Infosys Computer Networks Interview Notes
1. What is a Computer Network?
A computer network is a collection of interconnected devices that communicate and share
resources such as data, files, and printers. It allows data transfer between systems.
Examples: LAN, WAN, MAN, Internet.
2. Types of Computer Networks
1. LAN – Local Area Network (within a building)
2. MAN – Metropolitan Area Network (within a city)
3. WAN – Wide Area Network (across countries)
4. PAN – Personal Area Network (Bluetooth, hotspot)
3. Network Topologies
Topology Description Advantage
Bus All nodes connected to a single backbone. Easy to implement, cost-effective.
Star All nodes connected to a central hub. Easy to manage, fault isolation.
Ring Nodes connected in a circular loop. Uniform data transfer speed.
Mesh Each node connected to every other node. High reliability and redundancy.
4. OSI Reference Model (7 Layers)
Layer Function Example
7. Application User interaction HTTP, FTP, SMTP
6. Presentation Data translation, encryption SSL, JPEG
5. Session Manages sessions APIs, Sockets
4. Transport Reliable delivery TCP, UDP
3. Network Routing and addressing IP, ICMP
2. Data Link Error detection, framing Ethernet, MAC
1. Physical Transmission of bits Cables, Hubs
5. TCP/IP Model
TCP/IP model has 4 layers: Application, Transport, Internet, and Network Access. It is the
backbone of the Internet and more practical than OSI.
6. IP Addressing
1. What is a Computer Network?
A computer network is a collection of interconnected devices that communicate and share
resources such as data, files, and printers. It allows data transfer between systems.
Examples: LAN, WAN, MAN, Internet.
2. Types of Computer Networks
1. LAN – Local Area Network (within a building)
2. MAN – Metropolitan Area Network (within a city)
3. WAN – Wide Area Network (across countries)
4. PAN – Personal Area Network (Bluetooth, hotspot)
3. Network Topologies
Topology Description Advantage
Bus All nodes connected to a single backbone. Easy to implement, cost-effective.
Star All nodes connected to a central hub. Easy to manage, fault isolation.
Ring Nodes connected in a circular loop. Uniform data transfer speed.
Mesh Each node connected to every other node. High reliability and redundancy.
4. OSI Reference Model (7 Layers)
Layer Function Example
7. Application User interaction HTTP, FTP, SMTP
6. Presentation Data translation, encryption SSL, JPEG
5. Session Manages sessions APIs, Sockets
4. Transport Reliable delivery TCP, UDP
3. Network Routing and addressing IP, ICMP
2. Data Link Error detection, framing Ethernet, MAC
1. Physical Transmission of bits Cables, Hubs
5. TCP/IP Model
TCP/IP model has 4 layers: Application, Transport, Internet, and Network Access. It is the
backbone of the Internet and more practical than OSI.
6. IP Addressing
