Illustrate the role of a hub in the OSI model, emphasizing its function at the physical layer and its limitations in modern network environments.

Discuss the advantages and challenges of implementing Network Function Virtualization (NFV) in modern network architectures, considering the OSI model's role.

Describe the relationship between the terms dependability and availability in the context of a computer network. The reasons behind a network HUB's depreciation and Is it necessary to have a more in-depth discussion about? obsolescence

What is the primary function of a hub in a network, and how does it operate within the OSI model? Provide an example of a situation where hubs are still used.