1. VoIP over 802.11b (Part 2)

3. Bandwidth Usage  How do we determine the the maximum amount of bandwidth for one call?  Account for constant signals (Beacons)  Theoretcial and Experimental Calculation Account for the packets that theoretically should be transmitted for one call Account for the packets that theoretically should be transmitted for one call Use a packet Sniffer to sniff packets on the wireless link and calculate the bandwidth consumed Use a packet Sniffer to sniff packets on the wireless link and calculate the bandwidth consumed

4. Beacons  Frequency 100ms  Packet Size = 240 bytes  Beacons/sec= 1/.1 = 10/sec  (10*240bytes*8bits)/10 6 = 0.0192Mbit/sec

5. 1 Call Theoretical Bandwidth  50 Packets/sec Voice Data  G.711  Total bytes to transmit all voice packets = (100 * 380) + (102 * 158) + 221 + 226=54563 bytes/sec  Theoretical Bandwidth of one call = (54563*8) / 10 6 = 0.436504 Mbit/sec

6. 1 Call Experimental BW Compare to 0.455704 Mbit / Sec

7. 2 Call Theoretical BW  Theoretically expected value = (2 * 0.436504) + 0.0192 = 0.892208 Mbit/sec

8. 2 Call Experimental BW Compare to 0.892208 Mbit / sec

9. Future  Continue the research on maximum calls supportable by 802.11b and use a packet generator to simulate the phone traffic  Use results as part of a paper on VoIP over a wifi network