Introduction

There are no rules of architecture for a castle in the clouds.

—G.K. Chesterton

Is “provisioning a web server in 5 minutes for $5” the most interesting thing about the cloud?

Those responsible for IT in their enterprise are quickly discovering that the cloud is a game-

changing trend that offers a completely new methodology for service provision. The cloud not only

lets you cut IT costs and be greener—it also accelerates innovation within your enterprise. These are

the values driving architects to look at how they can build a private cloud for their enterprise.

We are at the start of a decade where network designers will use infrastructure consolidation and

virtualization to create next-generation cloud services. Network virtualization is the bedrock for this

solution because it can consolidate diverse networks into a single virtual entity, the first step in cre-

ating a service-oriented infrastructure. On this foundation, IT resources can be scaled up and down

virtually to provision on-demand services (a.k.a. private cloud services) without the addition of

new physical devices or entities through server virtualization. From a business perspective, this

enables cost savings and increases the ability to rapidly react and adjust to the volatile business cli-

mate. This enables more agile balancing of expense reduction with business growth initiatives.

Data centers are the current focus of virtualization because they currently host the largest number

of services. To fully realize the cloud vision, one must also look outward to regional and branch offices

to find more services eligible for consolidation and to ensure that cloud performance is acceptable to

the enterprise. Challenges can come from neglecting the wide area network (WAN) that interconnects

the users and services, with inherent delay, packet loss, congestion, and bandwidth limitations. The

WAN can be the weakest link in implementing the cloud vision. Broad enterprise cloud computing

adoption moves users’ computing and storage distant from them; the ensuing latency and bandwidth

limitations threaten to reduce performance and thus productivity. WAN optimization is the solution

to overcome this obstacle. With WAN optimization, these performance constraints are alleviated,

enhancing the performance of a WAN to be nearly that of a local area network.

While there is abundant technical documentation dedicated solely to WAN optimization, next-

generation data centers, and virtualization, this book is the first look at all three conjoined as a topic

under the mega-trend of cloud computing. This book examines the path toward building a service-

oriented infrastructure (SOI) for cloud computing services. It investigates how data center consolida-

tion techniques, and WAN optimization and virtualization (of servers, storage, and networks) enable

new structures with increased productivity. Another key factor in data center consolidation is

requirements for redundancy to support business availability goals, and we explore the challenges

and solutions in data replication for disaster recovery.

Essential to any enterprise cloud is security. We explore it in general for the cloud context and

specifically how it applies to the Cisco Unified Computing System. Tying it all together, we provide

case studies and examples to demonstrate how enterprises are moving toward a service-oriented

infrastructure.

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xvi Introduction

WHO SHOULD READ THIS BOOK

One’s destination is never a place but rather a new way of looking at things.

—Henry Miller

This book is intended for network engineers, solution architects, internetworking professionals,

IT managers, CIOs, service providers, and everyone else who is interested in building or managing

a state-of-art solution for private cloud services. The information in this book enables you to consol-

idate services from data centers and remote branch offices, leverage WAN optimization to keep per-

formance high, and build a routing and switching platform to provide a foundation for cloud

computing services. In general, it is assumed that the reader is familiar with basic TCP/IP network-

ing. As we progress from simple to more complex topics, the book addresses hard-to-understand

concepts and difficult areas through each chapter and provides case studies and configuration exam-

ples to guide comprehension. If you like really knowing how things work, this is a book for you.

WHO SHOULDN’T READ THIS BOOK

“Beware of the man who works hard to learn something, learns it, and finds himself no wiser than

before,” Bokonon tells us. “He is full of murderous resentment of people who are ignorant without

having come by their ignorance the hard way.”

—Kurt Vonnegut

This book is not intended for people who just want to know how to use EC2; it is geared for people

who want to learn the underlying concepts required to build their own private cloud infrastructure.

Also be warned: we spend the vast majority of our time focused on the technology and market

leaders—Cisco for routing/switching, VMware for virtualization, and Riverbed for WAN optimiza-

tion. Other vendors have relevant products in some cases, but space does not permit more than a nod

in their direction. Finally, it is essential to understand automation in building a cloud; that said, it is

barely touched upon here.