Software-defined networking (SDN) a few months back was just a theory, but now, with several leading industry players, including Juniper, Cisco, Calsoft, VMWare, HP and Brocade lending their support for the technology, virtualized networking has started to take a definite shape. Research firm IDC forecasts that SDN will grow from a $200 million market in 2013 to $2 billion in 2016.
SDN broadly means letting networking pros specify configurations in high-level languages, and those instructions tell routers and switches how to prioritise and manage traffic. It can help IT teams quickly provision network services that underpin business applications. It will allow more automation of networking, letting companies put more resources into innovation. In an environment where Cloud computing has become a common trend, aiding data generation from several points and dissemination of data to various end-points in real-time, it becomes essential that network too evolves to provide flexibility at par. To get elasticity in the Cloud, one needs elasticity of the network, and SDN is the way to do that. The network technology that first took root in Stanford University, allows application developers to access the network as a platform and develop workload specific solutions on a centralised port, which in turn controls an army of functions.
In a conventional switch, packet forwarding (the data path) and high-level routing (the control path) occur on the same device. An OpenFlow switch separates the data path from the control path. The data path portion resides on the switch itself; a separate controller makes high-level routing decisions. The switch and controller communicate by means of the OpenFlow protocol. This methodology, known as SDN, allows for more effective use of network resources than is possible with traditional networks. OpenFlow is fast gaining favour in applications such as virtual machine (VM), mobility, mission-critical networks, and next generation IP based mobile networks.
OpenFlow allows the path of network packets through a network of switches to be determined by software running on a separate, basic and cheaper server. This provides enterprises more sophisticated traffic management as it bypasses some of the more expensive proprietary software sold with networking hardware today. The OpenFlow-enabled switches drive real-world deployments. This technology is an emerging network virtualization technology that provides customers flexibility and control to configure their networking environment to their specifications.
“Today networks are inefficient, difficult to scale, cost-intensive in time and resources, and incapable of supporting flexible operations. In most cases, all networking intelligence is distributed across physical switches and routers using standardized protocols. Configuration of networking equipment is primarily performed on each switch independently
Propelling adoption
SDN is initially aimed at large data centres such as Google trying to simplify their massive networks. However, HP is already serving a carrier who is working with the technology, and Google is working with telcos to get them to adopt the OpenFlow technology it now runs internally.
HP, a founding member of the Open Networking Foundation and one of the early entrant in the SDN space has an OpenFlow-enabled switch portfolio of about 16 models. The company also plans to expand support for OpenFlow across all switches in the HP FlexNetwork architecture. The company’s research arm, HP Labs also has been working on developing programmable networks since 2008, and has published research that enterprises can use as a guideline for deploying OpenFlow technology. OpenFlow has found favour with the enterprise segment due to several factors, one of them being cost. The cost of the product depends on the quantum of data flow through the product. If a company can reduce the data flow through the box controller, the cost is reduced substantially. Although there has been a lot of advancement on the controller side as well as on the storage or infrastructure side, one does not see many innovations on the protocol side of the network. One of the reasons for this is that all networks currently work on the production side and one cannot do a lot of experimentation there as it is a mission-critical environment. The technology also allows companies to draw a box in the production network that, while being in the network, can still run different sets of protocols. Another factor that has aided OpenFlow’s popularity is its open platform. It enables a contributory environment, where several application developers can innovate and create, directly on the network, specific solutions for various functions of an organisation including human resource management, business process management or marketing. OpenFlow allows innovation to be done in the networking industry and allows it to be tested in a production environment. Due to its open nature OpenFlow-enabled software have been deployed by academic and commercial researchers worldwide to achieve simplified management. Industry players say the move to SDN will be led by the service providers first – the ones with the most to gain in terms of large operating savings because of the scale of their data centres.
Enterprise data centres are in the midst of a massive transformation driven by data centre consolidation, server virtualization, web-based applications and new security requirements, which has created numerous network challenges that can’t be addressed with existing legacy networks and manual processes. “It is an emerging concept that promises improved network performance, flexibility and manageability. SDN has the potential to revolutionise networking by unlocking a wave of innovation for application services,Unnikrishnan of Brocade said. OpenFlow is a protocol that allows a server to tell network switches where to send packets. In a conventional network, each switch has proprietary software that tells it what to do. With OpenFlow, the packet-moving decisions are centralised, so that the network can be programmed independently of the individual switches and data centre gear.
With SDN, the ability to control multiple disparate sites under the same network control opens up one of the chief promises of Cloud computing elastic scaling of applications between an on-premise private Cloud and a service provider’s public Cloud, creating a hybrid Cloud. In the long term, even as Cloud computing continues to popularise, many enterprises will not be comfortable having all of their workloads in the public Cloud. They will still have on-premise applications. SDN allows users to be able to manage both of those networks through a common framework. SDN can be an opportunity to actually improve network security, too.
Although large service providers are expected to be the early adopters of the technology, smaller campus environments and enterprise data centres controlling LANs and WANs are also likely to adopt SDN and OpenFlow in the long run. Deploying the OpenFlow standard enables enterprises to significantly reduce the complexity of network devices and automate tasks using simplified network management. By reducing the time it takes to make changes to the network, OpenFlow allows IT staff to better respond to changing needs in real time.
Early days
Even though SDN and virtual network technology has generated a lot of interest in the enterprise segment, it is still early days for the technology to become revolutionary. Despite its potential, SDN adoption has been slow so far. Industry players say it could take three to five years for SDN to be the common networking framework. So far, early adopters of SDN have been interested in the technology for two main reasons. First, virtualizing the network by abstracting core networking functions from the hardware, making the network environment more efficient, just like how server virtualization made computing more efficient. Second, SDN allows networks to programmatically scale, providing much more agility in controlling the network. These features have so far appealed most to service providers who are looking to scale VLANs to create more segmented and secure multi-tenant environments, or by large enterprises that need to span different infrastructures but want to use the same networking architecture. However, industry players feel the technology will take at least five years to gain hold in the enterprise segment as issues of standardisation and interoperability still persist. In the initial stages of adoption, SDN will require compatibility with the traditional networks already installed by the companies. It is unlikely that companies will completely overhaul their network to adopt OpenFlow networks.
“Today applications have very low role in networks. Every application has different network requirement. If application and network is integrated application delivery becomes easy. Right now there is no application awareness and no clear vendor environment,Paul of Juniper said. While the overseas market has seen a few pilot projects and deployments in the space, in India the technology is still an infant. Some players are pushing for SDN model that allows for more automation and flexibility without doing away with the switch’s prominent role in determining optimal network pathways, while few vendors have still not declared their commitment for it.
“Indian companies will also adopt. The usual trend in India is that they adopt a technology when it is developed, vendor environment is established and when there is clear standardisation. The traction will initially come from large and multi national companies. Vodafone is deploying the technology in its European market, it may replicate the same in India,Purkayastha of Calsoft said.
SDN could prove highly disruptive to the networking industry. One approach to SDN would overturn the current role that switches and other network devices play by turning them into fast but dumb machines that forward packets, while network intelligence would reside in a centralized controller. This approach threatens dominant networking vendors, who command high prices for network switches. “SDN has the ability to break vendor lock-in as the intelligence resides in on a central port, which is software enabled. This will be a significant shift for the networking industry,Purkayastha said.
Networking hardware is a $37 billion market, and everyone from Cisco, Calsoft, Juniper, Dell, HP, Brocade and even software players like Oracle and VMWare are angling for a piece of it.
SDN could seriously upend the way networking hardware is bought and sold, favoring cheaper, simpler boxes running more sophisticated software. Its arrival has already lead to some big acquisitions including the $1.26 billion purchase of 100-person startup Nicira by VMware in July, and Oracle’s acquisition of Xsigo.
However, OpenFlow-based solutions have to overcome numerous problems ranging from compatibility with existing chipsets to incomplete and fast-changing specifications and also there are problems pf scalability. In a network controllers need to work in a distributed environment, so the network policies can be managed across a diverse set of network devices across the globe. SDN and OpenFlow standards and API? are still in development impacting how a particular ISP can interact with another using OpenFlow. “OpenFlow is scalable, but the controllers do not has the ability to scale-up beyond a point, so the response time between controller and switch become a bottleneck. That is one of the primary problems that is being discussed and researched upon,Purkayastha of Calsoft said.
Every new technology triggers an unlimited wave of enthusiasm and OpenFlow is no exception. Believed to be a revolutionary technology in the networking space, SDN has attracted a lot of interest from the large enterprises as it gives high level of control to them in terms of managing internal functions. Just like Apple’s app store took the mobile handset industry by storm, SDN’s open platform can do the same with networking industry, however, it remains to be seen how it is used to innovate business specific applications. There are also concerns of interoperability and standardisation that need to be solved before the technology becomes the primary networking framework for enterprises.