Semester 4Year 2 · EvenCore Subject★★★ Moderate
CS 403

Computer Networks

Study of network protocols, TCP/IP, OSI model, routing, and network security fundamentals.

4Units
27Topics
4Credits
60hLecture hrs
100Max marks
Your Progress
0 / 27 topics
0% complete
Overview
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Why it matters
Every app you build talks to servers over networks. Understanding HTTP, TCP, IP, DNS explains why websites load slowly, why video calls lag, why downloads fail. Networks power the internet.
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Placement relevance
Backend roles test REST APIs, HTTP protocols. Network companies (Cisco, Juniper) directly test this. Cloud roles (AWS, Azure) need networking. Interview question: 'What happens when you type google.com?' — this is Networks.
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Prerequisites for
Cloud Computing · Distributed Systems · Network Security · IoT · Web Development · System Design
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Recommended books
Computer Networking: A Top-Down Approach by Kurose and Ross · Data Communications and Networking by Forouzan · Computer Networks by Andrew S. Tanenbaum
Curriculum — 4 Units
U1
Unit 1 · 6 Topics · 0% complete
Network Fundamentals & OSI Model
⚡ Key Formulae
OSI Layers:Physical, Data Link, Network, Transport, Session, Presentation, Application
TCP/IP Layers:Network Interface, Internet, Transport, Application
Network Topologies
Transmission Modes
OSI 7 Layers
TCP/IP Model
Protocols
Network Devices
U2
Unit 2 · 7 Topics · 0% complete
Data Link Layer
⚡ Key Formulae
CRC:Polynomial division for error detection
Hamming Distance:To detect d errors, need d+1 distance; To correct d errors, need 2d+1
Efficiency:η = (Useful data / Total transmission time)
Framing
Error Detection (Parity, CRC)
Error Correction (Hamming)
Flow Control
Stop-and-Wait
Sliding Window
HDLC, PPP
U3
Unit 3 · 7 Topics · 0% complete
Network & Transport Layer
⚡ Key Formulae
Subnetting:Network bits + Subnet bits + Host bits = 32 (IPv4)
TCP 3-way Handshake:SYN → SYN-ACK → ACK
Sliding Window:Window Size = 2^n - 1 for n-bit sequence number
IP Addressing
Subnetting
IPv4 vs IPv6
Routing Algorithms
Distance Vector, Link State
TCP vs UDP
Congestion Control
U4
Unit 4 · 7 Topics · 0% complete
Application Layer
⚡ Key Formulae
HTTP Methods:GET, POST, PUT, DELETE, PATCH
HTTP Status Codes:2xx Success, 3xx Redirect, 4xx Client Error, 5xx Server Error
HTTP/HTTPS
DNS
FTP
SMTP, POP3, IMAP
DHCP
Telnet, SSH
Socket Programming
Previous Year Questions
Unit 32023 · End Semester10 marks
Given IP address 192.168.10.0/24. Create 4 subnets. For each subnet, find: Network address, Broadcast address, First usable IP, Last usable IP, Subnet mask.
Unit 22023 · Mid Semester8 marks
Explain Stop-and-Wait ARQ protocol with diagram. If sender sends 5 frames and 3rd frame is lost, show the sequence of ACKs and retransmissions.
Unit 42022 · End Semester6 marks
Explain DNS resolution process. What happens when you type www.google.com? Include recursive and iterative queries.
Exam Strategy
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OSI vs TCP/IP — always asked
Draw both models side by side. OSI has 7 layers, TCP/IP has 4. Know which protocols belong to which layer (HTTP→Application, TCP→Transport, IP→Network). Asked in EVERY exam.
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Subnetting = practice 20 problems
Subnetting is pure calculation. Practice: Given IP/CIDR, find network/broadcast/range. Remember: /24 = 256 IPs, /25 = 128 IPs, /26 = 64 IPs. Show working clearly.
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Protocol diagrams earn marks
TCP 3-way handshake, sliding window, DNS resolution — draw sequence diagrams with arrows showing message flow. Even if explanation is weak, diagram shows understanding.
Related Subjects
Semester 4
Operating Systems
CS 402
Semester 5
Cloud Computing
CS 505
Semester 7
Network Security
CS 702