index.md (1208B)
1 +++ 2 title = "MAC: Use in Wifi & Broadband" 3 +++ 4 5 # MAC: Use in Wifi & Broadband 6 **802.11 — WiFi** 7 8 - stations cannot detect collisions, relies on acknowledging to determine if collision occurred 9 - uses CSMA/CA (collision avoidance, not detection) 10 - inserts backoff slots to avoid collisions 11 - physical channel sensing: 12 - sense if channel is being used 13 - if yes, wait for it to be idle and then send 14 - virtual channel sensing: 15 - frames have a Network Allocation Vector indicating length of exchange 16 - simply wait until end of transmission 17 18 - frame format: 19 20  21 22 - power saving: 23 - beacon frames: client wakes up for every beacon and checks traffic map to see if there is buffered traffic that it can request 24 - automatic power save delivery (APSD): access point buffers frames and sends them to client right after client sends frames, then client goes to sleep 25 - authentication — WEP (Wired Equivalent Privacy), then WPA (Wifi Protected Access) and WPA2 26 27 **802.16 — Broadband Wireless** 28 29  30 