Network Engineer interview questions

The OSI model is a conceptual framework used to understand network interactions in seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application. It is important because it standardizes networking protocols and allows different systems to communicate.

A switch connects devices within a single network and operates at the data link layer, whereas a router connects different networks and operates at the network layer to route data between them.

Subnetting is the practice of dividing a network into smaller, distinct subnetworks, which helps improve network performance and security by reducing broadcast traffic and organizing the IP address space efficiently.

To troubleshoot network issues, start with physical checks, verify cable connections, use tools like ping and traceroute to check connectivity, and review configuration settings on devices for errors or misconfigurations.

A VPN, or Virtual Private Network, creates a secure, encrypted connection over the internet from a device to a network. It is used to protect private web traffic from interference, snooping, and censorship.

Network topologies refer to the arrangement of elements (links, nodes, etc.) in a network. Common topologies include bus, star, ring, mesh, and hybrid.

TCP (Transmission Control Protocol) is connection-oriented, ensuring data delivery with error-checking and reliability, useful for applications like web browsing. UDP (User Datagram Protocol) is connectionless, offering faster transmission without error correction, suitable for streaming and gaming.

A firewall is a network security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules, establishing a barrier between a trusted network and untrusted external network.

NAT, or Network Address Translation, is used to modify network address information in IP packet headers while in transit. NAT conserves global address space and enhances security by masking internal IP addresses.

To stay up to date, a network engineer can follow industry news, take relevant certification courses, engage with tech communities and forums, practice with labs and simulators, and attend conferences and webinars.