1. Cloud Computing Overview

Cloud computing is a new model for the delivery and consumption of IT Services. It has
gained considerable currency as businesses face the economic uncertainties of the future
whilst recognising that continued investment in IT enables business innovation. As a result,
many business leaders are looking for new ways to service their IT needs, whilst driving
efficiency in service delivery and establishing a predictable cost base upon which to build.
Cloud services respond to these imperatives by offering an alternative to owning and
operating some or all of an organisation’s IT services. There are a number of cloud models
available, offering different types of services.
Cloud computing models fall into four categories:
 Public clouds are typically internet based services that enable on-demand or utility
based user access to computing, storage and software applications. The applications
are securely hosted on remote datacentres, rather than on site – many organisations
may use the same base applications though they are customised at the point of
delivery, whilst application data is not shared and remains private. Some cloud service
providers offer access to public cloud services via secure private connections, rather
than the Internet, thereby providing a higher level of service to business customers.
 Private clouds are dedicated services (not shared as with pubic cloud services)
located either within data centres inside the user organisations, or dedicated resource
and space within a cloud provider’s data centre. Private clouds deliver virtualisation
and service automation efficiencies, but for a specific customer organisation.
 Community clouds are private cloud services that are shared between several
organisations, usually drawn from a specific community or sharing common concerns,
such as academic research, or public service provision. As with public clouds,
community clouds are multi-tenant (applications, but not data, are shared by user
organisations).
 Hybrid clouds provide a combination of some or all of the attributes of public, private
and community clouds, enabling additional flexibility for organisations looking for
enhanced Disaster Recovery, access to resource for shorter periods of time for
applications that experience seasonal bursts, or for non-production services, such as
Test and Development.
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2. Business benefits
The specific benefits of moving to a cloud computing model will always depend on the
nature and requirements of the individual user organisation. However, the models also
enable a range of more general benefits, such as:
 Providing access to a huge range of services and business applications without the
need to buy, install and support them locally
 Enabling users to access services and applications irrespective of geographic location
 Radically reduce capital expenditure on customer owned hardware and software
 Predictable cost model, allowing for better financial planning
 Reduced total cost of technology ownership
 Flexibility and scalability
Considerations
As with any decision to select ICT services or to migrate to new ICT equipment and
architectures, businesses should assess providers and solutions thoroughly before
committing, focussing in particular on issues such as:
 Reliability and service availability: Strong service level agreements are vital, as is the
provider’s reputation when it comes to reliability and provisions for continuity during
service disruption
 Future-proofing: Is the provider financially sound and viable long term? What
happens to your data if the provider goes under or is acquired by a larger entity?
 Data migration: Be sure to understand how a provider would support data migration
should you choose to move to a new one. Does the provider operate using standards
and technologies that are common across the industry, or do you risk being locked in
to proprietary approaches or technologies?
 Security: Special attention must be given to cloud providers in areas such as
screening their privileged administrators, data centre location, willingness to submit to
compliance audits, data segregation, investigative support
 Upgrades: Is the provider committed to technology refreshes, upgrading and keeping
software, hardware and infrastructure current?
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3. Glossary
Cloud Applications: Software applications that are not installed on local machines, but are
delivered via a cloud service
Cloud Storage: A service enabling organisations to save data by transferring it to an offsite
storage facility
IaaS: Infrastructure as a service. Cloud computing services whereby clients buy resources
such as servers, storage, software, data centre space and network equipment as a service,
rather than buying them as a capital purchase
PaaS: Platform as a service. A service arrangement through which organisations buy a
computing platform (operating system and services) as a service
SaaS: Software as a Service - the delivery of applications based on cloud hosted software
and services
Service migration: The process of moving from one cloud service or vendor to another
Vendor lock-in: Dependency on a particular cloud provider, perhaps because a lack of
common standards and technologies make it difficult to migrate to a new provider
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