So you see that using Google Search meets all the requirements necessary for this to be classified as “cloud computing”. As shown in Figure 2 above the Internet “cloud” is the communications medium and the requesting processes, signal transmission and routing, Google's data center request processing, results compilation and search results transmission back to the requesting user via the Internet all take place transparently without the user's knowledge or any control over the information technology systems involved in their successful search query. In a nutshell this is Cloud Computing.
Cloud Architectures and Infrastructures
Decentralized Models - Today we find that some successful cloud computing architectures have very little truly centralized infrastructure or billing systems. Examples here include Peer-to-Peer networks like BitTorrent and Skype along with “volunteer” computing implementations such as SETI@home.
Centralized Models - Other cloud computing implementations such as the Google search and Google Apps scenarios outlined above are patterned around a distributed centralized computing infrastructure.
Distributed Centralized Processing Model - Centralized because centrally located servers perform the processing and distributed since multiple processing facilities are incorporated into the production environment implementation.
The reasons for adopting a distributed centralized infrastructure are to provide for greater resiliency, scalability and redundancy of assets with the objective of eliminating potential single-point-of-failure scenarios.
This usually involves multiple ultra high-speed links to the Internet backbone for each such facility thereby reducing the impact of a single link failure bringing the entire cloud computing facility and its services down.
We must bear in mind that the majority of cloud computing services consist of reliable services delivered from state-of-the-art “green” data centers designed and built on compute (processing) and storage virtualization technologies. Not surprisingly blade centers and traditional rack mount systems in clusters play a leading role.
Anywhere Accessibility - Having services, applications and data available and accessible from anywhere and everywhere on the global stage with the Internet cloud acting as a single point of access for all of the computing needs of a group or many groups of large numbers of users is one of the primary benefits promised by the cloud computing model. Only time will tell as to whether or not this is delivered by cloud computing providers to the satisfaction of customers.
Commercial Cloud Computing Implementations
From a commercial perspective the cloud computing service provider; such as a web hosting service, will need to meet some very demanding and widely varied metrics requirements including Quality-of-Service (QoS) that will need specific and custom service level agreements (SLAs) far different to the majority of those we have seen in the past.
Open Standards - In these regards open standards (don't forget that the Internet owes its success to being an open standard) and open source software have a lot to offer and may well prove to be the critical factors in the successful growth and deployment scenarios for the cloud computing world in the years ahead.
Reduced Capital Expenditure - Because customers of cloud computing service providers are not burdened with the fiscal outlays; that would normally accompany the rollout of new information technologies and their supporting infrastructure, they can budget their costs as a consumable service utility.
This means that they will pay for what they use in very much the same way as we pay for other utilities such as water, power and gas etc. There is also no need to overspend in order to make provision for peak and seasonal demands.
This is an area which costs business considerably as a recent Forester research report has shown that most companies use only 10% of their computing resources 95% of the time with public holidays and the Christmas period being the exceptions to standard usage patterns. With many businesses so reliant on this peak trade to ensure year-long viability they have no choice but to plan for the exception rather than the rule. “Make hay while the sun shines” is the modus operandi behind this type of strategy.
Utility and Subscription Billing Models - It is no surprise to find that many cloud computing offerings have indeed adopted the utility model and have tailored their services and billing structures accordingly. Yet another variation on this theme is the subscription model which charges customers on a subscription basis.
Both models have the own structural strengths and weaknesses and will probably co-exist side-by-side rather than directly compete head-to-head as it were. This latter prospect is given weight by the fact that some of the largest players in the cloud computing service provider game (Microsoft, IBM, HP, Google, Yahoo and Amazon.com) do in fact offer both billing structures to their clients.
Improved Efficiency and Cost Effectiveness - The sharing of computing resources among multiple “tenants” is one of the easiest to implement of all strategies to deliver greatly improved asset and resources utilization rates. This means that servers do what they were designed and built to do; that is to serve and have very little idle time. More bangs for your processing buck.
