August 2000
NI222 : NETWORKS AND THE INTERNET

QUESTION 1 (Compulsory)

Total Marks: 30 Marks

• Question 2
• Question 3
• Question 4
• Question 5
• Cover Page

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SUGGESTED SOLUTIONS
for Question 1

(a) Architecture, Algorithm and Implementation are the three aspects of computer networks. Briefly explain the following concepts, and identify to which aspect of networks they refer.
1. Shortest Path Routing [1]
2. EIA and RS232C [1]
3. TCP/IP for HP-UNIX [1]
4. ATM Network Model [1]
5. Congestion Control [1]
6. TCP/IP for Linux [1]

(b) Identify the main differences between the two Internet transport layer protocols TCP and UDP. [3]

(c) Although hosts on the Internet are identified using IP addresses, most network applications do not use IP addresses directly. Briefly explain what they do instead, and how this scheme is implemented. [3]

(d) Briefly describe three levels of hierarchy at which routers are used. [3]

(e) For each of the following examples of Internet Control Message Protocol
messages, identify to which class of ICMP message they belong to. [3]
-Echo request & reply
-TTL expired or bad port number
-Routing redirect

(f) Explain two reasons for using layered protocols, using examples to illustrate
your answer. [4]

(g) Describe two advantages and two disadvantages of having international
standards for network protocols. [4]

(h) IPv6 is gradually replacing the familiar IPv4. Explain two major differences in IPv6, giving reasons why the changes have been made. [4]