Before 2010, most organizations use their own computing infrastructure to support emails, web sites, e-commerce sites, applications, ect...Recently, they have been moving towards using the cloud. The cloud is almost like renting a house but you are renting space to store your datas. It can be defined as the elastic of pooled computer resources over the internet. The reason clouds are pooled because many organizations use the same physical hardware. They are being shared through virtualization. Cloud vendors provide servers according to the amount of demand during a specific time. A company may needs more servers during a popular time where they know there will be millions of site visits, so they need to pre-provision the servers ahead of time.
The cloud use resources “ over the internet”. This means that the cloud vendors can provide services solely over the internet by a set of standards ways of requesting and receiving.
Cloud servers are preferred over in-house hosting for many reasons. Cloud requires minimal capital costs with superior flexibility and is able to fluctuate to demands. There is no obsolescence and create speedy development. While an in-house benefit is simply having control of data location and possibly disaster preparedness. In-house have a long list of why it is negative such as having a high cost, significant development effort, annual maintenance costs, ongoing support costs, increased management requirements, difficult to accommodate fluctuating demand, and obsolescence.
The four basic types of network technology are personal area networks, local area networks, wide area networks and the internet. A PAN or personal area network is a device connected around a single person. PAN devices can connect within 10 meters. A LAN or a local area network connects computer in the same location. The unique characteristic of LAN is that it is a single location. A WAN or wide area network connects computers in different locations. If the company is located in different locations, then they must use a WAN to connect their computers. The internet is defined as a network of networks. The Internet is networks that is public where internet is where networks that is used privately within an organization.
So how does a cloud work? In order for the cloud to operate, we need the internet. For example, if you are making reservation on a website, you are using the cloud by hopping from network to network. Hop is a term used by cloud vendors to describe provisioning servers to minimize hops. Big internet carriers such as Sprint, AT&T, Verizon Business, and XO communication are able to exchange traffic freely without charging each other fees through “peering” agreement. One of the big problem of peering is that some companies use more bandwidth than others. Netflix, Ebay, Yahoo!, and Amazon argue for net neutrality principle, where all data are treated equally. IP address is a set of numbers that identifies a particular device in a location. A URL or uniform resource locator is an address for websites over the internet. A three-tier architecture is a design in which users computer consist of 3 tiers: computers, phones, and mobile devices. SOA or service-oriented architecture is a design philosophy use for the cloud. This philosophy enables all the pieces of the cloud to connect together. SOA principles are very standardized and formal. Each department would send requests and receive requests as promise without personal contact. No departments need to know who will work in another department nor how they do their work. SOA is applied the same way to cloud. Each service request the data, the data will return. JAvascript is part of the web page an invokes the service. Cloud service divides into 3 categories: Software as a service, platform as a service, infrastructure as a service.
Content delivery network or CDN is a system of software and hardware that store data for users from different locations. These datas are readily available when users request them. An example for CDN usage would be a news organization using CDN to store copies of its news articles.
A virtual private network or VPN is private connection using the internet. VPN is made possible by connecting to public internet first, then create a tunnel as a private pathway over the shared network from the VPN client to the VPN server. Virtual private cloud is a public cloud that is restricted to the public. VPC is build on top of public cloud infrastructure in an organization to store sensitive datas.
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