How the emergence of OpenFlow and SDN will change the networking landscape Software-defined networking (SDN) powered by the OpenFlow protocol has the potential to be an important and necessary game-changer in network architecture. SDN helps network designers address some of the most fundamental challenges they are facing as virtualization continues to proliferate and bandwidth needs continue to grow exponentially. SDN and OpenFlow could help enable next-generation networks that are simpler to design and scale, much less expensive to build and operate, more agile and customizable, more virtualized, and built on open standards for maximum flexibility and interoperability. Page 1 of 10
The potential impact of OpenFlow will likely first be felt by traditional service providers such as telcos, cable companies, mobile service providers, and huge Internet powerhouses that are building large, complex, and heavily data-centric networks. In fact, Deutsche Telekom, Facebook, Google, Microsoft, Verizon, and Yahoo make up the six-member board of directors of the Open Networking Foundation, an organization dedicated to promoting SDN and the OpenFlow protocol. The involvement of these companies should provide a sense of where the immediate impact of OpenFlow will likely be felt. However, in addition to the service provider market, SDN will eventually impact enterprise networking in data centers and on campus networks as a catalyst for potentially significant changes in the networking landscape. The shift will be toward networks that are built entirely on open standards and that take advantage of shared resources and off-the-shelf components. Many industry experts are ebullient about the prospects of OpenFlow bringing fundamental architectural change to data networking. In fact, InformationWeek has described OpenFlow as the biggest thing since Ethernet. 1 Potential is one thing; reality is another. The impact of SDN and OpenFlow will likely not be immediate, and much work is required to continue defining the protocol and actually deploy it in production environments. If, as many believe, OpenFlow will help to redefine the networking landscape in terms of openness, 1 The Biggest Thing Since Ethernet: OpenFlow, InformationWeek, October 17, 2011 Page 2 of 10
scalability, performance, costs, simplicity, and other areas, it is likely that the change will take place over time and the results will not be immediately dramatic. If you look at virtualization technology, the transformation from the availability of virtualization on commodity servers to the emergence of cloud computing has taken place over the course of more than a decade and still continues to evolve today. Understanding SDN and OpenFlow So what are SDN and OpenFlow, and why do they have so much potential to dramatically affect networking? OpenFlow began at Stanford University as an attempt to create an open standard that could be used by researchers to run experimental protocols on the campus production network. OpenFlow is added as a feature to commercial Ethernet switches, routers, and wireless access points. In the experimental environment, it provides researchers the opportunity to run experiments without requiring vendors to expose the internal workings of their network devices. SDN with the OpenFlow protocol separates the router control plane from the data plane, as depicted in the following graphic: Classical Router OpenFlow-Enabled Router Control Plane (software) Data Plane (hardware) Control Plane OpenFlow Client Data Plane Flow Table OpenFlow protocol OpenFlow Controller Page 3 of 10
In a traditional router or switch, the data path and the control path occur on the same device. In an OpenFlow device, these two functions are separated. The data path function still resides on the switch, while high-level routing decisions are moved to a separate controller, usually a standard server. The result is much greater efficiency in how packets are routed throughout the network and an open networking environment that allows organizations to easily deploy innovative routing and switching protocols. Among the early and obvious applications are virtual machine mobility, high-security networks, and next-generation IP-based mobile networks. The developers of OpenFlow at Stanford have said OpenFlow and SDN will: n Empower network owners and operators by customizing networks to local needs, eliminating unneeded features and enabling the creation of virtual, isolated networks. n Increase the pace of network innovation by enabling innovation at software speed, creating standards that will follow software deployment, and promoting technology exchanges with partners and researchers. n Diversify the supply chain by allowing a variety of software suppliers, enabling common hardware abstraction with extensions, and increasing the types of application developers to include vendors as well as homegrown, outsourced, and open-source applications. Page 4 of 10
n Build a robust foundation for future networking by providing a standardized forwarding abstraction and provable network properties at every step. 2 Understanding SDN and OpenFlow While the first uses of OpenFlow have been in academia among researchers, the availability of technology for commercial applications is well under way. Equipment based on the SDN concept is already on the market and has already been deployed by some large data center operators and on some university campuses, according to Carrier Ethernet News. 3 Deutsche Telekom is already using OpenFlow-enabled switches, and work on its network has helped to inform much of the research about the potential opportunities provided by OpenFlow on carrier networks. Several key equipment vendors have come out in support of OpenFlow, particularly Brocade, which was one of the first major networking vendors to publicly endorse the protocol in June 2010. Brocade is offering an OpenFlow-enabled IP/MPLS router as part of its service provider product portfolio for application verification and interoperability testing with its partners and customers. Brocade is initially focusing its efforts on delivering solutions that enable the scalability and manageability required in hyperscale cloud infrastructures. Brocade has long been a supplier that has supported open standards and multi-vendor environments. 2 How SDN Will Shape Networking, Nick McKeown, Open Networking Summit 2011 3 What Impact Will OpenFlow Have on Carrier Ethernet? Carrier Ethernet News, January 24, 2012 Page 5 of 10
There are many potential benefits to using OpenFlow in building and adapting large-scale networks. The most critical ones driving early interest are: n The ability to use shared resources n Open industry standards n Enhanced user customization and agility n Fast adaption n Cost savings Among the areas where OpenFlow will have the largest impact on future network generations and the vendors that supply them is in the openness of its approach. In the data switching market, there has traditionally been a reliance on proprietary switching protocols. The need for those proprietary protocols is obviated with OpenFlow, and the network can be programmed separately from the hardware and software of the switch vendor. This gives the network/service provider much more flexibility and control in developing new services and applications, particularly in self-service environments that are increasingly enabled by cloud computing and virtualization. It also paves the way for a much more commoditized approach to networking equipment, similar to that in the early days of the microprocessor market. Increased commoditization, as the technology industry has often seen, can be a big driver of increased usage, scalability, ease of deployment, and overall market development. Page 6 of 10
Cost is another major consideration, particularly for service providers of all types, from traditional telcos and cable companies to the new breed of data-oriented service providers that have built their businesses through the Internet (such as Google, Facebook, and Yahoo). These companies have absolutely massive data and network requirements, and they need the ability to scale rapidly, simplify management, and reduce costs. They must have the highest degree of openness and scalability, which is the potential promise of SDN and OpenFlow. According to one report, OpenFlow will reduce the costs of each switch in a network by as much as 70 percent or more, savings that add up quickly across any large network environment. Organizations will also save money in personnel and support costs because scalability will be dramatically simplified and management complexity will be greatly reduced. Organizations that are offering cloud services will be able to not only improve network speed and performance, but also quickly make changes in their underlying infrastructures without having to reconfigure the network and without having to worry about supporting the unique protocol of any particular vendor. Where SDN and Openflow Will Have a Significant Impact Given the cost and agility advantages of OpenFlow in building huge and highly scalable networks, it is no surprise that most experts expect the biggest impact to be on companies that are building the largest and fastest-growing networks. The first likely impact of OpenFlow will be in the service provider arena and perhaps on campus networks in academia, eventually extending to Page 7 of 10
other enterprise organizations. And that, in reality, is exactly where the biggest impact is taking place. Understanding SDN and OpenFlow Traditional service providers: All around the world telcos and cable companies are under tremendous pressure to cut costs and drive up average revenue per user. At the same time, they must deliver more and more bandwidth than ever, often without having proper business models in place to drive incremental revenue. Basically, they have to deliver the bandwidth even without incremental revenue just to ensure quality of service, quality of experience, and customer retention. SDN is a critical technology in enabling them to scale up on bandwidth delivery while reducing overall network costs. The other important challenge and opportunity for traditional service providers is to create new revenue streams, either on their own or through partnerships in inter-related industries, such as Internet, gaming, retail, and others. The fact that OpenFlow provides openness and enhanced programmability for application developers is another driving force for traditional service providers. Mobile service providers: In many ways, these companies are facing the same challenges as traditional telcos. And in many cases, they are, in fact, the same company or a division within the same company. To remain competitive, they must dramatically increase bandwidth. The explosive growth of smartphones, tablets, and other highly intelligent portable devices has created demand beyond anyone s wildest expectations. Mobile users demand video streaming and access to social networks, but mobile providers don t necessarily have in place the business models to support endless expectations for bandwidth increases. And, like Page 8 of 10
traditional telcos, these service providers will be increasingly reliant on new revenue streams that provide value-added services customers will actually pay to receive. Again, the challenge is to build networks that can scale quickly and inexpensively. For these types of companies, where there is a clear demand for services, new applications, and more bandwidth, OpenFlow can have an immediate and measurable impact. Data services and cloud services providers: This includes some of the giants backing the OpenFlow protocol, such as Google, Yahoo, Facebook, and Microsoft, and also includes the burgeoning market of cloud services providers, such as Salesforce.com, Amazon, and many, many others. According to InformationWeek, the first consideration for using OpenFlow outside of academia was to scale bandwidth in massive data centers: For uses such as Google s search engine, parallel processing of massive data sets takes place across clusters of tens of thousands of servers, an approach that simply can t be addressed by today s tree-based network architecture. 4 Aside from the largest vendors, any organization building a cloud-based service is a candidate for early adoption of OpenFlow. The agility, scalability, and simple programmability offered by OpenFlow make it ideal for cloud environments. Organizations that are looking to provide new applications through cloud services can take advantage of the ease of use in programming, as well as the simplicity involved in deploying new services. While service providers of all types are expected to be the earlier drivers of OpenFlow adoption, it is only a matter of time before 4 The Biggest Thing Since Ethernet: OpenFlow, InformationWeek, October 17, 2011 Page 9 of 10
enterprises also begin deploying SDN solutions on a larger scale. In organizations where network performance and scalability are critical, such as in healthcare or financial services, organizations will be able to see immediate benefits without having to replace all of the switches in their existing networks. The process will take time, however: Even as OpenFlow is beginning to be used in production networks outside of academia, its developers are still adapting and building major aspects of the protocol standard. The reality is that existing data network infrastructures are destined for dramatic change. They simply were not designed to support the levels of speed, volume, velocity, resilience, scalability, and robustness required in today s environment. According to IDC s Digital Universe Study, the amount of data being created globally is doubling every single year. 5 Software-defined networking powered by OpenFlow is one of the technology solutions that have real, viable potential to dramatically change the networking landscape over the next technology generation, driven initially by the service providers and cloud services companies that need it most and can take the best advantage of all it has to offer. If you are a player or potential player in the services market and haven t yet made the commitment to examine OpenFlow, two things are clear: Your need to deliver bandwidth will continue to grow, and at some point, you will need to consider OpenFlow as a potential costeffective solution. 5 The 2011 Digital Universe Study: Extracting Value from Chaos, IDC, June 2011 Page 10 of 10