Software Defined Networking

Software Defined Networking better known as SDN is the latest buzz in the Networking Technology. No doubt that SDN in conjunction with Network Function Virtualization (NFV) is going to create a second wave in NW technology modernization that will greatly impact Data Center, Enterprise, and Campus networks. Interestingly, these two technologies do complement each other but not necessarily depend on each other.

Despite IT transformation in last 10 years due to virtualization technology that changed IT business model from cost center to profit center, we are still slow in revolutionizing IT networks. Virtualization technology has dramatically brought down servers & storage costs to a level never imagined before. But it is more difficult to keep pace if the progress in the area of network is holding us back.

Networking is in vogue, and at the breaking point. New breed of network facing applications are still not performing well despite progress in virtualization. Networks are source of constrains for the new breed of applications because the way software has been configured, delivered and managed—literally within a box
until now. Each network device must be configured indi¬vidually & manually.

Networks can’t keep pace with the on-the-fly-changes required by mod¬ern network facing applications. For a service provider, the network is their business, so they are looking to introduce new capabilities to enable new business opportunities via dynamic configurations in a matter of seconds.

Operators, typical response is to add more servers & NW gears leading to creating even NW traffic congestion, server clutters, cable sprawl, and sluggish re-provisioning process. Throwing more network equipment at the problem both helped and hurt the situation.

Service Providers expect networks to be not only to be resilient but to adjust and respond dynamically, based on their business policy and service level agreements, and the real time demand of the application. So policies must be automated and adjusted to the needs of the application dynamically.

With the rise of cloud computing, virtualization, and big data, M2M communication, businesses are looking for more flexibility, agility, and on-demand provisioning. SDN is supposed to provide these benefits. ).

SDN High Level Goals:

Software-defined networking (SDN is supposed to cure all the ills associated with today’s networking, making it easier for customers to manage their networks, and adding a virtual layer on top of the physical network.

•          Reduce excessive deployment of networking gears every time a new services are introduced
• Real time provisioning of network based on application demand 
• Centralized management of entire Network
• Separation of networking planes/layers

Today’s networking software sitting on network gears (Routers/Firewalls/Switches) can be separate into four layers or planes (Forwarding, Control. Services, and Management). These layers must be separated in order to build the next generation, and highly scalable network.

Operators would like to manage the network as a system and Centralized Management does that job. When we centralize management, it becomes the config¬uration master; all of the devices keep just a copy. Services can also move to the center and are performed on behalf of all devices. Manual configuration often leads misconfiguration or missteps leading to outages and also, requires a small number of network specialists. Management planes can run on one or more general purpose computers. 

Architecture Core principles: 

•         Cleanly separate networking software into four layers (planes): Management, Services, Control, and Forwarding. 
• Centralize the appropriate aspects of the Management, Services and Control planes 
• Use the Cloud principles for elastic scale and flexible deployment, and enable UBB 
• Create a platform for network applications, services, and integration into management systems by providing APIs 
• Standardize protocols for interoperable, heterogeneous support across vendors, providing choice and lowering cost
• Extend SDN principles to all networking gears utilized in Data center, Enterprise, Campus, Mobile, and wireline

SDN Benefits: 

•       Transforming the network to meet organization’s needs for mobility, virtualization, high-definition video, rich-media collaboration tools, and cloud computing.
•        Reap the full value of your network investment and free IT administrators from the drudgery of manual network of configuration and reconfiguration because the network will be automatically tuned to application and business needs.
•        Guarantee true end-to-end service level for network performance, quality of service, and security, which can be tuned to application needs. For example, SDN applications can provision the network, inspect flows, or perform other network control functions via SDN controller.
•        Extensibility and open APIs of the SDN Controller will allow innovative new applications that make requests of the underlying network, without the need to physically uproot or reconfigure the underlying infrastructure.

SDN Migration Path:

So in order to move from past to future, I believe that NW operators will most probably follow multiple steps because we have to deal with the reality. We live in a world where some things will be centralized with SDN and others will not because legacy network will continue to exist side by side for a while. Some of the steps are:

• Leverage existing hybrid Switches supporting both
• Use Servers ( like Blades) that support internal switching fabrics to control cable cluttering
•      Utilize Open programmable interfaces
•      Utilize Centralized, Resilient Control
• Integration with Intelligent Management Center (IMC) 

Good Application Candidates:

•        Multi-tenant & Business Applications like SAP/Oracle Financials.
•     Cloud Bursting Applications which require integration of public & private clouds
•        Unified Communications & Collaboration Application— to improve the user experience of products by automating deployment of QoS policies & dynamically adjusts network priorities to support voice/video/collaboration traffic
•        Security Applications - Applications enabling real-time threat detection & security policy enforcement at the edge of campus networks like secure BYOD from malware & spyware threats.
•         Dynamic WAN bandwidth provisioning - applications that enable service providers to automate the provisioning of cloud data centers to support on-demand scalability & business-continuity requirements.