Swapna Bapat, Director for Systems Engineering, Brocade India

Software-defined networking (SDN) presents a new approach to introducing network services rapidly with centralised management and control. The benefits promised by SDN create real value for organisations bringing about a revolution in networking.

Besides increasing efficiency, reducing costs, and ensuring openness and flexibility, SDN can cater to rising security demands (which is not possible with hard-wired networks) placed on network infrastructure by new applications and virtual machines. Simply put, SDN is a new way of managing networks, which virtually separates network control (intelligence) from the network plane (actual work of packet forwarding).

SDN offers programmability

The most basic requirement for implementing SDN is that network elements need to be programmable. Emerging o­­rches­­tration platforms such as Cloud­Stack, OpenStack, Eucalyptus, Chef and Puppet enable the user interface to create, configure and connect server, storage and networking resources on demand. The DevOps movement goes even further in abstracting data centre resources to the point that they can be called in-line within a code which defines the operation of the data centre. Some of the SDN products that are currently available use OpenFlow as a common interface between a controller and the actual switching elements. The principle behind this usage is that centralised control improves the efficiency of the entire network. The most significant benefit of using SDN is that it makes networks programmable and res­ponsive to demand.

SDN offers abstraction

SDN enables direct network-related abs­traction of services, which can be accomplished on both logical as well as physical infrastructure, but is not actually defined by specific physical devices or logical components. Emerging SDN products use new encapsulation methods such as Virtual eXtensible LAN, Network Virtualisation using Generic Routing Encapsulation, and stateless transport tunneling, to segment a department’s network. The departments can use any IP address and virtual LAN (VLAN) they want to use without restriction. This greatly simplifies the coordination required from the operations team.

Is SDN ready to be built yet?

Vendors and users are working together to drive SDN to maturity. To this end, some SDN deployments and proof-of-concept tests are in place. The key challenge faced by SDN is the misconceptions that organisations associate with it. For instance, it is believed that SDN is applied only to data centre networking, while in reality, it can be applied to all forms of networking and networking services across enterprise data centres, campuses and service provider networks.

It is expected that SDN adoption will continue to grow as its underlying technologies mature.

Transition to SDN

For more than 30 years, networking and security technologies have been evolving in order to adapt to a wide variety of special cases. Every enterprise network is built on a complex set of established networking technologies that have been installed, updated and optimised over time. It is challenging for an enterprise to consider a complete restart of their networking and security systems or to ask them to trust business-critical operations to an entirely new technology such as SDN. Therefore, it makes sense for enterprises to use established protocols to upgrade/modify existing networks with new SDN installations.

The transition to SDN would include the coexistence of current networks and SDN networks. It is important that SDN networks support hybrid capabilities to ensure the gradual migration of application traffic from non-SDN flows to SDN-based flows in a mixed environment.


The consumers of technology want simplicity while vendors lean toward complexity. When VLANs were first introduced, they were widely used because they offered a solution to simplify networks. Network complexity is a current “pain point” for enterprises, and SDN is the solution. As data centres begin to offer services resembling internal utilities, a new way of providing networking is needed.