The Cloud Challenge
Cloud computing is increasing demands on applications and the application-delivery infrastructure must change to meet the challenge. Virtualization does not solve the problems with applications scaling, in fact it adds complexity. Infrastructure alone does not solve the challenge either. You don’t want to oversubscribe or just add capacity on demand. The infrastructure needs to respond to user demand based on business value and maintain a favorable cost structure. This means that you need intelligent load processing to manage scale, especially given the evolution of applications, which now make numerous backend function calls, which create more traffic than at the front end.
The Need for Scale
Cloud-computing applications are characterized by stateful access, with differentiated service levels, charged to the end user using the pay-per-use pricing model. Implicit in this model is the assumption that a cloud application is always on. Scaling the cloud delivery model to an Internet scale (millions of users) is a challenge that next-generation Layer 4–7 infrastructure needs to overcome.
Scaling a cloud application involves scaling three mechanisms: location (mobility), replication, and load balancing. Virtualization was an early catalyst for cloud computing because it substantially lowered the cost of replication and mobility of a prepackaged application. It does not, however, solve the load-balancing problem. Load balancing involves scaling the address, name space, transport, session, identity, and business logic of the application. Clustering enables scaling of application business logic but leaves the rest of the problem to a proxy infrastructure.
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Tags: cloud, data center, IaaS, paas, slb, virtualization
The Route to PaaS
When cloud computing emerged a few years ago Communications Service Providers (CSPs) saw the opportunity to build the infrastructure layer and offer services on it. CSPs had data center facilities that when combined with their network assets created a cloud service offer with higher service delivery assurance than some alternatives. CSPs are now delivering infrastructure-based cloud services, especially Compute as a Service and Storage as a Service, to the public and to their large Enterprise customers in private cloud offers. As the cloud service model matures, providers who have invested in cloud infrastructure are finding that they are well positioned to evolve their Infrastructure as a Service (IaaS) offerings into new service delivery models by leverage their services, systems, and expertise to take on the next great opportunity in cloud services which is Platform as a Service.
The Value of PaaS
PaaS is an integral component to development and delivery of cloud-based applications delivered as Software as a Service—or SaaS. Developing a PaaS offer gives CSPs the opportunity to take advantage of the huge and growing SaaS market and help to accelerate the development of SaaS offers. CSP’s can take an active role by leveraging their assets and developing their capabilities, via a PaaS offer, rather than just hosting and transporting SaaS services. The capability they can provide is to enable development and then deploy applications that are created using tools that they support on to their cloud infrastructure. PaaS enables CSPs to carve out a new and essential role in SaaS development and delivery, situated between software developers and end users, for both business and consumers.
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Tags: cloud, data center, IaaS, paas, UCS