SIT202 Computer Networks Trimester 2, 2017
Page 14 of 14

SECTION B:

1. Draw an illustration of a topology indicating a PC (PC-A), connected to a router,
connected to a switch, connected to another (Server-B). Assuming that PC-A wishes
to establish a TELNET session with PC-B, illustrate the use of layers at each device in
the path, including which protocol is used at each layer. A reminder that TELNET is
an application layer protocol.

2. Consider two network layer protocols, one using a datagram approach, the second
using a virtual circuit approach. Describe, compare, and contrast how reliable
delivery and ordered delivery can be achieved in each system.

3. Demonstrate the calculation of the CRC for the following input:
Dataword: 10011100
Divisor: 1100

4. Consider the RIP and OSPF routing algorithms. Identify which of these two protocols
results in faster convergence and explain why.

5. Consider the go-back-n and selective retransmit approaches to error control.
Identify which of these approaches minimises the amount of buffer space (to store
required on the receiver’s side and explain why.



END OF EXAMINATION