|By Jim Morin||
|April 11, 2013 01:00 PM EDT||
The success or failure of public cloud services can be measured by whether they deliver high levels of performance, security and reliability that are on par with, or better than, those available within enterprise-owned data centers.
Gartner predicts that the global public cloud computing market is set to reach US$131 billion in 2013, up from $111 billion last year. To serve this market with the performance, security and reliability needed, cloud providers are moving quickly to build a virtualized multi-data center service architecture, or a "data center without walls."
This approach is made possible by cloud orchestration software that federates the data centers of both the enterprise customer and cloud service provider so that all compute, storage, and networking assets are treated as a single, virtual pool with optimal placement, migration, and interconnection of workloads and associated storage. This "data center without walls" architecture gives IT tremendous operational flexibility and agility to better respond and support business initiatives by transparently using both in-house and cloud-based resources. In fact, internal studies show that IT can experience resource efficiency gains of 35 percent over isolated provider data center architectures.
However, this architecture is not without its challenges. The migration of workload between enterprise and public cloud creates traffic between the two, as well as between clusters of provider data centers. In addition, transactional loads and demands placed on the backbone network, including self-service customer application operations (application creation, re-sizing, or deletion in the cloud) and specific provider administrative operations can cause variability and unpredictability to traffic volumes and patterns. To accommodate this variability in traffic, providers normally would have to over-provision the backbone to handle the sum of these peaks - an inefficient and costly approach.
In the future, rather than over-provisioning, service providers will employ intelligent networks that can be programmed to allocate bandwidth from a shared pool of resources where and when it is needed. This software-defined network (SDN) framework consists of the infrastructure layer - the transport and switching network elements; the network control layer (or SDN controller) - the software that configures the infrastructure layer to accommodate service demands; and the application layer - the service-creation/delivery software that determines required network connectivity - e.g., the cloud orchestrator.
SDN enables cloud services to benefit from performance-on-demand
The logically centralized control layer software is the lynchpin to providing orchestrated performance-on-demand. This configuration allows the orchestrator to request allocation of those resources without needing to understand the complexity of the underlying network.
For example, the orchestrator may simply request a connection between specified hosts in two different data centers to handle the transfer of 1 TB with a minimum flow rate of 1 Gb/s and packet delivery ratio of 99.9999% to begin between the hours of 1:00 a.m. and 4:00 a.m. The SDN controller first verifies the request against its policy database, performs path computation to find the best resources for the request, and orchestrates the provisioning of those resources. It subsequently notifies the cloud orchestrator so that the orchestrator may initiate the inter-data center transaction.
The benefits to this approach include cost savings and operational efficiencies. Delivering performance-on-demand in this way can reduce cloud backbone capacity requirements by up to 50 percent compared to over-provisioning, while automation simplifies planning and operational practices, and reduces the costs associated with these tasks.
The network control and cloud application layers also can work hand-in-hand to optimize the service ecosystem as a whole. The network control layer has sight of the entire landscape of all existing connections, anticipated connections, and unallocated resources, making it more likely to find a viable path if one is possible - even if nodes or links are congested along the shortest route.
The cloud orchestrator at the application layer also has full visibility of inter-data center workload requirements and can choose destination data centers and schedule transactions to maximize the performance of the cloud service. Through communication with the network control layer, it can select the best combination of connection profile, time window and cost.
Intelligent Networking + Cloud for a Data Center Without Walls
Enterprise dependence on public cloud services is poised for the fast track; however enterprise networks between data centers, and from data centers to the cloud, need to evolve to make the promise of cloud services a reality. Using a "data center without walls" architecture which employs SDN-methodology to link physical, virtual and cloud resources, can help enterprises smooth out demand curves and deploy new services and applications with the robustness and performance that business requires.