Computer Networks
“Master packet flows, sliding window arithmetic, CIDR subnetting, IP fragmentation, and TCP congestion control for university exams and GATE CS/IT.”
A rigorous, comprehensive study notebook covering computer networking fundamentals, mathematical channel capacities, flow control protocols, IP routing, and transport layer mechanisms. Built specifically for B.Tech semester exams and high-percentile GATE CS/IT preparation.
Structured Notes & Exam Lens
A · B.Tech Structured Study Sequence
9 Sections · Full CurriculumProtocol Layering & Network Delays
Architectural principles of computer networking: OSI 7-layer vs TCP/IP 5-layer stacks, packet encapsulation, and end-to-end delay mathematics.
Layer responsibilities, protocol data units (PDU), and header encapsulation.
Nyquist bit rate, Shannon-Hartley capacity, SNR decibels, and circuit vs packet switching.
Data Link Layer, Error Detection & Correction
Framing methods, bit-stuffing, checksum, Cyclic Redundancy Check (CRC) polynomial arithmetic, and Hamming distance bounds.
Flag bytes, HDLC bit-stuffing, and binary modulo-2 CRC division.
Flow Control & Sliding Window Protocols
Stop-and-Wait ARQ, Go-Back-N (GBN), Selective Repeat (SR), window size limits, link utilization, and sequence number bit requirements.
Window sizes, link efficiency eta = W / (1 + 2a), and timer retransmissions.
Medium Access Control (MAC) & Ethernet
Random access protocols (Pure ALOHA, Slotted ALOHA), CSMA/CD, CSMA/CA, Ethernet frame format, and minimum frame size constraints.
L >= 2 * T_p * Bandwidth, binary exponential backoff, and collision domains.
Collision vs broadcast domains, transparent bridge backward learning, and Spanning Tree Protocol.
Network Layer, IPv4 Addressing & CIDR Subnetting
IPv4 header format, IP packet fragmentation, classful addressing, CIDR prefixes, subnet masks, and NAT translation tables.
Header fields, MTU fragmentation offsets, and VLSM network bit masks.
Routing Protocols & Algorithms
Distance Vector Routing (Bellman-Ford, Count to Infinity, Split Horizon), Link State Routing (Dijkstra SPF, OSPF), and BGP path vector fundamentals.
Bellman-Ford updates, count-to-infinity, split horizon, and Dijkstra SPF.
Transport Layer, TCP Flow & Congestion Control
UDP vs TCP, 3-way handshake, connection termination, flow control, and TCP congestion algorithms (Slow Start, Congestion Avoidance, Fast Recovery).
SYN/ACK sequence tracking, advertised window, cwnd and ssthresh dynamics.
Connect the transport service to the programming interface named in the GATE 2027 CS/IT syllabus.
Application Layer Protocols
DNS hierarchy and resolution (Iterative vs Recursive), HTTP persistent vs non-persistent RTT analysis, and electronic mail architecture (SMTP, POP3, IMAP).
Iterative vs recursive queries, HTTP/1.0 vs 1.1 pipelining, and RTT counting.
Network Security, Cryptography & Firewalls
Symmetric vs asymmetric ciphers, RSA public-key algorithm, Diffie-Hellman key exchange, SHA cryptographic hashes, digital signatures, and firewall packet filtering.
Symmetric vs asymmetric ciphers, RSA modular exponentiation, Diffie-Hellman, and packet-filtering firewalls.
B · GATE 2027 Syllabus Scope
Official syllabus scope and related lesson coverage; topics outside the syllabus are marked as enrichment.
- •Principles of layering: OSI and TCP/IP protocol stacks
- •Basics of packet switching, circuit switching, and delay analysis
- •Physical layer: Nyquist bit rate, Shannon-Hartley capacity formula, SNR dB conversions, transmission media
- •Data link layer: framing, error detection (CRC, checksum), flow control (Stop-and-Wait, GBN, SR)
- •Medium Access Control: ALOHA, CSMA/CD, Ethernet frame formats, transparent bridges, Spanning Tree Protocol (STP)
- •Network layer: IPv4 addressing, CIDR, subnetting, NAT, fragmentation
- •Routing algorithms: Distance Vector (RIP), Link State (OSPF), BGP path vector
- •Transport layer: UDP, TCP connection management, flow control, congestion control (Tahoe vs Reno)
- •Application layer: DNS resolution, HTTP persistent/non-persistent connections, SMTP, POP3
- •Network security: RSA public-key algorithm, Diffie-Hellman key exchange, SHA-256 digital signatures, firewalls
Interactive Labs & Verified PYQs
Revision & Rapid Review Sheets
Authoritative Textbooks & Video Lectures
All notes in this notebook cross-reference standard academic literature. We do not pretend student notes substitute for classical texts — they guide you through them.
Curated lectures from verified educators (Gate Smashers, Neso Academy, Knowledge Gate, and MIT OCW) selected specifically for difficult concept visualizations.
These notes are open and maintained together.
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