Networking Questions for IBPS PO

Types of Networks

Networks are classified by their geographic coverage. LAN (Local Area Network) covers a small area like an office or building. MAN (Metropolitan Area Network) covers a city-level area. WAN (Wide Area Network) covers countries or the globe — the internet itself is the biggest WAN. PAN (Personal Area Network) covers a very short range like Bluetooth between your phone and earphones.

• LAN: small area, high speed, privately owned (office, school lab)
• MAN: city-wide, medium speed, example is cable TV networks
• WAN: global, slowest among the three, example is the Internet
• PAN: personal devices, very short range, uses Bluetooth or Infrared
• VPN (Virtual Private Network): a secure private network built over a public network like the Internet

Network Devices

Each device in a network has a specific job. Hub broadcasts data to all connected devices — it is dumb and inefficient. Switch is smarter — it sends data only to the intended device using MAC addresses. Router connects different networks and directs data packets using IP addresses — your home Wi-Fi box is a router. Modem converts digital signals to analog (modulation) and back (demodulation) for transmission over telephone lines. Repeater boosts weak signals over long distances. Gateway connects two networks that use different protocols — it is the translator of the network world.

• Hub: works at Physical layer, broadcasts to all ports, no filtering
• Switch: works at Data Link layer, uses MAC address, sends to specific device only
• Router: works at Network layer, uses IP address, connects different networks
• Modem: MOdulator-DEModulator, converts digital to analog and vice versa
• Repeater: regenerates signal, extends network range
• Gateway: protocol translator between two different types of networks

OSI Model — 7 Layers

OSI (Open Systems Interconnection) model is a conceptual framework that divides network communication into 7 layers. Each layer has a specific responsibility. IBPS PO commonly asks which device or protocol belongs to which layer. Remember the layers from bottom to top using the mnemonic: Please Do Not Throw Sausage Pizza Away.

• Layer 1 Physical: cables, hubs, repeaters — transmits raw bits
• Layer 2 Data Link: switches, MAC addresses — frames data
• Layer 3 Network: routers, IP address — routing and logical addressing
• Layer 4 Transport: TCP, UDP — end-to-end delivery and error checking
• Layer 5 Session: manages sessions/connections between applications
• Layer 6 Presentation: data translation, encryption, compression (SSL works here)
• Layer 7 Application: HTTP, FTP, SMTP — interface the user interacts with

Key Protocols and Their Port Numbers

Protocols are rules that govern how data is sent and received. IBPS PO loves asking which protocol does what, and sometimes the port number. TCP (Transmission Control Protocol) is reliable and connection-oriented — it confirms delivery. UDP (User Datagram Protocol) is faster but unreliable — used for video streaming. HTTP runs websites, HTTPS is its secure version. SMTP sends emails, POP3 and IMAP receive emails. FTP transfers files.

• HTTP: port 80, browses web pages
• HTTPS: port 443, secure web browsing (uses SSL/TLS encryption)
• FTP: port 21, file transfer between computers
• SMTP: port 25, sending emails
• POP3: port 110, receiving/downloading emails
• DNS: port 53, converts domain names to IP addresses
• TCP: reliable, connection-oriented; UDP: fast, connectionless

IP Addressing and Related Concepts

Every device on a network has an IP address — like a home address for your computer. IPv4 uses 32-bit addresses written as four octets (example: 192.168.1.1). IPv6 uses 128-bit addresses to solve the shortage of IPv4 addresses. DNS (Domain Name System) is the phonebook of the internet — it converts human-readable names like www.google.com into IP addresses. MAC address is a hardware address permanently embedded in a network card — 48-bit, written in hexadecimal.

• IPv4: 32-bit, written as 4 sets of numbers (0-255), about 4.3 billion addresses
• IPv6: 128-bit, written in hexadecimal, created to replace IPv4 due to address exhaustion
• DNS: translates domain name to IP address — think of it as a contacts list
• MAC address: 48-bit physical address of NIC, unique to every device, cannot be changed easily
• DHCP (Dynamic Host Configuration Protocol): automatically assigns IP addresses to devices on a network

Network Topologies

Topology is the layout or arrangement of devices in a network. Bus topology uses a single central cable — if the cable fails, whole network fails. Star topology connects all devices to a central hub/switch — most common in offices. Ring topology connects devices in a circle — data travels in one direction. Mesh topology connects every device to every other device — most reliable but expensive.

• Bus: single backbone cable, easy to set up, single point of failure
• Star: all connected to central device, easy to troubleshoot, most popular
• Ring: data flows in a loop, one failure can disrupt the network
• Mesh: every node connected to every other, most fault-tolerant, very expensive
• Tree (Hybrid): combination of star and bus, used in large organizations

• Confusing Hub and Switch — Hub broadcasts to ALL devices, Switch sends only to the TARGET device using MAC address. Hub is Layer 1, Switch is Layer 2.
• Mixing up SMTP and POP3 — SMTP is for SENDING emails (think S for Send), POP3 and IMAP are for RECEIVING emails.
• Confusing Router and Modem — Router connects networks using IP addresses, Modem converts signal types. Your home broadband box is actually both combined into one unit.
• Getting OSI layers wrong — many aspirants mix up Presentation and Session layers. Remember SSL/TLS is at Presentation (Layer 6), not Application.
• Thinking IPv4 and IPv6 are interchangeable — IPv4 is 32-bit with about 4.3 billion addresses, IPv6 is 128-bit created specifically because IPv4 addresses ran out.

• OSI layers bottom to top: Please Do Not Throw Sausage Pizza Away = Physical, Data Link, Network, Transport, Session, Presentation, Application
• For devices and layers: Hub is Helpless (Layer 1, no intelligence), Switch is Smart (Layer 2, uses MAC), Router is Really smart (Layer 3, uses IP)
• SMTP vs POP3: S in SMTP = Send, P in POP3 = Pull/Receive. You PUSH mail out via SMTP, you PULL mail in via POP3.
• Modem = MOdulator DEModulator — the name itself tells you what it does. It MODs and DEMODs signals.

• In IBPS PO, networking questions are usually 2-4 direct factual questions — not calculation-based. They test definition and classification, so pure memorization wins here.
• Most frequent PYQ pattern: identify the correct device for a given function (example: which device connects two different networks using IP addresses — answer is Router). Practice these match-the-column type questions.
• OSI layer questions are a favourite — typically ask which layer HTTP, FTP, or a specific device belongs to. Memorize the 7 layers and 3-4 examples per layer.
• Protocol-port combinations (HTTP-80, HTTPS-443, FTP-21, SMTP-25) have appeared in multiple years. Spending 5 minutes memorizing these 6-7 pairs gives guaranteed marks.
• Do not spend more than 30-40 seconds per networking question. These should be your speed-scoring questions in the Computer section — skip and move on only if genuinely unsure, as negative marking applies.