Computer Networks · topic
Single and two-dimensional parity, the Internet checksum with end-around carry, Hamming distance for detection and correction, Hamming check-bit count, and CRC: mod-2 long division worked bit by bit, the receiver check, and exactly which error patterns a generator is guaranteed to catch.
Single parity and what it misses, two-dimensional parity and the error patterns it detects, corrects and misses (checked exhaustively by script), the Internet checksum with one's-complement addition and end-around carry, computed on a real IPv4 header, Hamming distance and the bounds for detecting and correcting errors, the check-bit count of a Hamming code and a Hamming(7,4) encode and syndrome example.
A partial preview of the top of the sheet. The full sheet is in the Computer Networks cheat sheet pack.
Cyclic redundancy check for GATE CS: generator polynomials as bit strings, appending r zeros, mod-2 long division shown line by line, the receiver check and a detected one-bit error, a solved 2026 past question, and the guaranteed detection properties (single-bit, double-bit, odd-weight and burst errors) with the conditions on the generator, each confirmed by exhaustive enumeration in a script.
A partial preview of the top of the sheet. The full sheet is in the Computer Networks cheat sheet pack.
