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SDN concepts are moving beyond the data center to make wide area networks faster and less expensive, fueling the growth of a spate of vendors offering products and services aimed at the software-defined WAN architecture.
In the past, the network consisted simply of a single link, possibly with a backup, between each branch and the data center. There was no need to link branches elsewhere, since data was collected and stored in the data center where applications were executed.
Today, both branch office and data center staff use cloud-based applications, participate in video conferences and view video training over the Internet. Remote users execute sophisticated applications on smartphones and tablets, and all employees require efficient Internet access. A simple link between each branch and the data center is no longer adequate.
SDN is making inroads in large data centers and clouds, thanks to its ability to centralize switching decisions via a software controller. This approach enables the quick responses necessary to maintain efficient data paths and meet quality of service (QoS) parameters. SDN eliminates the limitations faced by traditional switching and routing algorithms, which cannot always react quickly enough to meet escalating traffic demands.
Similarly, SDN platforms can help accommodate the rapidly changing connectivity needs of WANs by dynamically mixing and matching broadband Internet, Carrier Ethernet and LTE connections. Together with traditional Multiprotocol Label Switching (MPLS), these technologies create cost-effective networks with redundant links spanning branch offices, mobile users, the data center and the cloud.
Vendors respond to requirements of the software-defined WAN architecture
Startup network vendors and established firms have responded to the need to extend SDN concepts to the WAN with a varying suite of products for enterprises and service providers. These products all consist of a central controller linked to subordinate units in branch locations across the network. The controller has comprehensive network visibility and constantly receives information about each active application. It monitors every link and directs traffic to the least expensive routes available, while maintaining required data rates and QoS for each application.
As traffic levels rise and fall, the controller dynamically assigns application data streams with a less stringent data transfer rate and QoS parameters to lower-quality (less expensive) links, while reserving high-quality links for traffic requiring higher throughput and strict QoS. When MPLS was the only reliable technology, it was necessary for users to contract for enough capacity to support usage peaks. By shifting some traffic to less-expensive links, it becomes possible to reduce capacity on MPLS links, thereby reducing expense.
Among the vendors that have announced and released software-defined WAN products and services are:
Cisco Systems' Intelligent WAN combines the company's Application Visibility and Control (AVC) software suite with other features of its integrated services routers. The AVC controller identifies traffic by application and routes each data stream to its destination via an appropriate path. For service providers, Cisco's WAN automation engine configures and manages customer networks with features such as global load-balancing, bandwidth-on-demand and premium service creation.
CloudGenix aims its software-defined WAN product to enterprise networks with anywhere from tens to thousands of branches. CloudGenix relies on all available network technologies -- broadband, MPLS, LTE, etc. -- to connect users to cloud-based applications, the data center and the Internet. End-to-end encryption protects data over all links. No proprietary hardware is required and the controller can be hosted in a cloud or in the corporate data center.
Ipanema Networks, recently acquired by InfoVista, offers its Autonomic Network System (ANS), which incorporates agents that provide application visibility and control, WAN optimization and dynamic WAN selection. ANS tracks application and network performance under the direction of a central controller, and includes a tool it calls "Network Rightsizing," which assists network managers in identifying requirements for additional or reduced network capacity. The system is implemented using proprietary devices or virtualized packages installed in branches, data centers and clouds. ANS is targeted at retail, banking, manufacturing or other large networks with high-performance requirements.
Nuage Networks, which spun off from Alcatel-Lucent in 2013, offers its Virtualized Services Platform (VSP) software. VSP provides a network environment that unifies the cloud, the data center and the WAN network. It consists of an application directory, an OpenFlow controller and an enhanced Open vSwitch. VSP constructs an overlay network extending to branch offices and connecting users to both public and private cloud-based applications. By leveraging the available IP network, VSP allocates data streams to pathways that meet application throughput and QoS requirements.
Pertino Networks creates a secure overlay network over the Internet, connecting devices wherever they are located. Connectivity is managed via the Internet for a monthly fee. Apps installed on end-user devices connect to the network over any Internet technology, making it easy for mobile users to connect. No hardware is required. Pertino offers different monthly pricing plans based on the number of devices in use.
Talari Networks' Thinking WAN is based on a series of propriety appliances; a high-capacity unit is installed in the data center, with lower capacity units in each branch. Branch units and the data center may be connected via MPLS and the Internet, or solely by either MPLS or the Internet. The appliances coordinate to route application data along an appropriate path. All aggregate bandwidth is tapped for applications such as bulk data transfers that require high rates, but don't have stringent delay requirements.
VeloCloud Inc. replaces traditional WANs with a subscription-based service delivered through the cloud. Branches and data centers are connected through the cloud via either Internet, MPLS links or a combination of both. Cloud-based gateways coordinate with edge appliances installed at customer sites to direct data streams along appropriate paths. VeloCloud installs, configures and manages the appliances, and no additional hardware investment is required.
Viptela Inc. provides secure communication over any transport medium between a central site and branches through its Secure Extensible Network, which was released last year. Components include software that executes at the central site, physical routers at branch sites and software that operates within the routers. Data communication is protected by end-to-end encryption. Viptela recently made waves at the Open Networking User Group spring 2015 conference, when it presented an unofficial hybrid WAN partnership with Verizon.
These vendors offer different products and services aimed at a variety of target markets. Since the software-defined WAN architecture field is new, other vendors will undoubtedly enter the fray. Prospective customers eager to reduce network costs or to offload management tasks should examine each product carefully to choose an approach that meets their requirements.
About the author:
David B. Jacobs of The Jacobs Group has more than 20 years of networking industry experience. He has managed leading-edge software development projects and consulted to Fortune 500 companies, as well as software start-ups.
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