Question
Your cousin Cathy runs a part-time business out of her apartment. She buys and sells collectibles such as antique prints, baseball cards, and cartoon cells and has recently discovered the Web with its many auction sites. She has begun buying and selling on the Web by bidding on collectibles at lesser-known sites and selling them at a profit at more well-known sites. She downloads and uploads lots of graphics (pictures of the items she’s buying and selling). She is getting frustrated with the slow Internet access she has with her 56-Kbps dial-up modem and asks you for advice. DSL is available at a cost of $60 per month for 1.5 Mbps down and 384 Kbps up. Cable modem service is available for a cost of $50 per month for 1.5 Mbps down and 640 Kbps up. Wireless DSL is available in her apartment building for $45 per month for 1.5 Mbps down and 256 Kbps up. Explain the differences in these services and make a recommendation.
Answer
When it comes to DSL (Digital Subscriber Line) it is a point to point technology that provides high-speed data transmission over traditional telephone lines. The reason for the limited capacity on traditional telephone circuits lies with the telephone and the switching equipment at the end offices. With DSL the shorter the distance, the higher the speed, because with a shorter distance, the circuit suffers less attenuation and higher-frequency signals can be used, providing a greater bandwidth for modulation. With the speed of 1.5 Mbps down and 384 Kbps up the maximum length of the local loop is 18,000 feet which is better than cable modem.
The Cable modem architecture is very similar to DSL with one very important difference. DSL is a point-to-point technology whereas cable modems use shared multipoint circuits. With cable modems, each user must compete with other users for the available capacity. Furthermore, because the cable circuit is a multipoint circuit, all messages on the circuit
Cited: Fitzgerald, J., Dennis, A. (2009). Business Data Communications and Networking (10th). Wiley. John Wiley & Sons, Inc