Cloudware Economics - Guide to Cloud Computing for Business and Technology Managers - page 289

14.3 Provisioning Configurations
14.3.1 Traditional Internal IT
In the traditional internal IT model, or zero-outsource model, all aspects that
constitute an IT application or service are purchased and managed using
internal resources. The most common form is office IT infrastructure. In
many offices, an Internet connection is provisioned from an ISP and con-
nected to the internal network via a router. This internal network is then
provisioned with firewalls, switches, central file and print servers, desktop
computers, and perhaps a wireless network and laptops. Internal IT pur-
chases, installs, and operates all this equipment as well as general office soft-
ware. IT for more specialized business applications can be handled in the
same manner, with custom or packaged applications that are loaded onto
hardware provisioned for that purpose.
You can also deploy applications for external audiences, such as a corporate
website in a traditional IT model. Depending on the scale of such an applica-
tion, it can either share the network connection (typically on a separate VLAN
to isolate it from internal traffic for security reasons) or be provisioned with
its own dedicated Internet connectivity and an isolated network.
14.3.2 Colocation
Another possible model for deploying an application is within a third-
party data center, otherwise known as a colocation facility. In this model,
the company is still responsible for purchasing the server hardware and
developing or purchasing the required software for running the applica-
tion. The colocation facility provides that third party with power, cooling,
rack space, and network connectivity for their hardware. The collocation
facility typically also provides redundant network connectivity, backup
power, and physical security.
Colocation services are typically purchased as annual contracts with an
initial service fee and monthly charges based on the amount of rack space
(usually bundled with a specified allocation of power) and committed band-
width. For hardware housed in facilities that are not in close proximity to a
company's IT resources, you can purchase what some call remote-hands capa-
bility in case a manual intervention is required on your behalf.
14.3.3 Managed Service
In the managed-service model, in addition to outsourcing the core infra-
structure, such as power and network connectivity, the company no longer
purchases server and networking hardware. The managed-service provider
rents these to the company and also takes on the responsibility of managing
the hardware systems and base operating system software. In some cases,