CS1302 Computer Networks B.E Question Bank : niceindia.com

Name of the College : Noorul Islam College of Engineering
University : Anna University
Degree : B.E
Department : Computer Science and Engineering
Subject Code/Name : CS 1302 – Computer Networks
Document Type : Question Bank
Website : niceindia.com

Download :https://www.pdfquestion.in/uploads/ni…r_Networks.pdf

NICE Computer Networks Question Paper

Unit – I

Data Communication :
Part A :
1. What is mean by data communication? :
Data communication is the exchange of data (in the form of 1s and 0s) between two devices via some form of transmission medium (such as a wire cable).

Related : Noorul Islam College of Engineering XCS353 Computer Networks M.Sc Question Bank : www.pdfquestion.in/3143.html

2. What are the three criteria necessary for an effective and efficient network? :
The most important criteria are performance, reliability and security. Performance of the network depends on number of users, type of transmission medium, the capabilities of the connected h/w and the efficiency of the s/w. Reliability is measured by frequency of failure, the time it takes a link to recover from the failure and the network’s robustness in a catastrophe. Security issues include protecting data from unauthorized access and viruses.

3. What are the three fundamental characteristics determine the effectiveness of the data communication system? :
The effectiveness of the data communication system depends on three fundamental characteristics :
Delivery : The system must deliver data to the correct destination.
Accuracy : The system must deliver data accurately.
Timeliness : The system must deliver data in a timely manner.

4. What are the advantages of distributed processing? :
Advantages of distributed processing include security/encapsulation, distributed databases, faster problem solving, security through redundancy and collaborative processing.

5. Why are protocols needed? :
In networks, communication occurs between the entities in different systems. Two entities cannot just send bit streams to each other and expect to be understood. For communication, the entities must agree on a protocol. A protocol is a set of rules that govern data communication.

6. Why are standards needed? :
Co-ordination across the nodes of a network is necessary for an efficient communication. If there are no standards, difficulties arise. A standard provides a model or basis for development to which everyone has agreed.

7. For n devices in a network, what is the number of cable links required for a mesh and ring topology? :
Mesh topology – n (n-1)/2
Ring topology – n

8. What is the difference between a passive and an active hub? :
An active hub contains a repeater that regenerates the received bit patterns before sending them out. A passive hub provides a simple physical connection between the attached devices.

9. Distinguish between peer-to-peer relationship and a primary-secondary relationship :
Peer-to-peer relationship : All the devices share the link equally.
Primary-secondary relationship : One device controls traffic and the others must transmit through it.

10. Assume 6 devices are arranged in a mesh topology. How many cables are needed? : How many ports are needed for each device?:
Number of cables=n (n-1)/2=6(6-1)/2=15
Number of ports per device=n-1=6-1=5

UNIT-II

Data Link Layer
1.What are the responsibilities of data link layer? Specific responsibilities of data link layer include the following.
a) Framing
b) Physical addressing
c) Flow control
d) Error control
e) Access control

2. Mention the types of errors.
There are 2 types of errors
a) Single-bit error.
b) Burst-bit error.

3. Define the following terms.
Single bit error: The term single bit error means that only one bit of a given data unit (such as byte character/data unit or packet) is changed from 1 to 0 or from 0 to 1.
Burst error: Means that 2 or more bits in the data unit have changed from 1 to 0 from 0 to 1.

4. What is redundancy?
It is the error detecting mechanism, which means a shorter group of bits or extra bits may be appended at the destination of each unit.

5. List out the available detection methods.
There are 4 types of redundancy checks are used in data communication.
a) Vertical redundancy checks (VRC).
b) Longitudinal redundancy checks (LRC).
c) Cyclic redundancy checks (CRC).
d) Checksum.

UNIT III

NETWORK LAYER
1. What are the network support layers and the user support layers?
Network support layers:
The network support layers are Physical layer, Data link layer and Network layer. These deals with electrical specifications, physical connection, transport timing and reliability.

User support layers:
The user support layers are: Session layer, Presentation layer, Application layer. These allow interoperability among unrelated software system.

2. With a neat diagram explain the relationship of IEEE Project to the OSI model?
layer into two sub layers:
* Logical link control (LLC)
* Medium access control (MAC)
LLC is non-architecture specific. The MAC sub layer contains a number of distinct modules, each carries proprietary information specific to the LAN product being used.

3. What are the functions of LLC?
The IEEE project 802 models takes the structure of an HDLC frame and divides it into 2 sets of functions. One set contains the end user portion of the HDLC frame – the logical address, control information, and data. These functions are handled by the IEEE 802.2 logical link control (LLC) protocol.

4. What are the functions of MAC?
MAC sub layer resolves the contention for the shared media. It contains synchronization, flag, flow and error control specifications necessary to move information from one place to another, as well as the physical address of the next station to receive and route a packet.

5. What is protocol data unit?
The data unit in the LLC level is called Protocol Data Unit (PDU). It contains four fields.
• Destination Service Point Address (DSAP)
• Source Service Access Point
• Control field
• Information field