Cloud computing is defined by the National Institute
of Standards and Technology (NIST)2 as “a model
for enabling convenient, on-demand network access
to a shared pool of configurable computing resources
(eg, networks, servers, storage, applications, and
services) that can be rapidly provisioned and released
with minimal management e ffort or service provider
interaction. Cloud computing is defined to have
several deployment models, each of which provides
distinct trade-offs for agencies which are migrating
applications to a cloud environment. cloud
deployment models as follows: