Chapter 5 Part 4 Computation

Chapter 5 Part 4 Computation

A) 10mbps Ethernet B) Bluetooth technology C) IEEE 802.11b D) IEEE 802.11g

1) Assume that the effective communication rate is 40% for all the above communication technologies. Also assume that the average size of a music file is 4MB per song. Estimate the time needed to download 15 songs.

A)
Effective Speed = 10mpbs * 40% = 10 (1,000,000) bps * 0.40 = 4,000,000 bps
Data Amount = 4MB * 15songs = 4 * 1024 * 1024 * 8 * 15 = 503,316,480 bits
Time = 503,316,480 bits / 4,000,000 bps = 125.83 seconds / 60 = 2.1 minutes

B)
Effective Speed = 1Mbps * 40% = 1 (1,000,000) bps * 0.40 = 400,000 bps
Data Amount = 4MB * 15songs = 4 * 1024 * 1024 * 8 * 15 = 503,316,480 bits
Time = 503,316,480 bits / 400,000 bps = 1258.29 seconds / 60 = 20.97 minutes

C)
Effective Speed = 11Mbps * 40% = 11 (1,000,000) bps * 0.40 = 4,400,000 bps
Data Amount = 4MB * 15songs = 4 * 1024 * 1024 * 8 * 15 = 503,316,480 bits
Time = 503,316,480 bits / 4,400,000 bps = 114.39 seconds / 60 = 1.91 minutes

D)
Effective Speed = 54Mbps * 40% = 54 (1,000,000) bps * 0.40 = 21,600,000 bps
Data Amount = 4MB * 15songs = 4 * 1024 * 1024 * 8 * 15 = 503,316,480 bits
Time = 503,316,480 bits / 4,400,000 bps = 23.30 seconds / 60 = .39 minutes

2) Except for communication speed, discuss other pros and cons of implementing those technologies. Based on your discussion, give your choice.

IEEE 802.11g is obviously the fastest but it can have interference with microwaves and cordless phones. IEEE 802.11b which is the second fastest has similar problems. Bluetooth is the slowest of the four options and has security issues. Ethernet seems to be the safest best. It is not extremely slower than IEEE 802.11b or IEEE 802.11g and it will definitely have less interference because it is hardwired. Therefore, I choose Ethernet as the most efficient way to transfer the songs.

3) Why Wimax is not being considered in this application?

WiMax is not being considered in this application because it is not readily available and is expensive. Companies are still working on it to make it a reality. WiMax is the next wave, not the current wave.