Software Define Networking

SDN short for software defined networking is an approach to using open protocols, to apply globally aware software control at the edges of the network to access network switches and routers that typically would use closed and proprietary firmware.

Software-Defined Networking (SDN) is an emerging architecture that is dynamic, manageable, cost-effective, and adaptable, making it ideal for the high-bandwidth, dynamic nature of today’s applications. This architecture decouples the network control and forwarding functionsenabling the network control to become directly programmable and the underlying infrastructure to be abstracted for applications and network services.

The goal of SDN is to allow network engineers and administrators to respond quickly to changing business requirements. In a software-defined network, a network administrator can shape traffic from a centralized control console without having to touch individual switches, and can deliver services to wherever they are needed in the network, without regard to what specific devices a server or other hardware components are connected to. The key technologies for SDN implementation are functional separation, network virtualization and automation through programmability.

The SDN Architecture is:


Network control is directly programmable because it is decoupled from forwarding functions.


Abstracting control from forwarding lets administrators dynamically adjust network-wide traffic flow to meet changing needs.


Network intelligence is (logically) centralized in software-based SDN controllers that maintain a global view of the network, which appears to applications and policy engines as a single, logical switch.


SDN lets network managers configure, manage, secure, and optimize network resources very quickly via dynamic, automated SDN programs, which they can write themselves because the programs do not depend on proprietary software.


When implemented through open standards, SDN simplifies network design and operation because instructions are provided by SDN controllers instead of multiple, vendor-specific devices and protocols.

Here’s a list of some of the specific advantages of software defined networking:

  1. Centralized network provisioning.

Software defined networks provide a centralized view of the entire network, making it easier to centralize enterprise management and provisioning. For example, more VLANs are becoming part of physical LANs, creating a Gordian knot of links and dependencies. By abstracting the control and data planes, SDN can accelerate service delivery and provide more agility in provisioning both virtual and physical network devices from a central location.

  1. Holistic enterprise management.

Enterprise networks have to set up new applications and virtual machines on demand to accommodate new processing requests such as those for big data. SDN allows IT managers to experiment with network configuration without impacting the network. SDN also supports management of both physical and virtual switches and network devices from a central controller; something you can’t do with SNMP. SDN provides a single set of APIs to create a single management console for physical and virtual devices.

  1. More granular security.

One of the advantages of security defined networking that appeals most to IT managers is centralized security.  Virtualization has made network management more challenging. With virtual machines coming and going as part of physical systems, it’s more difficult to consistently apply firewall and content filtering polices. When you add in complexities such as securing BYOD devices, the security problem is compounded.

The SDN Controller provides a central point of control to distribute security and policy information consistently throughout the enterprise. Centralizing security control into one entity, like the SDN Controller, has the disadvantage of creating a central point of attack, but SDN can effectively be used to manage security throughout the enterprise if it is implemented securely and properly.,/p>

  1. Lower operating costs.

Administrative efficiency, improvements in server utilization, better control of virtualization, and other benefits should result in operational savings. Although it is still early to show real proof of savings, SDN should lower overall operating costs and result in administrative savings since many of the routine network administration issues can be centralized and automated.,/p>

  1. Hardware savings and reduced capital expenditures.

Adopting SDN also gives new life to existing network devices. SDN makes it easier to optimize commoditized hardware. Existing hardware can be repurposed using instructions from the SDN controller and less expensive hardware can be deployed to greater effect since new devices essentially become “white box” switches with all the intelligence centered at the SDN controller.

  1. Cloud abstraction.

Cloud computing is here to stay and it is evolving into a unified infrastructure. By abstracting cloud resources using software defined networking, it’s easier to unify cloud resources. The networking components that make up massive data center platforms can all be managed from the SDN controller.

  1. Guaranteed content delivery.

The ability to shape and control data traffic is one of the primary advantages of software defined networking. Being able to direct and automate data traffic makes it easier to implement quality of services (QoS) for voice over IP and multimedia transmissions. Streaming high quality video is easier because SDN improves network responsiveness to ensure a flawless user experience.

The specific advantages of software defined networking will vary from network to network, but there are benefits from network abstraction and the agility it offers for network administration and automation. The best way to get the most out of SDN is to assess the network components and infrastructure to determine if SDN can help address issues such as resource availability, virtualization, and network security. Software defined networking isn’t the right approach for every network environment, but when there are clear benefits, SDN could be just the solution you need to optimize your data center.

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