Can you explain the OSI and TCP/IP models? What are the key differences? How does subnetting work, and why is it important? Can you calculate a specific subnet mask? Describe the differences between TCP and UDP. When would you use each protocol? Explain BGP and OSPF. How do they differ, and when would you use one over the other? What are VLANs, and how do they work? Why are they used in network design? How do you troubleshoot network latency issues? What tools and steps would you use? What is NAT, and how does it help with IP address management? Can you describe the process of setting up a VPN? How do firewalls work, and what’s the difference between stateful and stateless firewalls? Explain load balancing and the methods commonly used for it.