index.md (1097B)
1 +++ 2 title = "Shit I don't remember and need to remember" 3 +++ 4 5 # Shit I don't remember and need to remember 6 Layers: 7 Physical — digital bits as analog signals 8 Data link — frames of digital bits over one link 9 Network — packets of frames over multiple links 10 Transport — end-to-end packet delivery 11 Application — what the user needs 12 13 to compute hamming distance, xor the two bit strings and count the number of ones. 14 15  16 17 CDMA — code division multiple access, in physical layer with that chip sequence bullshit 18 19 CSMA — carrier sense multiple access, in mac protocol 20 difference in CSMA types (MAC protocol) 21 22 - 1-persistent — always listens to channel, sends as soon as idle 23 - nonpersistent — senses channel, if not idle waits a random period of time and tries again. does not always listen. 24 - p-persistent — some probability fuckshit 25 26 -