioning Network Controller
The Provisioning Network Controller (PNC) oversees configuring the The Provisioning Network Controller (PNC) oversees configuring the
network elements, monitoring the topology (physical or virtual) of network elements, monitoring the topology (physical or virtual) of
the network, and collecting information about the topology (either the network, and collecting information about the topology (either
raw or abstracted). raw or abstracted).
The PNC functions can be implemented as part of an SDN domain The PNC functions can be implemented as part of an SDN domain
controller, a Network Management System (NMS), an Element Management controller, a Network Management System (NMS), an Element Management
System (EMS), an active PCE-based controller [Centralized] or any System (EMS), an active PCE-based controller [RFC8283], or any other
other means to dynamically control a set of nodes and implementing a means to dynamically control a set of nodes that implements a
north bound interface from the standpoint of the nodes (which is out northbound interface from the standpoint of the nodes (which is out
of the scope of this document). A PNC domain includes all the 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 resources under the control of a single PNC. It can be composed of
different routing domains and administrative domains, and the different routing domains and administrative domains, and the
resources may come from different layers. The interconnection resources may come from different layers. The interconnection
between PNC domains is illustrated in Figure 3. between PNC domains is illustrated in Figure 3.
_______ _______ _______ _______
_( )_ _( )_ _( )_ _( )_
_( )_ _( )_ _( )_ _( )_
( ) Border ( ) ( ) Border ( )
( PNC ------ Link ------ PNC ) ( PNC ------ Link ------ PNC )
( Domain X |Border|========|Border| Domain Y ) ( Domain X |Border|========|Border| Domain Y )
( | Node | | Node | ) ( | Node | | Node | )
( ------ ------ ) ( ------ ------ )
(_ _) (_ _) (_ _) (_ _)
(_ _) (_ _) (_ _) (_ _)
(_______) (_______) (_______) (_______)
Figure 3: PNC Domain Borders Figure 3: PNC Domain Borders
3.4. ACTN Interfaces 3.4. ACTN Interfaces
Direct customer control of transport network elements and Direct customer control of transport network elements and virtualized
virtualized services is not a viable proposition for network services is not a viable proposition for network operators due to
operators due to security and policy concerns. Therefore, the security and policy concerns. Therefore, the network has to provide
network has to provide open, programmable interfaces, through which open, programmable interfaces, through which customer applications
customer applications can create, replace and modify virtual network can create, replace, and modify virtual network resources and
resources and services in an interactive, flexible and dynamic services in an interactive, flexible, and dynamic fashion.
fashion.
Three interfaces exist in the ACTN architecture as shown in Figure Three interfaces exist in the ACTN architecture as shown in Figure 2.
2.
. CMI: The CNC-MDSC Interface (CMI) is an interface between a CNC 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 an MDSC. The CMI is a business boundary between customer and
and network operator. It is used to request a VNS for an network operator. It is used to request a VNS for an application.
application. All service-related information is conveyed over All service-related information is conveyed over this interface
this interface (such as the VNS type, topology, bandwidth, and (such as the VNS type, topology, bandwidth, and service
service constraints). Most of the information over this constraints). Most of the information over this interface is
interface is agnostic of the technology used by network agnostic of the technology used by network operators, but there
operators, but there are some cases (e.g., access link are some cases (e.g., access link configuration) where it is
configuration) where it is necessary to specify technology- necessary to specify technology-specific details.
specific details.
. MPI: The MDSC-PNC Interface (MPI) is an interface between an o MPI: The MDSC-PNC Interface (MPI) is an interface between an MDSC
MDSC and a PNC. It communicates requests for new connectivity and a PNC. It communicates requests for new connectivity or for
or for bandwidth changes in the physical network. In multi- bandwidth changes in the physical network. In multi-domain
domain environments, the MDSC needs to communicate with environments, the MDSC needs to communicate with multiple PNCs,
multiple PNCs each responsible for control of a domain. The each responsible for control of a domain. The MPI presents an
MPI presents an abstracted topology to the MDSC hiding abstracted topology to the MDSC hiding technology-specific aspects
technology specific aspects of the network and hiding topology of the network and hiding topology according to policy.
according to policy.
. SBI: The Southbound Interface (SBI) is out of scope of ACTN. o SBI: The Southbound Interface (SBI) is out of scope of ACTN. Many
Many different SBIs have been defined for different different SBIs have been defined for different environments,
environments, technologies, standards organizations, and technologies, standards organizations, and vendors. It is shown
vendors. It is shown in Figure 3 for reference reason only. in Figure 3 for reference reason only.
4. Advanced ACTN Architectures 4. Advanced ACTN Architectures
This section describes advanced configurations of the ACTN This section describes advanced configurations of the ACTN
architecture. architecture.
4.1. MDSC Hierarchy 4.1. MDSC Hierarchy
A hierarchy of MDSCs can be foreseen for many reasons, among which A hierarchy of MDSCs can be foreseen for many reasons, among which
are scalability, administrative choices, or putting together are scalability, administrative choices, or putting together
different layers and technologies in the network. In the case where different layers and technologies in the network. In the case where
there is a hierarchy of MDSCs, we introduce the terms higher-level there is a hierarchy of MDSCs, we introduce the terms "higher-level
MDSC (MDSC-H) and lower-level MDSC (MDSC-L). The interface between MDSC" (MDSC-H) and "lower-level MDSC" (MDSC-L). The interface
them is a recursion of the MPI. An implementation of an MDSC-H between them is a recursion of the MPI. An implementation of an
makes provisioning requests as normal using the MPI, but an MDSC-L MDSC-H makes provisioning requests as normal using the MPI, but an
must be able to receive requests as normal at the CMI and also at MDSC-L must be able to receive requests as normal at the CMI and also
the MPI. The hierarchy of MDSCs can be seen in Figure 4. at the MPI. The hierarchy of MDSCs can be seen in Figure 4.
Another implementation choice could foresee the usage of an MDSC-L Another implementation choice could foresee the usage of an MDSC-L
for all the PNCs related to a given technology (e.g., Internet for all the PNCs related to a given technology (e.g., Internet
Protocol (IP)/Multiprotocol Label Switching (MPLS)) and a different Protocol (IP) / Multiprotocol Label Switching (MPLS)) and a different
MDSC-L for the PNCs related to another technology (e.g., Optical MDSC-L for the PNCs related to another technology (e.g., Optical
Transport Network (OTN)/Wavelength Division Multiplexing (WDM)) and Transport Network (OTN) / Wavelength Division Multiplexing (WDM)) and
an MDSC-H to coordinate them. an MDSC-H to coordinate them.
+--------+ +--------+
| CNC | | CNC |
+--------+ +--------+
| +-----+ | +-----+
| CMI | CNC | | CMI | CNC |
+----------+ +-----+ +----------+ +-----+
-------| MDSC-H |---- | -------| MDSC-H |---- |
| +----------+ | | CMI | +----------+ | | CMI
skipping to change at page 16, line 26 skipping to change at page 16, line 26
| MDSC-L | | MDSC-L | | MDSC-L | | MDSC-L |
+---------+ +---------+ +---------+ +---------+
MPI | | | | MPI | | | |
| | | | | | | |
----- ----- ----- ----- ----- ----- ----- -----
| PNC | | PNC | | PNC | | PNC | | PNC | | PNC | | PNC | | PNC |
----- ----- ----- ----- ----- ----- ----- -----
Figure 4: MDSC Hierarchy Figure 4: MDSC Hierarchy
The hierarchy of MDSC can be recursive, where an MDSC-H is in turn The hierarchy of MDSC can be recursive, where an MDSC-H is, in turn,
an MDSC-L to a higher level MDSC-H. an MDSC-L to a higher-level MDSC-H.
4.2. Functional Split of MDSC Functions in Orchestrators 4.2. Functional Split of MDSC Functions in Orchestrators
An implementation choice could separate the MDSC functions into two An implementation choice could separate the MDSC functions into two
groups, one group for service-related functions and the other for groups: one group for service-related functions and the other for
network-related functions. This enables the implementation of a network-related functions. This enables the implementation of a
service orchestrator that provides the service-related functions of service orchestrator that provides the service-related functions of
the MDSC and a network orchestrator that provides the network- the MDSC and a network orchestrator that provides the network-related
related functions of the MDSC. This split is consistent with the functions of the MDSC. This split is consistent with the YANG
Yet Another Next Generation (YANG) service model architecture service model architecture described in [RFC8309]. Figure 5 depicts
described in [Service-YANG]. Figure 5 depicts this and shows how this and shows how the ACTN interfaces may map to YANG data models.
the ACTN interfaces may map to YANG models.
+--------------------+ +--------------------+
| Customer | | Customer |
| +-----+ | | +-----+ |
| | CNC | | | | CNC | |
| +-----+ | | +-----+ |
+--------------------+ +--------------------+
CMI | Customer Service Model CMI | Customer Service Model
| |
+---------------------------------------+ +---------------------------------------+
skipping to change at page 17, line 30 skipping to change at page 17, line 45
| +------+ Controller | | +------+ Controller |
| | PNC | | | | PNC | |
| +------+ | | +------+ |
+------------------------+ +------------------------+
SBI | Device Configuration SBI | Device Configuration
| Model | Model
+--------+ +--------+
| Device | | Device |
+--------+ +--------+
Figure 5: ACTN Architecture in the Context of the YANG Service Figure 5: ACTN Architecture in the Context of the YANG Service Models
Models
5. Topology Abstraction Methods 5. Topology Abstraction Methods
Topology abstraction is described in [RFC7926]. This section Topology abstraction is described in [RFC7926]. This section
discusses topology abstraction factors, types, and their context in discusses topology abstraction factors, types, and their context in
the ACTN architecture. the ACTN architecture.
Abstraction in ACTN is performed by the PNC when presenting Abstraction in ACTN is performed by the PNC when presenting available
available topology to the MDSC, or by an MDSC-L when presenting topology to the MDSC, or by an MDSC-L when presenting topology to an
topology to an MDSC-H. This function is different to the creation MDSC-H. This function is different from the creation of a VN (and
of a VN (and particularly a Type 2 VN) which is not abstraction but particularly a Type 2 VN) that is not abstraction but construction of
construction of virtual resources. virtual resources.
5.1. Abstraction Factors 5.1. Abstraction Factors
As discussed in [RFC7926], abstraction is tied with policy of the As discussed in [RFC7926], abstraction is tied with the policy of the
networks. For instance, per an operational policy, the PNC would networks. For instance, per an operational policy, the PNC would not
not provide any technology specific details (e.g., optical provide any technology-specific details (e.g., optical parameters for
parameters for Wavelength Switched Optical Network (WSON) in the Wavelength Switched Optical Network (WSON) in the abstract topology
abstract topology it provides to the MDSC. Similarly, policy of the it provides to the MDSC. Similarly, the policy of the networks may
networks may determine the abstraction type as described in Section determine the abstraction type as described in Section 5.2.
5.2.
There are many factors that may impact the choice of abstraction: There are many factors that may impact the choice of abstraction:
- Abstraction depends on the nature of the underlying domain o Abstraction depends on the nature of the underlying domain
networks. For instance, packet networks may be abstracted with networks. For instance, packet networks may be abstracted with
fine granularity while abstraction of optical networks depends on fine granularity while abstraction of optical networks depends on
the switching units (such as wavelengths) and the end-to-end the switching units (such as wavelengths) and the end-to-end
continuity and cross-connect limitations within the network. continuity and cross-connect limitations within the network.
- Abstraction also depends on the capability of the PNCs. As o Abstraction also depends on the capability of the PNCs. As
abstraction requires hiding details of the underlying network abstraction requires hiding details of the underlying network
resources, the PNC's capability to run algorithms impacts the resources, the PNC's capability to run algorithms impacts the
feasibility of abstraction. Some PNC may not have the ability to feasibility of abstraction. Some PNCs may not have the ability to
abstract native topology while other PNCs may have the ability to abstract native topology while other PNCs may have the ability to
use sophisticated algorithms. use sophisticated algorithms.
- Abstraction is a tool that can improve scalability. Where the o Abstraction is a tool that can improve scalability. Where the
native network resource information is of large size there is a native network resource information is of a large size, there is a
specific scaling benefit to abstraction. specific scaling benefit to abstraction.
- The proper abstraction level may depend on the frequency of o The proper abstraction level may depend on the frequency of
topology updates and vice versa. topology updates and vice versa.
- The nature of the MDSC's support for technology-specific o The nature of the MDSC's support for technology-specific
parameters impacts the degree/level of abstraction. If the MDSC parameters impacts the degree/level of abstraction. If the MDSC
is not capable of handling such parameters then a higher level of is not capable of handling such parameters, then a higher level of
abstraction is needed. abstraction is needed.
- In some cases, the PNC is required to hide key internal o In some cases, the PNC is required to hide key internal
topological data from the MDSC. Such confidentiality can be topological data from the MDSC. Such confidentiality can be
achieved through abstraction. achieved through abstraction.
5.2. Abstraction Types 5.2. Abstraction Types
This section defines the following three types of topology This section defines the following three types of topology
abstraction: abstraction:
. Native/White Topology (Section 5.2.1) o Native/White Topology (Section 5.2.1)
. Black Topology (Section 5.2.2) o Black Topology (Section 5.2.2)
. Grey Topology (Section 5.2.3) o Grey Topology (Section 5.2.3)
5.2.1. Native/White Topology 5.2.1. Native/White Topology
This is a case where the PNC provides the actual network topology to 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 the MDSC without any hiding or filtering of information, i.e., no
abstraction is performed. In this case, the MDSC has the full abstraction is performed. In this case, the MDSC has the full
knowledge of the underlying network topology and can operate on it knowledge of the underlying network topology and can operate on it
directly. directly.
5.2.2. Black Topology
5.2.2. Black Topology
A black topology replaces a full network with a minimal A black topology replaces a full network with a minimal
representation of the edge-to-edge topology without disclosing any representation of the edge-to-edge topology without disclosing any
node internal connectivity information. The entire domain network node internal connectivity information. The entire domain network
may be abstracted as a single abstract node with the network's may be abstracted as a single abstract node with the network's
access/egress links appearing as the ports to the abstract node and access/egress links appearing as the ports to the abstract node and
the implication that any port can be 'cross-connected' to any other. the implication that any port can be "cross-connected" to any other.
Figure 6 depicts a native topology with the corresponding black Figure 6 depicts a native topology with the corresponding black
topology with one virtual node and inter-domain links. In this topology with one virtual node and inter-domain links. In this case,
case, the MDSC has to make a provisioning request to the PNCs to the MDSC has to make a provisioning request to the PNCs to establish
establish the port-to-port connection. If there is a large number the port-to-port connection. If there is a large number of
of inter-connected domains, this abstraction method may impose a interconnected domains, this abstraction method may impose a heavy
heavy coordination load at the MDSC level in order to find an coordination load at the MDSC level in order to find an optimal end-
optimal end-to-end path since the abstraction hides so much to-end path since the abstraction hides so much information that it
information that it is not possible to determine whether an end-to- is not possible to determine whether an end-to-end path is feasible
end path is feasible without asking each PNC to set up each path without asking each PNC to set up each path fragment. For this
fragment. For this reason, the MPI might need to be enhanced to reason, the MPI might need to be enhanced to allow the PNCs to be
allow the PNCs to be queried for the practicality and queried for the practicality and characteristics of paths across the
characteristics of paths across the abstract node. abstract node.
..................................... .....................................
: PNC Domain : : PNC Domain :
: +--+ +--+ +--+ +--+ : : +--+ +--+ +--+ +--+ :
------+ +-----+ +-----+ +-----+ +------ ------+ +-----+ +-----+ +-----+ +------
: ++-+ ++-+ +-++ +-++ : : ++-+ ++-+ +-++ +-++ :
: | | | | : : | | | | :
: | | | | : : | | | | :
: | | | | : : | | | | :
: | | | | : : | | | | :
: ++-+ ++-+ +-++ +-++ : : ++-+ ++-+ +-++ +-++ :
skipping to change at page 20, line 5 skipping to change at page 20, line 26
: +--+ +--+ +--+ +--+ : : +--+ +--+ +--+ +--+ :
:.................................... :....................................
+----------+ +----------+
---+ +--- ---+ +---
| Abstract | | Abstract |
| Node | | Node |
---+ +--- ---+ +---
+----------+ +----------+
Figure 6: Native Topology with Corresponding Black Topology Expressed Figure 6: Native Topology with Corresponding
as an Abstract Node Black Topology Expressed as an Abstract Node
5.2.3. Grey Topology 5.2.3. Grey Topology
A grey topology represents a compromise between black and white A grey topology represents a compromise between black and white
topologies from a granularity point of view. In this case, the PNC topologies from a granularity point of view. In this case, the PNC
exposes an abstract topology containing all PNC domains border nodes exposes an abstract topology containing all PNC domain border nodes
and an abstraction of the connectivity between those border nodes. and an abstraction of the connectivity between those border nodes.
This abstraction may contain either physical or abstract This abstraction may contain either physical or abstract nodes/links.
nodes/links.
Two types of grey topology are identified: Two types of grey topology are identified:
. In a type A grey topology, border nodes are connected by a full
mesh of TE links (see Figure 7). o In a type A grey topology, border nodes are connected by a full
. In a type B grey topology, border nodes are connected over a mesh of TE links (see Figure 7).
more detailed network comprising internal abstract nodes and
abstracted links. This mode of abstraction supplies the MDSC o In a type B grey topology, border nodes are connected over a more-
with more information about the internals of the PNC domain and detailed network comprising internal abstract nodes and abstracted
allows it to make more informed choices about how to route links. This mode of abstraction supplies the MDSC with more
connectivity over the underlying network. 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.
..................................... .....................................
: PNC Domain : : PNC Domain :
: +--+ +--+ +--+ +--+ : : +--+ +--+ +--+ +--+ :
------+ +-----+ +-----+ +-----+ +------ ------+ +-----+ +-----+ +-----+ +------
: ++-+ ++-+ +-++ +-++ : : ++-+ ++-+ +-++ +-++ :
: | | | | : : | | | | :
: | | | | : : | | | | :
: | | | | : : | | | | :
: | | | | : : | | | | :
skipping to change at page 21, line 11 skipping to change at page 21, line 35
: | \ / | : : | \ / | :
: | \/ | : : | \/ | :
: | /\ | : : | /\ | :
: | / \ | : : | / \ | :
: ++-+ +-++ : : ++-+ +-++ :
-------+ +----+ +------- -------+ +----+ +-------
: +--+ +--+ : : +--+ +--+ :
:..................: :..................:
Figure 7: Native Topology with Corresponding Grey Topology Figure 7: Native Topology with Corresponding Grey Topology
5.3. Methods of Building Grey Topologies 5.3. Methods of Building Grey Topologies
This section discusses two different methods of building a grey This section discusses two different methods of building a grey
topology: topology:
. Automatic generation of abstract topology by configuration o Automatic generation of abstract topology by configuration
(Section 5.3.1) (Section 5.3.1)
. On-demand generation of supplementary topology via path
computation request/reply (Section 5.3.2)
5.3.1. Automatic Generation of Abstract Topology by Configuration o On-demand generation of supplementary topology via path
computation request/reply (Section 5.3.2)
Automatic generation is based on the abstraction/summarization of 5.3.1. Automatic Generation of Abstract Topology by Configuration
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").
Note that the configuration parameters for this abstract topology Automatic generation is based on the abstraction/summarization of the
can include available bandwidth, latency, or any combination of whole domain by the PNC and its advertisement on the MPI. The level
defined parameters. How to generate such information is beyond the of abstraction can be decided based on PNC configuration parameters
scope of this document. (e.g., "provide the potential connectivity between any PE and any
ASBR in an MPLS-TE network").
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.
This abstract topology may need to be periodically or incrementally This abstract topology may need to be periodically or incrementally
updated when there is a change in the underlying network or the use updated when there is a change in the underlying network or the use
of the network resources that make connectivity more or less of the network resources that make connectivity more or less
available. available.
5.3.2. On-demand Generation of Supplementary Topology via Path Compute 5.3.2. On-Demand Generation of Supplementary Topology via Path Compute
Request/Reply Request/Reply
While abstract topology is generated and updated automatically by While abstract topology is generated and updated automatically by
configuration as explained in Section 5.3.1, additional configuration as explained in Section 5.3.1, additional supplementary
supplementary topology may be obtained by the MDSC via a path topology may be obtained by the MDSC via a path compute request/reply
compute request/reply mechanism. mechanism.
The abstract topology advertisements from PNCs give the MDSC the The abstract topology advertisements from PNCs give the MDSC the
border node/link information for each domain. Under this scenario, border node/link information for each domain. Under this scenario,
when the MDSC needs to create a new VN, the MDSC can issue path when the MDSC needs to create a new VN, the MDSC can issue path
computation requests to PNCs with constraints matching the VN computation requests to PNCs with constraints matching the VN request
request as described in [ACTN-YANG]. An example is provided in as described in [ACTN-YANG]. An example is provided in Figure 8,
Figure 8, where the MDSC is creating a P2P VN between AP1 and AP2. where the MDSC is creating a P2P VN between AP1 and AP2. The MDSC
The MDSC could use two different inter-domain links to get from could use two different inter-domain links to get from domain X to
domain X to domain Y, but in order to choose the best end-to-end domain Y, but in order to choose the best end-to-end path, it needs
path it needs to know what domain X and Y can offer in terms of to know what domain X and Y can offer in terms of connectivity and
connectivity and constraints between the PE nodes and the border constraints between the PE nodes and the border nodes.
nodes.
------- -------- ------- --------
( ) ( ) ( ) ( )
- BrdrX.1------- BrdrY.1 - - BrdrX.1------- BrdrY.1 -
(+---+ ) ( +---+) (+---+ ) ( +---+)
-+---( |PE1| Dom.X ) ( Dom.Y |PE2| )---+- -+---( |PE1| Dom.X ) ( Dom.Y |PE2| )---+-
| (+---+ ) ( +---+) | | (+---+ ) ( +---+) |
AP1 - BrdrX.2------- BrdrY.2 - AP2 AP1 - BrdrX.2------- BrdrY.2 - AP2
( ) ( ) ( ) ( )
------- -------- ------- --------
skipping to change at page 22, line 25 skipping to change at page 23, line 4
( ) ( ) ( ) ( )
- BrdrX.1------- BrdrY.1 - - BrdrX.1------- BrdrY.1 -
(+---+ ) ( +---+) (+---+ ) ( +---+)
-+---( |PE1| Dom.X ) ( Dom.Y |PE2| )---+- -+---( |PE1| Dom.X ) ( Dom.Y |PE2| )---+-
| (+---+ ) ( +---+) | | (+---+ ) ( +---+) |
AP1 - BrdrX.2------- BrdrY.2 - AP2 AP1 - BrdrX.2------- BrdrY.2 - AP2
( ) ( ) ( ) ( )
------- -------- ------- --------
Figure 8: A Multi-Domain Example Figure 8: A Multi-Domain Example
The MDSC issues a path computation request to PNC.X asking for The MDSC issues a path computation request to PNC.X asking for
potential connectivity between PE1 and border node BrdrX.1 and potential connectivity between PE1 and border node BrdrX.1 and
between PE1 and BrdrX.2 with related objective functions and TE between PE1 and BrdrX.2 with related objective functions and TE
metric constraints. A similar request for connectivity from the metric constraints. A similar request for connectivity from the
border nodes in domain Y to PE2 will be issued to PNC.Y. The MDSC 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 merges the results to compute the optimal end-to-end path including
the inter domain links. The MDSC can use the result of this the inter-domain links. The MDSC can use the result of this
computation to request the PNCs to provision the underlying computation to request the PNCs to provision the underlying networks,
networks, and the MDSC can then use the end-to-end path as a virtual and the MDSC can then use the end-to-end path as a virtual link in
link in the VN it delivers to the customer. the VN it delivers to the customer.
5.4. Hierarchical Topology Abstraction Example 5.4. Hierarchical Topology Abstraction Example
This section illustrates how topology abstraction operates in This section illustrates how topology abstraction operates in
different levels of a hierarchy of MDSCs as shown in Figure 9. different levels of a hierarchy of MDSCs as shown in Figure 9.
+-----+ +-----+
| CNC | CNC wants to create a VN | CNC | CNC wants to create a VN
+-----+ between CE A and CE B +-----+ between CE A and CE B
| |
| |
+-----------------------+ +-----------------------+
| MDSC-H | | MDSC-H |
+-----------------------+ +-----------------------+
/ \ / \
/ \ / \
+---------+ +---------+
+---------+ +---------+ | MDSC-L1 | | MDSC-L2 |
| MDSC-L1 | | MDSC-L2 | +---------+ +---------+
+---------+ +---------+ / \ / \
/ \ / \ / \ / \
/ \ / \ +----+ +----+ +----+ +----+
+----+ +----+ +----+ +----+ CE A o----|PNC1| |PNC2| |PNC3| |PNC4|----o CE B
CE A o----|PNC1| |PNC2| |PNC3| |PNC4|----o CE B +----+ +----+ +----+ +----+
+----+ +----+ +----+ +----+
Virtual Network Delivered to CNC
CE A o==============o CE B Virtual Network Delivered to CNC
Topology operated on by MDSC-H CE A o==============o CE B
CE A o----o==o==o===o----o CE B Topology operated on by MDSC-H
Topology operated on by MDSC-L1 Topology operated on by MDSC-L2 CE A o----o==o==o===o----o CE B
_ _ _ _
( ) ( ) ( ) ( )
( ) ( ) ( ) ( )
CE A o--(o---o)==(o---o)==Dom.3 Dom.2==(o---o)==(o---o)--o CE B
( ) ( ) ( ) ( )
(_) (_) (_) (_)
Actual Topology Topology operated on by MDSC-L1 Topology operated on by MDSC-L2
___ ___ ___ ___ _ _ _ _
( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )
( o ) ( o ) ( o--o) ( o ) ( ) ( ) ( ) ( )
( / \ ) ( |\ ) ( | | ) ( / \ ) CE A o--(o---o)==(o---o)==Dom.3 Dom.2==(o---o)==(o---o)--o CE B
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 Domain 1 Domain 2 Domain 3 Domain 4
Where Where
o is a node o is a node
--- is a link --- is a link
=== border link === is a border link
Figure 9: Illustration of Hierarchical Topology Abstraction Figure 9: Illustration of Hierarchical Topology Abstraction
In the example depicted in Figure 9, there are four domains under In the example depicted in Figure 9, there are four domains under
control of PNCs PNC1, PNC2, PNC3, and PNC4. MDSC-L1 controls PNC1 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 and PNC2, while MDSC-L2 controls PNC3 and PNC4. Each of the PNCs
provides a grey topology abstraction that presents only border nodes provides a grey topology abstraction that presents only border nodes
and links across and outside the domain. The abstract topology and links across and outside the domain. The abstract topology
MDSC-L1 that operates is a combination of the two topologies from MDSC-L1 that operates is a combination of the two topologies from
PNC1 and PNC2. Likewise, the abstract topology that MDSC-L2 PNC1 and PNC2. Likewise, the abstract topology that MDSC-L2 operates
operates is shown in Figure 9. Both MDSC-L1 and MDSC-L2 provide a is shown in Figure 9. Both MDSC-L1 and MDSC-L2 provide a black
black topology abstraction to MDSC-H in which each PNC domain is topology abstraction to MDSC-H in which each PNC domain is presented
presented as a single virtual node. MDSC-H combines these two as a single virtual node. MDSC-H combines these two topologies to
topologies to create the abstraction topology on which it operates. create the abstraction topology on which it operates. MDSC-H sees
MDSC-H sees the whole four domain networks as four virtual nodes the whole four domain networks as four virtual nodes connected via
connected via virtual links. virtual links.
5.5. VN Recursion with Network Layers 5.5. VN Recursion with Network Layers
In some cases the VN supplied to a customer may be built using In some cases, the VN supplied to a customer may be built using
resources from different technology layers operated by different resources from different technology layers operated by different
operators. For example, one operator may run a packet TE network operators. For example, one operator may run a packet TE network and
and use optical connectivity provided by another operator. use optical connectivity provided by another operator.
As shown in Figure 10, a customer asks for end-to-end connectivity 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 between CE A and CE B, a virtual network. The customer's CNC makes a
a request to Operator 1's MDSC. The MDSC works out which network request to Operator 1's MDSC. The MDSC works out which network
resources need to be configured and sends instructions to the resources need to be configured and sends instructions to the
appropriate PNCs. However, the link between Q and R is a virtual 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. link supplied by Operator 2: Operator 1 is a customer of Operator 2.
To support this, Operator 1 has a CNC that communicates to Operator 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 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 component that does not dictate implementation: it may be embedded in
in a PNC. a PNC.
Virtual CE A o===============================o CE B Virtual CE A o===============================o CE B
Network Network
----- CNC wants to create a VN ----- CNC wants to create a VN
Customer | CNC | between CE A and CE B Customer | CNC | between CE A and CE B
----- -----
: :
*********************************************** ***********************************************
: :
skipping to change at page 25, line 35 skipping to change at page 27, line 50
\ : : : / \ : : : /
Lower \v v v/ Lower \v v v/
Layer X--Y--Z Layer X--Y--Z
Network Network
Where Where
--- is a link --- is a link
=== is a virtual link === is a virtual link
Figure 10: VN recursion with Network Layers Figure 10: VN Recursion with Network Layers
6. Access Points and Virtual Network Access Points 6. Access Points and Virtual Network Access Points
In order to map identification of connections between the customer's In order to map identification of connections between the customer's
sites and the TE networks and to scope the connectivity requested in 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 the VNS, the CNC and the MDSC refer to the connections using the
Access Point (AP) construct as shown in Figure 11. Access Point (AP) construct as shown in Figure 11.
------------- -------------
( ) ( )
- - - -
+---+ X ( ) Z +---+ +---+ X ( ) Z +---+
|CE1|---+----( )---+---|CE2| |CE1|---+----( )---+---|CE2|
+---+ | ( ) | +---+ +---+ | ( ) | +---+
AP1 - - AP2 AP1 - - AP2
( ) ( )
------------- -------------
Figure 11: Customer View of APs Figure 11: Customer View of APs
Let's take as an example a scenario shown in Figure 11. CE1 is 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 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 link. Before the creation of any VN between AP1 and AP2, the
customer view can be summarized as shown in Table 1. customer view can be summarized as shown in Figure 12.
+----------+------------------------+ +----------+------------------------+
|End Point | Access Link Bandwidth | | Endpoint | Access Link Bandwidth |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
|AP id| CE,port | MaxResBw | AvailableBw | |AP id| CE,port | MaxResBw | AvailableBw |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
| AP1 |CE1,portX | 10 Gbps | 10 Gbps | | AP1 |CE1,portX | 10 Gbps | 10 Gbps |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
| AP2 |CE2,portZ | 40 Gbps | 40 Gbps | | AP2 |CE2,portZ | 40 Gbps | 40 Gbps |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
Table 1: AP - Customer View Figure 12: AP - Customer View
On the other hand, what the operator sees is shown in Figure 12. On the other hand, what the operator sees is shown in Figure 13
------- ------- ------- -------
( ) ( ) ( ) ( )
- - - - - - - -
W (+---+ ) ( +---+) Y W (+---+ ) ( +---+) Y
-+---( |PE1| Dom.X )----( Dom.Y |PE2| )---+- -+---( |PE1| Dom.X )----( Dom.Y |PE2| )---+-
| (+---+ ) ( +---+) | | (+---+ ) ( +---+) |
AP1 - - - - AP2 AP1 - - - - AP2
( ) ( ) ( ) ( )
------- ------- ------- -------
Figure 12: Operator view of the AP Figure 13: Operator View of the AP
Which results in a summarization as shown in Table 2. which results in a summarization as shown in Figure 14.
+----------+------------------------+ +----------+------------------------+
|End Point | Access Link Bandwidth | | Endpoint | Access Link Bandwidth |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
|AP id| PE,port | MaxResBw | AvailableBw | |AP id| PE,port | MaxResBw | AvailableBw |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
| AP1 |PE1,portW | 10 Gbps | 10 Gbps | | AP1 |PE1,portW | 10 Gbps | 10 Gbps |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
| AP2 |PE2,portY | 40 Gbps | 40 Gbps | | AP2 |PE2,portY | 40 Gbps | 40 Gbps |
+-----+----------+----------+-------------+ +-----+----------+----------+-------------+
Table 2: AP - Operator View Figure 14: AP - Operator View
A Virtual Network Access Point (VNAP) needs to be defined as binding A Virtual Network Access Point (VNAP) needs to be defined as binding
between an AP and a VN. It is used to allow for different VNs to between an AP and a VN. It is used to allow different VNs to start
start from the same AP. It also allows for traffic engineering on from the same AP. It also allows for traffic engineering on the
the access and/or inter-domain links (e.g., keeping track of access and/or inter-domain links (e.g., keeping track of bandwidth
bandwidth allocation). A different VNAP is created on an AP for allocation). A different VNAP is created on an AP for each VN.
each VN.
In this simple scenario we suppose we want to create two virtual In this simple scenario, we suppose we want to create two virtual
networks. The first with VN identifier 9 between AP1 and AP2 with networks: the first with VN identifier 9 between AP1 and AP2 with
bandwidth of 1 Gbps, while the second with VN identifier 5, again bandwidth of 1 Gbps and the second with VN identifier 5, again
between AP1 and AP2 and with bandwidth 2 Gbps. between AP1 and AP2 and with bandwidth 2 Gbps.
The operator view would evolve as shown in Table 3. The operator view would evolve as shown in Figure 15.
+----------+------------------------+ +----------+------------------------+
|End Point | Access Link/VNAP Bw | | Endpoint | Access Link/VNAP Bw |
+---------+----------+----------+-------------+ +---------+----------+----------+-------------+
|AP/VNAPid| PE,port | MaxResBw | AvailableBw | |AP/VNAPid| PE,port | MaxResBw | AvailableBw |
+---------+----------+----------+-------------+ +---------+----------+----------+-------------+
|AP1 |PE1,portW | 10 Gbps | 7 Gbps | |AP1 |PE1,portW | 10 Gbps | 7 Gbps |
| -VNAP1.9| | 1 Gbps | N.A. | | -VNAP1.9| | 1 Gbps | N.A. |
| -VNAP1.5| | 2 Gbps | N.A | | -VNAP1.5| | 2 Gbps | N.A |
+---------+----------+----------+-------------+ +---------+----------+----------+-------------+
|AP2 |PE2,portY | 4 0Gbps | 37 Gbps | |AP2 |PE2,portY | 4 0Gbps | 37 Gbps |
| -VNAP2.9| | 1 Gbps | N.A. | | -VNAP2.9| | 1 Gbps | N.A. |
| -VNAP2.5| | 2 Gbps | N.A | | -VNAP2.5| | 2 Gbps | N.A |
+---------+----------+----------+-------------+ +---------+----------+----------+-------------+
Table 3: AP and VNAP - Operator View after VNS Creation
6.1. Dual-Homing Scenario Figure 15: AP and VNAP - Operator View after VNS Creation
Often there is a dual homing relationship between a CE and a pair of 6.1. Dual-Homing Scenario
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, PEs. This case needs to be supported by the definition of VN, APs,
and VNAPs. Suppose CE1 connected to two different PEs in the and VNAPs. Suppose CE1 connected to two different PEs in the
operator domain via AP1 and AP2 and that the customer needs 5 Gbps operator domain via AP1 and AP2 and that the customer needs 5 Gbps of
of bandwidth between CE1 and CE2. This is shown in Figure 12. bandwidth between CE1 and CE2. This is shown in Figure 16.
____________ ____________
AP1 ( ) AP3 AP1 ( ) AP3
-------(PE1) (PE3)------- -------(PE1) (PE3)-------
W / ( ) \ X W / ( ) \ X
+---+/ ( ) \+---+ +---+/ ( ) \+---+
|CE1| ( ) |CE2| |CE1| ( ) |CE2|
+---+\ ( ) /+---+ +---+\ ( ) /+---+
Y \ ( ) / Z Y \ ( ) / Z
-------(PE2) (PE4)------- -------(PE2) (PE4)-------
AP2 (____________) AP2 (____________)
Figure 12: Dual-Homing Scenario Figure 16: Dual-Homing Scenario
In this case, the customer will request for a VN between AP1, AP2, In this case, the customer will request a VN between AP1, AP2, and
and AP3 specifying a dual homing relationship between AP1 and AP2. AP3 specifying a dual-homing relationship between AP1 and AP2. As a
As a consequence no traffic will flow between AP1 and AP2. The dual consequence, no traffic will flow between AP1 and AP2. The dual-
homing relationship would then be mapped against the VNAPs (since homing relationship would then be mapped against the VNAPs (since
other independent VNs might have AP1 and AP2 as end points). other independent VNs might have AP1 and AP2 as endpoints).
The customer view would be shown in Table 4. The customer view would be shown in Figure 17.
+----------+------------------------+ +----------+------------------------+
|End Point | Access Link/VNAP Bw | | Endpoint | Access Link/VNAP Bw |
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
|AP/VNAPid| CE,port | MaxResBw | AvailableBw |Dual Homing| |AP/VNAPid| CE,port | MaxResBw | AvailableBw |Dual Homing|
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
|AP1 |CE1,portW | 10 Gbps | 5 Gbps | | |AP1 |CE1,portW | 10 Gbps | 5 Gbps | |
| -VNAP1.9| | 5 Gbps | N.A. | VNAP2.9 | | -VNAP1.9| | 5 Gbps | N.A. | VNAP2.9 |
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
|AP2 |CE1,portY | 40 Gbps | 35 Gbps | | |AP2 |CE1,portY | 40 Gbps | 35 Gbps | |
| -VNAP2.9| | 5 Gbps | N.A. | VNAP1.9 | | -VNAP2.9| | 5 Gbps | N.A. | VNAP1.9 |
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
|AP3 |CE2,portX | 50 Gbps | 45 Gbps | | |AP3 |CE2,portX | 50 Gbps | 45 Gbps | |
| -VNAP3.9| | 5 Gbps | N.A. | NONE | | -VNAP3.9| | 5 Gbps | N.A. | NONE |
+---------+----------+----------+-------------+-----------+ +---------+----------+----------+-------------+-----------+
Table 4: Dual-Homing - Customer View after VN Creation Figure 17: Dual-Homing -- Customer View after VN Creation
7. Advanced ACTN Application: Multi-Destination Service 7. Advanced ACTN Application: Multi-Destination Service
A further advanced application of ACTN is in the case of Data Center A more-advanced application of ACTN is the case of data center (DC)
selection, where the customer requires the Data Center selection to selection, where the customer requires the DC selection to be based
be based on the network status; this is referred to as Multi- on the network status; this is referred to as "Multi-Destination
Destination in [ACTN-REQ]. In terms of ACTN, a CNC could request a Service" in [ACTN-REQ]. In terms of ACTN, a CNC could request a VNS
VNS between a set of source APs and destination APs and leave it up between a set of source APs and destination APs and leave it up to
to the network (MDSC) to decide which source and destination access the network (MDSC) to decide which source and destination APs to be
points to be used to set up the VNS. The candidate list of source used to set up the VNS. The candidate list of source and destination
and destination APs is decided by a CNC (or an entity outside of APs is decided by a CNC (or an entity outside of ACTN) based on
ACTN) based on certain factors which are outside the scope of ACTN. certain factors that are outside the scope of ACTN.
Based on the AP selection as determined and returned by the network Based on the AP selection as determined and returned by the network
(MDSC), the CNC (or an entity outside of ACTN) should further take (MDSC), the CNC (or an entity outside of ACTN) should further take
care of any subsequent actions such as orchestration or service care of any subsequent actions such as orchestration or service setup
setup requirements. These further actions are outside the scope of requirements. These further actions are outside the scope of ACTN.
ACTN.
Consider a case as shown in Figure 14, where three data centers are Consider a case as shown in Figure 18, where three DCs are available,
available, but the customer requires the data center selection to be but the customer requires the DC selection to be based on the network
based on the network status and the connectivity service setup status and the connectivity service setup between the AP1 (CE1) and
between the AP1 (CE1) and one of the destination APs (AP2 (DC-A), one of the destination APs (AP2 (DC-A), AP3 (DC-B), and AP4 (DC-C)).
AP3 (DC-B), and AP4 (DC-C)). The MDSC (in coordination with PNCs) The MDSC (in coordination with PNCs) would select the best
would select the best destination AP based on the constraints, destination AP based on the constraints, optimization criteria,
optimization criteria, policies, etc., and setup the connectivity policies, etc., and set up the connectivity service (virtual
service (virtual network). network).
------- ------- ------- -------
( ) ( ) ( ) ( )
- - - - - - - -
+---+ ( ) ( ) +----+ +---+ ( ) ( ) +----+
|CE1|---+---( Domain X )----( Domain Y )---+---|DC-A| |CE1|---+---( Domain X )----( Domain Y )---+---|DC-A|
+---+ | ( ) ( ) | +----+ +---+ | ( ) ( ) | +----+
AP1 - - - - AP2 AP1 - - - - AP2
( ) ( ) ( ) ( )
---+--- ---+--- ---+--- ---+---
| | | |
AP3-+ AP4-+ AP3-+ AP4-+
| | | |
+----+ +----+ +----+ +----+
|DC-B| |DC-C| |DC-B| |DC-C|
+----+ +----+ +----+ +----+
Figure 14: End-Point Selection Based on Network Status Figure 18: Endpoint Selection Based on Network Status
7.1. Pre-Planned End Point Migration 7.1. Preplanned Endpoint Migration
Furthermore, in case of Data Center selection, customer could Furthermore, in the case of DC selection, a customer could request a
request for a backup DC to be selected, such that in case of backup DC to be selected, such that in case of failure, another DC
failure, another DC site could provide hot stand-by protection. As site could provide hot stand-by protection. As shown in Figure 19,
shown in Figure 15 DC-C is selected as a backup for DC-A. Thus, the DC-C is selected as a backup for DC-A. Thus, the VN should be set up
VN should be setup by the MDSC to include primary connectivity by the MDSC to include primary connectivity between AP1 (CE1) and AP2
between AP1 (CE1) and AP2 (DC-A) as well as protection connectivity (DC-A) as well as protection connectivity between AP1 (CE1) and AP4
between AP1 (CE1) and AP4 (DC-C). (DC-C).
------- ------- ------- -------
( ) ( ) ( ) ( )
- - __ - - - - __ - -
+---+ ( ) ( ) +----+ +---+ ( ) ( ) +----+
|CE1|---+----( Domain X )----( Domain Y )---+---|DC-A| |CE1|---+----( Domain X )----( Domain Y )---+---|DC-A|
+---+ | ( ) ( ) | +----+ +---+ | ( ) ( ) | +----+
AP1 - - - - AP2 | AP1 - - - - AP2 |
( ) ( ) | ( ) ( ) |
---+--- ---+--- | ---+--- ---+--- |
| | | | | |
AP3-| AP4-| HOT STANDBY AP3-| AP4-| HOT STANDBY
| | | | | |
+----+ +----+ | +----+ +----+ |
|DC-D| |DC-C|<------------- |DC-D| |DC-C|<-------------
+----+ +----+ +----+ +----+
Figure 15: Pre-planned End-Point Migration Figure 19: Preplanned Endpoint Migration
7.2. On the Fly End-Point Migration 7.2. On-the-Fly Endpoint Migration
Compared to pre-planned end point migration, on the fly end point Compared to preplanned endpoint migration, on-the-fly endpoint
selection is dynamic in that the migration is not pre-planned but selection is dynamic in that the migration is not preplanned but
decided based on network condition. Under this scenario, the MDSC decided based on network condition. Under this scenario, the MDSC
would monitor the network (based on the VN Service-level Agreement would monitor the network (based on the VN SLA) and notify the CNC in
(SLA) and notify the CNC in case where some other destination AP the case where some other destination AP would be a better choice
would be a better choice based on the network parameters. The CNC based on the network parameters. The CNC should instruct the MDSC
should instruct the MDSC when it is suitable to update the VN with when it is suitable to update the VN with the new AP if it is
the new AP if it is required. required.
8. Manageability Considerations 8. Manageability Considerations
The objective of ACTN is to manage traffic engineered resources, and The objective of ACTN is to manage traffic engineered resources and
provide a set of mechanisms to allow customers to request virtual provide a set of mechanisms to allow customers to request virtual
connectivity across server network resources. ACTN supports connectivity across server-network resources. ACTN supports multiple
multiple customers each with its own view of and control of a customers, each with its own view of and control of a virtual network
virtual network built on the server network, the network operator built on the server network; the network operator will need to
will need to partition (or "slice") their network resources, and partition (or "slice") their network resources, and manage the
manage the resources accordingly. resources accordingly.
The ACTN platform will, itself, need to support the request, The ACTN platform will, itself, need to support the request,
response, and reservations of client and network layer connectivity. response, and reservations of client- and network-layer connectivity.
It will also need to provide performance monitoring and control of It will also need to provide performance monitoring and control of TE
traffic engineered resources. The management requirements may be resources. The management requirements may be categorized as
categorized as follows: follows:
. Management of external ACTN protocols o Management of external ACTN protocols
. Management of internal ACTN interfaces/protocols o Management of internal ACTN interfaces/protocols
. Management and monitoring of ACTN components o Management and monitoring of ACTN components
. Configuration of policy to be applied across the ACTN system o Configuration of policy to be applied across the ACTN system
The ACTN framework and interfaces are defined to enable traffic The ACTN framework and interfaces are defined to enable traffic
engineering for virtual network services and connectivity services. engineering for virtual network services and connectivity services.
Network operators may have other Operations, Administration, and Network operators may have other Operations, Administration, and
Maintenance (OAM) tasks for service fulfillment, optimization, and Maintenance (OAM) tasks for service fulfillment, optimization, and
assurance beyond traffic engineering. The realization of OAM beyond assurance beyond traffic engineering. The realization of OAM beyond
abstraction and control of traffic engineered networks is not abstraction and control of TE networks is not discussed in this
considered in this document. document.
8.1. Policy 8.1. Policy
Policy is an important aspect of ACTN control and management. Policy is an important aspect of ACTN control and management.
Policies are used via the components and interfaces, during Policies are used via the components and interfaces, during
deployment of the service, to ensure that the service is compliant deployment of the service, to ensure that the service is compliant
with agreed policy factors and variations (often described in SLAs), with agreed-upon policy factors and variations (often described in
these include, but are not limited to: connectivity, bandwidth, SLAs); these include, but are not limited to connectivity, bandwidth,
geographical transit, technology selection, security, resilience, geographical transit, technology selection, security, resilience, and
and economic cost. economic cost.
Depending on the deployment of the ACTN architecture, some policies Depending on the deployment of the ACTN architecture, some policies
may have local or global significance. That is, certain policies may have local or global significance. That is, certain policies may
may be ACTN component specific in scope, while others may have be ACTN component specific in scope, while others may have broader
broader scope and interact with multiple ACTN components. Two scope and interact with multiple ACTN components. Two examples are
examples are provided below: provided below:
o A local policy might limit the number, type, size, and o A local policy might limit the number, type, size, and scheduling
scheduling of virtual network services a customer may request of virtual network services a customer may request via its CNC.
via its CNC. This type of policy would be implemented locally This type of policy would be implemented locally on the MDSC.
on the MDSC.
o A global policy might constrain certain customer types (or o A global policy might constrain certain customer types (or
specific customer applications) to only use certain MDSCs, and specific customer applications) only to use certain MDSCs and be
be restricted to physical network types managed by the PNCs. A restricted to physical network types managed by the PNCs. A
global policy agent would govern these types of policies. global policy agent would govern these types of policies.
The objective of this section is to discuss the applicability of The objective of this section is to discuss the applicability of ACTN
ACTN policy: requirements, components, interfaces, and examples. policy: requirements, components, interfaces, and examples. This
This section provides an analysis and does not mandate a specific section provides an analysis and does not mandate a specific method
method for enforcing policy, or the type of policy agent that would for enforcing policy, or the type of policy agent that would be
be responsible for propagating policies across the ACTN components. responsible for propagating policies across the ACTN components. It
It does highlight examples of how policy may be applied in the does highlight examples of how policy may be applied in the context
context of ACTN, but it is expected further discussion in an of ACTN, but it is expected further discussion in an applicability or
applicability or solution specific document, will be required. solution-specific document, will be required.
8.2. Policy Applied to the Customer Network Controller 8.2. Policy Applied to the Customer Network Controller
A virtual network service for a customer application will be A virtual network service for a customer application will be
requested by the CNC. The request will reflect the application requested by the CNC. The request will reflect the application
requirements and specific service needs, including bandwidth, requirements and specific service needs, including bandwidth, traffic
traffic type and survivability. Furthermore, application access and type and survivability. Furthermore, application access and type of
type of virtual network service requested by the CNC, will be need virtual network service requested by the CNC, will be need adhere to
adhere to specific access control policies. specific access control policies.
8.3. Policy Applied to the Multi-Domain Service Coordinator 8.3. Policy Applied to the Multi-Domain Service Coordinator
A key objective of the MDSC is to support the customer's expression 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 of the application connectivity request via its CNC as a set of
desired business needs, therefore policy will play an important desired business needs; therefore, policy will play an important
role. role.
Once authorized, the virtual network service will be instantiated Once authorized, the virtual network service will be instantiated via
via the CNC-MDSC Interface (CMI); it will reflect the customer the CNC-MDSC Interface (CMI); it will reflect the customer
application and connectivity requirements, and specific service application and connectivity requirements and specific service-
transport needs. The CNC and the MDSC components will have agreed transport needs. The CNC and the MDSC components will have agreed-
connectivity end-points; use of these end-points should be defined upon connectivity endpoints; use of these endpoints should be defined
as a policy expression when setting up or augmenting virtual network as a policy expression when setting up or augmenting virtual network
services. Ensuring that permissible end-points are defined for CNCs services. Ensuring that permissible endpoints are defined for CNCs
and applications will require the MDSC to maintain a registry of and applications will require the MDSC to maintain a registry of
permissible connection points for CNCs and application types. permissible connection points for CNCs and application types.
Conflicts may occur when virtual network service optimization Conflicts may occur when virtual network service optimization
criteria are in competition. For example, to meet objectives for criteria are in competition. For example, to meet objectives for
service reachability a request may require an interconnection point service reachability, a request may require an interconnection point
between multiple physical networks; however, this might break a between multiple physical networks; however, this might break a
confidentially policy requirement of specific type of end-to-end confidentially policy requirement of a specific type of end-to-end
service. Thus an MDSC may have to balance a number of the service. Thus, an MDSC may have to balance a number of the
constraints on a service request and between different requested constraints on a service request and between different requested
services. It may also have to balance requested services with services. It may also have to balance requested services with
operational norms for the underlying physical networks. This operational norms for the underlying physical networks. This
balancing may be resolved using configured policy and using hard and balancing may be resolved using configured policy and using hard and
soft policy constraints. soft policy constraints.
8.4. Policy Applied to the Provisioning Network Controller 8.4. Policy Applied to the Provisioning Network Controller
The PNC is responsible for configuring the network elements, The PNC is responsible for configuring the network elements,
monitoring physical network resources, and exposing connectivity monitoring physical network resources, and exposing connectivity
(direct or abstracted) to the MDSC. It is therefore expected that (direct or abstracted) to the MDSC. Therefore, it is expected that
policy will dictate what connectivity information will be exported policy will dictate what connectivity information will be exchanged
between the PNC, via the MDSC-PNC Interface (MPI), and MDSC. on the MPI.
Policy interactions may arise when a PNC determines that it cannot Policy interactions may arise when a PNC determines that it cannot
compute a requested path from the MDSC, or notices that (per a compute a requested path from the MDSC, or notices that (per a
locally configured policy) the network is low on resources (for locally configured policy) the network is low on resources (for
example, the capacity on key links become exhausted). In either example, the capacity on key links became exhausted). In either
case, the PNC will be required to notify the MDSC, which may (again case, the PNC will be required to notify the MDSC, which may (again
per policy) act to construct a virtual network service across per policy) act to construct a virtual network service across another
another physical network topology. physical network topology.
Furthermore, additional forms of policy-based resource management Furthermore, additional forms of policy-based resource management
will be required to provide virtual network service performance, will be required to provide VNS performance, security, and resilience
security and resilience guarantees. This will likely be implemented guarantees. This will likely be implemented via a local policy agent
via a local policy agent and additional protocol methods. and additional protocol methods.
9. Security Considerations 9. Security Considerations
The ACTN framework described in this document defines key components The ACTN framework described in this document defines key components
and interfaces for managed traffic engineered networks. Securing and interfaces for managed TE networks. Securing the request and
the request and control of resources, confidentially of the control of resources, confidentiality of the information, and
information, and availability of function, should all be critical availability of function should all be critical security
security considerations when deploying and operating ACTN platforms. considerations when deploying and operating ACTN platforms.
Several distributed ACTN functional components are required, and Several distributed ACTN functional components are required, and
implementations should consider encrypting data that flows between implementations should consider encrypting data that flows between
components, especially when they are implemented at remote nodes, components, especially when they are implemented at remote nodes,
regardless these data flows are on external or internal network regardless of whether these data flows are on external or internal
interfaces. network interfaces.
The ACTN security discussion is further split into two specific The ACTN security discussion is further split into two specific
categories described in the following sub-sections: categories described in the following subsections:
o Interface between the Customer Network Controller and Multi- o Interface between the Customer Network Controller and Multi-Domain
Domain Service Coordinator (MDSC), CNC-MDSC Interface (CMI) Service Coordinator (MDSC), CNC-MDSC Interface (CMI)
o Interface between the Multi-Domain Service Coordinator and o Interface between the Multi-Domain Service Coordinator and
Provisioning Network Controller (PNC), MDSC-PNC Interface (MPI) Provisioning Network Controller (PNC), MDSC-PNC Interface (MPI)
From a security and reliability perspective, ACTN may encounter many From a security and reliability perspective, ACTN may encounter many
risks such as malicious attack and rogue elements attempting to risks such as malicious attack and rogue elements attempting to
connect to various ACTN components. Furthermore, some ACTN connect to various ACTN components. Furthermore, some ACTN
components represent a single point of failure and threat vector, components represent a single point of failure and threat vector and
and must also manage policy conflicts, and eavesdropping of must also manage policy conflicts and eavesdropping of communication
communication between different ACTN components. between different ACTN components.
The conclusion is that all protocols used to realize the ACTN The conclusion is that all protocols used to realize the ACTN
framework should have rich security features, and customer, framework should have rich security features, and customer,
application and network data should be stored in encrypted data application and network data should be stored in encrypted data
stores. Additional security risks may still exist. Therefore, stores. Additional security risks may still exist. Therefore,
discussion and applicability of specific security functions and discussion and applicability of specific security functions and
protocols will be better described in documents that are use case protocols will be better described in documents that are use case and
and environment specific. environment specific.
9.1. CNC-MDSC Interface (CMI) 9.1. CNC-MDSC Interface (CMI)
Data stored by the MDSC will reveal details of the virtual network Data stored by the MDSC will reveal details of the virtual network
services, and which CNC and customer/application is consuming the services and which CNC and customer/application is consuming the
resource. The data stored must therefore be considered as a resource. Therefore, the data stored must be considered a candidate
candidate for encryption. for encryption.
CNC Access rights to an MDSC must be managed. The MDSC must CNC Access rights to an MDSC must be managed. The MDSC must allocate
allocate resources properly, and methods to prevent policy resources properly, and methods to prevent policy conflicts, resource
conflicts, resource wastage, and denial of service attacks on the waste, and denial-of-service attacks on the MDSC by rogue CNCs should
MDSC by rogue CNCs, should also be considered. also be considered.
The CMI will likely be an external protocol interface. Suitable The CMI will likely be an external protocol interface. Suitable
authentication and authorization of each CNC connecting to the MDSC authentication and authorization of each CNC connecting to the MDSC
will be required, especially, as these are likely to be implemented will be required; especially, as these are likely to be implemented
by different organizations and on separate functional nodes. Use of by different organizations and on separate functional nodes. Use of
the AAA-based mechanisms would also provide role-based authorization the AAA-based mechanisms would also provide role-based authorization
methods, so that only authorized CNC's may access the different methods so that only authorized CNC's may access the different
functions of the MDSC. functions of the MDSC.
9.2. MDSC-PNC Interface (MPI) 9.2. MDSC-PNC Interface (MPI)
Where the MDSC must interact with multiple (distributed) PNCs, a Where the MDSC must interact with multiple (distributed) PNCs, a PKI-
PKI-based mechanism is suggested, such as building a TLS or HTTPS based mechanism is suggested, such as building a TLS or HTTPS
connection between the MDSC and PNCs, to ensure trust between the connection between the MDSC and PNCs, to ensure trust between the
physical network layer control components and the MDSC. Trust physical network layer control components and the MDSC. Trust
anchors for the PKI can be configured to use a smaller (and anchors for the PKI can be configured to use a smaller (and
potentially non-intersecting) set of trusted Certificate Authorities potentially non-intersecting) set of trusted Certificate Authorities
(CAs) than in the Web PKI. (CAs) than in the Web PKI.
Which MDSC the PNC exports topology information to, and the level of Which MDSC the PNC exports topology information to, and the level of
detail (full or abstracted), should also be authenticated, and detail (full or abstracted), should also be authenticated, and
specific access restrictions and topology views should be specific access restrictions and topology views should be
configurable and/or policy-based. configurable and/or policy based.
10. IANA Considerations 10. IANA Considerations
This document has no actions for IANA. This document has no IANA actions.
11. References 11. Informative References
11.1. Informative References [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.
[RFC2702] Awduche, D., et. al., "Requirements for Traffic [ACTN-YANG]
Engineering Over MPLS", RFC 2702, September 1999. 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.
[RFC4655] Farrel, A., Vasseur, J.-P., and J. Ash, "A Path [ONF-ARCH]
Computation Element (PCE)-Based Architecture", IETF RFC Open Networking Foundation, "SDN Architecture", Issue
4655, August 2006. 1.1, ONF TR-521, June 2016.
[RFC5654] Niven-Jenkins, B. (Ed.), D. Brungard (Ed.), and M. Betts [RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
(Ed.), "Requirements of an MPLS Transport Profile", RFC McManus, "Requirements for Traffic Engineering Over MPLS",
5654, September 2009. RFC 2702, DOI 10.17487/RFC2702, September 1999,
<https://www.rfc-editor.org/info/rfc2702>.
[RFC7149] Boucadair, M. and Jacquenet, C., "Software-Defined [RFC3945] Mannie, E., Ed., "Generalized Multi-Protocol Label
Networking: A Perspective from within a Service Provider Switching (GMPLS) Architecture", RFC 3945,
Environment", RFC 7149, March 2014. DOI 10.17487/RFC3945, October 2004,
<https://www.rfc-editor.org/info/rfc3945>.
[RFC7926] A. Farrel (Ed.), "Problem Statement and Architecture for [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Information Exchange between Interconnected Traffic- Element (PCE)-Based Architecture", RFC 4655,
Engineered Networks", RFC 7926, July 2016. DOI 10.17487/RFC4655, August 2006,
<https://www.rfc-editor.org/info/rfc4655>.
[RFC3945] Manning, E., et al., "Generalized Multi-Protocol Label [RFC5654] Niven-Jenkins, B., Ed., Brungard, D., Ed., Betts, M., Ed.,
Switching (GMPLS) Architecture2, RFC 3945, October 2004. 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>.
[ONF-ARCH] Open Networking Foundation, "SDN architecture", Issue [RFC7149] Boucadair, M. and C. Jacquenet, "Software-Defined
1.1, ONF TR-521, June 2016. Networking: A Perspective from within a Service Provider
Environment", RFC 7149, DOI 10.17487/RFC7149, March 2014,
<https://www.rfc-editor.org/info/rfc7149>.
[Centralized] Farrel, A., et al., "An Architecture for Use of PCE [RFC7926] Farrel, A., Ed., Drake, J., Bitar, N., Swallow, G.,
and PCEP in a Network with Central Control", draft-ietf- Ceccarelli, D., and X. Zhang, "Problem Statement and
teas-pce-central-control, work in progress. 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>.
[Service-YANG] Lee, Y., Dhody, D., and Ceccarelli, C., "Traffic [RFC8283] Farrel, A., Ed., Zhao, Q., Ed., Li, Z., and C. Zhou, "An
Engineering and Service Mapping Yang Model", draft-lee- Architecture for Use of PCE and the PCE Communication
teas-te-service-mapping-yang, work in progress. Protocol (PCEP) in a Network with Central Control",
RFC 8283, DOI 10.17487/RFC8283, December 2017,
<https://www.rfc-editor.org/info/rfc8283>.
[ACTN-YANG] Lee, Y., et al., "A Yang Data Model for ACTN VN [RFC8309] Wu, Q., Liu, W., and A. Farrel, "Service Models
Operation", draft-lee-teas-actn-vn-yang, work in progress. Explained", RFC 8309, DOI 10.17487/RFC8309, January 2018,
<https://www.rfc-editor.org/info/rfc8309>.
[ACTN-REQ] Lee, Y., et al., "Requirements for Abstraction and [TE-TOPO] Liu, X., Bryskin, I., Beeram, V., Saad, T., Shah, H., and
Control of TE Networks", draft-ietf-teas-actn- O. Dios, "YANG Data Model for Traffic Engineering (TE)
requirements, work in progress. Topologies", Work in Progress,
draft-ietf-teas-yang-te-topo-18, June 2018.
[TE-Topo] X. Liu et al., "YANG Data Model for TE Topologies", draft- Appendix A. Example of MDSC and PNC Functions Integrated in a Service/
ietf-teas-yang-te-topo, work in progress. Network Orchestrator
12. Contributors 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.
Customer
+-------------------------------+
| +-----+ |
| | CNC | |
| +-----+ |
+-------|-----------------------+
|
Service/Network | CMI
Orchestrator |
+-------|------------------------+
| +------+ MPI +------+ |
| | MDSC |---------| PNC2 | |
| +------+ +------+ |
+-------|------------------|-----+
| MPI |
Domain Controller | |
+-------|-----+ |
| +-----+ | | SBI
| |PNC1 | | |
| +-----+ | |
+-------|-----+ |
v SBI v
------- -------
( ) ( )
- - - -
( ) ( )
( Domain 1 )----( Domain 2 )
( ) ( )
- - - -
( ) ( )
------- -------
Contributors
Adrian Farrel Adrian Farrel
Old Dog Consulting Old Dog Consulting
Email: adrian@olddog.co.uk Email: adrian@olddog.co.uk
Italo Busi Italo Busi
Huawei Huawei
Email: Italo.Busi@huawei.com Email: Italo.Busi@huawei.com
Khuzema Pithewan Khuzema Pithewan
Infinera Peloton Technology
Email: kpithewan@infinera.com Email: khuzemap@gmail.com
Michael Scharf Michael Scharf
Nokia Nokia
Email: michael.scharf@nokia.com Email: michael.scharf@nokia.com
Luyuan Fang Luyuan Fang
eBay eBay
Email: luyuanf@gmail.com Email: luyuanf@gmail.com
Diego Lopez Diego Lopez
Telefonica I+D Telefonica I+D
Don Ramon de la Cruz, 82 Don Ramon de la Cruz, 82
28006 Madrid, Spain 28006 Madrid
Spain
Email: diego@tid.es Email: diego@tid.es
Sergio Belotti Sergio Belotti
Alcatel Lucent Nokia
Via Trento, 30 Via Trento, 30
Vimercate, Italy Vimercate
Italy
Email: sergio.belotti@nokia.com Email: sergio.belotti@nokia.com
Daniel King Daniel King
Lancaster University Lancaster University
Email: d.king@lancaster.ac.uk Email: d.king@lancaster.ac.uk
Dhruv Dhody Dhruv Dhody
Huawei Technologies Huawei Technologies
Divyashree Techno Park, Whitefield Divyashree Techno Park, Whitefield
Bangalore, Karnataka 560066 Bangalore, Karnataka 560066
India India
Email: dhruv.ietf@gmail.com Email: dhruv.ietf@gmail.com
Gert Grammel Gert Grammel
Juniper Networks Juniper Networks
Email: ggrammel@juniper.net Email: ggrammel@juniper.net
Authors' Addresses Authors' Addresses
Daniele Ceccarelli Daniele Ceccarelli (editor)
Ericsson Ericsson
Torshamnsgatan,48 Torshamnsgatan, 48
Stockholm, Sweden Stockholm
Sweden
Email: daniele.ceccarelli@ericsson.com Email: daniele.ceccarelli@ericsson.com
Young Lee Young Lee (editor)
Huawei Technologies Huawei Technologies
5340 Legacy Drive 5340 Legacy Drive
Plano, TX 75023, USA Plano, TX 75023
Phone: (469)277-5838 United States of America
Email: leeyoung@huawei.com
APPENDIX A - Example of MDSC and PNC Functions Integrated in A
Service/Network Orchestrator
This section provides an example of a possible deployment scenario,
in which Service/Network Orchestrator can include a number of
functionalities, among which, in the example below, PNC
functionalities for domain 2 and MDSC functionalities to coordinate
the PNC1 functionalities (hosted in a separate domain controller)
and PNC2 functionalities (co-hosted in the network orchestrator).
Customer Email: leeyoung@huawei.com
+-------------------------------+
| +-----+ |
| | CNC | |
| +-----+ |
+-------|-----------------------+
|
Service/Network | CMI
Orchestrator |
+-------|------------------------+
| +------+ MPI +------+ |
| | MDSC |---------| PNC2 | |
| +------+ +------+ |
+-------|------------------|-----+
| MPI |
Domain Controller | |
+-------|-----+ |
| +-----+ | | SBI
| |PNC1 | | |
| +-----+ | |
+-------|-----+ |
v SBI v
------- -------
( ) ( )
- - - -
( ) ( )
( Domain 1 )----( Domain 2 )
( ) ( )
- - - -
( ) ( )
------- -------
 End of changes. 260 change blocks. 
838 lines changed or deleted 860 lines changed or added

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