As they build and expand their cloud[] services infrastructures, carriers need to be sure they don't end up rebuilding the mainframe computer. The monolithic icon of a bygone computing era isn't what service providers are aiming for as they look to enable their customers to store and access data and applications from cloud. They want to be able to leverage a more distributed pool of resources that are aligned with their business objectives.

Being too centralized likely adds bandwidth costs to the cost of a cloud service and results potentially in less margin that what is possible, while providing competitively differentiated network characteristics, according to David Frattura, senior director of strategy, cloud solutions, at Alcatel-Lucent.

Centralization also has the potential to introduce site specific single points of failure, thus threatening service reliability promises.

What's needed is a model that distributes the most popular cloud resources closer to the customer, which keeps bandwidth costs down for service providers,. Bell Labs research studies have shown that for the most heavily-used applications, it is generally better economically for the carrier to have them delivered via a distributed data center model.

Also, a service provider with a large network footprint can leverage broadly distributed cloud architecture to deliver customer benefits. For example, a distributed model allows a network operator to better manage bandwidth, while potentially offering customers better distance-related traffic latency options. Also, a distributed cloud configuration allows operators to respond to the needs of customers whose data must remain within their own national boundaries for regulatory reasons-for instance when that data pertains to the private medical records of individuals.

Ultimately, with physical locations and network POPs in every metro area, network service providers are uniquely equipped with the network resources, the geographic footprint and the planning and connectivity expertise to create a more distributed model in the markets where it makes the most sense. And, even if they operate more centralized environments now, the conversion to a more distributed architecture doesn't have to be a hardship. They can co-locate computing and network infrastructure resources in existing central offices if they have the space to spare, or in many cases can create adjacent cloud centers by outfitting shipping containers or similar spaces with servers, power supplies and connectivity.

"If you do this, you can save a lot of the costs related to constructing a new building," Frattura said. "Having a lot of resources everywhere you need to be is the first key to building a distributed cloud architecture. "

Even when taking a more distributed approach, Frattura said there is still room for use of a centralized architecture in the service provider cloud if that best suits the applications involved-applications that have periodic or infrequent consumption.

"Service provider clouds are likely to contain a mix of centralized and distributed data center architectures, and it is probably really best to have that mix," said Guy Shemesh, senior director, cloud enablement solutions, Alcatel-Lucent. "Every provider has to look at their own economic situation to make the decision about distributed vs. centralized. If you've got a large footprint and a centralized cloud architecture, you are going to need a lot of fiber and backbone capacity for backhaul. For a provider in New York state, for example, it might make economic sense to have one data center in Albany and another in Buffalo, rather than building one big data center in one location. Even a smaller regional service provider can think about a distributed cloud."

Adopting a more distributed cloud architecture where it makes sense results in a more manageable, more reliable cloud services business. By leveraging existing assets, it can also be a very cost-effective migration that increases backbone bandwidth savings and provides service providers with an underlying cost structure to keep them competitive in a crowded marketplace.