Organizational Scenarios in cloud computing, benefits and limitations of cloud

Discuss Organizational Scenarios in cloud computing. What are the benefits and limitations of cloud in business model?

 Scenarios

• End user to cloud 

End user data is managed in cloud.End user does not need to be keep up with anything other than password. For example: Email applications

Concerned Issues 

• The cloud service must authenticate the users.(Identity theft)
• Cloud vendors should be very clear about service level agreements.(SLAs)
• Access to cloud should not require a particular platform or technology.(Open Client)

• Enterprise to cloud to end user

When end user interacts with enterprise, enterprise accesses data from cloud,manipulates it and sends it to end user

• Enterprise to cloud

Enterprise using cloud services for its internal processes.

• Enterprise to cloud to Enterprise

Two enterprise using same cloud

• Private cloud

Useful for larger enterprises.

• Hybrid clouds

Both public and private clouds work together. 

Benefits

On-demand self-service: A client can provision computer resources without the need for interaction with cloud service provider personnel.
• Broad network access: Access to resources in the cloud is available over the network using standard methods in a manner that provides platform-independent access to clients of all types.
This includes a mixture of heterogeneous operating systems, and thick and thin platforms such as laptops, mobile phones, and PDA.
• Resource pooling: A cloud service provider creates resources that are pooled together in a system that supports multi-tenant usage.
Physical and virtual systems are dynamically allocated or reallocated as needed. Intrinsic in this concept of pooling is the idea of abstraction that hides the location of resources such as virtual machines, processing, memory, storage, and network bandwidth and connectivity.
• Rapid elasticity: Resources can be rapidly and elastically provisioned.
The system can add resources by either scaling up systems (more powerful computers) or scaling out systems (more computers of the same kind), and scaling may be automatic or manual. From the standpoint of the client, cloud computing resources should look limitless and can be purchased at any time and in any quantity.
• Measured service: The use of cloud system resources is measured, audited, and reported to the customer based on a metered system.
A client can be charged based on a known metric such as amount of storage used, number of transactions, network I/O (Input/Output) or bandwidth, amount of processing power used, and so forth. A client is charged based on the level of services provided. 

Lower costs: Because cloud networks operate at higher efficiencies and with greater utilization, significant cost reductions are often encountered.
• Ease of utilization: Depending upon the type of service being offered, you may find that you do not require hardware or software licenses to implement your service.
• Quality of Service: The Quality of Service (QoS) is something that you can obtain under contract from your vendor.
• Reliability: The scale of cloud computing networks and their ability to provide load balancing and failover makes them highly reliable, often much more reliable than what you can achieve in a single organization.
• Outsourced IT management: A cloud computing deployment lets someone else manage your computing infrastructure while you manage your business. In most instances, you achieve considerable reductions in IT staffing costs.
• Simplified maintenance and upgrade: Because the system is centralized, you can easily apply patches and upgrades. This means your users always have access to the latest software versions.

• Low Barrier to Entry: In particular, upfront capital expenditures are dramatically reduced. In cloud computing, anyone can be a giant at any time.

Limitations

While the benefits of cloud computing are myriad, the disadvantages are just as numerous. As a general rule, the advantages of cloud computing present a more compelling case for small organizations than for larger ones. Larger organizations can support IT staff and development efforts that put in place custom software solutions that are crafted with their particular needs in mind.
When you use an application or service in the cloud, you are using something that isn't necessarily as customizable as you might want. Additionally, although many cloud computing applications are very capable, applications deployed on-premises still have many more features than their cloud counterparts.
All cloud computing applications suffer from the inherent latency that is intrinsic in their WAN connectivity. While cloud computing applications excel at large-scale processing tasks, if your application needs large amounts of data transfer, cloud computing may not be the best model for you.
Additionally, cloud computing is a stateless system, as is the Internet in general. In order for communication to survive on a distributed system, it is necessarily unidirectional in nature. All the requests you use in HTTP: PUTs, GETs, and so on are requests to a service provider. The service provider then sends a response. Although it may seem that you are carrying on a conversation between client and provider, there is an architectural disconnect between the two. That lack of state allows messages to travel over different routes and for data to arrive out of sequence, and many other characteristics allow the communication to succeed even when the medium is faulty. Therefore, to impose transactional coherency upon the system, additional overhead in the form of service brokers, transaction managers, and other middleware must be added to the system. This can introduce a very large performance hit into some applications.
If you had to pick a single area of concern in cloud computing, that area would undoubtedly be privacy and security. When your data travels over and rests on systems that are no longer under your control, you have increased risk due to the interception and malfeasance of others. You can't count on a cloud provider maintaining your privacy in the face of government actions