Computer Networks - CS3591 - Question Bank and Important 2 Marks Questions with Answer.pdf

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DEPARTMENT OF COMPUTER SCIENCE & ENGINEERING
CS3591– COMPUTER NETWORKS
Question Bank
III YEAR – V SEM
BATCH: 2021 -2025
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2
Vision of Institution
To build Jeppiaar Engineering College as an Institution of Academic Excellence in Technical
education and Management education and to become a World Class University.
Mission of Institution
M1 To excel in teaching and learning, research and innovation by promoting the principles
of scientific analysis and creative thinking
M2
To participate in the production, development and dissemination of knowledge and
interact with national and international communities
M3
To equip students with values, ethics and life skills needed to enrich their lives and
enable them to meaningfully contribute to the progress of society
M4 To prepare students for higher studies and lifelong learning, enrich them with the
practical and entrepreneurial skills necessary to excel as future professionals and
contribute to Nation’s economy
Program Outcomes (POs)
PO1
Engineering knowledge: Apply the knowledge of mathematics, science,
engineering fundamentals, and an engineering specialization to the solution of
complex engineering problems.
PO2
Problem analysis: Identify, formulate, review research literature, and analyze
complex engineering problems reaching substantiated conclusions using first
principles of mathematics, natural sciences, and engineering sciences.
PO3
Design/development of solutions: Design solutions for complex engineering
problems and design system components or processes that meet the specified
needs with appropriate consideration for the public health and safety, and the
cultural, societal, and environmental considerations
PO4
Conduct investigations of complex problems: Use research-based knowledge
and research methods including design of experiments, analysis and
interpretation of data, and synthesis of the information to provide valid
conclusions.
PO5
Modern tool usage: Create, select, and apply appropriate techniques, resources,
and modern engineering and IT tools including prediction and modeling to
complex engineering activities with an understanding of the limitations.
PO6
The engineer and society: Apply reasoning informed by the contextual
knowledge to assess societal, health, safety, legal and cultural issues and the
consequent responsibilities relevant to the professional engineering practice.
PO7
Environment and sustainability: Understand the impact of the professional
engineering solutions in societal and environmental contexts, and demonstrate
the knowledge of, and need for sustainable development.
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PO8
Ethics: Apply ethical principles and commit to professional ethics and
responsibilities and norms of the engineering practice.
PO9
Individual and team work: Function effectively as an individual, and as a
member or leader in diverse teams, and in multidisciplinary settings.
PO10
Communication: Communicate effectively on complex engineering activities
with the engineering community and with society at large, such as, being able to
comprehend and write effective reports and design documentation, make
effective presentations, and give and receive clear instructions.
PO11
Project management and finance: Demonstrate knowledge and understanding
of the engineering and management principles and apply these to one’s own
work, as a member and leader in a team, to manage projects and in
multidisciplinary environments.
PO12
Life-long learning: Recognize the need for, and have the preparation and ability
to engage in independent and life-long learning in the broadest context of
technological change.
Vision of Department
To emerge as a globally prominent department, developing ethical computer professionals,
innovators and entrepreneurs with academic excellence through quality education and research.
Mission of Department
M1
To create computer professionals with an ability to identify and formulate the
engineering problems and also to provide innovative solutions through effective teaching
learning process.
M2 To strengthen the core-competence in computer science and engineering and to create
an ability to interact effectively with industries.
M3 To produce engineers with good professional skills, ethical values and life skills for the
betterment of the society.
M4 To encourage students towards continuous and higher-level learning on technological
advancements and provide a platform for employment and self-employment.
Program Educational Objectives (PEOs)
PEO1 To address the real time complex engineering problems using innovative approach
with strong core computing skills.
PEO2 To apply core-analytical knowledge and appropriate techniques and provide
solutions to real time challenges of national and global society
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PEO3 Apply ethical knowledge for professional excellence and leadership for the
betterment of the society.
PEO4 Develop life-long learning skills needed for better employment and entrepreneurship
PROGRAMME SPECIFIC OUTCOME(PSOs)
PSO1 – An ability to understand the core concepts of computer science and engineering and to
enrich problem solving skills to analyze, design and implement software and hardware based
systems of varying complexity.
PSO2 - To interpret real-time problems with analytical skills and to arrive at cost effective and
optimal solution using advanced tools and techniques.
PSO3 - An understanding of social awareness and professional ethics with practical proficiency
in the broad area of programming concepts by lifelong learning to inculcate employment and
entrepreneurship skills
BLOOM TAXANOMY LEVELS
BTL1: Remembering
BTL2: Understanding.,
BTL3: Applying.,
BTL4: Analyzing.,
BTL5: Evaluating.,
BTL6: Creating.,
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CS3591-Computer Networks 2023-2024
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SYLLABUS
CS3591 COMPUTER NETWORKS L T P C 3 0 2 4
UNIT I INTRODUCTION AND APPLICATION LAYER 10
Data Communication - Networks - Network Types - Protocol Layering - TCP/IP Protocol suite - OSI
Model - Introduction to Sockets - Application Layer protocols: HTTP - FTP - Email protocols (SMTP -
POP3 - IMAP - MIME) - DNS - SNMP
UNIT II TRANSPORT LAYER 9
Introduction - Transport-Layer Protocols: UDP - TCP: Connection Management - Flow control -
Congestion Control - Congestion avoidance (DECbit, RED) - SCTP - Quality of Service
UNIT III NETWORK LAYER 7
Switching: Packet Switching - Internet protocol - IPV4 - IP Addressing - Subnetting - IPV6, ARP, RARP,
ICMP, DHCP
UNIT IV ROUTING 7
Routing and protocols: Unicast routing - Distance Vector Routing - RIP - Link State Routing - OSPF
- Path-vector routing - BGP - Multicast Routing: DVMRP - PIM.
UNIT V DATA LINK AND PHYSICAL LAYERS 12
Data Link Layer - Framing - Flow control - Error control - Data-Link Layer Protocols - HDLC - PPP -
Media Access Control - Ethernet Basics - CSMA/CD - Virtual LAN - Wireless LAN (802.11)
- Physical Layer: Data and Signals - Performance - Transmission media- Switching - Circuit Switching.
45 PERIODS
COURSE OUTCOMES:
At the end of this course, the students will be able to:
CO 1: Explain the basic layers and its functions in computer networks.
CO 2: Understand the basics of how data flows from one node to another.
CO 3: Analyze different routing algorithms.
CO 4: Describe protocols for various functions in the network.
CO 5: Analyze the working of various application layer protocols.
TEXT BOOKS
1. James F. Kurose, Keith W. Ross, Computer Networking, A Top-Down Approach Featuring the
Internet, Eighth Edition, Pearson Education, 2021.
2. Behrouz A. Forouzan, Data Communications and Networking with TCP/IP Protocol Suite, Sixth
Edition TMH, 2022
REFERENCES
1. Larry L. Peterson, Bruce S. Davie, Computer Networks: A Systems Approach, Fifth Edition, Morgan
Kaufmann Publishers Inc., 2012.
2. William Stallings, Data and Computer Communications, Tenth Edition, Pearson Education, 2013.
3. Nader F. Mir, Computer and Communication Networks, Second Edition, Prentice Hall, 2014.
4. Ying-Dar Lin, Ren-Hung Hwang, Fred Baker, “Computer Networks: An Open Source Approach”,
McGraw Hill, 2012.
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CS3591: ComputerNetworks
Corresponding Lab, with code (If any): Nil
Course Prerequisites: -
Course Outcomes
On successful completion of this course, the student will be able to
C301.1 Understand the concept of layering in networks and basic application layer protocols
C301.2 Familiar with the Transport layer protocols like UDP, TCP and SCTP and their functions
C301.3 Understand switching in Internet, IP addressing protocol versions 4 and 6, Supporting
C301.4 Intra domain routing and Inter domain routing protocols and multicast routing protocols
C301.5 Familiar with the services provided by Datalink layer and Physical Layer.
MAPPING BETWEEN CO AND PO, PSO WITH CORRELATION LEVEL 1/2/3
CS3591
Pos PSOs
PO1 PO2 PO3 PO4 PO5 PO6 PO7 PO8 PO9 PO10 PO11 PO12 PSO1 PSO2 PSO3 PSO4
C301.1 - 2 - - - - - - - - - - 3 2 2 2
C301.2 - 1 - - 2 - - - - - - 2 2 2 2 2
C301.3 - 2 - - 3 - - - - - - - 3 3 2 2
C301.4 - - - 1 2 - - - - 3 - - 3 3 2 1
C301.5 - 1 - - 1 - - - - 1 - - 2 1 2 2
RELATION BETWEEN COURSE CONTENT WITH Cos
UNIT I-INTRODUCTION AND APPLICATION LAYER
S. No Topic
Knowledge
level
No. of Hrs to
be handled
Books
Referred
1. Data Communication – Networks L2 1 T2
2. Network Types L2 1 T2
3. Protocol Layering L2 1 T2
4. TCP/IP Protocol suite L2 1 T2
5. OSI Model L2 2 T2
6. Introduction to Sockets L1, L2 2 T2
7. Application Layer Protocols – HTTP – FTP L2 2 T2
8. Email Protocols (SMTP – POP3 – IMAP –
MIME)
L2
1 T2
9. DNS – SNMP L2 2 T2
UNIT II-TRANSPORT LAYER
S. No Topic
Knowledge
level
No. of Hrs to
be handled
Books
Referred
1. Introduction – Transport Layer Protocols L1, L2 1 T2
2. UDP L2 2 T2
3. TCP: Connection Management, Flow control L2 2 T2
4. Congestion Control L2 2 T2
5. Congestion Avoidance – DECbit, RED L2 1 R1
6. SCTP L2 1 T2
7. Quality of Service L2 1 T2
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UNIT III-NETWORK LAYER
S. No Topic
Knowledge
level
No. of Hrs to
be handled
Books
Referred
1. Switching - Packet switching L2 2 T2
2. Internet Protocol – Ipv4 L1,L2 1 T2
3. IP Addressing L2 2 T2
4. Subnetting L1,L2,L3 1 T2
5. IPv6 L2 2 T2
6. APR, RARP L2 1 T2
7. ICMP, DHCP L2 2 T2
UNIT IV-ROUTING
S. No Topic
Knowledge
level
No. of Hrs to
be handled
Books
Referred
1. Routing and Protocols L1,L2 1 T2
2. Unicast Routing – Distance Vector Routing L2 1 T2
3. RIP L2 1 T2
4. Link State Routing – OSPF L2 2 T2
5. Path Vector Routing L2 1 T1
6. BGP L2 1 R1
7. Multicast Routing: DVMRP, PIM L2 2 T2
UNIT V-DATALINK AND PHYSICAL LAYER
S. No Topic
Knowledge
level
No. of Hrs to
be handled
Books
Referred
1. Datalink Layer – Framing L2 1 T2
2. Flow control, Error control L2 2 T2
3. Datalink layer Protocols – HDLC, PPP L2 2 T2
4. Media Access Control – Ethernet Basics L2 1 T2
5. CSMA/CD, Virtual LAN L2 2 T2
6. Wireless LAN (IEEE802.11) L2 2 T2
7. Physical Layer – Data and Signals, L2 1 T2
8. Transmission Media L2 2 T2
9. Switching – Circuit Switching L2 2 T2
L1- Remember; L2- Understand; L3- Apply; L4- Analyze; L5- Evaluate; L6- Create
S. No Content beyond syllabus PO Mapping PSO Mapping
1. Network Security – Cryptography PO5 PSO2
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UNIT I INTRODUCTION AND APPLICATION LAYER
Data Communication - Networks - Network Types - Protocol Layering - TCP/IP Protocol suite - OSI
Model - Introduction to Sockets - Application Layer protocols: HTTP - FTP - Email protocols (SMTP -
POP3 - IMAP - MIME) - DNS - SNMP
PART-A CO
Stmt
Knowledge
Level(R/U/Ap
/An/E/C)
1 Compare LAN and WAN.
C301.1
BL2
LAN WAN
Scope of Local Area Network
is restricted to a small/ single
building
Scope of Wide Area Network
spans over large geographical area
country/ Continent
LAN is owned by some
organization.
A part of network asserts is owned
or not owned.
Data rate of LAN 10-.10-
100mbps.
Data rate of WAN is Gigabyte.
2 Define Full Duplex and simplex transmission system.
With Full duplex transmission, two stations can simultaneously
send and receive data from each other. This mode is known as
two-way simultaneous. The signals are transmitted in only one
direction. One is the sender and another is the receiver.
C301.1 BL1
3 Define networks. (Nov 12)
A computer network is a group of computer systems and other
computing hardware devices that are linked together through
communication channels to facilitate communication and
resource-sharing among a wide range of users. Networks are
commonly categorized based on their characteristics.
C301.1 BL1
4 Why do we need a Domain Name System? What role does the
DNS Resolver play in the DNS system? (Nov 12)
Domain Name System can map a name to an address and
conversely an address to name. The Domain Name System
converts domain names into IP numbers. IP numbers uniquely
identify hosts on the Internet
C301.1 BL2
5 What are the four fundamental characteristics that the data
communication system depends on?
The four fundamental characteristics are: Delivery, Accuracy,
Timeliness and Jitter.
C301.1 BL2
6 What are the five components of data communications system?
The five components are Message, Sender, Receiver, Transmission
Medium and Protocol.
C301.1 BL2
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7 Define link and state the types of connection.
A link is the communication pathway that transfers data from one
device to another. The two possible types of connections are point
to point and multipoint
C301.1 BL1
8 Define point to point and Multipoint.
Point to point: A point to point connection provides a dedicated
link between two devices.
Multipoint: A multipoint connection is one in which more than
two specific devices share a single link.
C301.1 BL1
9 What is Network topology? List its types.
Network topology is the interconnected pattern of network
elements. A network topology may be physical, mapping
hardware configuration, or logical, mapping the path that the data
must take in order to travel around the network. The types are Bus
topology, Star topology, Mesh topology and Ring Topology.
C301.1 BL1
10 What are the four main properties of HTTP?
 Global Uniform Resource Identifier.
 Request-response exchange.
 Statelessness.
 Resource metadata.
C301.1 Bl1
11 What is a protocol? What are the key elements of a protocol? (Nov
15)
Protocol is the set of rules governing the exchange of data between
two entities. It defines what is communicated, how it is
communicated, when it is communicated. The Key elements of a
Protocol are as follows,
 Syntax – It refers to the structure or format of data meaning the
order in which they are presented.
 Semantics – It refers to the meaning of each section of bit. How
to do interpretation.
 Timing – When data should be sent and how fast they can be
sent.
C301.1 BL1
12 Define File Transfer Protocol. (Nov 21)
The File Transfer Protocol is a standard communication protocol
used for the transfer of computer files from a server to a client on
a computer network. FTP is built on a client–server model
architecture using separate control and data connections between
the client and the server.
C301.1 BL1
13 What is WWW and SMTP? (Nov 10,15 ) (May 15)
World Wide Web is an internet application that allows user to view
pages and move from one web page to another.
C301.1 R
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It helps to store and share data across varied distances. The
TCP/IP protocol that supports electronic mail on the Internet is
called Simple Mail Transfer (SMTP). It is a system for sending
messages to other computer users based on e-mail addresses.
14 List the two types of DNS message. (May 16)
There are two types of DNS messages – Query and Response
 Query message – consists of the header and question records.
 Response message – consists of header, question record,
authoritative record and additional record.
C301.1 BL1
15 What is a layered Network Architecture?
A layer is created when a different level of abstraction occurs at
protocol. Each layer should perform a well-defined function.
Function of each layer should be chosen using internationality
standardized protocols. Boundaries between should be chosen to
minimize information flow across the interfaces.
C301.1 BL1
16 Compare OSI and TCP/IP models. C301.1 BL2
OSI Model TCP / IP Model
It distinguishes between
Service, Interface, Protocol
It does not distinguish between
Service, Interface, Protocol
Protocols are well hidden Protocols are not just hidden
Dejure standard Fit Model Defacto standard Fit Model
In transport layer only
connection-oriented services
are available
In Transport layer choice is for
connection oriented and
connectionless
Contains 7 layers Contains 5 layers
17 How do layers of the internet model correlate to the layers of the
OSI model?
C301.1 BL2
OSI TCP/IP
Physical Layer Physical Layer
Data Link Layer Network Access Layer
Network Layer IP Layer
Transport Layer TCP Layer
Session Layer
Application Layer
Presentation Layer
Application layer
18 Describe why HTTP is defined as a stateless protocol.
Maintaining state across request – Response connections
significantly increases the initial interactions in a connection, since
the identity of each party needs to be established and any saved
state much be retrieved. HTTP is therefore stateless to ensure that
C301.1 BL2
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internet is scalable since state is not contained in a HTTP request /
response pair by default.
19 What are the four groups of HTTP Headers? What are the two
methods of HTTP? (May 15) (Nov 15)
The four groups of HTTP headers are
 General headers
 Entity Headers
 Request Headers
 Response Headers.
Two methods of HTTP are Get Method( ) Post Method( )
C301.1 BL1
20 Justify the need for layer five in the OSI model. (Nov 21)
Layer 5 of the OSI Model: Session Layer is the layer of the ISO
Open Systems Interconnection (OSI) model that controls the
dialogues (connections) between computers. It establishes,
manages, and terminates the connections between the local and
remote application.
C301.1 BL2
21 What are the functions of Application Layer? (Apr 11)
It enables the user (human/software) to access the network. It
provides user interfaces and support for services such as electronic
mail, remote file access and transfer, shared database management
and other types of distributed information services. Services
provided by the application layer are Network Virtual terminal,
File transfer, access and management. Mail services, Directory
services.
C301.1 BL1
22 Define anonymous FTP. (May / June 2021)
An anonymous FTP is where users are given access to a
distributed file where they do not need to sign in with a specific
username and password.
C301.1 BL1
23 What are the transmission modes of FTP?
Stream mode: Default mode and data is delivered from FTP to
TCP as a continuous stream of data.
Block mode: Data is delivered from FTP to TCP in terms of blocks.
Each data block follows the three-byte header.
Compressed mode: File is compressed before transmitting if size
is big. Run length encoding method is used for compression.
C301.1 BL1
24 Why is an application such as POP needed for electronic
messaging? (May 12)
Workstations interact with the SMTP host, which receives the mail
on behalf of every host in the organization, to retrieve messages by
using a client-server protocol such as Post Office Protocol.
Although POP3 is used to download messages from the server, the
C301.1 BL2
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SMTP client still needed on the desktop to forward messages from
the workstation user to its SMTP mail server.
25 What is the difference between IMAP and POP? (May / June
2021)
C301.1 BL2
POP IMAP
POP allows downloading
messages from your Inbox to
your local computer
IMAP allows the user to see all
the folders on the mail server.
The mail can only be accessed
from a single device at a time.
Messages can be accessed
across multiple devices
To read the mail it has to be
downloaded on the local
system
The mail content can be read
partially before downloading.
The user cannot organize mails
in the mailbox of the mail
server.
The user can organize the
emails directly on the mail
server.
26 What is the use of MIME Extension?
Multipurpose Internet Mail Extensions (MIME) is a
supplementary protocol that allows non-ASCII data to be sent
through SMTP. MIME transforms non-ASCII data at the sender
site to NVT ASCII data and deliverers it to the client SMTP to be
sent through the Internet. MIME converts binary files, executed
files into text files. Then only it can be transmitted using SMTP
C301.1 BL2
27 How are the subgroups of the OSI model layers segregated by
their functions? (May / June 2021)
The lower 4 layers (transport, network, data link and physical) are
concerned with the flow of data from end to end through the
network and hence are called as network support layers. The
upper four layers of the OSI model (application, presentation and
session) are orientated more toward services to the applications
and hence are called user support layers.
C301.1 BL1
28 Identify the Port number of Hyper Text Transfer Protocol and
Telnet. (Nov 21)
By default, these two protocols are on their standard port number
of 80 for HTTP and 443 for HTTPS. For telnet port number is 23.
C301.1 BL1
29 Discuss the three main division of the domain name space. (May
12)
Domain name space is divided into three different sections:
generic domains, country domains & inverse domain.
 Generic domain: Define registered hosts according to their
generic behavior, uses generic suffixes.
C301.1 BL1
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 Country domain: Uses two characters to identify a country as
the last suffix.
Inverse domain: Finds the domain name given the IP address.
30 Define SNMP. (May 12)
Simple Network Management Protocol (SNMP) is an "Internet-
standard protocol for managing devices on IP networks". Devices
that typically support SNMP include routers, switches, servers,
workstations, printers, & modem. It is used mostly in network
management systems to monitor network-attached devices for
conditions that warrant administrative attention.
C301.1 BL1
31 List the two types of DNS message. (May 16)
There are two types of DNS messages,
 Query
 Response
Query message – consists of the header and question records.
Response message – consists of header, question record,
authoritative record and additional record.
C301.1 BL1
PART-B
1 Explain different types of networks in detail with neat diagram
(Nov/Dec 2021)
C301.1 BL1
3 Discuss in detail about the layers in OSI model. (Nov
10,11,12,15,19) (May 12) (May / June 2021)
C301.1 BL2
4 Explain in detail about the TCP/IP protocol suite with neat
diagram
C301.1 BL1
5 Discuss how the Simple Mail Transfer Protocol (SMTP) is useful in
electronic mail. (May 12,15) (Nov 13,15) (Nov 19) (May/June 2021)
(Nov 21)
C301.1 BL2
6 Explain the role of a DNS on a computer network, including its
involvement in the process of a user accessing a web page. (May
13) (Nov 15, 19) (Nov 21)
C301.1 BL1
7 Explain about HTTP. Give their uses, state strengths and
weaknesses. (Nov 10,13)
C301.1 BL1
8 Explain about FTP. (Nov 12, 13, 19), May 13) C301.1 BL1
9 Explain in detail about SNMP. C301.1 BL1
10 Explain in detail about sockets with an example. C301.1 BL1
UNIT II TRANSPORT LAYER
Introduction - Transport-Layer Protocols: UDP - TCP: Connection Management - Flow control -
Congestion Control - Congestion avoidance (DECbit, RED) - SCTP - Quality of Service
PART-A CO
Stateme
Knowledge
Level(R/U/Ap
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nt /An/E/C)
1 Give any two Transport layer service. (Dec 12)
Multiplexing: Transport layer performs multiplexing/de-
multiplexing function. Multiple applications employ same
transport protocol, but use different port number. According to
lower layer n/w protocol, it does upward multiplexing or
downward multiplexing.
Reliability: Error Control and Flow Control.
C301.2 BL1
2 How IANA has divided port numbers?
IANA (Internet Assigned Number Authority) has divided port
numbers into three ranges: 1) Well Known ports
2) Registered ports 3) Dynamic Ports.
C301.2 BL2
3
List few well known ports for UDP. C301.2 BL1
Port Protocol Description
7 Echo Echoes a received datagram back to the sender
9 Discard Discards any datagram received
11 Users Active Users
13 Daytime Returns Date and Time
4 How congestion occurs in a network? (May / June 2021)
The routers / switches in a network have a limited buffer size to
store the received packets. If the packets arrive at a faster rate than
what the receiver can store, then the packets are dropped leading
to congestion.
C301.2 BL2
5 What is a Port? (Nov 21)
In computer networking, a port is a communication endpoint. At
the software level, within an operating system, a port is a logical
construct that identifies a specific process or a type of network
service.
C301.2 BL1
6 Give the datagram format of UDP?
The basic idea of UDP is for a source process to send a message to
a port and for the destination process to receive the message from
a port.
C301.2 BL1
Source Port
Address
16 bits
Destination Port
Address
16 bits
Total Length
16 bits
Checksum
16 bits
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7 C301.2 BL2
What is the main difference between TCP & UDP?
TCP UDP
It provides connection-
oriented service
Provides connectionless service.
Connection Establishment
delay will be there
No connection establishment
and no delay
Provides reliable service Provides unreliable, but fast
service
It is used by FTP, SMTP It is used by DNS, SNMP, audio,
video and multimedia
applications.
8 Name the techniques and policies that can prevent (avoid)
congestion.
Techniques to avoid congestion:
 DEC (Digital Equipment Corporation) bit.
 Random Early Detection (RED).
 Source based congestion avoidance.
The congestion may be avoided by two policies:
 BECN - Backward Explicit Congestion Notification
 FECN - Forward Explicit Congestion Notification.
C301.2 BL1
9 List out various congestion control techniques.
AIMD (Additive Increase Multiplicative Decrease), Slow start, Fast
retransmit, Fast Recovery
C301.2 BL1
10 What are the advantages of using UDP over TCP? (Nov 10)
UDP is very useful for audio or video delivery which does not need
acknowledgement. It is useful in the transmission of multimedia
data. Connection Establishment delay will occur in TCP.
C301.2 BL1
11 What is the use of UDP’s Pseudo header?
The pseudo header consists of three field from the IP header
protocol number, source IP address and destination IP address
plus the UDP length field (which is included twice in checksum
calculation). The pseudo header is used to check whether the
message is delivered between 2 endpoints.
C301.2 BL1
12 What are the four aspects related to the reliable delivery of data?
(May 12)
The four aspects are
(i) Error control,
(ii) Sequence control
(iii) Loss control
(iv) Duplication control.
C301.2 BL1
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13 Outline Stop and Wait ARQ mechanism. (Nov 19)
In the stop-and-wait ARQ mechanism, sender sends one frame at
a time; it is a special case of the general sliding
window protocol with transmit and receive window sizes equal to
one in both cases.
C301.2 BL1
14 What do you mean by slow start in TCP congestion? (May 16)
TCP slow start is an algorithm which balances the speed of a
network connection. Slow start gradually increases the amount of
data transmitted until it finds the network’s maximum carrying
capacity.
C301.2 BL1
15
Differentiate congestion control and flow control. (Nov 13,15)
C301.2 BL2
Congestion Control Flow Control
Congestion control means
preventing the source
from sending data that
will end up getting
dropped by a router
because its queue is full.
Flow control means preventing the
source from sending data that the
receiver will end up dropping
because it runs out of buffer space.
This is more complicated,
because packets from
different sources
travelling different paths
can converge on the same
queue.
This is fairly easy with a sliding
window protocol
16 List the different phases used in TCP Connection. (May 16)
The different phases used in TCP connection are Connectio
establishment Phase, Data transfer and Connection Terminatio
Phase
C301.2 BL1
17 List the advantages of Connection oriented services over
connectionless services. (May 17)
Connection Oriented:
Advantages:
1. Buffers can be reserved in advance
2. Sequencing can be guaranteed.
Short headers.
C301.2 BL1
18 How do fast retransmit mechanism of TCP works? (May 17)
Fast Retransmit is an enhancement to TCP that reduces the time
sender waits before retransmitting a lost segment. A TCP sende
uses a timer to recognize lost segments. If an acknowledgement i
not received for a particular segment within a specified time (
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function of the estimated round-trip delay time), the sender wil
assume the segment was lost in the network, and will retransmit th
segment.
19 Define SCTP (Nov 21)
SCTP (Stream Control Transmission Protocol) is a reliable,
message-oriented transport layer protocol. It combines the best
features of UDP and TCP. It is mostly designed for internet
applications.
C301.2 BL1
20 What is the use of SCTP Multiple stream service?
SCTP allows multi stream service in each connection, which is
called association in SCTP terminology. If one of the streams is
blocked, the other streams can still deliver their data. The idea is
similar to multiple lanes on a highway. The figure shows the idea
of multi stream delivery.
C301.2 BL2
21 Define Multihoming Concept of SCTP
Multihoming is the ability of an SCTP association to support
multiple IP paths to its peer endpoint. The benefit
of multihoming associations is that it makes the association more
fault-tolerant against physical network failures and other issues on
the interfaces.
C301.2 BL1
22 What happens in a three-way handshaking between any 2
devices? (May/June 2021)
The three-way handshake involves the exchange of three messages
between the client and the server.
The client sends a segment to the server stating the initial sequence
number it plans to use (Flags = SYN, Sequence Num = x).
The server responds with a single segment that both acknowledges
the client’s sequence number (Flags = ACK, ACK = x +1) and states
its own beginning sequence number, (Flags = SYN, Sequence Num
= y).
Both the SYN and ACK bits are set in the Flags field of this second
message.
C301.2 BL2
23 What are the two categories of QoS attributes?
User Oriented and Network Oriented. User related attributes are
C301.2 BL1
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SCR – Sustainable Cell Rate
PCR – Peak Cell Rate
MCR- Minimum Cell Rate
CVDT – Cell Variation Delay Tolerance.
The network related attributes are, Cell loss ratio (CLR), Cell
transfer delay (CTD), Cell delay variation (CDV), Cell error ratio
(CER).
UNIT-II / PART-B
1 Write short notes on (May 12) (Nov 19) (Nov 21)
(i) TCP segment format (ii) Silly window syndrome (Or) discuss
the silly window syndrome and explain how to avoid it.
C301.2 BL1
2 With neat architecture, Explain TCP and its sliding window
algorithm for flow control. (Nov 15)
C301.2 BL2
3 Describe with examples the three mechanisms by which
congestion control is achieved in TCP. (Nov 13,15)(May 15,16)(Nov
19)
C301.2 BL2
4 Discuss congestion avoidance algorithm like DEC bit method and
random early detection in transport layer with an example.(May
12,17)
C301.2 BL2
5 What are the 2 broad categories of congestion control mechanisms?
Briefly explain all the techniques. (May / June 2021)
C301.2 BL1
6 Explain connection establishment and connection closing in TCP
(Or) Describe how reliable and ordered delivery is achieved
through TCP. (Nov 13) (May 15)
C301.2 BL2
7 Explain the significance of Clark’s solution and Nagle’s algorithm.
(Or) What is the need for Nagle’s algorithm? How does it
determine when to transmit data? (May 13)
C301.2 BL4
8 Define UDP. Discuss the operations of UDP. Explain UDP
checksum with one example. (Nov 21)
C301.2 BL2
9 Discuss the effectiveness of Go Back N and Selective Repeat ARQ
among the Sliding window Protocols. (Nov 21)
C301.2 BL2
10 Explain SCTP in Detail (May 17) C301.2 BL2
11 Explain the association establishment of SCTP through four-way
handshake in detail.
C301.2 BL2
12 Furnish the packet format of Stream Control Transmission
Protocol with its fields. How the data are transferred using 4-way
handshaking? (May / June 2021)
C301.2 BL1
13 Explain the various approaches to improve quality of services in a
data transmission network.
C301.2 BL2
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UNIT III NETWORK LAYER
Switching: Packet Switching - Internet protocol - IPV4 - IP Addressing - Subnetting - IPV6, ARP, RARP,
ICMP, DHCP
UNIT-III / PART-A CO
Stateme
nt
Knowledge
Level (R/U/Ap
/An/E/C)
1 What is packet switching? (Nov 12)
In a packet-switched network, it’s not necessary to dedicate
transmission capacity along a path through the network. Rather,
data are sent out in a sequence of small chunks, called packets.
C301.3 BL1
2 What is subnetting? (Nov 11,15)
The whole network can’t manage by single server, so that the entire
network divided into small network in order to manage the
network easily. Subnetting provides an elegantly simple way to
reduce the total number of network numbers that are assigned. The
idea is to take a single IP network number and allocate the IP
address with that network to several physical networks, which are
now referred to as subnets.
C301.3 BL1
3 What is subnet mask?
A subnet mask is a number that defines a range of IP
addresses available within a network. A single subnet mask limits
the number of valid IPs for a specific network. Multiple subnet
masks can organize a single network into smaller networks (called
subnetworks or subnets).
C301.3 BL1
4 Define CIDR?
CIDR, which stands for Classless Inter-Domain Routing, is an IP
addressing scheme that improves the allocation of IP addresses. It
replaces the old system based on classes A, B, and C. This helped
to extend the life of IPv4 as well as slow the growth of routing
tables.
C301.3 BL1
5 How many network addresses and host addresses are supported
by class A, class B networks?
Class A: Number of networks = 127 Number of hosts = 224 -1
Class B: Number of networks = 214 -1
Number of hosts = 216 – 1 = 65,535
C301.3 BL1
6 List out the functions of IP.
IP services are unreliable, best-effort, connectionless packet
delivery system. Unreliable – delivery is not guaranteed,
Connectionless – each pocket is treated independent from others,
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Best-effort delivery – it makes an earnest attempt to deliver
packets. It defines basic unit of data transfer through TCP/IP.
7 What do you mean by ICMP?
ICMP is an error reporting mechanism. It does not specify the
action to be taken for each possible error. The source must relate
the error to an individual application program and take other
actions to correct the problem.
C301.3 BL1
8 To whom ICMP reports error message will be sent?
ICMP allows routers to send error messages to other router or
hosts. ICMP is an error reporting mechanism. It does not specify
the action to be taken for each possible error. It is informing the
source that the error has occurred and the source has to take
actions to rectify the errors.
C301.3 BL2
9 When ICMP redirect message is used? (May 17)
An ICMP redirect is an error message sent by a router to the
sender of an IP packet Redirects are used when a router believes a
packet is being routed sub optimally and it would like to inform
the sending host that it should forward the subsequent packets to
that same destination through a different gateway.
C301.3 BL2
10 State the rules of non-boundary-level masking? (May 12)
 The bytes in the IP address that corresponds to 255 in the mask
will be repeated in the sub network address.
 The bytes in the IP address that corresponds to 0 in the mask
will change to 0 in the sub network address.
 For other bytes, use the bit-wise AND operator.
Example-
IP address 45 123 21 8
Mask 255 192 0 0
Subnet 45 64 0 0
123 0 1 1 1 1 0 1 1
192 1 1 0 0 0 0 0 0
64 0 1 0 0 0 0 0 0
C301.3 BL3
Class A: Number of networks = 127 Number of hosts = 224 -1
Class B: Number of networks = 214 -1
Number of hosts = 216 – 1 = 65,535
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12 What is the network address in a class A subnet with the IP
addresses of one of the hosts as 25.34.12.56 and mask
255.255.0.0? (May 14)
IP Address - 25.34.12.56 , Mask - 255.255.0.0 , Network Address
- 25.34.0.0
C301.3 BL2
13 What is IP address?
An Internet Address is made of four bytes (32 bits) that define a
host’s connection to a network. There are currently 5 different field
lengths patterns, each define a class of addresses. These are
designed to cover the needs of different types of organizations,
class A, B, C, D, E.
C301.3 BL1
14 Explain IPV6 protocol. Why IPV6 is preferred over IPV4? (May
/ June 2021)
IPv6 (Internet Protocol version 6) is a set of basics of IPv6 are
similar to those of IPv4. The most obvious improvement in IPv6
over IPv4 is that IP addresses are lengthened from 32 bits to 128
bits. This extension anticipates considerable future growth of the
Internet and provides relief for what was perceived as an
impending shortage of network addresses.
C301.3 BL2
15 What is DHCP? (Nov 19)
DHCP (Dynamic Host Configuration Protocol) is a protocol that
provides quick, automatic, and central management for the
distribution of IP addresses within a network. DHCP is
also used to configure the subnet mask, default gateway, and DNS
server information on the device.
C301.3 BL1
16 Explain IPV4 protocol.
IPv4 (Internet Protocol Version 4) is the fourth revision of the
Internet Protocol (IP) used to identify devices on a
network through an addressing system. The Internet Protocol is
designed for use in interconnected systems of packet-switched
computer communication networks. IPv4 is the most widely
deployed Internet protocol used to connect devices to the Internet.
IPv4 uses a 32-bitaddress scheme
C301.3 BL2
17 Present an outline of IPv6 addressing. (Nov 19)
An IPv6 address is 128 bits in length and consists of eight, 16-bit
fields, with each field bounded by a colon. Each field must contain
a hexadecimal number, in contrast to the dotted-decimal notation
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of IPv4 addresses. In the below figure, the x's represent
hexadecimal numbers.
18 C301.3 BL1
What are the differences between IPV4 and IPV6? (Nov 21)
IPV4 IPV6
A 32-bit numeric address in
IPv4 is written in decimal as
four numbers separated by
periods. Each number can be
zero to 255.
For eg,
1.160.10.240 could be an IP
address.
IPv6 addresses are 128-bit IP
address written in hexadecimal
and separated by colons. An
example IPv6 address could be
written like this:
3ffe:1900:4545:3:200:f8ff:fe21:67
cf
19 Identify the class of the following IP Address: (May / June 2021)
11000001 10000011 00011011 11111111 = Class C
252.5.15.111 = Class D
C301.3 BL2
20 Why is IPV4 to IPV6 transition required? (May 17)
IPv4 and IPv6 networks are not directly interoperable, transition
technologies are designed to permit hosts on either network type
to communicate with any other host.
C301.3 BL2
21 C301.3 BL2
Compare ARP and RARP.
ARP RARP
Address Resolution Protocol. Reverse Address Resolution
Protocol.
Retrieves the physical address
of the receiver.
Retrieves the logical address for
a computer from the server.
22 What is the need of ARP? (Nov/Dec 2015)
ARP is used to find the physical address of the node when its
Internet address is known. Any time a host/router needs to find
the physical address of another host on its network, it formats an
ARP query packet that includes the IP address and broadcasts it.
All hosts in the network process the ARP packet but only the
required station sends back physical address.
C301.3 BL2
23 Define RARP.
Allows a host to discover its internet address when it knows only
its physical address (a diskless computer). The host wishing to
retrieve its internet address broadcasts an RARP query packet that
contains its physical address to every host on its physical network.
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A server on the network recognizes the RARP packet and returns
the host’s internet address.
 Class A: Number of networks = 127
Number of hosts = 224 -1
 Class B: Number of networks = 214 -1
Number of hosts = 216 – 1 = 65,535
C301.3 BL1
25 List the difference between Packet Switching and Circuit
Switching. (Apr/May 2011, Nov/Dec 2011, May/June 2014)
C301.3 BL1
Issue Packet switching Circuit Switching
Circuit setup Not Required Required
Transmission
path
No Transmission path Dedicated path
Delay Packet transmission
delay
Call setup delay
Addressing Each packet contains
the full source and
destination address
Only data is sent
Bandwidth Dynamic Bandwidth Fixed Bandwidth
Routing Each packet is routed
independently
Entire data is sent
through the same path
Congestion
control
Difficult Easy if enough buffers
can be located in
advance for each VC set
up
Complexity In the transport layer In the network layer
Suited for Connection-oriented
and connectionless
service
Connection-oriented
service
UNIT-III / PART-B
1 Explain Packet Switching in detail. C301.3 BL2
2 i) Discuss the IP addressing methods. (May/June2014)
ii) Write short notes on ARP. (May/June2014) or Explain in detail
ARP. (Nov/Dec 2015)
C301.3 BL2
3 Explain in detail about DHCP. (Nov/Dec 2015) C301.3 BL2
4 What is the need for ICMP? Mention ICMP MESSAGES and their
purpose. (May/June 2013)
C301.3 BL1
5 Explain about IPV6? Compare IPV4 and IPV6 (May 16)(Nov 21) C301.3 BL2
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6 Discuss about address Resolution protocols. (Nov/Dec 2013) C301.3 BL2
7 Explain in detail about: i) ICMP ii) ARP iii) RARP. (Nov 19) C301.3 BL2
8 Explain IPv4 packet format and how fragmentation is applied in
datagram delivery.
C301.3 BL3
9 Draw an IPv4 datagram and explain about the fields present in it. C301.3 BL2
UNIT IV ROUTING
Routing and protocols: Unicast routing - Distance Vector Routing - RIP - Link State Routing - OSPF
- Path-vector routing - BGP - Multicast Routing: DVMRP - PIM.
UNIT IV - PART A CO
Stateme
nt
Knowledge
Level(R/U/Ap
/An/E/C)
1 Define routing. (Nov12,15)
It is the process of building up the tables that allow the collect
output for a packet to be determined. It is a lot harder to create the
forwarding tables in large, complex networks with dynamically
changing topologies and multiple paths between destinations.
Routing is a process that takes place in the background so that,
when a data packet turns up, we will have the right information
in the forwarding table to be able to forward, or switch, the packet.
C301.4 BL1
2 Write on the packet cost referred in distance vector and link state
routing. (May 2012)
In distance vector routing, cost refer to hop count while in case of
link state routing, cost is a weighted value based on a variety of
factors such as security levels, traffic or the state of the link.
C301.4 BL1
3 What is source routing? (Nov 13)
Rotation, stripping off and using pointers are the different types
of source routing approach.
C301.4 BL1
4 What is the function of a router? (Nov 10)(Nov 21)
Routers relay packets among multiple interconnected networks.
They route packets from one network to any of a number of
potential destination networks on internet. A router operates at
the physical, data link and network layer of the OSI model.
C301.4 BL1
5 Write the difference between Distance vector routing and Link
state routing.
C301.4 BL2
Distance Vector Routing Link state routing
Basic idea is each node sends
its knowledge about the entire
network to its neighbors.
Basic idea is every node sends
its knowledge about its
neighbors to the entire
network
It is dynamic routing It is dynamic routing
RIP uses Distance vector
routing
OSPF uses link state routing
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6 What does a router do when it receives a packet with a
destination address that it does not have an entry for, in its
routing table?
Default Router: If IP Software is not able to find the destination, from
routing table then it sends the datagram to default router. It is useful
when a site has small set of local address connected to it and connected
to the rest of the Internet.
C301.4 BL1
7 What is piggybacking? (Nov 19)
The technique of temporarily delaying outgoing acknowledgment
so that they can be hooked onto the next outgoing data frame is
widely known as piggybacking.
C301.4 BL1
8 Explain Multicast routing?
Multicast IP Routing protocols are used to distribute data for
example, audio/video streaming broadcasts) to multiple
recipients. Using multicast, a source can send a single copy of data
to a single multicast address, which is then distributed to an entire
group of recipients.
C301.4 BL2
9 What is RIP?
RIP (Routing Information Protocol) is a widely-used protocol for
managing router information within a self-contained network
such as a corporate local area network or an interconnected group
of such LANs. Using RIP, a gateway host (with a router) sends its
entire routing table (which lists all the other hosts it knows about)
to its closest neighbor host every 30 seconds.
C301.4 BL1
10 Explain about OSPF.
OSPF (Open Shortest Path First) is a router protocol used within
larger autonomous system networks in preference to the Routing
Information Protocol (RIP), an older routing protocol that is
installed in many of today's corporate networks.
C301.4 BL2
11 What is PIM?
Protocol-Independent Multicast (PIM) is a family
of multicast routing protocols for Internet Protocol (IP) networks
that provide one-to-many and many-to-many distribution of data
over a LAN, WAN or the Internet. It is termed protocol-
independent because PIM does not include its own topology
discovery mechanism, but instead uses routing information
supplied by other routing protocols.
PIM Source-Specific Multicast, Bidirectional PIM
PIM Dense Mode, PIM Sparse Mode
C301.4 BL1
12 What is DVMRP?
The Distance Vector Multicast Routing Protocol (DVMRP), is
a routing protocol used to share information between routers to
facilitate the transportation of IP multicast packets among
networks. The protocol is based on the RIP protocol. The router
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generates a routing table with the multicast group of which it has
knowledge with corresponding distances. When a multicast
packet is received by a router, it is forwarded by the router's
interfaces specified in the routing table.
13 What are the metrics used by routing protocols? (Apr/May 2015)
Path length, bandwidth, load, hop count, path cost, delay,
Maximum Transmission Unit (MTU), reliability and
communications cost.
C301.4 BL1
14 Define Unicasting, Broadcasting and Multicasting. (Nov/Dec
2011)
Unicasting: Transmitting data from a single sender to a single
receiver.
Broadcasting: Transmitting data from a single source to all the
other nodes in the network
Multicasting: Transmitting data from a single source to a group of
destination nodes.
C301.4 BL1
15 Explain BGP.
BGP stands for Border Gateway Protocol. It can be defined as a
standardized exterior gateway protocol which is developed to
interchange routing information and reachability information
between various autonomous systems (AS) on the Internet. It is
classified as a path vector protocol as well as a distance-vector
routing protocol.
C301.4 BL2
16 What is a path vector routing protocol?
A path-vector routing protocol is a network routing protocol
which maintains the path information that gets updated
dynamically. Updates that have looped through the network and
returned to the same node are easily detected and discarded.
C301.4 BL1
17 What is count to infinity problem in distance vector routing?
1. One of the important issues in Distance Vector Routing is
County of Infinity Problem.
2. Counting to infinity is just another name for a routing loop.
3. In distance vector routing, routing loops usually occur when an
interface goes down.
4. It can also occur when two routers send updates to each other
at the same time.
C301.4 BL2
18 What techniques are used to overcome the count to infinity issue
in distance vector routing?
Split horizon technique and split horizon with poison reverse
technique are used to overcome count to infinity issue in distance
vector routing.
C301.4 BL1
19 What are the contents of a link spate packet (LSP)?
LSP contains the following information:
1. The ID of the node that created the LSP
2. A list of directly connected neighbors of that node, with the
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cost of the link to each one
3. A sequence number
4. A time to live for this packet
20 What is the main difference between BGP and Distance vector
routing.
BGP differs from Distance Vector and Link State routings as it
advertises complete paths as an enumerated list of ASs to reach a
particular network.
C301.4 R
UNIT IV - PART B
1 Explain what is Distance Vector Routing and Demonstrate how
distance table gives routing table (Nov 21)
C301.4 BL2
2 Discuss about Link-state routing and routers. (Nov 12) (May 15) C301.4 BL2
3 Explain about the inter domain routing (BGP) routing algorithms. C301.4 BL2
4 Explain the Routing Information protocol/Distance vector
routing in detail. (Nov 13,15) (May 15,16)(Nov 19)
C301.4 BL2
5 What are the different routing algorithms? List out their pros and
cons. (May / June 2021)
C301.4 BL1
6 Explain Link state routing with Dijkstra's algorithm for the
following graph.
C301.4 BL3
7 Explain Distance Vector Routing Algorithm for the graph given
below.
C301.4 BL3
8 Explain in detail the operation of OSPF protocol by considering a
suitable network. (May 17)
C301.4 BL3
9 Explain DVMRP multicast routing in detail C301.4 BL2
10 Explain PIM multicast routing in detail. C301.4 BL2
UNIT V DATA LINK AND PHYSICAL LAYERS
Data Link Layer - Framing - Flow control - Error control - Data-Link Layer Protocols - HDLC - PPP -
Media Access Control - Ethernet Basics - CSMA/CD - Virtual LAN - Wireless LAN (802.11)
- Physical Layer: Data and Signals - Performance - Transmission media- Switching - Circuit Switching.
UNIT V - PART A CO
Stateme
nt
Knowledge
Level(R/U/Ap
/An/E/C)
1 List out the functions of data link layer (May / June 2021) C301.5 BL1
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Data link layer deals with node-to-node delivery of data. The
services provided by the data link layer include: framing, flow
control, error control and access control.
2 What do you mean by framing? (Nov/Dec2013 and Nov/Dec
2014)
The data link layer divides the stream of bits received from the
network layer into manageable data units called frames. The ways
to address the framing problem are
 Byte-Oriented Protocols (PPP)
 Bit-Oriented Protocols (HDLC)
 Clock-Based Framing (SONET)
C301.5 BL1
3 What are the two types of errors occurred during data
transmission? (May/June 2012)
Single bit error and burst error
C301.5 BL1
4 Compare error detection and correction. (Nov/Dec 2012) C301.5 BL2
Error Detection Error Correction
Only the occurrence of an error
is checked
The exact number of bits that
are corrupted and location of
error in the message are known.
5 Define bit stuffing. (Apr/May 2011)
HDLC denotes both the beginning and the end of a frame with the
distinguished bit sequence 01111110. This sequence might appear
anywhere in the body of the frame, it can be avoided by bit
stuffing. On the sending side, any time five consecutive 1’s has
been transmitted from the body of the message (i.e., excluding
when the sender is trying to transmit the distinguished 01111110
sequence), the sender inserts a 0 before transmitting the next bit.
C301.5 BL1
6 What do you mean by Flow Control? (Nov/Dec 2011)
Flow control is a technique for assuring that a transmitting entity
does not overwhelm a receiving entity with data. It is a feedback
mechanism by which the receiver is able to regulate the sender.
Such a mechanism is used to keep the sender from overrunning
the receiver, i.e., from transmitting more data than the receiver is
able to process
C301.5 BL1
7 Why is flow control and error control duplicated in different
layers?
Like the data link layer, the transport layer is responsible for flow
and error control. Flow control and error control at data link layer
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is node-to-node level. But at transport layer, flow control and error
control is performed end-end rather than across a single link.
8 Differentiate between lost frame and damaged frame? C301.5 BL2
Lost Frame Damaged Frame
Lost frame is the frame that
fails to arrive at the other side.
The damaged frame is a
recognizable frame does arrive,
but some of the bits are in error
9 What is the difference between stop and wait and sliding
window protocol? (Nov/Dec 2012)
C301.5 BL2
Stop and Wait Protocol Sliding Window Protocol
In stop and wait protocol,
we can send one frame at
a time
In sliding window protocol, we can
send multiple frames at a time.
Shows poor performance
than Sliding Window
Protocol, comparatively
As sliding window doesn't waste
network bandwidth compared with
stop-n-wait, both in normal and in
congested condition, sliding window
show better performance than stop-n-
wait.
10 Why sliding window flow control is considered to be more
efficient than stop and wait flow control?
In sliding window flow control, the transmission link is treated as
a pipeline that may be filled with frames in transit. But with stop-
and-wait flow control only one frame may be in the pipe at a time.
C301.5 BL1
11 Define Piggybacking?
The technique of temporarily delaying outgoing acknowledgment
so that they can be hooked onto the next outgoing data frame is
widely known as piggybacking.
C301.5 BL1
12 Find the hamming distance between the two pair of code words:
A = 01011; B = 11110 (May / June 2021)
Hamming distance is the numbers of bits by which two codes
differ. Here hamming distance = 3
C301.5 BL3
13 Define hidden node problem. (May 16)
In wireless networking, the hidden node problem or hidden
terminal problem occurs when a node is visible from a wireless
access point (AP), but not from other nodes communicating with
that AP. This leads to difficulties in media access control sub layer.
C301.5 BL1
14 What is the access method used by wireless LAN? (May 14) C301.5 BL1
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The access method used by wireless LAN is Carrier Sense Multiple
Access with Collision Avoidance (CSMA/CA)
15 What is meant by Exponential back of algorithm?
After first collision, each station waits either 0 or 1 slot time before
trying again. If two stations collide and each one picks same
random number 0/1. After second collision, each one picks 0, 1, 2
or 3 slot at random and waits. If collision occurs again, then next
time the number of slots to wait is chosen at random from 0 to [23
– 1]. This algorithm is called binary exponential “back off
algorithm”.
C301.5 BL1
16 What is High Level data link control? (Nov 21)
High-Level Data Link Control is a bit-oriented code-transparent
synchronous data link layer protocol developed by the
International Organization for Standardization. The standard for
HDLC is ISO/IEC 13239:2002. HDLC provides both connection-
oriented and connectionless service.
C301.5 BL1
17 Give the format of Ethernet address. C301.5 BL1
Preambl
e
64
Dest
addr
48
Src addr
48
Type
16
Body CRC
32
18 Outline the use of cyclic redundancy check. (Nov 19)
A cyclic redundancy check (CRC) is an error-detecting code
commonly used in digital networks and storage devices to detect
accidental changes to raw data.
C301.5 BL2
19 What is CSMA/CD? (Nov 11)
Carrier Sense Multiple Access with Collision Detection is one of
the methods of medium access. It is used to sense whether a
medium is busy before transmission. If the medium is busy, it
refrains from transmitting the data or else proceeds with the
transmission. Also has the ability to check whether a transmission
has collided with another.
C301.5 BL1
20 Examine how Network Interface Card works. (Nov 21)
A Network Interface Card provides a computer with a dedicated,
full-time connection to a network. It implements the physical layer
circuitry necessary for communicating with a data link layer
standard, such as Ethernet or Wi-Fi.
C301.5 BL2
21 List the rules for CSMA/CD.
1. If the medium is idle, transmit; otherwise go to step 2.
2. If the medium is busy, continue to listen until the channel is idle,
and then transmit immediately.
C301.5 BL1
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Page 27 of 28
3. If a collision detected during transmission, transmit a brief
jamming signal to all station to indicate collision has occurred and
then cease transmission.
22 Mention some of the physical properties of Ethernet.
(May 11)
The Ethernet is a multiple-access network, meaning that a set of
nodes send and receive frames over a shared link. An Ethernet is
like a bus that has multiple stations plugged into it.
C301.5 BL1
23 Write the parameters used to measure network performance.
(May 2016)
The parameters used to measure network performance are
Latency, Throughput, Delay and Bandwidth.
C301.5 BL1
24 Outline the need for switching. (Nov 19)
Switched communication networks are those in which data
transferred from source to destination is routed between various
intermediate nodes. Switching is the technique by which nodes
control or switch data to transmit it between specific points on a
network. There are three common switching techniques:
Circuit Switching, message switching and packet switching.
C301.5 BL2
25 List the types of Transmission media. (Nov 21)
Transmission Media is broadly classified into the following types:
Guided Media: It is also referred to as Wired or Bounded
transmission media. Common types are: (i) Twisted Pair Cable (ii)
Coaxial Cable (iii) Optical Fiber Cable
Unguided Media: Wireless Transmission. Common Types are:
(i) Satellite (ii) Infrared (iii) Broadcast (iv)Wi-Fi
C301.5 BL1
26 Define Bandwidth
Bandwidth refers to the number of bits per second that a channel,
a link, or even a network can transmit.
C301.5 BL1
27 What is Throughput?
It is a measure of how data can actually be sent through network.
C301.5 BL1
28 What is meant by the contention period of Ethernet?
When several stations on an Ethernet have data to send, there are
contention periods during which collisions happen and no data is
successfully transmitted.
C301.5 BL1
29 What does IEEE 10 Base 5 standard signify?
 10 represents data rate 10 Mbps.
 5 refers to segment length 5* 100 m that can run without
repeaters
 Base represents Base band communication.
C301.5 BL1
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Page 28 of 28
30 What do you mean by CSMA protocol? (Apr/May 2015)
Carrier sense multiple access (CSMA) is a media access
control (MAC) protocol in which a node verifies the absence of
other traffic before transmitting on a shared transmission
medium.
Carrier sense means that a transmitter attempts to determine
whether another transmission is in progress before initiating a
transmission. If a carrier is sensed, the node waits for the
transmission in progress to end before initiating its own
transmission. In other words, CSMA is based on the principle
"sense before transmit". Multiple access means that multiple nodes
may send and receive on the medium. Transmissions by one node
are generally received by all other nodes connected to the medium.
C301.5 BL1
UNIT-V / PART-B
1 Given a remainder of 111, a data unit of 10110011 and a divisor of
1001, is there an error in the data unit. Justify your answer with
necessary principles. (May 14)
C301.5 BL3
2 Explain the various error detection techniques with example. (Nov
10,12), (May 12,16)
C301.5 BL2
3 The message X5 + X4 + X 11001001 is to be transmitted, using CRC
error detection algorithm. Assuming the CRC polynomial to be X3
+ X2 + 1, determine the three-bit CRC code that should be
appended to message. (May / June 2021)
C301.5 BL3
4 Discuss in detail about the HDLC protocol (Bit Oriented Protocol).
(May 16) (Nov 19)
C301.5 BL2
5 Explain various flow control mechanisms. i) Stop Wait protocol ii)
Go Back-N iii) Selective Repeat (Nov 15)
C301.5 BL2
6 Discuss in detail about the PPP protocol (Byte Oriented Protocol). C301.5 BL2
7 Describe the CSMA/CD protocol and comment on its performance
for medium access. (May 11,14,17) (Nov 19)
C301.5 BL4
8 Explain the functioning of wireless LAN in detail. (Nov 10,12,15)
(May 15)
C301.5 BL2
9 Explain how hidden node and exposed node problem is solved in
IEEE 802.11 (Nov 13)
C301.5 BL2
10 Explain Transmission media and its types in detail. (May / June
2021)
C301.5 BL2
11 Explain the various performance metrics in detail. C301.5 BL2
12 Explain Circuit Switching in detail. (Nov 19)(Nov/Dec 2021) C301.5 BL2
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