What does the term 'overlay network' refer to in the context of Aviatrix?

The term 'overlay network' in the context of Aviatrix refers to a virtual network built on existing cloud infrastructure. This concept involves the creation of a network layer that sits on top of the physical network infrastructure provided by cloud service providers. An overlay network allows for the abstraction of the underlying hardware and facilitates the management, segmentation, and encryption of traffic between various resources across different cloud environments.

This virtual network enables seamless connectivity and can run software-defined networking (SDN) protocols, which provide advanced networking features that are often not available in the base cloud infrastructure. By utilizing overlay networking, organizations can create a more flexible and scalable network that can easily adapt to changing requirements and multi-cloud strategies, without being restricted by the limitations of the underlying physical networking devices.

The other options do not accurately describe the primary function of an overlay network within Aviatrix, as they focus on attributes such as hardware dependency, security subnets, or isolated environments for application testing, which do not encapsulate the primary use case of being a virtual network atop existing infrastructure.