🌐Computer Networks Notes

Computer Networks (CN)

Zero-fluff engineering notes, layered architecture deep-dives, protocol packet traces, and high-yield interview frameworks for university semester exams, engineering foundations, and technical placement rounds.

10Modules

42Topics

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Introduction & Network Architectures

Data communication components, network criteria, transmission modes, physical topologies, OSI 7-layer architecture, and transmission media.

1.1Network Fundamentals & Data Communication→1.2Network Topologies & Connection Types→1.3The OSI Reference Model & 7-Layer Architecture→1.4Physical Layer & Transmission Media→

Module 025 Topics

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Data Link Layer: Framing, Flow & Error Control

Bit-oriented and byte-oriented framing, stop-and-wait, sliding window protocols (GBN, Selective Repeat), and CRC error detection.

2.1Data Link Layer Responsibilities & Framing Techniques→2.2Error Detection: Parity, Checksum & Cyclic Redundancy Check (CRC)→2.3Flow Control: Stop-and-Wait ARQ & Efficiency Derivation→2.4Sliding Window Protocol: Go-Back-N (GBN) ARQ→2.5Sliding Window Protocol: Selective Repeat (SR) ARQ→

Module 035 Topics

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Data Link Layer: MAC Sublayer & Ethernet

Multiple access protocols (ALOHA, CSMA/CD, CSMA/CA), collision domains, Ethernet frame format, and transparent bridging.

3.1Random Access Protocols: Pure ALOHA & Slotted ALOHA→3.2CSMA, CSMA/CD & Exponential Backoff Algorithm→3.3Ethernet Frame Format (IEEE 802.3) & Minimum Frame Size→3.4Controlled Access & Channelization: Token Ring, FDMA, TDMA, CDMA→3.5Network Switching: Bridges, Collision vs Broadcast Domains→

Module 046 Topics

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Network Layer: IPv4/IPv6 Addressing & Subnetting

Classful vs classless addressing (CIDR), variable length subnet masking (VLSM), IPv4 header analysis, and NAT translation.

4.1Network Layer Core Goals & Virtual Circuits vs Datagrams→4.2Classful IP Addressing (Classes A, B, C, D, E) & Special Addresses→4.3Classless Inter-Domain Routing (CIDR) & Subnetting→4.4Variable Length Subnet Masking (VLSM) & Route Aggregation→4.5IPv4 Datagram Header Format, Flags & Fragmentation Mechanics→4.6Network Address Translation (NAT) & IPv6 Header Architecture→

Module 056 Topics

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Network Layer: Routing Protocols & Control Plane

Intra-domain and inter-domain routing, Distance Vector (Bellman-Ford), Link State (Dijkstra), Count-to-Infinity, and ICMP.

5.1Shortest Path Routing: Distance Vector Routing & Bellman-Ford→5.2Count-to-Infinity Problem, Split Horizon & Poison Reverse→5.3Link State Routing (Dijkstra's Algorithm) & OSPF Internals→5.4Border Gateway Protocol (BGP) & Path Vector Routing→5.5Internet Control Message Protocol (ICMP) & Ping / Traceroute→5.6Address Resolution Protocol (ARP) & Reverse ARP (RARP)→

Module 065 Topics

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Transport Layer: UDP, TCP & Connection Flow

Process-to-process multiplexing, port numbers, User Datagram Protocol (UDP), TCP segment format, and 3-way handshake.

6.1Transport Layer Services & Port Addressing Architecture→6.2User Datagram Protocol (UDP): Header Format & Lightweight Delivery→6.3Transmission Control Protocol (TCP): Segment Header Structure→6.4TCP Connection Management: 3-Way Handshake & 4-Way Teardown→6.5TCP State Machine & TIME_WAIT Socket Mechanics→

Module 075 Topics

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Transport Layer: Congestion Control & Reliability

TCP flow control vs congestion control, Slow Start, Congestion Avoidance, Fast Retransmit, Fast Recovery, and TCP timers.

7.1Congestion Principles & Leaky Bucket / Token Bucket Algorithms→7.2TCP Sliding Window Flow Control & Silly Window Syndrome→7.3TCP Congestion Control: AIMD, Slow Start & Thresholds→7.4Fast Retransmit & Fast Recovery (TCP Tahoe vs TCP Reno)→7.5TCP Retransmission Timers, Karn's Algorithm & Round Trip Estimation→

Module 085 Topics

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Application Layer Protocols

Client-server architecture, Domain Name System (DNS), HTTP/1.1 vs HTTP/2 vs HTTP/3, email protocols (SMTP, IMAP, POP3), and FTP.

8.1Client-Server Architecture vs Peer-to-Peer (P2P)→8.2Domain Name System (DNS): Hierarchical Namespaces & Resolution→8.3Hypertext Transfer Protocol: HTTP/1.0, HTTP/1.1, HTTP/2 & QUIC→8.4Electronic Mail Protocols: SMTP, POP3 & IMAP4 Architecture→8.5File Transfer Protocol (FTP) & Dynamic Host Configuration (DHCP)→

Module 096 Topics

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Network Security & Cryptography

Symmetric vs asymmetric encryption, RSA mathematics, digital signatures, hash functions, TLS/SSL handshakes, and firewalls.

9.1Network Security Foundations: Confidentiality, Integrity & Availability→9.2Symmetric Key Cryptography: DES & Advanced Encryption Standard (AES)→9.3Asymmetric Key Cryptography: Diffie-Hellman & RSA Algorithm→9.4Cryptographic Hash Functions (SHA-256) & Digital Signatures→9.5Public Key Infrastructure (PKI), Digital Certificates & TLS/SSL→9.6Firewalls (Packet Filtering, Stateful Inspection) & IDS/IPS→

Module 104 Topics

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Physical Layer Devices & Wireless Networks

Modulation techniques, Nyquist and Shannon theorems, repeaters, hubs, Wi-Fi architectures (IEEE 802.11), and Bluetooth.

10.1Data Rate Limits: Nyquist Bit Rate & Shannon Channel Capacity→10.2Digital-to-Digital Encoding: NRZ, Manchester & Differential Manchester→10.3Physical Layer Hardware: Repeaters, Active Hubs & Modems→10.4Wireless LANs: IEEE 802.11 Architecture, CSMA/CA & RTS/CTS Handshake→

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