A geography is a discrete market, typically containing two or more regions, that preserves data residency and compliance boundaries. Geographies allow customers with specific data-residency and compliance needs to keep their data and applications close. Geographies are fault-tolerant to withstand complete region failure through their connection to Microsoft dedicated high-capacity networking infrastructure. Geos examples: US, Europe, Asia Pacific, Japan, Brazil, Australia, China. Learn more >
A region is a set of datacenters deployed within a latency-defined perimeter and connected through a dedicated regional low-latency network. With more global regions than any other cloud provider, Azure gives customers the flexibility to deploy applications where they need to. Azure is generally available in 40 regions around the world, with plans announced for 10 additional regions
Availability Zones are physically separate locations within an Azure region. Each Availability Zone is made up of one or more datacenters equipped with independent power, cooling, and networking. Availability Zones allow customers to run mission-critical applications with high availability and low-latency replication.
Infrastructure as a Service (IaaS) – servers, storage, network and operating systems – as an on-demand service. Rather than purchasing servers, software, datacenter space or network equipment, clients instead buy those resources as a fully outsourced service on demand.
Platform as A Service (PaaS ) can be defined as a computing platform that allows the creation of web applications or software quickly and easily and without the complexity of buying and maintaining the software and infrastructure underneath it.
Software as a Service (SaaS) is software that is deployed over the internet. In a SaaS you are provided access to application services installed at a server. You don’t have to worry about installation, maintenance or coding of that software. An obvious example of SaaS is Microsoft’s Office 365, where the applications run remote from the user’s computer.
Watch this video. I like his style of explanation: