Characteristics
Konrad Walser and Olivier Brian
Description
Measured service The service used must be commensurable with the resources required. This enables usage‐based billing.
2.2 Cloud service models
The following section deals with different cloud service models and their respective advantages and disadvantages.
Table 2: Advantages and disadvantages of different cloud service models
Type / Brief description |
Advantages |
Disadvantages |
Infrastructure as a Service( IaaS): The client is offered computing, storage and network capacity. Using this infrastructure, the client operates its own platform, software and operating systems. |
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Platform as a Service( PaaS): Includes a complete platform with development tools. Such solutions are used for proprietary developments or for a special software that runs on the platform. The underlying infrastructure is made available and administered by the provider.
High scalability of the required systems, as per the need; redundant data storage; physical separation of stored and used data; no maintenance costs for setting up and operating the infrastructure. OPEX instead of CAPEX; Pay‐asyou‐Go. OPEX stands for OPerational EXpenditure. This covers expenses for the operational business. CAPEX stands for CAPital EXpenditure. This covers investment expenditure for longer‐term assets. Low administrative expense, as user does not have to provide or implement the necessary infrastructure; development in the team( also geographically distributed). One single platform with minimal costs( standardisatrion); no maintenance costs for setting up and operating the platform and its tools; no maintenance costs for setting up and operating the platform and its tools; OPEX instead of CAPEX; Pay‐as‐you‐Go
Location of the data for public and private clouds not always evident; strongly dependent on availability of infrastructure and networks; lack of or deficient demarcation / isolation of data manipulation; possible unauthorised access to data due to incorrect configuration; warranty and liability in the event of breach of confidentiality, security and data integrity.
Vendor‐lock‐in; lack of portability; lack of interoperability; no standardised technologies; lack of flexibility; requirements of proprietary applications or development environments.
Software as a Service( SaaS);, complete applications are made available, generally via a web interface. The client has no influence on the platform and the underlying infrastructure.
Separability / multi‐client capability of the applications; quickly ready for use / faster project initiation( time to market); no maintenance costs for operating the business functionalities; OPEX instead of CAPEX; Pay‐as‐you‐Go; lower total costs( TCO); mobility / location independence.
Selection of the right provider; lack of portability; lower ease of integration into existing application landscapes; fewer adaptation options, due to inherent standardisation; poss. longer response times; impact of security gaps when using joint SaaS solutions; no use without internet access.
Table 3 gives an overview of service models, together with a brief description of these and an explanation of the advantages and disadvantages of the different models( EuroCloud Swiss 2012).
Table 3: Possible organisational models for cloud offerings
Organisational model Private cloud
Community cloud
Public cloud
Hybrid cloud
Brief description The solution user is explicitly an organisation or an organisational unit. A private cloud can be operated both internally and by an external provider. The benefits of the private cloud approach can only be partially exploited, but it is possible to make extensive customisations. In contrast to private cloud architecture, the service is used by several groups. These are defined. This service can, however, also be offered by a community i. e. by several solution providers. The service offered is available to the public and is generally only offered by only one provider. The benefits of scalability and resource pooling can be best exploited. The hybrid cloud offers a combination of the different organisational forms described and their advantages and disadvantages. For example, data can be stored internally in a private cloud, whereas the application is run in a public cloud.
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