Give me 10 medium-difficulty technical questions for data communication network engineers.

Here are ten medium-difficulty technical questions for data communication network engineers:

**Explain the OSI Model:** Describe the seven layers of the OSI model and their functions. How do they relate to TCP/IP?

**Subnetworking:** Given an IP address of 192.168.1.0/24, how would you split this network into 4 subnets? Provide the subnet addresses and their corresponding ranges.

**Routing Protocols:** Compare and contrast RIP, OSPF, and EIGRP. What are the key differences in terms of convergence time, scalability, and administrative distance?

**VLAN Configuration:** What is a VLAN, and how does it improve network performance and security? Describe how to configure a VLAN on a managed switch.

**TCP vs. UDP:** What are the main differences between TCP and UDP? In what scenarios would you prefer to use one over the other?

**Network Address Translation (NAT):** What is NAT, and how does it work? Discuss its advantages and disadvantages in a network environment.

**QoS Mechanisms:** Explain the different mechanisms of Quality of Service (QoS) in networking. How do you prioritize traffic on a congested network?

**Wireless Standards:** Discuss the key differences between the IEEE 802.11a, 802.11b, 802.11g, and 802.11n wireless standards in terms of frequency, range, and data rate.

**IPSec and VPNs:** What is IPSec, and how is it used to secure data in a Virtual Private Network (VPN)? Explain the two modes of operation in IPSec.

**Network Security:** Describe the purpose of firewalls and intrusion detection/prevention systems (IDS/IPS) in a network. What are the key differences between them?

These questions will help evaluate the understanding and expertise of data communication network engineers at a medium level.