During the past few years, the deployment of cloud architectures has accelerated to support various consumer and enterprise applications such as email, word processing, enterprise resource planning, customer relationship management and the like. Traditionally, co-located servers, storage and networking moved to the cloud en masse in the form of a service, with overlying applications that have been and remain very insensitive to delay and jitter.

But the fast-emerging next generation of business applications require much tighter service level agreements (SLA) from cloud providers. Applications such as Internet of Things, smart grids, immersive communications, hosted clients and gaming are some good examples. These use cases tend to be marked by periods of high interactivity, so delay and jitter for the network, computer and storage must be minimized.  During times of normal interactivity, the applications are in steady-state condition, requiring minimal SLAs from the infrastructure resources.

Emerging use cases drive demand for two-tier cloud architectures
These emerging use cases are driving the rise of two-tier cloud architectures. The key for these architectures to succeed is efficiency: they must be cost-effective to deploy and guarantee a tight SLA for applications while leaving the rest of the carrier and cloud infrastructure unchanged. What’s more, the application service needs to move closer to the end user, but only for the duration of the real-time interaction. These measures help ensure that the customer’s application-specific requirements for delay and jitter are met without requiring major upgrades to the carrier or cloud infrastructures.

In this two-tier cloud architecture, the first cloud tier, also referred to in the industry as centralized cloud, is where the applications typically reside. The second cloud tier is invoked on demand, and the application’s virtual machine along with its relevant network, application and storage data shift to this tier. Keep in mind that the second tier can be instantiated as part of an existing service provider network element or as a stand-alone infrastructure element closer to the end user.

A connected patient heart monitor provides a useful example. During most of its operational time, the device may be collecting data only periodically, and with no need for any interactions with medical staff. But when the heart monitor detects an abnormality, the application hosted in the cloud must instantly be moved closer to the user in order to provide interactivity. For this use case, the second tier cloud must host the application, assess the patient’s condition, retrieve relevant historical information and alert the medical staff for a possible medical response.

The key, then, is to move applications from tier one to tier two clouds seamlessly. LSI® Axxia® multi-core communication processors feature an architectural scalability for network acceleration and computer cluster capabilities that provide this seamless bridge between the two clouds. In order for the two-tier cloud architectures to thrive, they need three fundamental elements:

a.       On-demand resource provisioning
Many cloud datacenters are squarely focused on deploying end-to-end resource provisioning tools to improve efficiency. Not the least among these is the fast-growing end-to-end orchestration ecosystem for OpenStack® software, though there are many proprietary solutions. End-to-end orchestration tools need to be aware of all the second-tier cloud datacenter components. In some cases, OpenStack is even being deployed to boot up second tier cloud components. However, a big challenge remains – maintaining a steady state and full capabilities of various distributed second-tier cloud components.

b.       Efficient virtual machine movements
For tiered cloud architectures to thrive, they must also transfer enough network, application and storage data to sustain continuing operations of the application at the second tier. However, many of today’s virtual machine migration solutions are not geared to moving datacenter resources efficiently. In a two-tier cloud architecture, the virtual machine migration may traverse many hops of carrier infrastructure, increasing total cost of ownership (TCO). In addition, complete virtual machine images must be transferred before the destination station can start the machines, extending the time it takes for the second tier to take control. The upshot is that optimized solutions need to be developed to enable seamless virtual machine migrations.

c.       Network and storage acceleration of resource-constrained tier-two clouds
Unlike the first cloud tier, the second cloud tier is bound to be resource-constrained, requiring significant data acceleration for both the networking and storage layers. A 16-core full SMP ARM®-based processor like the LSI Axxia 5500 processor, with its processor cores and, more importantly, its fully programmable acceleration engines for offloading security, deep packet inspection, traffic management and other functions is well-suited for network acceleration of the second cloud tier. Keep in mind that specific acceleration needs vary based on the location of the second tier cloud. For example, the acceleration requirements of the second cloud tier would differ depending on whether it is part of a service provider access aggregation router or located on a remote lamp post. The need for security acceleration, in particular, increases tremendously in cases where data associated with particular data events must be authenticated before further processing. To support these various acceleration needs, the second cloud tier can be built out of fairly homogeneous and scalable ARM-based hardware components with differing acceleration builds tuned to specific tasks running on it.

Momentum for greater connectivity builds
Momentum behind billions of connected things/machines across industrial and consumer applications to create a more connected, interactive world is building. Two-tier clouds and other innovative architectures are emerging at an accelerated pace to meet demand for this higher order of connectivity. And it is solutions like the LSI Axxia processor that promise to enable the scalable, flexible acceleration required for these emerging two-cloud architectures.


Raghu Kondapalli has rich experience and deep knowledge of the cloud-based, service provider and enterprise networking business,... Read more

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