SDN and the Dynamic Application Environment
Few people seem to realize that SDN isn't about networks or software, but applications.
The buzz around software defined networking has been so hot lately because of the tremendous flexibility it brings to traditionally static architectures. In a nutshell, it allows enterprises to unburden themselves from rigid network configurations at just the right time for advanced cloud computing and mobile data environments.
However, few people seem to realize that SDN isn't so much about networks, or software for that matter, as it is about applications. The end-game in all of this is about delivering the right applications to the right people wherever they are and regardless of what access device or underlying infrastructure is called for.
In that light, one of the more intriguing aspects of SDN is its ability to continuously rework the network environment so as to define and provision exactly what is needed to fulfill user requirements − at once providing secure, reliable service for the individual while maintaining high utilization and broad resource scalability for the community.
It is for this reason that tech experts like Enterprise Management Associates' Jim Frey are so enthusiastic about SDN's "application awareness" capabilities. His take is that SDN would be more accurately described as "service defined networking" because it takes the messy process of network provisioning and resource allocation away from the IT department and places it on the service, or application, where it belongs. This is particularly important in the cloud, given that it will be called on to support a constantly shifting menagerie of users, services and environments.
Others, like network software developer Lyatiss, are going even further by envisioning a scenario in which the applications themselves construct their own network environments on the fly. This "application defined networking" would require an advanced set of APIs that would apply to underlying infrastructure and higher order control and data planes, essentially forcing the network to accede to the demand of the application, rather than the other way around. To get there, however, we'll have to answer some fundamental questions as to the basic function of networks and applications and how they relate to each other in highly dynamic environments.
Although it is too early to tell, the roots of such an arrangement could already be taking shape. Citrix recently opened up the NetScaler SDX platform to third-party network services, allowing enterprises to compile diverse L4-7 network service portfolios in the application control layer. In itself, this does not engender the kind of application functionality that Lyatiss is talking about, but it does provide a high degree of application awareness, allowing for a wide range of app-centric policies to be implemented across diverse network architectures. Perhaps Lyatiss and Citrix should have a meeting.
Another key development is network intelligence firm Qosmos' decision to join the Open Networking Foundation, keepers of the OpenFlow protocol that is likely to form the heart of many SDN deployments. The company specializes in deep packet inspection (DPI), which is what gives networking systems the ability to identify and adapt to the applications and data they are carrying. As with NetScaler, the goal is to increase app awareness in Layers 4 through 7, and then institute intelligent networking capabilities to virtual switches and controllers to allow for more effective, policy-based traffic control across all layers of the network.
This may sound like heady stuff, but in reality it is the logical extension of data and infrastructure flexibility that revealed itself in the deployment of the first virtual server. Hardware is no longer a limiting factor in enterprise data environments because pools of resources can be easily compiled and reconfigured at the virtual/logical level.
Storage and networking are running a little behind their server counterparts in this regard, but once SDN gains a footing in real-world enterprise environments, there's no telling how far it will go.
Arthur Cole covers networking and the data center for IT Business Edge. He has served as editor of numerous publications covering everything from audio/video production and distribution, multimedia and advanced enterprise infrasructure.