Table Of ContentVerizon Network Infrastructure Planning
SDN-NFV Reference Architecture
Version 1.0
February 2016
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SDN-NFV Reference Architecture v1.0
Legal Notice
This document contains information regarding the development and evolution of SDN and NFV. The
views expressed in this document are not final, and are subject to change at any time. Although this
document contains contributions from multiple parties, it is not a consensus document and does not
necessarily reflect the views of any or all contributors. Verizon reserves all rights with respect to its
technology and intellectual property that may be disclosed, covered, or reflected in this document. The
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names used in this document are for identification purposes only. Use of these names, logos, and brands
does not imply endorsement. Neither Verizon nor any contributor to this document shall be responsible
for any action taken by any person in reliance on anything contained herein.
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SDN-NFV Reference Architecture v1.0
Executive Summary
The intersection of telecommunications, Internet and IT networking paradigms combined with advances in
hardware and software technologies has created an environment that is ripe for rapid innovations and
disruptions. This document is aimed at laying a foundation for enabling various industries to benefit from
applications and devices that change how industries are run. ‘Software defined networking’ (SDN) and
‘network function virtualization’ (NFV) are two promising concepts developed in the telecommunications
industry. SDN is based on the separation of control and media planes. The control plane in turn lays the
foundation for dynamically orchestrating the media flows in real-time. NFV, on the other hand, separates
software from hardware enabling flexible network deployment and dynamic operation.
Advances in hardware technologies, software technologies, cloud computing, and the advent of DevOps
have led to agile software development in the IT and web application industries. These same
methodologies can be used to enable the transformation of the telecommunications network to simplify
operations, administration, maintenance and provisioning (OAM&P) and also to lay the network
foundation for new access technologies (e.g., 5G).
Several industry bodies are working on various aspects of SDN and NFV. However, operator network
transformation needs to get started now. This architecture consolidates and enhances existing SDN, NFV
and orchestration into an implementable and operable framework. This document enhances the industry
developed architectures to address several operating scenarios that are critical for network evolution.
Standalone NFV architecture where virtual network functions (VNFs) can be deployed: This scenario
is to migrate network functions that continue to grow and require continued capital investment. Some
operational changes like DevOps, automation of workflows, and orchestration of services can be
initiated while continuing to leverage existing backend systems as needed.
Hybrid NFV where physical network functions (PNFs) and virtual network functions co-exist.
Standalone SDN with new SDN controllers and white boxes: This scenario covers Data Center and
Inter-DC use cases initially and could later expand to wide area networks (WANs).
Hybrid SDN where new SDN controllers will work with existing forwarding boxes and optionally
vendor-specific domain controllers.
SDN-NFV networks.
The architecture extends the concepts of NFV to maintain SDN catalogs in addition to VNF catalogs.
Concepts of NFV network services based on forwarding graphs of VNFs are extended to combo SDN-
NFV network services. End-to-End Orchestration (EEO) extends the concepts of NFV orchestration to
support orchestration of SDN services (transport/WAN/enterprise) and end-to-end network services.
The document covers all aspects of network operation like provisioning, capacity planning, KPIs and
service assurance of infrastructure and software; charging; and security. It is intended to provide Verizon
planning and operations teams an understanding of the end-to-end architecture.
This Architecture document has been co-authored with several Verizon industry participants – Cisco,
Ericsson, Hewlett Packard Enterprise, Intel, Nokia, Red Hat and Samsung.
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Contributors and Acknowledgements
Organization Contributors Acknowledgements
Verizon Kalyani Bogineni, Fellow Dave McDysan, Anil Guntupalli, Girish
Denny Davidson, Document Editor Nair, Mike Ryan, Luay Jalil, Phil Ritter,
Antonia Slauson, Project Manager Mike Altland, Sankaran Ramanathan,
Lorraine Molocznik, Graphic Artist Andrea Caldini, Chris Emmons, Gagan
Puranik, Fernando Oliveira, Raquel
Morera Sempere, and their teams.
Cisco Christian Martin Ken Gray, Ravi Guntupalli, Humberto
Kirk McBean LaRoche, Scott Wainner, Mike Geller
Ericsson Doug Brayshaw Mehul Shah, Tarmo Kuningas,
Torbjorn Cagenius Francesco Caruso
HPE Tariq Khan Stinson Mathai, Noah Williams, Ajay
Kevin Cramer Sahai, Raju Rajan, David Lenrow, Paul
Burke, Jonas Arndt, Marie-Paule Odini
Intel Kevin Smith David Lowery, Gerald Rogers, Kapil
Joseph Gasparakis Sood
Nokia Peter Busschbach Peter Kim, Volker Mendisch, Tuomas
Nabeel Cocker Niemelä, Marton Rozman, Norbert
Jukka Hongisto Mersch, Hui-Lan Lu
Steve Scarlett
Red Hat Rimma Iontel Bret Luango, Stephen Bates
Gordon Keegan
Samsung Ray Yuhanna Robbie Martinez
Nurig Anter
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Table of Contents
Executive Summary .................................................................................................................................... 3
1 Introduction ..................................................................................................................................... 8
2 Architecture Framework ............................................................................................................... 14
3 NFV Infrastructure ......................................................................................................................... 18
4 VNF Manager ................................................................................................................................. 35
5 VNF Descriptors ............................................................................................................................ 39
6 End-to-End Orchestration ............................................................................................................ 45
7 End-to-End Network Service Descriptors ................................................................................... 50
8 Policy Framework ......................................................................................................................... 51
9 SDN Controller Framework .......................................................................................................... 54
10 Interfaces ....................................................................................................................................... 64
11 Architectural Considerations ....................................................................................................... 72
12 VNF considerations for NFVI ....................................................................................................... 78
13 Reliability ....................................................................................................................................... 90
14 IMS Functions ................................................................................................................................ 93
15 EPC Functions ............................................................................................................................. 104
16 L1 – L3 Functions ........................................................................................................................ 113
17 SGi-LAN Architecture ................................................................................................................. 117
18 Charging Architecture ................................................................................................................ 131
19 Service Assurance ...................................................................................................................... 138
20 Key Performance Indicators ...................................................................................................... 145
21 Security ........................................................................................................................................ 157
22 Devices and Applications ........................................................................................................... 173
Annex A: Intent-Based Networking ....................................................................................................... 192
Annex B: Federated Inter-Domain Controller....................................................................................... 194
Annex C: Segment Routing.................................................................................................................... 196
Annex D: SDN Controllers ...................................................................................................................... 203
Annex E: IMS VNF Management Example ............................................................................................ 205
References ............................................................................................................................................... 210
Acronyms ................................................................................................................................................. 213
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1 Introduction
Traditional networks have been designed with purpose-built network equipment (e.g., Routers, Ethernet
switches, EPC hardware, firewalls, load balancers, etc.) based on vendor-specific hardware and software
platforms. Deploying these monolithic network elements has resulted in long development and installation
cycles (slowing time-to-market for new products and services), overly complex lifecycle management
practices (adding to operational inefficiency and overhead) and increasing levels of investment driven by
escalating customer demand at a rate that exceeds revenue growth.
An operator’s network is currently composed of a variety of “bundled” network elements, where the
control, management, and data (user data traffic) functions are physically tied together and the bundled
network elements are each provided by the same supplier. Deployment of new services or upgrades or
modifications to existing services must be done on an element-by-element basis and requires tight
coordination of internal and external resources. This bundling limits operational flexibility while increasing
reliance on proprietary solutions from suppliers.
The goals of the SDN-NFV program in Verizon are the following:
1. Operational Efficiencies
Elastic, scalable, network-wide capabilities
Automated OAM&P; limited human touch
Dynamic traffic steering and service chaining
2. Business Transformation
Time-to-market improvements; elimination of point solutions
Agile service creation and rapid provisioning
Improved customer satisfaction
Verizon SDN-NFV Based Network
The following are key features of the network based on SDN and NFV:
Separation of control and data plane;
Virtualization of network functions;
Programmatic control of network;
Programmatic control of computational resources using orchestration;
Standards-based configuration protocols;
A single mechanism for hardware resource management and allocation;
Automation of control, deployment, and business processes; and
Automated resource orchestration in response to application/function needs.
Combining these techniques facilitates dynamic adaptation of the network based on the application,
increases operational flexibility, and simplifies service development. Functions may be dynamically
scaled to meet fluctuations in demand.
SDN and NFV together change the traditional networking paradigms. This significant shift in how an
operator designs, develops, manages and delivers products and services brings with it a variety of
technological and operational efficiencies. These benefits are aimed at fundamentally redefining the cost
structure and operational processes, enabling the rapid development of flexible, on-demand services and
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SDN-NFV Reference Architecture v1.0
maintaining a competitive position in the industry.
Enhancements to the Software Defined Networking (SDN) Concept
The fundamental concept of ‘Software Defined Networking’ (SDN) changes the current network design
paradigm by introducing network programmability and abstraction. In its initial, narrow definition, SDN is
about separating the network control and data planes in L1, L2, L3, and L4 switches (Figure 1-1). This
enables independent scaling of control plane resources and data plane resources, maximizing utilization
of hardware resources. In addition, control plane centralization reduces the number of managed control
plane instances, simplifies operations, and enables orchestration.
The idea of centralized network control can be generalized, resulting in the broader definition of SDN: the
introduction of standard protocols and data models that enable logically centralized control across multi-
vendor and multi-layer networks. Such SDN Controllers expose abstracted topology and service data
models towards northbound systems, simplifying orchestration of end-to-end services and enabling the
introduction of innovative applications that rely on network programmability.
Orchestration OSS/BSS
Open API
Management Control
Plane Plane
Data Plane Legacy Hardware
(Forwarding Box) (Switch/Router)
Figure 1-1: SDN Concept: separation of control and data planes
Enhancements to Network Functions Virtualization
The second concept is network function virtualization (NFV). This concept is based on the use of
commercial off-the-shelf (COTS) hardware for general purpose compute, storage and network. Software
functions (implementations of physical network functions) necessary for running the network are now
decoupled from the hardware (NFV infrastructure).
NFV enables deployment of virtual network functions (VNFs) as well as network services described as NF
Forwarding Graphs of interconnected NFs and end points within a single operator network or between
different operator networks.
VNFs can be deployed in networks that already have corresponding physical network functions (PNFs)
and can be deployed in networks that do not have corresponding PNFs. The proposed architecture
enables service assurance for NFV in the latter scenario and enables data collection for KPIs from the
hardware and software components of NFV.
End-to-End Orchestration
This section provides a high-level description of the Management and Control aspects of the SDN and
NFV architecture. This serves as an introduction to the more detailed description of the architecture
shown in Figure 1-2 below.
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Description:This architecture consolidates and enhances existing SDN, NFV Standalone NFV architecture where virtual network functions (VNFs) can be
