Information Technology Reference
In-Depth Information
Fig. 3.
Hierarchy of infrastructure requirements
A
requirement
can be either
hard requirement
or
soft requirement
.A
hard requirement
is a compulsory requirement which remains invariant over
the application's lifecyle - an example might be legislation regulation; a
soft
requirement
is a desired requirement which can change or be re-prioritised -
for example, it might be budget or performance related. This concept is repre-
sented using the
hasRequirementType
property and the
requirementType
emumeration property. A
priority level
data property is defined to indicate the
importancy of a
requirement
. This property can be used to measure and calcu-
late weightings during requirement prioritisation and resource filtering process.
Requirements
may depend on each other. For example, UK Data Protection
Act (
compliance requirement
) indicates that no data can be processed or
stored outside the UK boundary. This translates to a dependency relationship
on
geographical requirement
. Figure 4 illustrates the
requirement
ontology.
Infrastructure
and
requirement
are core entities in the infrastructure re-
quirement ontology. Every
infrastructure
has at least one
site
.A
site
has one
or more
resource groups
.A
resource group
is a set of
resources
.
Require-
ments
can be applied at different levels of the infrastructure layout:
infras-
tructure
,
site
,
resource group
or
resource
level. The relationship between
infrastructure
and
requirement
is expressed using the
hasRequirement
property (see Figure 5).
A
restriction
class is defined to identify the conditions or constraints asso-
ciated with a
requirement
.Each
requirement
has at least one
restriction
which is expressed using
isConstrainedBy
property (see Figure 4).
Cost requirement
is constrained by
cost restriction
.A
cost restriction
can be a
total cost
or it can be divided into
compute cost
,
software cost
,
storage cost
,or
bandwidth cost
.Each
cost restriction
is associated with
cost frequency
(per hour, per day) and
cost money
(amount, currency).
Fig. 4.
Requirement
Fig. 5.
Infrastructure and requirement
