Running head: Software-Defined Networking (SDN) Software-Defined Networking Starla Wachsmann University Of North Texas
What is Software-Defined Networking? Software-Defined Networking has one consistent but universal definition, which emphasis is on how it is done. In a universal way Software-Defined Networking is described as the decoupling of the systems that decides where traffic is sent from the control plane to the data plane and what it uses to get there. So by invention Software-Defined Networking takes the control of data networking from hardware devices such as routers and gives it to software applications called a controller. However In this article I found in TechTarget SDN was best described as this, When a packet arrives at a switch in a conventional network, rules built into the switch's proprietary firmware tell the switch where to forward the packet. The switch sends every packet going to the same destination along the same path -- and treats all the packets the exact same way. In the enterprise, smart switches designed with application-specific integrated circuits (ASICs) are sophisticated enough to recognize different types of packets and treat them differently, but such switches can be quite expensive. The goal of SDN is to allow network engineers and administrators respond quickly to changing business requirements. In a softwaredefined network, a network administrator can shape traffic from a centralized control console without having to touch individual switches. The administrator can change any network switch's rules when necessary -- prioritizing, de-prioritizing or
even blocking specific types of packets with a very granular level of control. This is especially helpful in a cloud computing multi-tenant architecture because it allows the administrator to manage traffic loads in a flexible and more efficient manner. Essentially, this allows the administrator to use less expensive, commodity switches and have more control over network traffic flow than ever before. Factors driving the new network architecture are the heavy loads of data that need to be moved quickly. This has occurred in order to meet the explosion we have had in mobility, bandwidth, and cloud services that will meet the needs of consumers. The online Business Insider made some good points as well in one of their articles pointing out the old way versus the new way. The old way uses switches and routers at the center of everything and links the data directly to them. So if you change your network you have to reconfigure all of your routers and switches. This is a very time consuming process and sometimes challenging process. The new way of SDN layers the hardware with software along with the applications. The diagrams below extracted from this article will give you a good visual of how the process changes.
Figure 1 - OLD WAY Figure 2 - NEW WAY This creates several areas where startups can play: the "control plane," which is the new SDN software, and the "data plane" which is the hardware, like routers and switches.
On top of the control plane is another area of opportunity: networking apps. These weren't previously possible to write for proprietary networking hardware and software, but SDN opens things up for developers. The main enabling technology today for the control plane is called OpenFlow. It was created by the founders of Nicira, a startup bought by VMware last summer. OpenFlow is an interface that allows direct access and manipulation of the forwarding plane of network devices. Basically OpenFlow is a program that can be implemented and used with a carriers existing infrastructure and provide a bridge transition for segments of the network that use SDN. There are several benefits of OpenFlow-Based SDN s pointed out in a ONF paper titled, Software- Defined Networking: The New Norm for Networks The benefits listed include: Centralized control of multi-vendor environments: SDN control software can control any OpenFlow-enabled network device from any vendor, including switches, routers, and virtual switches. Rather than having to manage groups of devices from individual vendors, IT can use SDN-based orchestration and management tools to quickly deploy, configure, and update devices across the entire network. Reduced complexity through automation: OpenFlow-based SDN offers a flexible network automation and management framework, which makes it
possible to develop tools that automate many management tasks that are done manually today. These automation tools will reduce operational overhead, decrease network instability introduced by operator error, and support emerging IT-as-a-Service and self-service provisioning models. Higher rate of innovation: SDN adoption accelerates business innovation by allowing IT network operators to literally program and reprogram the network in real time to meet specific business needs and user requirements as they arise. By virtualizing the network infrastructure and abstracting it from individual network services, for example, SDN and OpenFlow give IT and potentially even users the ability to tailor the behavior of the network and introduce new services and network capabilities in a matter of hours. Increased network reliability and security: SDN makes it possible for IT to define high-level configuration and policy statements, which are then translated down to the infrastructure via OpenFlow. An OpenFlow-based SDN architecture eliminates the need to individually configure network devices each time an end point, service, or application is added or moved, or a policy changes, which reduces the likelihood of network failures due to configuration or policy inconsistencies. More granular network control: OpenFlow s flow-based control model allows IT to apply policies at a very granular level, including the session, user,
device, and application levels, in a highly abstracted, automated fashion. This control enables cloud operators to support multi-tenancy while maintaining traffic isolation, security, and elastic resource management when customers share the same infrastructure. Better user experience: By centralizing network control and making state information available to higher-level applications, an SDN infrastructure can better adapt to dynamic user needs. For instance, a carrier could introduce a video service that offers premium subscribers the highest possible resolution in an automated and transparent manner. Today, users must explicitly select a resolution setting, which the network may or may not be able to support, resulting in delays and interruptions that degrade the user experience. With OpenFlow-based SDN, the video application would be able to detect the bandwidth available in the network in real time and automatically adjust the video resolution accordingly. While the history and development of Software-Defined Networking dates back to around 1995 the main concentration on development came to fruition in 2011 when the Open Network Foundation was founded to promote SDN and OpenFlow. Whether out of need or the desire to use the increasing technologies available SDN has evolved from these inventions. In addition I also see this in all areas of business that technology has increased the usage but
the manner in which we process it has not grown. The potential for this to help IT departments could change things significantly by increasing service response times and eliminate some of the manual processes that take so much time to correct when there are changes. In addition flexibility to streamline processes is or should be at the top of every ones list. Although SDN has not advanced quickly it has received a wider range of acknowledgment and focus of study recently. There are over 25 Software-Defined Networking participants including some well known such as Google, HP, IBM, intel, Infoblox, and NEC just to name a few. Their participation in SDN ranges at all different levels from NEC creating ProgrammableFlow Networking, which is an OpenFlow based technology to Intel s support for SDN, based on their key enabler that allows network administrators to gradually migrate to OpenFlow and SDN. Software-Defined Networking is removing restrictions and allowing companies and technology to move forward and respond to the ever changing technology needs. However with advancement comes a challenge like the main barrier to the adoption of this technology and the lack of industry standards in vendor implementations. Other areas of concern are the security downsides as reflected in an article by Michael Kassner that include points such as, Unfortunately, SDN also introduce new potential security challenges. For
example, one could imagine an adversary who attempts DDoSing the SDN stack itself. Rather than flooding routers or attacking the hosts or applications, an adversary might craft traffic streams simply to increase the interactions between the switches and the controller, i.e., a Control Flow saturation attack. We outline such an attack in our FRESCO paper at NDSS 2013. There are always pros and cons to everything but convenience seems to prevail and drive the will for continued research and resolutions to these issues. Growth and change are inevitable we just have to decide the safest most efficient route. I am looking forward to this advancement because I know the down time we have incurred as a business waiting on re-routing and programming of our data information. The future of IT infrastructure will drive us into this direction however acceptance will cause hesitation along the way until one system can be fully transitioned and be shown that security measures are in place.
References TechTarget article posted by Margaret Rouse http://searchsdn.techtarget.com/definition/software-defined-networking-sdn Business Insider article by Kyle Forster January 19,2013 Read more: http://www.businessinsider.com/software-defined-networking-startups-2013-1?op=1#ixzz3z7qshla2
"Software-Defined Networking: The New Norm for Networks" (PDF). White paper. Open Networking Foundation. April 13, 2012. Retrieved August 22, 2013. 25 Software-Defined Networking Players To Know bychad Berndtson on April 30, 2012, 6:00 am EDT http://www.crn.com/slide-shows/networking/232900998/25-software-definednetworking-players-to-know.htm/pgno/0/12 Software-Defined Networking: How it affects network security By Michael Kassner in IT Security, April 8, 2013, 12:13 AM PST http://www.techrepublic.com/blog/it-security/softwaredefined-networking-how-it-affects-network-security/