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Q2 What Network Technology Supports the Cloud? 211

don’t know where your data—which may be a large part of your organization’s value—is located.
Nor do you know how many copies of your data there are or even if they’re located in the same
country as you are. Finally, you have no visibility into the security and disaster preparedness that
is actually in place. Your competition could be stealing your data and you won’t know it.
The positives and negatives of in-house hosting are shown in the second column of
Storing valuable information Figure 6-3. For the most part, they are the opposite of those for cloud-based computing; note,
in the cloud can be risky. The
Security Guide on pages 238–239 however, the need for personnel and management. With in-house hosting, not only will you
looks at why your information have to construct your own data center, you’ll also need to acquire and train the personnel to
may not be as safe as you think. run it and then manage those personnel and your facility.
Why Now?

A skeptic might respond to Figure 6-3 by saying, “If it’s so great, why hasn’t cloud hosting been
used for years? Why now?”
In fact, cloud-based hosting (or a version of it under a different name) has been around
since the 1960s. Long before the creation of the personal computer and networks, time-sharing
vendors provided slices of computer time on a use-fee basis. However, the technology of that
time, continuing up until the first decade of this century, did not favor the construction and use
of enormous data centers, nor did the necessary Internet standards exist.
Companies can save a lot of Three factors have made cloud-based hosting advantageous today. First, processors, data
money by using the cloud, and communication, and data storage are so cheap that they are nearly free. At the scale of a Web
these savings translate into profit. farm of hundreds of thousands of processors, providing a virtual machine for an hour costs es-
This profit does not come without
ethical concerns, however. The sentially nothing, as suggested by the 1.5 cent-per-hour price. Because data communication is
Ethics Guide on pages 212–213 so cheap, getting the data to and from that processor is also nearly free.
examines these concerns. Second, virtualization technology enables the near instantaneous creation of a new virtual
machine. The customer provides (or creates in the cloud) a disk image of the data and programs
of the machine it wants to provision. Virtualization software takes it from there. Finally, as
stated, Internet-based standards enable cloud-hosting vendors to provide processing capabili-
ties in flexible yet standardized ways.

When Does the Cloud Not Make Sense?

Cloud-based hosting makes sense for most organizations. The only organizations for which it may
not make sense are those that are required by law or by industry standard practice to have physical
control over their data. Such organizations might be forced to create and maintain their own hosting
infrastructure. A financial institution, for example, might be legally required to maintain physical
control over its data. Even in this circumstance, however, it is possible to gain many of the benefits
of cloud computing using private clouds and virtual private clouds, possibilities we consider in Q6.

Q2 What Network Technology Supports the Cloud?

A computer network is a collection of computers that communicate with one another over
transmission lines or wirelessly. As shown in Figure 6-4, the three basic types of networks are
local area networks, wide area networks, and internets.

Type Characteristic

Local area network (LAN) Computers connected at a single
physical site
Wide area network (WAN) Computers connected between
two or more separated sites
Figure 6-4 The Internet and internets Networks of networks
Basic Network Types