Jaycee's Networking

May 4, 2009

Cloud Computing

Filed under: Information — Tags: — Jaycee @ 1:00 am

Cloud computing is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet. Users need not have knowledge of or control over the technology infrastructure “in the cloud” that supports them.

Cloud computing services usually provide common business applications online that are accessed from a web browser, while the software and data are stored on the servers. The concept incorporates CaaS, IaaS, PaaS and SaaS that have the common theme of reliance(依靠) on the Internet for satisfying the computing needs of the users.

The majority of cloud computing infrastructure consists of reliable services delivered through data centers and built on servers with different levels of virtualization technologies. The services are accessible anywhere that has access to networking infrastructure.

The Cloud appears as a single point of access for all the computing needs of consumers. Commercial offerings need to meet the quality of service requirements of customers and typically offer SLA (service level agreements). IBM, Amazon, Google, Microsoft or Yahoo are some of the major cloud computing service providers.


1. Cloud computing has been criticized for limiting the freedom of users and making them dependent on the cloud computing provider. Users had no freedom to install new applications and needed approval from the administrator to achieve certain tasks. Overall, it limited both freedom and creativity.

2. Cloud computing endangers liberties because users sacrifice their privacy and personal data to a third party.

3. The Cloud spans many borders and “may be the ultimate form of globalization.” As such it becomes subject to complex geopolitical issues: providers must satisfy myriad regulatory environments in order to deliver service to a global market.as of 2009[update] providers such as Amazon Web Services cater to the major markets (typically the United States and the European Union) by deploying local infrastructure and allowing customers to select “availability zones.”

4. Seven security issues should discuss with a cloud-computing vendor:

(1) Privileged user access—inquire about who has specialized access to data and about the hiring and management of such administrators

(2) Regulatory compliance(承諾)—make sure a vendor is willing to undergo external audits and/or security certifications

(3) Data location—ask if a provider allows for any control over the location of data

(4) Data segregation(隔離)—make sure that encryption is available at all stages and that these “encryption schemes were designed and tested by experienced professionals”

(5) Recovery—find out what will happen to data in the case of a disaster; do they offer complete restoration and, if so, how long that would take

(6) Investigative Support—inquire whether a vendor has the ability to investigate any inappropriate or illegal activity

(7) Long-term viability—ask what will happen to data if the company goes out of business; how will data be returned and in what format


1. Cost— Pricing on a utility computing basis with usage-based options.

2. Device and location independence— users access systems using a web browser regardless of their location or what device they are using

3. Multi-tenancy— sharing of resources and costs amoung a large pool of users:

(1) Centralization of infrastructure— lower real estate, electricity costs
(2) Peak-load capacity increases— users need not engineer for highest possible load-levels
(3) Utilization and efficiency

4. Reliability— improves through the use of multiple redundant sites

5. Scalability— via dynamic (“on-demand”) provisioning of resources on a fine-grained, self-service basis near real-time, without users having to engineer for peak loads. Performance is monitored and consistent and loosely-coupled architectures are constructed using web services as the system interface.

6. Security— Due to centralization of data, increased security-focused resources. Providers are able to devote resources to solving security issues that many customers cannot afford. Providers typically log accesses, but accessing the audit logs themselves can be difficult or impossible.

7. Sustainability(持續性)–comes about through improved resource utilization, more efficient systems.

<Six layers components of cloud computing>

1. Client— A cloud client consists of computer hardware and/or computer software which relies on cloud computing for application delivery, or which is specifically designed for delivery of cloud services and which, in either case, is essentially useless without it.

2. Services— A cloud service includes “products, services and solutions that are delivered and consumed in real-time over the Internet”. For example, Web Services (“software system[s] designed to support interoperable machine-to-machine interaction over a network”) which may be accessed by other cloud computing components, software, or end users directly.

3. Application— A cloud application leverages the Cloud in software architecture, often eliminating the need to install and run the application on the customer’s own computer, thus alleviating the burden of software maintenance, ongoing operation, and support.

4. Platform— A cloud platform, such as PaaS, the delivery of a computing platform, and/or solution stack as a service, facilitates deployment of applications without the cost and complexity of buying and managing the underlying hardware and software layers.

5. Storage Cloud storage involves the delivery of data storage as a service, including database-like services, often billed on a utility computing basis, e.g., per gigabyte per month.

6. Infrastructure Cloud infrastructure, such as IaaS, is the delivery of computer infrastructure, typically a platform virtualization environment, as a service.


  • Client
    • Browsers (AJAX)
    • Offline (HTML 5)
  • Service
  • Application
  • Platform
    • Solution stacks (LAMP)
  • Implementations
    • Virtualization (OVF)


The systems architecture of the software systems involved in the delivery of cloud computing, comprises hardware and software designed by a cloud architect who typically works for a cloud integrator. It typically involves multiple cloud components communicating with each other over application programming interfaces, usually web services.

This closely resembles the Unix philosophy of having multiple programs doing one thing well and working together over universal interfaces. Complexity is controlled and the resulting systems are more manageable than their monolithic counterparts.

Cloud architecture extends to the client, where web browsers and/or software applications access cloud applications.

Cloud storage architecture is loosely coupled, where metadata operations are centralized enabling the data nodes to scale into the hundreds, each independently delivering data to applications or users.

<Cloud Computing Providers>

Akamai Technologies
Amazon Web Services


A cloud computing provider or cloud computing service provider owns and operates live cloud computing systems to deliver service to third parties. Usually this requires significant resources and expertise in building and managing next-generation data centers. Some organizations realize a subset of the benefits of cloud computing by becoming “internal” cloud providers and servicing themselves, although they do not benefit from the same economies of scale and still have to engineer for peak loads.

The barrier to entry is also significantly higher with capital expenditure required and billing and management creates some overhead. Nonetheless, significant operational efficiency and agility advantages can be realised, even by small organisations, and server consolidation and virtualization rollouts are already well underway.

Amazon.com was the first such provider, modernising its data centers which, like most computer networks, were using as little as 10% of its capacity at any one time just to leave room for occasional spikes. This allowed small, fast-moving groups to add new features faster and easier, and they went on to open it up to outsiders as Amazon Web Services in 2002 on a utility computing basis.

<Cloud Computing Vendor>

Some vendors sells or gives products and services that facilitate the delivery, adoption and use of cloud computing.For example:


1 Comment »

  1. […] downloads or installation for developers, IT managers or end-users. It’s also known as cloud computing, in which dynamically scalable and often virtualized resources are provided as a service over the […]

    Pingback by Everything as a service « Packet Forwarding — May 22, 2010 @ 9:59 am

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