Cisco Systems Interview Question Bank – Part 3

Cisco Systems Interview Question Bank continued from Part 2

Q : What is the sliding window concept in protocols?

A : The sliding window is an abstract concept that defines the range of sequence numbers that are the concern of the sender and receiver. According to this concept, sender has its own concerned set of frames that are to be sent at a time and receiver has its own set of frames to be received. The protocols working under this concept are – Stop & Wait ARQ, Go-Back-N ARQ and Selective Repeat ARQ protocols.

Q : What is throughput?

A : Throughput is the maximum data rate which is available to a user using a network. A channel may have a capacity of say, 5 Mbps but the throughput would be lesser than 5 Mbps.

Q : What is the difference between TCP and IP?

A : TCP (Transmission Control Protocol) is a basic, connection-oriented and reliable transport protocol of the Internet. It is a core protocol of the Internet Protocol Suite. In comparison to IP (Internet Protocol), TCP operates on relatively higher level and provides communication services at an intermediate level whereas IP is responsible for encapsulates all data and is connection-less. TCP adds reliability and connection-oriented features to the services of IP.

Q : What are the advantages of CMOS over NMOS?

A : The advantages of CMOS over NMOS include low propagation delay, low power dissipation and high fan-out as compared to NMOS.

Q : What is the difference between microprocessor and microcontroller?

A : Microprocessor is an integrated circuit that only has processor (i.e. CPU – Central Processing Unit) inside it and requires RAM, ROM, peripheral devices such as keyboard, seven-segments etc. to be externally interfaced to it. Microcontroller, on the other hand, has IO (Input/Output) pins, fixed amount of RAM and ROM in addition to a processor on the chip. Microprocessor is generic device that can be used for any purpose but microcontroller is task-specific and can only perform the task for which it has been designed.

Q : What is the advantage of synchronous circuits over asynchronous circuits?

A : In synchronous circuits, common clock is used in whole circuit but in asynchronous circuits, different clocks are used in the circuit as per the requirement of the logic. So, asynchronous circuits have more overhead data (for synchronization) than synchronous ones and careful attention to delays is needed in asynchronous circuits. Synchronous designs are simple to design, portable and more reliable. Also, synchronous circuits are more resistant to unexpected failure modes than the asynchronous designs.

(Continued to Part 4…)

Gautam Vashisht