Computer Networking Fundamentals

Establishes the vocabulary and structural models that define how computers communicate — the network edge and core, performance, and layered architectures.

1. 1.1The Network Edge and Core: End systems, access networks, packet vs. circuit switching Watch free
2. 1.2Performance Metrics: Delay, loss, and throughput Watch free
3. 1.3Layered Architectures: The OSI 7-Layer and TCP/IP 4-Layer models Watch free
4. 1.4Encapsulation: How data is wrapped and unwrapped down and up the stack Watch free
5. 1.5Transmission vs. Propagation Delay (transmission delay = L / R) Watch free

How raw bits become physical signals, and how local devices share a common medium without talking over one another.

1. 2.1Physical Media: Copper wires, fiber optics, and radio spectrum
2. 2.2Signal Theory: Nyquist bit rate and Shannon capacity, C = B · log2(1 + S/N)
3. 2.3Error Detection: Parity checks, checksums, and Cyclic Redundancy Checks (CRC)
4. 2.4Multiple Access Protocols: CSMA/CD (Ethernet) and collision domains
5. 2.5LANs: MAC addressing, ARP (Address Resolution Protocol), and Layer 2 switching

The most in-depth module — how packets navigate the global internet across distinct networks.

1. 3.1The Data Plane vs. Control Plane: Forwarding packets vs. routing logic
2. 3.2Internet Protocol (IP): IPv4 packet format, fragmentation, and the move to IPv6
3. 3.3IP Addressing & Subnetting: CIDR and bitwise subnet masks
4. 3.4Network Address Translation (NAT)
5. 3.5Link-State Routing: Dijkstra's Algorithm
6. 3.6Distance-Vector Routing and the Bellman-Ford equation: Dx(y) = min over v of { c(x,v) + Dv(y) }

How the network provides process-to-process communication and manages reliability.

1. 4.1Multiplexing & Demultiplexing: Ports and sockets
2. 4.2Connectionless Transport (UDP): Best-effort delivery for streaming and gaming
3. 4.3Connection-Oriented Transport (TCP): The 3-way handshake, sequence numbers, and teardown
4. 4.4Reliable Data Transfer: Stop-and-Wait, Go-Back-N, and Selective Repeat
5. 4.5TCP Congestion Control: AIMD (Additive Increase/Multiplicative Decrease), Slow Start, and fairness

The top of the stack — the protocols that power the software users interact with every day.

1. 5.1The Web and HTTP: HTTP/1.1, HTTP/2, cookies, and caching mechanisms
2. 5.2Domain Name System (DNS): Hierarchical namespaces, iterative vs. recursive queries, and records
3. 5.3Electronic Mail: SMTP, POP3, and IMAP
4. 5.4Peer-to-Peer (P2P): BitTorrent architecture and distributed hash tables
5. 5.5Socket Programming: A multi-threaded client-server chat application in Python or Java

Unplugging the cables introduces high bit error rates, fading, and mobility challenges.

1. 6.1Wireless Characteristics: Signal attenuation, multipath propagation, and the hidden terminal problem
2. 6.2Wi-Fi (802.11): CSMA/CA (Collision Avoidance), RTS/CTS frames, and beaconing
3. 6.3Cellular Networks: Architecture from 3G to 4G (LTE) and 5G
4. 6.4Mobility Management: Mobile IP, handoffs between base stations, and roaming

Security treated as a foundational element of networking, not an afterthought.

1. 7.1Principles of Cryptography: Symmetric (AES) vs. public-key (RSA) encryption
2. 7.2Message Integrity: Cryptographic hash functions and digital signatures
3. 7.3Securing Applications & Transport: SSL/TLS handshakes and HTTPS
4. 7.4Securing the Network Layer: IPsec and Virtual Private Networks (VPNs)
5. 7.5Operational Security: Firewalls, Intrusion Detection Systems (IDS), and common attacks (DDoS, sniffing, spoofing)

How the industry evolved from manually configuring physical routers to programming virtual networks.

1. 8.1Inter-Domain Routing: Border Gateway Protocol (BGP) and internet peering policies
2. 8.2Software-Defined Networking (SDN): Decoupling the control plane and the OpenFlow protocol
3. 8.3Data Center Networking: Clos network topologies and load balancing
4. 8.4Cloud Networking: Virtual Private Clouds (VPCs) and network virtualization