The cloud computing phenomenon is generating a lot of interest worldwide because of its potential to offer services on demand, at lower cost than current options, and with less complexity, greater scalability, and wider reach. The opportunities for providers of managed services to benefit from this model are significant and exciting. But confusion over cloud terminology, existing services versus vaporware, and evolving service models are widespread. Many potential customers are uncertain about whether to adopt these services and many service providers are unsure of how to best integrate and market the cloud architecture.
Cloud Computing Overview
• IT as a service (ITaaS) is a service model where an organization or individual contracts with a service provider to obtain network connectivity and either individual or bundled services (for example, network backup, disaster recovery, VPN, VoIP, hosting, video surveillance, and web conferencing)
• Software as a service (SaaS) enables service subscribers to access a software application from a software vendor through the web. The SaaS provider hosts and operates the application. Customers do not pay to own the software but instead only pay to use it through a web API. The term SaaS has replaced the older designation for these software vendors, application service providers (ASPs).
• Platform as a service (PaaS) makes raw computing power and disk space available from a platform of resources in the network cloud. A recent example is the Google App Engine, a developer tool that enables developers to create scalable web applications and run them on Google's infrastructure (including 500 MB of persistent storage and bandwidth and CPU to enable five million monthly page views).
• Infrastructure as a service (IaaS) refers to the delivery of a virtual computer infrastructure environment as a service. Instead of purchasing servers, software, data center resources, network equipment, and the expertise to operate them, customers can buy these resources as an outsourced service delivered through the network cloud.
Figure 1. Cloud Computing Services

• Virtualization allows network resources to be available as virtual segments, with devices or portions of resources such as storage repositories accessible as needed, independent of their physical location or physical connection to the network.
• Multi-tenancy refers to the architectural principle allowing the sharing of resources (such as software, computing power, and storage repositories) and costs among a large pool of users. The virtual separation of those resources provides enterprise customers with private virtual domains that may provide access to different information and services by departments as well as shared services between departments. Public clouds can provide total isolation of information and services for individual customers.
Cloud Computing Incentives
• Software and middleware applications have evolved so they can take advantage of virtualized resources.
• Cheaper and more scalable computing power allows for the creation of large virtual machines that free customers from having to acquire and provision hardware and instead allows them to provision these virtual machines to run on the hardware within the service provider cloud. Customers can run multiple instances of their virtual machines on different hardware in the cloud or the service provider can scale existing machines by adding more CPU.
• Services delivered through the cloud provide competitive differentiation from other types of hosted and managed services.
• Cloud computing provides the platform for standardized managed services that can be sold into vertical market niches, including smaller customers.
• Cloud computing incentives for customers include:
• Depending upon the type of offering, reduced complexity related to the support of hardware and software components
• Lower total cost of ownership (TCO) with a pay-as-you-go model that gives customers the flexibility to start small and ramp up as required without an initial capital outlay
• Faster and easier acquisition of new services to speed time to market
Standards, Middleware, Interoperability, and Instrumentation
• Cloud middleware, also referred to as Cloud OS, is the major system that manages and controls services, Figure 2. Google App Engine and Amazon EC2/S3 are examples of cloud middleware. Using cloud middleware, users should be able to create cloud instances, acquire resources, and perform general resource lifecycle management on demand.
Figure 2. High-Level Cloud Middleware Architecture Example

• APIs for applications, acquisition of resources such as computing power and storage, and machine image management must be available to make applications suitable for network clouds. Currently, most cloud vendors maintain proprietary APIs that do not allow for the sharing of resources between different clouds. To date, the role of many network vendors has been relegated to providing basic plumbing. There is a market opportunity to more tightly integrate the underlying infrastructure using APIs.
• Resource management is a key area requiring development in cloud computing architectures. Typically, network resources are statically provisioned but computing, storage, and application resources in clouds must be capable of being provisioned dynamically and on demand. Additionally, network resources must be capable of being provisioned separately from application resources. In a typical enterprise IT environment, there are many administrative domains in separate silos. Each domain may operate in isolation. But in a cloud environment (where cloud instances must be created on demand and dynamically with minimum turnaround time) the administrative boundaries become a major issue that can increase the provisioning time dramatically. The resource management process or workflow in the cloud must be fully automated across the administrative boundaries, with minimum turnaround time.
• Virtualization technology has been around for several years. Adoption within data centers and by service providers is increasing rapidly. Different proprietary virtualization technologies exist and this lack of standardization poses a barrier to an open standards cloud that is interoperable with other clouds and a broad array of computing and information resources.
• Interoperability between clouds will require the equivalent of a standardized cloud interoperability control plane that will enable sharing and exchange of cloud resources and communications between clouds that may be owned by multiple service providers. One example is a control plane incorporated into a cloud middleware layer or through Border Gateway Protocol (BGP) extensions. Using protocols such as Extensible Messaging and Presence Protocol (XMPP) over an agreed-upon interface between different service provider clouds enables multiple clouds to check naming and presence details and user policy permissions to provide interoperable services. Cloud 1, for example, could learn what services (such as SPARQL Protocol and RDF Query Language and OWL) are available on Cloud 2 and if these services match a particular user's requirements. Upon receiving a response, Cloud 1 could determine if a user's requirements are met and understand how to hand over the user to Cloud 2. Cloud 1 would also know how to request, provision, and call services in Cloud 2 for the user and how to pass on the user requirements such as billing tariff and SLA. So a mobile user accessing email through a Microsoft Exchange server could be migrated to Cloud 2 without any disruption or changes to the original service agreement.
• Cross-layer dynamic policy control is required of applications that run in a cloud as they are in enterprises. When a user creates a cloud instance using a cloud computing service, the user should be able to associate relevant policies for resources within the cloud instance. Network resources must similarly be policy controlled in alignment with application policies.
1. Client sends service requests
2. System management finds correct resources
3. Systems provisioning finds correct resources
4. Computing resources are found and service request is executed
5. Results of the service requests are sent to the clients
Figure 3. Cloud Computing Workflow

The End-User Perspective
• The illusion of infinite computer resources available on demand that eliminate the need for customers to plan far ahead for provisioning
• No need for an up-front commitment by customers, allowing them to start small and increase their use of cloud services as needed
• The pay-as-you-go model that allows customers to buy just what they need, either on a short-term or ongoing basis
• Mobile, interactive applications that respond in real time to information provided by users or sensors or both must be highly available and rely on large data sets that are most conveniently hosted in large data centers. Services that combine two or more data sources or other services are a good example of interactive applications. The cloud environment is an excellent architecture for these applications, especially for mobile devices that are connected to the cloud nearly all the time.
• Parallel batch processing is uniquely suited to cloud computing because users can take advantage of the ability to utilize hundreds or thousands of computers for a short period of time to get the job done.
• Analytics is another computing-intensive activity that can be well served in the network cloud. The U.C. Berkeley study noted that a growing share of computing resources are being spent understanding customers, buying habits, and other factors through business analytics.
• Computing-intensive desktop applications such as symbolic mathematics that involve a lot of computing per unit of data, image rendering, and 3D animation can be offloaded to the extensive resources of a cloud computing environment (in this case a private cloud) served by a large data center.
Cloud Computing Service Opportunities
• SaaS opportunities: Customer relationship management (CRM) and enterprise resource planning (ERP) applications, email, web conferencing, digital content creation
• ITaaS opportunities: Storage, backup, unified threat management, security posture analysis, compliance
• IaaS and PaaS: Disk space, raw computing power for testing and development
Cisco and Cloud Computing
Summary
For More Information
http://blogs.cisco.com/news/comments/cisco_cto_on_cloud_computing/
http://blogs.cisco.com/datacenter/comments/services_in_a_cloud_computing_environment/
http://blogs.cisco.com/datacenter/comments/economic_downturn_driving_cloud_computing_evolution/
http://www.eecs.berkeley.edu/Pubs/TechRpts/2009/EECS-2009-28.html
