As IT leaders try to get the best performance and efficiency out of their virtualised environments, they're realising the need for virtual networking, and often a whole new networking architecture that's designed for virtualisation from the ground up.

This is hardly surprising. Server, storage and desktop virtualisation are putting an increasing amount of pressure on traditional networks.

“Forevermore, the tried and true ways of architecting, deploying, managing, and updating networks are no longer enough for the highly efficient, dynamic, and scalable infrastructure demands,” said Forrester Research senior analyst Andre Kindness.

Virtualised IT infrastructure requires a new approach, he said, which differs from the traditional strategy of "throwing bandwidth" at the problem. “Today's traditional three-tiered architectures are giving way to flatter, converged Ethernet fabrics,” Kindness explained.

Fundamentally, this ‘flatter’ next generation network architecture virtualises and combines two of the switching layers - the core and aggregation layers).

The advantages of flattening the networking topology include routing traffic more efficiently, helping to remove redundancy in SAN networks, and reducing computing inefficiencies.

But Kindness said: “This requires transforming today's bloated and static network into a dynamic, efficient, automated, and high-throughput entity. To do this, organisations need to deploy ‘fabric’ architecture, embracing five new investments: virtual switches, hybrid software and hardware switches, converged switching architecture, meshed topologies, and automation.” (A mesh is where each networking node captures and disseminates its own data, and also collaborates with, and relays information to other nodes.)

Virtualised and converged networking components can deliver the most dramatic benefits for organisations that use thousands of virtual servers around the world. This is because they can generate significant hardware cost savings, provide dynamic partitioning, facilitate performance across a global server infrastructure, and yield performance and quality of service improvements over physical switches.

Cisco released its first virtual software switch in 2008, which is designed to sit inside VMWare’s ESX server hypervisor. Other vendors are also developing virtualised networking products, but many are still in the early stages.

For example, Crossbeam Systems is currently in 'an embryonic phase' of virtualising networking based software components, says its director, Peter Dogart. Crossbeam manufactures a hardware network-in-a-box system, that allows organisations to virtualised and consolidate key security components, and create multiple iterations of each application.

Dogart argues that switches and routers "have become bloated over the years, with features and useless functionality that vendors told us we needed, to keep the price-per-port high". As well as lowering the cost of networking, virtualisation will also enable the abstraction of data, management and control, he said.

The result of this will be ‘context-aware’ networks, with the ability to automate themselves, optimise traffic flows, and shape the traffic synchronously and in real-time, to deliver an environment that is ‘in tune’ with the business. "Imagine an IT infrastructure that on demand can tune itself to become compliant, and then show you an audit report automatically," Dogart said. He added that enterprises will start to deploy ‘context aware’ technology in the lab this year, but full-scale deployments are many years away.

One element of the ‘context aware’ vision is something that Gartner calls ‘application fluency’, where the network, and the data centre, can accommodate and dynamically adapt to an increasingly demanding workload. Networking suppliers such as Alcatel-Lucent are incorporating application fluency into their next-generation data centre switching products, says Johan Ragmo, data business development manager for the Northern Region at Alcatel-Lucent Enterprise.

He said: "Until now many organisations have not been able to reap all of the benefits of server virtualisation because virtual machine movement requires manual intervention to modify network provisioning, and dealing with this is the next step towards application fluency."

He added: "Network virtualisation enables the data centre switching network to route traffic based on the optimal path in the network, and can deliver a switching fabric with extremely low latency."

One benefit of this is that the virtualised network infrastructure can adapt to the higher-bandwidth requirements of media-rich applications, such as video, in server and desktop virtualisation scenarios.

One emerging technology that is making data centre virtualisation simpler and more efficient is the Ethernet protocol, Shortest Path Bridging (SPB), said Jean Turgeon, VP and global general manager at Avaya Networking. “This next generation virtualisation technology will revolutionise the design, deployment and operations of the enterprise campus core networks, along with the enterprise data centre.”

SPB eliminates the need for multiple ‘overlay protocols’ in the core of the network by reducing the core to a single Ethernet-based ‘link state’ protocol which provides all virtualisation services (virtualisation of bridging, routing, and multicast) in an integrated model.

“The benefits of the technology will be clearly evident in its ability to provide massive scalability while at the same time reducing the complexity of the network. This will make network virtualisation a much easier paradigm to deploy within the enterprise environment,” said Turgeon.

Richard Thomas, CEO of network and application monitoring firm netEvidence, said: "Network virtualisation involves many new ideas and models and these are causing considerable concern among IT and business executives. These concerns are usually focused on how to manage such a large virtual domain where the components are linked, so one change in the network can affect other components, potentially causing a series of changes."

He said that organisations will need to gain visibility into all of the assets in the IT environment. "Without that insight, the environment will be difficult to manage and impossible to automate."

Jonathan Reeve, senior director at network management and monitoring supplier, SolarWinds, agrees that good visibility into next-generation virtual networks will be essential. "Cloud computing and virtualised environments require a close interaction of technologies, including networking, storage and server virtualisation. From a network management perspective, this means the complexity of the network setup has grown significantly. In cases of network troubleshooting in particular, it is important to ensure you can quickly visualise which applications are underperforming and if the problem is related to the network.”

Network virtualisation is here, albeit in its infancy. But it promises to bring greater efficiencies, scalability and cost savings to virtualised infrastructures, while introducing radically simpler network topologies. The question for IT leaders is where to start?