Table of Contents
- 1: What is the OSI Model? Explain its Layers.
- 2: What is the Difference Between TCP and UDP?
- 3: What is an IP Address?
- 4: What is Subnetting?
- 5: What is a MAC Address?
- 6: What is the Difference Between a Switch and a Router?
- 7: What is NAT and Why is it Used?
- 8: What is DHCP?
- 9: What is VLAN and Why is it Used?
- 10: What is the Difference Between Static Routing and Dynamic Routing?
- 11: Explain Port Numbers with Examples.
- 12: What is Ping and Traceroute?
- 13: Conclusion
- Pro Tip
What is the OSI Model? Explain its Layers.
The OSI (Open Systems Interconnection) Model is a conceptual framework that standardizes communication functions of a network into seven layers:
| Layer | Function |
|---|---|
| 7. Application | Provides network services to end-users |
| 6. Presentation | Data translation, encryption, compression |
| 5. Session | Manages sessions and controls dialogues |
| 4. Transport | Reliable data transfer (TCP/UDP) |
| 3. Network | Routing and logical addressing (IP) |
| 2. Data Link | Physical addressing (MAC), error detection |
| 1. Physical | Transmission of raw bit streams over the medium |
What is the Difference Between TCP and UDP?
| TCP (Transmission Control Protocol) | UDP (User Datagram Protocol) |
|---|---|
| Connection-oriented | Connectionless |
| Reliable (acknowledgments, retransmissions) | Unreliable (no guaranteed delivery) |
| Slower but secure | Faster but less reliable |
| Example: HTTP, FTP | Example: DNS, VoIP |
What is an IP Address?
An IP Address (Internet Protocol Address) is a unique numerical label assigned to each device connected to a network, used for identification and communication.
- IPv4: 32-bit address (e.g., 192.168.0.1)
- IPv6: 128-bit address (e.g., 2001:0db8::1)
HWhat is Subnetting?
Subnetting is the process of dividing a large network into smaller, manageable sub-networks (subnets). It improves network performance and security by reducing broadcast domains.
Subnetting 192.168.1.0/24 into two subnets of /25 gives:
- 192.168.1.0 - 192.168.1.127
- 192.168.1.128 - 192.168.1.255
What is a MAC Address?
A MAC (Media Access Control) Address is a unique physical address assigned to a network interface card (NIC).
It operates at the Data Link Layer (Layer 2) and is used for communication within a local network.
Format example: 00:1A:2B:3C:4D:5E
What is the Difference Between a Switch and a Router?
| Switch | Router |
|---|---|
| Operates at Layer 2 | Operates at Layer 3 |
| Connects devices within the same network | Connects different networks |
| Uses MAC address for forwarding | Uses IP address for routing |
| Example: LAN switch | Example: Internet router |
What is NAT and Why is it Used?
NAT (Network Address Translation) allows private IP addresses within a LAN to access external networks (like the Internet) using a single public IP address. It enhances security and conserves public IP addresses.
What is DHCP?
DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses, subnet masks, default gateways, and DNS information to devices in a network. It eliminates the need for manual IP configuration.
What is VLAN and Why is it Used?
A VLAN (Virtual Local Area Network) logically segments a network into different broadcast domains, regardless of physical location.
It enhances security, reduces congestion, and simplifies network management.
What is the Difference Between Static Routing and Dynamic Routing?
| Static Routing | Dynamic Routing |
|---|---|
| Manually configured | Automatically learns routes |
| No overhead | Requires protocol overhead |
| Suitable for small networks | Suitable for large, complex networks |
Example: ip route |
Example: OSPF, EIGRP |
Explain Port Numbers with Examples.
Port numbers are numerical identifiers used in TCP/UDP protocols to direct traffic to specific services.
| Service | Port |
|---|---|
| HTTP | 80 |
| HTTPS | 443 |
| FTP | 21 |
| SSH | 22 |
| DNS | 53 |
What is Ping and Traceroute?
Ping: Checks connectivity between devices by sending ICMP Echo Request packets.
Traceroute: Identifies the path packets take to reach a destination.
Conclusion
Being well-prepared for networking interviews requires not only memorizing definitions but understanding how concepts apply in real-world scenarios. Focus on clarity, use examples, and when possible, relate answers to your practical experience.
Pro Tip
Prepare for scenario-based questions like:
- How would you troubleshoot a network issue?
- How to secure a wireless network?