CS-68 Computer Networks Test Paper

Q.1.
(a) How are dual-ring systems used to maintain a link when a station fails? Explain this with the help of a diagram.

(b) Why is a twisted paid not used for LAN connectivity?

(c) For n devices in a network, what is the number of cable links required for a mesh, ring and star topology, respectively.

(d) Explain the factors which will determine the length of the sliding window.

(e) What are three similarities and three differences between OSI and TCP reference models?

(f) Explain the connection establishment and multiplexing in the transport layer protocol.

(g) Explain any three QoS parameters of a transport layer protocol.

Q.2.
(a) If a size of a window is 3 bits, how many packets can be sent using Go Back N without getting an acknowledgement? Explain your answer.

(b) How does a store-and-forward system affect the delivery of data traffic? Explain this.

(c) UDP is a connectionless protocol. Why does its exist? Explain this.
(d) Explain the three differences between CSMA/CD and token ring protocol.

Q.3.
(a) Differentiate between Hubs, Switches and bridges.

(b) A System has n-layer protocol hierarchy. Applications generate a message of length M bytes. At each layer, an h-byte header is added. What fraction of the network bandwidth is filled with headers, and why?

(c) What are the two popular approaches to packet switching? Explain any one of these approaches with the help of a diagram.

Q.4.
(a) The physical service is a non-confirmed service. If some data bits are lost during transmission over the interconnecting media, which layer detects their loss and takes recovery action? Explain this.

(b) Explain Source Routing Bridges, and write the pseudocode for Source Routing Bridges. How are they different from Spanning Tree Bridges?

(c) Draw, and explain, the structure of an ATM cell.

Q.5.
(a) What is the difference between IDN and ISDN? Explain the basic services of ISDN. Describe five applications of ISDN.

CS-68 Computer Networks Test paper