Which protocol is associated with traffic handling in the control plane?

OpenFlow is a protocol that plays a crucial role in traffic handling within the control plane of a network. It enables the separation of the data plane and control plane functions in networking devices, such as switches and routers. By using OpenFlow, network administrators can manage the way network traffic flows and implement policies for routing and switching directly from a centralized controller. This allows for more flexible and dynamic management of network resources, which is essential in software-defined networking (SDN) environments.

The relevance of OpenFlow in traffic handling stems from its ability to facilitate fine-grained control over traffic flows, allowing changes to be made in real time without the need for physical alterations to hardware. As such, it supports efficient traffic management and optimization in modern networks.

In contrast, the other options focus on different aspects of network communication. IPsec is primarily used for securing IP communications through encryption and authentication, HTTP is a protocol for transferring hypertext documents on the web, and FTP is used for transferring files over a network. None of these protocols serve the same function as OpenFlow in terms of managing traffic within the control plane.