WHAT REALLY IS SDN?
Software Defined Networking (SDN) is an emerging network architecture where network control is decoupled from forwarding and is directly programmable. This migration of control, formerly tightly bound in individual network devices, into accessible computing devices enables the underlying infrastructure to be abstracted for applications and network services, which can treat the network as a logical or virtual entity.
Traditional network architectures are ill-suited to meet the requirements of today’s enterprises, carriers, and end users. Thanks to a broad industry effort spearheaded by the Open Networking Foundation (ONF), Software Defined Networking (SDN) is transforming networking architecture in so many way and it continue to have positive influence in the network architecture.
In some cases, we define Software Defined Network as the approach to build computer networks that separate and abstracts elements of the systems. In order word, we can say that in Software Defined Network paradigm or architecture, not all processing happens inside the same device.
SDN represents a new approach that attempts to address these weaknesses of the current paradigm. SDN is a fundamentally novel way to program the switches utilized in modern data networks. SDN’s move to a highly scalable and centralized network control architecture is better suited to the extremely large networks prevalent in today’s megascale data centers. Rather than trying to crowbar application-specific forwarding into legacy architectures that are ill-suited to the task, SDN is designed from the outset to perform fine-grained traffic-forwarding decisions.
In the SDN architecture, the control and data planes are decoupled, network intelligence and state are logically centralized, and the underlying network infrastructure is abstracted from the applications. As a result, enterprises and carriers gain unprecedented programmability, automation, and network control, enabling them to build highly scalable, flexible networks that readily adapt to changing business needs.
WHAT ARE THE COMPONENTS OF SDL
Accordingly, in a classic SDN architecture, there are three main components:
The controllers,
The forwarding devices and
The communication protocols between them.
The most popular and the most widely deployed southbound standard for SDN is
OPENFLOW. There are many reviews and analysis research topics as well as industrial attractions towards SDN controllers and forwarding devices respectively.
HOW DOES OPENFLOW COME TO EXISTENCE?
Stanford University created clean Slate program in couple of years ago with Stamford's depth and breadth of expertise to explore what kind of Internet would be designed if they were to start with a Clean Slate and 20-30 hears of hindsight. Though the mission was well defined, the potential approach was not. They began with a number of small exploratory projects that led to a few flagship projects that show lot of promise.
They were pleased to report that Clean Slate program led to many small projects and the following four flagship projects that had the potential to transform different parts of the internet
- Internet Infrastructure: OPENFLOW AND SOFTWARE DEFINED NETWORK
- Mobile Internet: POMI 2020
- Mobile Social Networking: MOBSOCIAL
- Data Center: STANFORD EXPERIMENTAL DATA CENTER LAB
Clean Slate program has ceased to exist as of January 2012 and has successfully transformed into these above mentioned four large projects. They now invites scholars around the world to visit the website and contribute to the development.
FEW INFORMATION ABOUT OPENFLOW
The Open Networking Foundation (ONF) is a non-profit industry consortium that is leading the advancement of SDN and standardizing critical elements of the SDN architecture such as the OpenFlow™ protocol, which structures communication between the control and data planes of supported network devices. OpenFlow is the first standard interface designed specifically for SDN, providing high-performance, granular traffic control across multiple vendors’ network devices. OpenFlow-based SDN is currently being rolled out in a variety of networking devices and software, delivering substantial benefits to both enterprises and carriers, including:
- Centralized management and control of networking devices from multiple vendors;
- Improved automation and management by using common APIs to abstract the underlying networking details from the orchestration and provisioning systems and applications;
- Rapid innovation through the ability to deliver new network capabilities and services without the need to configure individual devices or wait for vendor releases; e.t.c
OpenFlow is the first standard communications interface defined between the control and forwarding layers of an SDN architecture. OpenFlow allows direct access to and manipulation of the forwarding plane of network devices such as switches and routers, both physical and virtual (hypervisor-based). It is the absence of an open interface to the forwarding plane that has led to the characterization of today’s networking devices as monolithic, closed, and mainframe-like. No other standard protocol does what OpenFlow does, and a protocol like OpenFlow is needed to move network control out of the networking switches to logically centralized control software
SUMMARY
For enterprises and carriers alike, SDN makes it possible for the network to be a competitive differentiator, not just an unavoidable cost center. OpenFlow-based SDN technologies enable IT to address the highbandwidth, dynamic nature of today’s applications, adapt the network to ever-changing business needs, and significantly reduce operations and management complexity
REFERENCES
https://www.opennetworking.org/images/stories/downloads/sdn-resources/white-papers/wp-sdn-newnorm.pdf
https://pdfs.semanticscholar.org/815c/4901c8e04141a54efdec61da6e8df3518895.pdf
https://www.cisco.com/web/europe/ciscoconnect2013/pdf/DC_3_SDN.pdf
https://cseweb.ucsd.edu/classes/fa16/cse291-g/applications/ln/SDN.pdf
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