Which node serves as the gateway between the fabric domain and external networks?

The border node is the correct answer because it is specifically designed to serve as the gateway between the fabric domain and external networks in a network architecture. This role involves forwarding traffic to and from other networks and providing various essential services, such as routing, firewalling, and sometimes even load balancing.

In this context, the border node facilitates communication between devices inside the fabric and those outside it, ensuring secure and efficient data exchange. It acts as a critical point for maintaining connectivity while enforcing security policies, traffic management rules, and network segmentation. This makes the border node an essential component of a well-architected network fabric, allowing it to interoperate with different external networks, such as the internet or remote branch offices.

While edge nodes and intermediate nodes play significant roles within a networking environment, they do not directly handle external connectivity in the same way that the border node does. Edge nodes primarily connect endpoint devices to the fabric, and intermediate nodes usually work on managing internal data traffic without serving as an interface to external networks. Control plane nodes typically handle the management and control functions within the network rather than acting as gateways. Therefore, the border node is uniquely positioned to fulfill the role of gateway, making it the correct choice.