Attempt all the problems.

Section-A

problem1) describe three approaches to detecting errors, including how they work, probability of detecting an error, and any other benefits or limitations.

problem2) Give the aim of the following devices in relation to networking:

a) Access points

b) Routers

c) Network access cards

d) Server

problem3) describe the three ways of reducing errors and the type of noise they affect?

problem4) Describe three trends in communications and networking.

Section-B

Eureka! is a telephone and Internet-based check service which specializes in obtaining things which are hard to find (like Superbowl tickets, first edition books from 1500s, Faberge eggs).  It presently employs 60 staff who work 24 hours per day (over three shifts).  Staff answers the phone and respond to requests entered on Eureka! Web site.  Much of their work is spent on phone and on computers searching on the Internet.  What type of connections must Eureka! consider from its offices to outside world, in terms of phone and Internet?  Outline the pros and cons of each alternative below and make a recommendation.  Company has four alternatives:

problems :

problem1) Should it use traditional analog services, with standard voice lines, and use modems to dial into its ISP ($40 per month for each voice line plus $20 per month for each Internet access line)?

problem2) Should company use standard voice lines but use DSL for its data ($60 per month per line for both services)?

problem3) Should company separate its voice and data needs, using standard analog services for voice but finding some advanced digital transmission services for data ($40 per month for each voice line and $300 per month for a circuit with 1.5 Mbps of data)?

problem4) Should company search for all digital services for both voice and data ($60 per month for the all-digital circuit which provides two PCM phone lines which could be used for two voice calls, one voice call and one data call at 64 Kbps, or one data call at 128 Kbps)?