Network Virtualization and How It Works

Network virtualization is the process of transforming network functions into software and disconnecting them from the hardware they traditionally run on.

The software still consumes the hardware’s resources, but is a separate entity that can be changed, moved, and segmented while the hardware remains the same.

Virtualizing the Network

VIrtualization makes provisioning network resources easier and more efficient. Networking software programs allow administrators to monitor the infrastructure, make changes to the network, provision resources, roll out updates to networking devices, and take action against detected security threats.

The virtualized and software-based version of the network is an overlay on top of the physical network infrastructure. The physical network’s devices like switches and routers still perform tasks like packet forwarding, while how to forward those packets is handled by the software running on the switches and routers.

Virtualization’s Evolution

According to Chris Antlitz, principal analyst at Technology Business Research there are three distinct phases of network virtualization taking place. The first phase was defined by the rise of virtual machines (VMs). Early on, however, some organizations struggled with large-scale VM deployments because of the added complexity of software integration.

The second and current phase is containerization. Containerization in a networking context means placing network functions and networking applications into dedicated runtime environments that only have the necessary software to run the function or application. These runtime environments are called containers.

Containerization is an intermediary step to the end-goal of a fully cloud-native network architecture.

A cloud-native network architecture is the third phase of virtualization. And while containers are often included in discussions about cloud-native architecture, there is more to it than that. A defining aspect of cloud-native networks is the orchestration and management of the disparate containers so everything works as one system.

Benefits and Challenges

A virtualized network brings with it cost savings from purchasing commodity hardware. Commercial off-the-shelf (COTS) boxes, also called white boxes, are examples of commodity hardware and are commonly less expensive than proprietary hardware.

However, those potential savings might be offset by expenses related to orchestrating and managing the new network infrastructure. For example, hiring the right people or hiring a managed service provider to operate the network.

Once the network is virtualized and there is staff to support it, then many operational benefits enter the picture.

Provisioning or otherwise working with the network is often done through a unified management console where the administrator has all of a network’s information displayed in one program. The benefit here is that the administrator doesn’t have to swap back and forth between programs and windows to get the full picture of what is happening on the network. The information is presented in a more condensed and simple way.

Another operational benefit is that a software-based network infrastructure makes scaling instances of VMs or containers easier and faster when resource demand increases.

The network administrators also gain visibility, which improves an organization’s network security posture because security software can see more of the network and report on vulnerabilities and security events.

However, having more visibility means more information. Automated monitoring software is almost a necessity for network administrators to make sense of all that network data. Such software will condense the data and present it in a digestible way that’s easier to manage.

Network Virtualization Use Cases

The web hyperscalers including Amazon Web Services (AWS), Google Cloud, and Microsoft Azure more fully utilize virtualization with a cloud-native architecture.

“The closest vision we have of [cloud-native architecture] in actual use today is what the web scale companies do. So, Amazon, Microsoft, and Google in particular, the way they run their cloud infrastructure … is the best representation of what the end state looks like,” Antlitz said. “They’re using the most advanced architecture for network and IT workloads.”

In this architecture, all of the networking functions are running as microservice-based software in containers on platform-agnostic servers.

From a telecom service provider perspective, network virtualization opened up a new revenue stream through SD-WAN. Telecoms turned their physical networks into SD-WANs by issuing virtualized CPE for enforcing SD-WAN routing policies.

“SD-WAN was one of the first virtualized use cases that a telco could offer and could monetize over virtual CPE,” Stephanie Gibbons, principal analyst at Omdia, said in an interview with SDxCentral. “It does go straight to an enterprise. Or a vendor that has an SD-WAN offering could go straight to an enterprise. But it’s really been one of the first virtualized use cases that took off in a telco environment.”

Network Virtualization: Key Takeaways

1. Network virtualization is the disaggregation of network functions from the underlying hardware and turning the functions into software.
2. The end state of network virtualization has microservice-based network functions running in containers on servers spread throughout a distributed cloud network.
3. Major benefits of virtualization include the speed and ease of scaling network resources, updating policies, and centralized control.
4. Major challenges of virtualization include potentially shifting cost to a managed service provider and the increased amount of network data.
5. Network virtualization improves connectivity in cloud data centers and allowed telecoms to become SD-WAN service providers.