Homework #3---Due October 10(Mon), 2005

1. Compare DSL(Digital Subscriber Loop) and Cable Modem in terms of the following aspects:

a) Speed(specify upload & download speeds)

b) Frequency Bandwidth usages & modulation methods, in other words, how do they send and receive data using the given channel bandwidths?

c) Describe how a DSL system can be installed in your house—necessary equipments, subscriptions to phone company, prices, …. What is the physical layer standard for DSL?

d) Describe how a Cable Modem system can be installed in your house—necessary equipments, subscriptions to cable company, prices, …. What is the physical layer standard for Cable Modem?

2. Make up a table for comparison of 3 generations of Ethernets. Compare the 3 generations in terms of Speed, Physical layer options(e.g. for 1^st generations; 10Base5, 10Base2, 10 BaseT, etc.), cable requirements(what kinds of cable needed?), Encoding methods, Network span(maximum distance), and current price per connection(also called as Per Port price).

3. Any layer(of OSI 7 layers or of TCP/IP protocols) may be designed to provide 3 (optional) services: Unacknowldeged Connectionless service, Acknowledged Connectionless service and Connection-Oriented service. Among them, since the second option(Acknowledged Connectionless service ) is not used, compare(pros and cons) of the remaining two:Unacknowldeged Connectionless service(sometimes called as “datagram service”) and Connection-Oriented service(sometimes called as “virtual circuit service”)