What are some examples of overlay networks?

Overlay networks are virtual networks that are built on top of existing physical networks. They use encapsulation techniques to create connections that are independent of the underlying infrastructure.

MPLS (Multiprotocol Label Switching) is an example of an overlay network because it can encapsulate packets of various protocols and enable efficient packet forwarding through label-based routing. CAPWAP (Control and Provisioning of Wireless Access Points) is another overlay technology that facilitates the management of wireless access points over a network by encapsulating wireless traffic into standard packets. LISP (Locator/Identifier Separation Protocol) separates the identifier (which identifies an endpoint) from the locator (which determines how to reach that endpoint), allowing for the creation of an overlay network that enhances routing efficiency.

The other options provided include technologies that either do not function as overlay networks or belong to different categories. For example, IPv4 and IPv6 are addressing protocols, while TCP and UDP are transport layer protocols. VLAN is a technology for creating segmented networks within a local area network rather than serving as an overlay. SSL (Secure Sockets Layer) is focused on encryption for secure data transmission, not on creating a network overlay.