August
1999 QUESTION 5 Total Marks: 20 Marks |
Click here to access other
questions
SUGGESTED SOLUTIONS |
| (a) | The Internet has seen explosive growth, but the vast majority of the world's population does not yet have access to it. Apart from the availability of power supplies and phone lines, what are seen as the two main obstacles blocking the general public out of full use of the Information Highway? | [4] |
| The Internet can only
be accessed through a computer. Computer costs are still relatively high, and a degree of
technical sophistication is still needed. The overwhelming majority of today's netizens use telephone lines via slow modems to access the Internet. The web is rich with multimedia content, and it is impossible to download much of it in real time with this technology.
|
||
| (b) | In designing better networks, asymmetric technologies are bring studied carefully. What does this mean, and why are they suitable for the average user? | [4] |
| Asymmetric
technologies deliver widely different bandwidth downstream (to the user) compared to
upstream (from the user). Most users 'consume' more information than they 'produce' .
Therefore, it is quite appropriate to offer such connections, as the chief bottleneck most
users experience is in download speed.
|
||
| (c) | Satellites can be used to deliver Internet
connectivity directly to end users. (i) Does this eliminate the need to an analog phone line and modem? Explain. (ii) Describe the drawbacks of using satellites in this way. |
[4] [4] |
| (i) No. The satellite offers only download capability, so a means of sending data and requests to the server (s) is still required, hence a phone line - or something equivalent - is still needed.
|
||
| (ii) Configuration and maintenance of satellite connection is non-trivial. Fixed connections are still needed; therefore the over-all technology is more complex. Throughput can still be a problem, because many users are sharing one satellite. This approach can accentuate other Internet bottlenecks, such as the server's connection speed/capacity.
|
||
| (d) | What is the difference between a 'cable modem' and a conventional modem? | [4] |
| A cable modem
incorporates a tuner to separate the data signal from the rest of the broadcast stream.;
network device components (functionality of bridges and routers); network management
software agents; encryption devices. Computer connects to cable modem via an Ethernet rather than a serial line, and appears therefore to be directly connected to the Internet. There are no numbers to dial.
|