Networks and network management are on the brink of fundamental change. Today’s data centers use physical switches and appliances that: haven’t been virtualized; are statically provisioned; require significant, certified expertise in each vendor’s equipment; and lack an API ecosystem that can be used to automate resource provisioning, scaling and optimization. The result is underutilized equipment and significant labor costs to cover manual configuration by highly trained administrators. As businesses demand more agility and flexibility through virtualization, it has become less cost-effective and too time-consuming to innovate in such a distributed environment. Software Defined Networking (SDN) enables more agile and flexible IT by simplifying the task of connecting applications and network appliances used in cloud, social networking, mobile and big data workloads. According to new research, by 2018, 46 percent of overall datacenter network spending will be on SDN-enabled optical, switching and routing hardware. This clearly shows that the concept of SDN is gaining attention in becoming an important strategy in addressing the network needs of organizations worldwide.
Let’s discuss what SDN is and how it matters...
SDN — Software Defined Networking — offers a next-generation alternative. Instead of managing network assets separately, using separate interfaces, they are controlled collectively and in software, via unified solutions running on a server cluster. More importantly, an open source based SDN platform provides a widely adopted API (Application Programming Interface) ecosystem, which can be used to automate multi-tier system configuration and optimization, including security and optimization appliances used between the tiers.
Such an approach offers many improvements over traditional networking approaches. For instance, it becomes possible to decouple the network's control plane and its data plane, where the control plane runs in a cluster, which can configure simpler data plane switches & network appliances to support business goals as needed. That means data itself can often be managed in a smarter and more efficient way at the network level — sent where it's needed, or blocked if it's deemed a security threat. A software implementation of network appliances and the switching control plane also means that policies can be created to respond in predefined ways to different conditions. If a particular application’s flow unexpectedly needs more bandwidth, it's possible for the networking architecture to recognize that in real time and automatically migrate the flow via policy-driven changes — a much faster reaction than would be possible without SDN. If a security appliance needs to be inserted between two tiers, its possible do so without changes in the physical infrastructure.
Most of the hottest developments in enterprise computing — such as cloud, mobile, social networking, and smart analytics — all presume that data can flow from point A to point B quickly enough to satisfy user expectations and fulfill business goals. Without SDN, however, that presumption may not be accurate, because changes in the way network traffic is managed require too much time and manual attention to implement. For example, for some companies the process for configuring all the necessary network appliances required to a specific data flow can take days.
In the particular case of clouds, networking as a technology class has typically not kept pace with the rest of the architecture. Though virtual servers can be created on demand, and resources like processing power and storage can be allocated to them dynamically as needed, there is often no optimized control of network bandwidth. As a result, services can easily become "starved" for bandwidth, resulting in an overall performance decline and generating a significant business impact. The evolving need for SDN due to server virtualization has basically taken the network to the server edge, and caused a 10-to100-fold explosion in number of nodes that need to be managed in the network. Networks today are statically provisioned, with devices that are managed at a box level scale and are under-utilized. SDN enables end-to-end based network equipment provisioning, reducing the network provisioning time from days to minutes, and distributing flows more evenly across the fabric allowing for better utilization.
SDN offers the prospect of making network resources as fluid, and network management as centralized and automated, as the rest of the cloud. Organizations benefit as SDN enables:
network administrators to centrally control network traffic through programming instead of relying on more manual approaches
the elimination of vendor lock-in for network products due to its open and vendor-neutral software
new services and applications to be provided quickly
a reduction in operational costs due to its simple, automated approach to deployment
most importantly, automation of multi-tier system configuration and optimization, including the network appliances used between the tiers
With SDN, instead of being a labor intensive, the network becomes automated and optimized. And it generates far more business value as a result!
IBM Fellow & System Networking CTO