In Part 1 of our Cloud and NG9-1-1 series we gave a brief overview of Cloud technology. This week we'll take a look at cloud service models and some of the different deployment options you need to understand as a framework for the deployment NG9-1-1 services.
Whether you realize it or not you're probably a regular user of the cloud, be it through personal online banking or even off-site storage of call recordings. The easiest example to consider is probably email. Before cloud computing, IT departments had no options for providing email other than to buy servers, buy software, buy firewalls and connectivity and then install and configure all those components. Emails were stored in your facility and delivered via servers and connections maintained by your IT team. Today, email is delivered as a simple service – you don't really worry about maintaining the hardware on your hotmail or gmail account. The spectrum of cloud services can be summarized in three different models:
Software as a Service Model. This is where the entire service has a set of defined, common capabilities that are offered as a web based service. Yahoo and Hotmail have delivered email as software-as-a-service for years. All the functions are accessed through a browser, your email is stored in remote databases, and you don't worry about the maintaining the email servers, scaling capacity as more users come on board, or outbound network connections. You simply access a set of defined functional capabilities through a web browser and off you go.
Platform as a Service. PaaS can be considered a development platform for building and delivering web applications and services. The PaaS user does not manage or control the underlying cloud infrastructure including networks, servers, operating systems or storage, but has control over the deployed applications (Cloud Security Alliance, 2009). The PaaS user can create custom applications using the cloud services tool set but you don't really worry about the underlying hardware, operating system, compatibility between software versions, security, storage set-up or connectivity (that's handled by your service provider).
Infrastructure as a Service. IaaS provides a great deal of flexibility to the user, allowing them to provision run arbitrary software including operating systems and applications. The core infrastructure, including computing power, storage and networking components are provided by the cloud vendor while the remaining stack of capabilities is managed by the user. Using IaaS, you are responsible for the operating system and higher level components but can easily scale up storage and computing power as needed.
Each of the different service models can be deployed differently. Either on private cloud, where you are the only consumer of the service, a public cloud, or models in between. As you evaluate options for deploying services, it's important to understand the differences.
Private cloud. The cloud infrastructure is operated solely for a single organization. It may be managed by the organization or a third party and may exist on premise or off premise. An IP-based call routing network shared amongst a number of public safety agencies would run on a private cloud.
Hybrid cloud. The cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by technology that enables data and application portability (e.g., cloud bursting for load-balancing between clouds). NG9-1-1 is a good example of a Hybrid cloud and will be covered in more detail in a later installment in this series.
Community cloud. The cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on premise or off premise.
In the next series installment, we'll look more carefully at how NG9-1-1 and its different components fits into each of these service and deployment models. Read Part 3 here.