Cloud computing is currently at the centre of a media storm. While some argue that it has the potential to revolutionise the information technology (IT) industry, others claim it is an over-hyped security disaster waiting to happen. ADVA Optical Networking's Christian Illmer (below) examines the debate and questions its impact on the enterprise market and the data centre
Evidence of the interest in cloud computing is everywhere: in the increase in conferences for enterprise data centre managers intrigued with the topic, in the announcements of service introductions and architecture rollouts, etc.

‘Cloud computing heralds an evolution of business that is no less influential than e-business,’ Gartner Inc. said in a June 26, 2008, press release.

A January 2009 BroadGroup report ‘predicts that by late 2009, Cloud Computing will be on the agenda of the CIO (chief information officer) of every forward looking organization that is responsive to changing technologies.’ BroadGroup cited an investment bank as valuing the cloud computing business opportunity at $100 billion.

Cloud computing is not exactly new. The same concept is at the heart of any form of IT outsourcing — such as for data centre space, applications and storage. Internet search engines and social media sites utilise cloud computing, and now more traditional business services, applications and tasks that once resided on end users’ PCs are being processed in the cloud. The growing array of examples includes Salesforce.com and Google Docs. In this light, cloud computing is simply the most advanced manifestation yet of the decade-old trend among data centres toward flexible sharing of hardware resources.

But while disparate services have shared network and storage hardware for some time, each application has utilised its own dedicated servers in the conventional data centre. (And, in most cases, this dedicated hardware was used inefficiently — with dormant processing power going untapped except at moments of peak usage.) In a cloud computing data centre, those applications now share servers, too. Software-based services are, for the first time, completely decoupled from underlying hardware. Hardware assets are dynamically and efficiently reassigned as needed by other services in the cloud.

The fervor of interest in cloud computing among managers of enterprise data centres is the product of a couple of converging factors. Firstly, the need for a less-static IT infrastructure had been illuminated by the proliferation of smart mobile devices, high-speed connectivity, higher-density computing and data-intensive Web 2.0 applications. Secondly, the contemporary economic challenges have intensified the pressure to cut costs. Enterprises must create more efficient and flexible IT environments that can be more cost-effectively adapted to fluctuating needs. Consequently, there appears to be gathering consensus among data centre managers that cloud computing is the future of enterprise networking.

Exactly how particular enterprises adopt cloud computing, however, will vary, depending on multiple factors. Some enterprises will choose to create their own ‘private’ clouds; others will contract for ‘public’ cloud services. The size of the company is not necessarily the key determinant. The enterprise that is already mirroring and copying applications across multiple data centres as part of a remote-backup and disaster-recovery strategy is more likely to implement and provision its own cloud computing services. This is a private cloud environment. The other enterprises–ones without a remote-backup/disaster-recovery concept in place–are more likely to reach out to top IT integrators like IBM or HP or outsourced data centres operators like EDS and CSC for public cloud computing services.

To the end user, the cloud itself —whether a private or public environment —is an abstract enabler of services through a browser and across broadband access. In fact, the cloud is a conglomerate of interconnected, redundant data centres undergirded by high-bandwidth, low-latency transport inside and among data centres and all the way to the end user. Services share virtualized hardware resources without interfering with one other; each software load runs in its own virtual environment.

In order to enable this sharing of resources throughout the cloud, the capabilities of multiple server farms must be efficiently bundled into a virtual machine within a data centre. High-speed interconnects — InfiniBand, 8 and 10 Gigabit Ethernet, proprietary technologies such as IBM’s Geographically Dispersed Parallel Sysplex (GDPS) and, perhaps, developing Fibre Channel over Ethernet (FCoE)—enable the virtual machines that deliver applications of unprecedented compute power such as grid computing.

Redundancy and fail-over concepts are hallmarks of cloud computing, and this means that the various data centres that comprise a cloud must be interlinked within a high-capacity network. But it is not enough that the network simply delivers the tremendous amount of bandwidth required for transporting user and storage traffic among the various sites; the network also must be able to accommodate changes in bandwidth requirements while minimizing latency. This is why Wavelength Division Multiplexing (WDM) assumes the unifying role in demanding, heterogeneous cloud computing networks. Latest-generation WDM technologies support transparent, 40G and 100G transport of up to 120 wavelengths of disparate application traffic —even the most latency-sensitive protocols. Plus, reconfigurable optical add/drop multiplexers (ROADMs) support fast, flexible bandwidth provisioning.

Another critical underpinning of the cloud that must be considered is access. Insufficient access, in fact, proved to be the undoing of some earlier IT outsourcing business models when either, one, traditional leased lines based on Plesiochronous Digital Hierarchy (PDH) and Synchronous Digital Hierarchy (SDH) technology failed to provide the bandwidth required between enterprise data centre and outsourced resources, or, two, high pricing sabotaged the value proposition. Recent rollout of higher-speed, cost-effective access technologies — copper-based Asymmetric Digital Subscriber Line (ADSL) and Very High-speed DSL (VDSL) and wireless High-speed Packet Access (HSPA) and Worldwide Interoperability for Microwave Access (WiMAX) — have been critical in the growth of IT outsourcing and resource sharing. But enabling Ethernet over any type of access medium will be necessary to deliver enough bandwidth to support offloading of the most sophisticated IT processes and services into the cloud.

In private cloud computing, data centres benefit from more efficient service provisioning and reduced responsibilities for deployment and maintenance of static hardware for IT labour. The primary risk that would slow introduction by enterprises creating their own private cloud environment might be the softening of boundaries among different services and departments across the company, as those boundaries will no longer be defined by hardware.

For enterprises contracting for public services, cloud computing presents the opportunity to adopt advanced business services — in some cases, for the first time — on a pay-as-you-go basis, while offloading all hardware management. (BT’s template of cloud computing services, for example, include Customer Relationship Management, expense reporting, email marketing, mobility and collaboration tools.) Despite those benefits, some data centre managers might have performance and security concerns around the notion of committing sensitive business data and services to external infrastructure that is shared by other users. The truth is that, in many cases, enterprises already are entrusting some information resources to the cloud, when using web-based email or software-as-a-service (SaaS) offerings. Still, the performance and security qualms can be mitigated by gradually moving into cloud computing; applications that are not mission-critical should be offloaded to the cloud first, with more services to be migrated as trust grows and cost benefits dictate.

The media storm surrounding cloud computing is understandable. Cloud computing represents the zenith of years of increased sharing of hardware resources, contributing to climbing levels of bandwidth power and efficiency. But even with the market enthusiasm, enterprises are unlikely to exchange prudence for zeal. Whether building their own private infrastructure or buying public services, data centre managers must address important questions in pursuing cloud computing’s undeniable business benefits.