In 2012, much of the industry was focused on what's going inside the data center to enable cloud computing. As we move into 2013 and beyond, enterprise IT will need to consider the network that connects the data centers - particularly how these inter-data center networks need to change to support new cloud use cases and associated network requirements for bandwidth scalability, low latency, security, virtualization and automation. As network specialists, Ciena has been concentrating on solving the connectivity issues between data centers, and data centers to the cloud.

There are multiple reasons for this. First, enterprise IT organizations are highly motivated to drive efficiencies. Enterprise is already deriving efficiencies from its network - first through data center consolidation, then virtualization. The cloud promises to offer up to 25 percent infrastructure savings on IT services and hardware expenses, according to some studies. In turn, the network is also a key enabler for cloud service providers to operate multiple data centers as a shared pool of virtual data centers. We've found through our own research that this can enable a 35 percent reduction in total cloud data center resources.

Second, the use of cloud services is still in its infancy at many enterprises. Cloud software and infrastructure-as-a-service applications today live in the service provider cloud, often locked behind semi-proprietary architectures. As cloud deployments get more sophisticated, IT will need to deploy a more open architecture with standards in place for APIs and management tools. By doing this, they will be able to unlock the potential to federate private data centers with multiple provider cloud data centers, enabling greater workload mobility and the ability to deploy entirely new applications - this will require a better network to run effectively.

How the Cloud Is Used Today
Enterprise today typically uses cloud infrastructure for simple storage backup to cloud data centers over low speed IP networks, trickling the data asynchronously as the network permits in a north-south traffic flow from user-to-machine that moves over a tiered IP network architecture.

Tomorrow, the enterprise will want to take advantage of lower cost cloud storage for large amounts of storage. It will want a network that can dynamically respond to moving terabytes when the data needs to move - without bottlenecks, security holes or dropped packets. This will require east-west traffic flows from machine-to-machine within, and increasingly between, data centers. Such traffic has much more stringent quality-of-service requirements.

In the near future, we'll see at least an order of magnitude more east-west data workloads driven by applications like storage synchronization, inter-data center storage virtualization and virtual machine migrations. This means the cloud network needs to be designed for performance to meet the traffic flow change and intensity challenges of the future. For example, a flatter Layer 0/1/2 network architecture between data centers would deliver better scalability, latency and deterministic performance. With this architecture, the network won't be a bottleneck when it's needed the most, and it will deliver the lowest cost per bit throughput.

The Network Is Key for Cloud Use Tomorrow
As enterprise use of the cloud becomes more prominent, IT will look for ways to automate cloud use cases using an intelligent network. Software defined networking (SDN) is the key to achieving greater flexibility and lower costs. Workload orchestration between cloud data centers, and between enterprise and cloud data centers, will be driven by policy-based software automation tools. On-demand change in performance parameters such as bandwidth scalability will be accomplished through high-level software interfaces into the network control planes, not by an operator using a command line interface to the equipment. This performance-on-demand will be triggered at the application level, ensuring that the adjustments to the network and to the cloud meet the business requirements. In order for this to happen, the network will need to become an integral part of the entire cloud framework - it is the key ingredient that ties everything together, serving as a backplane across the data centers for flexible delivery of applications and services.

Inter data center networks need to become virtual, too. A virtualized network partitions resources in many different ways, e.g., virtual circuits (EVPLs), virtual wavelengths (Optical Transport Network - OTN); virtual switches (VSIs) and virtual networks (VPNs, Optical Virtual Private Network - OVPNs). Virtualization of the network provides network efficiency, i.e., coordination of the bandwidth and topology to the specific application need at a point in time. This eliminates the need to size all data center network interconnection facilities for a peak capacity that is only rarely used, which lowers costs because you don't need to make unnecessary network equipment investment.

A Virtual Data Center Architecture Will Deliver a Data Center Without Walls
A virtual data center architecture - "A data center without walls" - will deliver cost savings and operational efficiency. At Ciena, we are leveraging our networking expertise to deliver a "Data Center Without Walls" architecture for our customers that creates a multi-data center, hybrid cloud environment able to function as a set of virtual data centers from a common resource pool to address any magnitude of workload demand and offer seamless workflow movement. Enterprises will be able to access cloud resources anywhere, anytime. Service providers will be able to offer cloud services differentiated by state-of-the-art, programmable network access, and economies of scale that leverage their data center footprints. Cloud providers will be able to handle uncertain demand requirements and failover by more efficiently allocating workloads across multiple data centers. This cloud backbone network will be the critical link for providing cost-effective scalability, security, and on-demand services that enable the virtual data center.