A software-defined network (SDN) is a category of technologies that make it possible to manage a network via software. SDN technology enables IT administrators to configure their networks using a software application. SDN software is interoperable, meaning it should be able to work with any router or switch, no matter which vendor made it1. SDN is used to build and manage interconnections between cloud resources within the same cloud environment, as it allows for greater flexibility, scalability, and automation of network configuration and operation2. SDN is also a key component of cloud computing, as it enables the creation of virtual networks that can span across different physical infrastructures3.
A firewall is a device or software that monitors and controls incoming and outgoing network traffic based on predefined rules. A firewall is used to protect a network from unauthorized access or malicious attacks, but it does not create or manage interconnections between cloud resources4.
A virtual private network (VPN) is a technology that creates a secure and encrypted connection over a public network, such as the Internet. A VPN is used to extend a private network across a public network, allowing users to access remote resources as if they were on the same local network. A VPN is not used to build or manage interconnections between cloud resources within the same cloud environment, but rather to connect different cloud environments or users to a cloud environment5.
Direct Connect is a service offered by some cloud providers, such as Amazon Web Services (AWS), that allows customers to establish a dedicated network connection between their premises and the cloud provider’s data center. Direct Connect is used to bypass the public Internet and provide a more consistent and secure network performance, as well as lower costs and latency. Direct Connect is not used to build or manage interconnections between cloud resources within the same cloud environment, but rather to connect a customer’s network to a cloud provider’s network. References: What is software-defined networking (SDN)? | Cloudflare, What is Software-Defined Networking? - IBM, Software-defined networking - Wikipedia, What is a firewall? | Cloudflare, What is a VPN? | Cloudflare, [AWS Direct Connect - Amazon Web Services]
