1 Wi-Fi Jason Orgill John Bodily Scott Rowberry

2 Background Purpose Develop MAC and PHY layer for wireless connectivity of fixed, portable and moving stations within a fixed area The higher OSI-layers are the same as in any other 802.X standard, this means that at this level there is no perceptible difference between wired and wireless media. When 1997 standard first published

3 Background – cont. Wi-Fi Alliance Major industry players formed an alliance in 1999 under the name of Wireless Ethernet Compatibility Alliance (WECA) to create interoperability standards Coined the term Wi-Fi Renamed to Wi-Fi Alliance in 2003 Establish the standards

Standards b Ratified in December 1999 Operates at 2.4 GHz Maximum throughput of 11 Mbps Actual throughput of 6.5 Mbps Typical Range of ~100 feet Uses Complementary Code Keying (CCK)

Standards – cont a Ratified in January 2000 Operates at 5 GHz Maximum throughput of 54 Mbps Actual throughput of 25 Mbps Typical range of ~100 feet Uses Orthogonal Frequency Division Multiplexing (OFDM)

Standards – cont g Ratified in January 2003 Operates at 2.4 GHz Maximum throughput of 54 Mbps Actual throughput of 25 Mbps Typical range of ~100 feet Uses Orthogonal Frequency Division Multiplexing (OFDM) Interoperable with b

Standards – cont n Yet to be ratified Operates at 2.4 GHz and 5 GHz Maximum throughput of 540 Mbps Actual throughput of 200 Mbps Typical range of ~165 feet Added Multiple Input – Multiple Output (MIMO)

8 Connectivity Modes Ad-Hoc Create Peer-to-peer networks Access Point Used to create hotspots where wi-fi devices can connect to the network Must have ethernet cable run to router/switch to access the network The router and switch will use this link for the wireless activity

9 Medium Access Control links the nodes Wi-fi nodes have transmission “gears” Link Layer Architecture: MAC BPSK – (for weakest signals) – 6-9 Mbps QPSK – (for weak signals) – Mbps QAM-16 – (for good signals) – Mbps QAM-64 – (for strongest signals) – Mbps Data Link (MAC) - Frames

10 Wi-Fi Security WEP – Wired Equivalency Privacy Easy to break WPA – WiFi Protected Access WPA2 MAC – Media Access Control Uses list of MACs to grant access

11 Any Questions?