Which of the following best describes an external cloud? (Select the best answer.)

A.
decentralized computer resources that can be accessed over the Internet

B.
a network zone between the Internet and a private or trusted network

C.
a portion of a private or trusted network that can be accessed by a business partner

D.
websites available only to users inside a private network

Explanation:
An external cloud is best described as decentralized computer resources that can be accessed over the
Internet. An external cloud allows for computer processes that are typically hosted internally to be moved to an
external provider, which can reduce the burden on system and network resources. In cloud computing, there
are two accepted types of cloud infrastructure: external and internal. External clouds are managed by a service
provider and are further broken down into two categories: public and private. With public clouds, the service
provider controls the cloud and its infrastructure, whereas with private clouds, the service provider controls only
the infrastructure. Internal clouds are similar to private clouds, except that the cloud is owned and managed by
the organization that uses it and not by a thirdparty service provider.
A portion of a private or trusted network that can be accessed by a business partner best describes an extranet,
not an external cloud. An extranet is a portion of a company’s internal network that is accessible to specific
people outside of the company, such as business partners, suppliers, or customers. By creating an extranet, a
company can provide a location for sharing information with external users. For example, a consulting company
could create an extranet for external customers to view and comment on the consulting company’s progress on
various projects. In many extranet implementations, the external customer network shares a bilateral
connection with the company’s internal network. This bilateral connection not only enables the external
customer to access portions of the company’s internal network, but it also enables portions of the company’s
internal network to access the portions of the external customer’s network.
A network zone between the Internet and a private or trusted network best describes a demilitarized zone
(DMZ), not an external cloud. DMZs are typically bordered by two firewalls: one that allows information to flow
between the DMZ and the Internet, and one that allows information to flow between the DMZ and the private, or
trusted, network.Websites available only to users inside a private network best describe an intranet, not an external cloud. An
intranet can be created to provide internal users with their own website. An intranet provides a location for
sharing information among members of the company. Unlike an extranet, which is a portion of the company’s
network that is accessible by people outside the company, an intranet is typically available only to internal
users.

Cisco: The Internet Protocol Journal, Volume 12, No.3: Cloud Computing A Primer