SDN深度解析：软件定义网络的未来

需积分: 9 22 浏览量更新于2024-07-22 收藏 6.34MB PDF 举报

"SDN: Software Defined Networks by Thomas D. Nadeau and Ken Gray" 软件定义网络（SDN，Software Defined Networking）是一种新兴的网络架构，它将网络控制平面与数据转发平面分离，使得网络可以更加灵活、可编程，并且便于集中管理和自动化。这种架构的核心思想是通过将网络的决策过程（即路由选择、策略实施等）从硬件转移到软件，从而实现网络资源的按需分配和快速部署。 SDN的主要特点包括： 1. **控制平面与数据平面分离**：在传统的网络中，路由和交换功能集成在硬件设备中。而在SDN中，控制平面被上移到独立的软件控制器，负责全局网络视图和策略制定，而数据平面则专注于数据包的转发，两者之间通过开放的接口进行通信。 2. **开放接口（OpenFlow协议）**：OpenFlow是SDN的最初和最著名的协议，它定义了控制器与转发设备之间的通信方式，允许控制器动态地配置、监控和修改网络设备的转发行为。 3. **集中式控制**：SDN控制器作为整个网络的“大脑”，它可以全局查看网络状态并做出决策，提高了网络策略的灵活性和一致性。 4. **可编程性**：由于控制平面运行在软件中，因此可以利用通用的编程语言进行编程，开发者可以创建新的网络应用和服务，以满足特定需求。 5. **标准化与生态系统**：SDN的发展推动了众多标准组织的工作，如ONF（Open Networking Foundation）负责OpenFlow标准，IETF则在制定其他SDN相关的协议和标准。这促进了供应商间的互操作性和生态系统的繁荣。 6. **应用领域广泛**：SDN的应用涵盖了数据中心网络、云计算、移动网络、网络安全、物联网等多个领域，通过提供灵活的网络资源管理，降低了运维成本，提升了服务质量。《SDN: Software Defined Networks》这本书由Thomas D. Nadeau和Ken Gray撰写，详细探讨了SDN的定义、协议和标准。书中可能涵盖了SDN的历史背景、核心概念、架构设计、OpenFlow详解、控制器平台、安全挑战、实际部署案例以及未来发展趋势等内容。通过这本书，读者可以全面了解SDN技术及其在现代网络中的应用。

and the network together for new use cases. In this case, systems can actually interact

with each other

, allowing for more infrastructure flexibility, whether physical, virtual,

or hybrid.

Traffic policy and rerouting based on network conditions and/or regulation shifts are

also common applications, as are the insertion of new services or data into applications

that may be able to more clearly prioritize bandwidth for a user that pays a premium

amount for faster connection speeds. When you apply SDN and a centralized manage‐

ment plane that is separate from the data plane, you can more quickly make decisions

on where data traffic can be rerouted, as this can occur programmatically with software

interfaces (APIs), versus on-the-box CLI methodology.

One advanced use case is the hybrid cloud. In this case, an application may run in a

private cloud or data center yet utilize the public cloud when the demand for computing

capacity spikes or cost can be reduced. Historically, cloud bursting was typically used

only in environments with non-mission critical applications or services, but with the

network tie-in and software principles applied, the use case shifts. Applications now

remain in compliance with the IT organizations’ policies and regulations. The applica‐

tion can also retain its dependency model if it is reliant on different data or information

that it typically has on premises versus off, or in the public cloud environment. It also

allows for the application to run across different platforms regardless of where the ap‐

plication was built.

As we look at SDN, we must also consider Network Functions Virtualization and how

this ties into the broader infrastructure and virtualization picture. The transition from

physical to virtual is one that is leading many of these changes in the industry. By tying

the hardware (physical) to software (virtual), including network, server, and storage,

there’s the opportunity to virtualize network services and have them orchestrated as fast

as any other workload. Tie this via programmatic interfaces to the WAN, and you can

absolutely guarantee service delivery. SDN coupled with NFV is a pivotal architectural

shift in both computing and networking. This shift is marked by dynamic changes to

infrastructure to closely match customer demand, analytics to assist in predicting per‐

formance requirements, and a set of management and orchestration tools that allow

network functions and applications to scale up, down, and out with greater speed and

less manual intervention. This change affects how we build cloud platforms for appli‐

cations and at the most basic level must provide the tools and techniques that allow the

network to respond to changing workload requirements as quickly as the platforms that

leverage them. It also allows workload requirements to include network requirements

and have them satisfied.

It’s important to note that not all networks are the same, and that’s why it’s critical to

understand the importance of the underlying infrastructure when abstracting control

from the network—either from physical or virtual devices. Network Functions Virtu‐

alization is simply the addition of virtual or off-premises devices to augment traditional

Foreword by David Ward | xv

infrastructure. However, the tie to both the on- and off-premises offerings must be

considered when running a

pplications and services to ensure a seamless experience not

just for the organization running the applications or services but also for the consumer

of the services (whether they be enterprise and in-house users or external customers).

So why should you care? From a technical perspective, SDN allows for more flexibility

and agility as well as options for your infrastructure. By allowing data to be controlled

centrally and tied into not just the network, but also the storage and server, you get a

more cohesive view on performance, speed, traffic optimization, and service guarantees.

With programmatic interfaces (APIs) that can be exposed in multiple languages and

utilized with tools, your operators and administrators can more quickly respond to the

demand of the business side of the house or external customer needs. They can now

apply policies for other development organizations in-house to allow them network

data to more effectively spin up server farms or even build applications with network

intelligence built in for faster, better performing applications. By allowing for the data

to be exposed in a secure and scalable way, the entire IT organization benefits, and with

faster development and deployment cycles and easier delivery of new services, so too

does the business. The promise that SOA gave developers—write once, run anywhere

—can now be fully realized with the underlying network’s ability to distribute infor‐

mation across the enterprise, access, WAN, and data center (both physical and virtual).

This allows for applications to break free from the boundaries of the OSS and manage‐

ment platforms that had previously limited their ability to run in different environments.

The IT industry is going through a massive shift that will revolutionize the way users

build, test, deploy, and monetize their applications. With SDN, the network is now closer

to applications (and vice versa), allowing for a new breed of smarter, faster, and better

performing applications. It enables the network to be automated in new ways, providing

more flexibility and scalability for users, and unleashes the potential for business cost

savings and revenue-generating opportunities. It’s a new era in networking and the IT

industry overall, and it will be a game-changing one. Check out this book—it’s required

reading.

—David Ward

CTO, Cisco Systems

xvi | Foreword by David Ward

2. http://www.gartner.com/technology/research/methodologies/hype-cycle.jsp

you can’t easily see. Under the waterline, some very muscular feet are paddling away to

move tha

t duck along. In many ways, this is analogous to the progress of software-

defined networks.

The surface view of SDN might lead the casual observer to conclude a few things. First,

defining what SDN is, or might be, is something many organizations are frantically

trying to do in order to resuscitate their business plans or revive their standards-

developing organizations (SDOs). Second, that SDN is all about the active rebranding

of existing products to be this mythical thing that they are not. Many have claimed that

products they built four or five years ago were the origins of SDN, and therefore ev‐

erything they have done since is SDN, too.

Along these lines, the branding of seemingly everything anew as SDN and the expected

hyperbole of the startup community that SDN has been spawning for the past three or

four years have also contributed negatively toward this end.

If observers are predisposed by their respective network religions and politics to dismiss

SDN, it may seem like SDN is an idea adrift.

Now go ahead and arm yourself with a quick pointer to the Gartner hype-cycle.

understand that perspective and can see where that cycle predicts things are at.

Some of these same aspects of the present SDN movement made us lobby hard for the

glitter-horned unicorn just to make a point—that we see things differently.

For more than two years, our involvement in various customer meetings, forums, con‐

sortia, and SDOs discussing the topic, as well as our work with many of the startups,

converts, and early adopters in the SDN space, leads us to believe that something worth

noting is going on under the waterline. This is where much of the real work is going on

to push the SDN effort forward toward a goal of what we think is optimal operational

efficiency and flexibility for networks and applications that utilize those networks.

There is real evidence that SDN has finally started a new dialogue about network pro‐

grammability, control models, the modernization of application interfaces to the net‐

work, and true openness around these things.

In that light, SDN is not constrained to a single network domain such as the data center

—although it is true that the tidal wave of manageable network endpoints hatched via

virtualization is a prime mover of SDN at present. SDN is also not constrained to a single

customer type (e.g., research/education), a single application (e.g., data center orches‐

tration), or even a single protocol/architecture (e.g., OpenFlow). Nor is SDN constrain‐

ed to a single architectural model (e.g., the canonical model of a centralized controller

and a group of droid switches). We hope you see that in this book.

xviii | Preface

At the time of writing of the first edition of this book, both Thomas Nadeau and Ken

Gra

y work at Juniper Networks in the Platform Systems Division Chief Technologist’s

Office. We both also have extensive experience that spans roles both with other vendors,

such as Cisco Systems, and service providers, such as BT and Bell Atlantic (now Veri‐

zon). We have tried our best to be inclusive of everyone that is relevant in the SDN space

without being encyclopedic on the topic still providing enough breadth of material to

cover the space. In some cases, we have relied on references or examples that came from

our experiences with our most recent employer (Juniper Networks) in the text, only

because they are either part of a larger survey or because alternative examples on the

topic are net yet freely available for us to divulge. We hope the reader finds any bias to

be accidental and not distracting or overwhelming. If this can be corrected or enhanced

in a subsequent revision, we will do so. We both agree that there are likely to be many

updates to this text going forward, given how young SDN still is and how rapidly it

continues to evolve.

Finally, we hope the reader finds the depth and breadth of information presented herein

to be interesting and informative, while at the same time evocative. We give our opinions

about topics, but only after presenting the material and its pros and cons in as unbiased

a manner as possible.

We do hope you find unicorns, fairy dust, and especially lots of paddling feet in this

book.

Assumptions

SDN is a new approach to the current world of networking, but it is still networking.

As you get into this book, we’re assuming a certain level of networking knowledge. You

don’t have to be an engineer, but knowing how networking principles work—and

frankly, don’t work—will aid your comprehension of the text.

You should be familiar with the following terms/concepts:

OSI model

The Open Systems Interconnection (OSI) model defines seven different layers of

technology: physical, data link, network, transport, session, presentation, and ap‐

plication. This model allows network engineers and network vendors to easily dis‐

cuss and apply technology to a specific OSI level. This segmentation lets engineers

divide the overall problem of getting one application to talk to another into discrete

parts and more manageable sections. Each level has certain attributes that describe

it and each level interacts with its neighboring levels in a very well-defined manner.

Knowledge of the layers above layer 7 is not mandatory, but understanding that

interoperability is not always about electrons and photons will help.

Preface | xix

剩余177页未读，继续阅读

jixiang99445

粉丝: 0
资源: 1

SDN深度解析：软件定义网络的未来

SDN深度解析：软件定义网络的新视野

SDN权威指南：软件定义网络深度解析

SDN权威指南：深入解析软件定义网络与OpenFlow

SDN：Software Defined Networks,Thomas.D.Nadeau

Counteracting Attacks From Malicious End Hosts__in Software Defined Networks

软件定义网络 SDN Software Defined Networks

SDN Software.Defined.Networks .Thomas.D.Nadeau.文字版

SDN software defined netwrok

Local Fast Reroute With Flow Aggregation in Software Defined Networks

最新资源