a) What is Data communication? List and briefly describe the five main components of a data communication system.

b) Calculate the time required to transmit 1024 bytes of data using serial transmission at 9600 bps. Compare this with the time required for parallel transmission assuming an 8-bit parallel channel with a clock rate of 1 MHz.

a) Explain the concept of network topology. Briefly describe the following topologies: bus, star, ring and mesh.

b) Draw the seven layers architecture of OSI model and describe the main function of each layer.

a) Describe the various types of transmission impairments that can affect communication signals and what measures can be taken to mitigate these impairments.

b) What is Message switching? How does it differ from packet switching? Discuss the advantages and disadvantages of message switching.

a) Describe the different methods of framing in data communication. How do these methods help in error detection and data integrity.

b) A message "1011001" needs to be transmitted using a Longitudinal Redundancy Check (LRC). Show how the LRC code is generated and how it helps in error detection.

a) Explain the High-Level Data Link Control (HDLC) protocol. What are its main features and modes of operation?

b) Compare and contrast Token Bus and Token Ring LAN architectures.

a) Discuss the architecture and operation of the Distributed Queue Dual Bus (DQDB) protocol specified in the IEEE 802.6 standard. How does it support data transmission in a MAN?

b) What is Asynchronous Transfer Mode (ATM)? Describe its cell-based architecture and switching mechanisms.

a) Discuss the roles and functions of repeaters, bridges, gateways and other networking devices in a computer network.

b) Define link state routing. How does it differ from distance vector routing in terms of routing table updates and route calculation?

a) Line Encoding

b) Stop and Wait Protocol

c) FDDI

d) TCP/IP