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Computer Networks
How data travels across the internet: layers, handshakes, routing and reliable delivery.
OSI & TCP/IP Layers
Follow one web request down the 7 layers of the sender, across the wire, and up the receiver — watching each layer add and remove its header in 3D.
CRC (Cyclic Redundancy Check)
A few check bits that let the receiver spot damaged frames. CRC is long division with XOR, and the remainder becomes the check bits.
Hamming Code
Parity bits at positions 1, 2, 4, 8… each watch a different group. When one bit flips, the failed checks spell out its position in binary.
Sliding Window Protocol
Send many frames before waiting for acknowledgements. Compare Stop-and-Wait, Go-Back-N and Selective Repeat when a frame gets lost — in 3D.
Subnetting & CIDR (IPv4)
Split an IP address into network bits and host bits. Find the mask, network, broadcast and usable hosts, then carve one network into subnets.
Routing Algorithms (Distance Vector)
How routers learn the best path to every network without seeing the whole map. Watch distance-vector tables update round by round in 3D.
TCP 3-Way Handshake
How two computers agree to start a reliable conversation — SYN, SYN-ACK, ACK — plus data acknowledgements and the 4-way close, as a 3D sequence diagram.
TCP Congestion Control
TCP probes for the right speed. The window doubles in slow start, grows by one per round in congestion avoidance, and backs off after a loss.
Token Bucket (Traffic Shaping)
Limit how fast a sender may transmit while still allowing short bursts. Tokens drip into a bucket and each packet spends one.
DNS Resolution
Follow a domain name from your browser through the resolver, root, TLD and authoritative servers until the IP address comes back.
About Computer Networks
Every web page you open travels through layers, handshakes and routers. Follow a request down the OSI and TCP/IP stacks, watch the TCP three-way handshake with real sequence numbers, see distance-vector routing converge, and compare Stop-and-Wait, Go-Back-N and Selective Repeat when a frame gets lost. Token buckets shape traffic and DNS resolution turns names into addresses.