Galgotias College of Engineering & Technology

1, Knowledge Park‐II, Greater Noida, Uttar Pradesh, 201310

Affiliated to Dr. A. P. J. AKTU, Lucknow

CONTINUOUS ASSESSMENT EXAMINATION-2 SOLUTION

(EVEN Semester, 2024-25)

Course: B.Tech

Department: ECE

Subject Code: BEC-062

Subject Name: Data Communication Network

Semester: VIth

Prepared By: Dr. Arun Rana, Dr. Richa sharma, Ms. Sakshi Mittal

Signature of Reviewer:

HoD Name with Signature:

 Roll No. : …………………………………….
Galgotias College of Engineering and Technology, Greater Noida
Continuous Assessment Exam (CAE) – II : Even Semester 2024-2025

Course/Branch : ECE Semester : VI

Subject Name : Data Communication Network Max. Marks : 40
Subject Code : BEC-062 Time : 90 min
CO-3 : Demonstrate the knowledge of multiple access to design a access technique for a particular
application.
CO-4 : Realize protocols at different layers of a network hierarchy.
Section – A (CO - 3 ) # Attempt both the questions # 20 Marks
Q.1 : Attempt any FIVE questions (Short Answer Type). Each question is of two marks. (5 x 2 = 10 Marks)

a) What do you mean by Multiple Access? (K1).

ANS. Multiple Access Protocols are methods used in computer networks to control how data is
transmitted when multiple devices are trying to communicate over the same network.

b) What is CSMA? (K1).

ANS. Carrier Sense Multiple Access (CSMA) is a network protocol that helps reduce collisions
when multiple stations attempt to send data simultaneously over a shared medium. It operates by
requiring each station to check the state of the medium before transmitting.

c) What is MAC address? (K1).

ANS. A MAC address (Media Access Control address) is a unique identifier assigned to a network
interface controller (NIC) for use as a network address in communications within a network
segment. This identifier is crucial for network communication and is used in various networking
technologies, including Ethernet, Wi-Fi, and Bluetooth

d) What do you mean by IEEE 802.3? (K1).

ANS. IEEE 802.3 is a working group and a collection of standards defining the physical layer and
data link layer's media access control (MAC) of wired Ethernet. The standards are produced by the
working group of the Institute of Electrical and Electronics Engineers (IEEE).

e) What is ALOHA? (K2).

ANS. ALOHA is a multiple access protocol for transmission of data via a shared network channel.
It operates in the medium access control sublayer (MAC sublayer) of the open system
interconnection (OSI) model. Using this protocol, several data streams originating from multiple
nodes are transferred through a multi-point transmission channel.

f) Define Fast Ethernet. (K1).

ANS. In the fast-evolving world of computers, speed plays a vital role in the present and has
become paramount. As the technology is advancing and the demands on the networks are
increasing significantly, the quest for transferring the data at faster rates has become a priority. A
very crucial evolution in networking technology developed to meet the escalating features and
demands head-on - enters the Fast Ethernet. Fast Ethernet has transformed the landscape of
communication enabling unparalleled speeds and unleashing a new era of connectivity through
speed.
Q.2 : Attempt any TWO questions (Medium Answer Type). Each question is of 5 marks. (2 x 5 = 10 Marks)

a) Explain the timers and time registers in FDDI. (K2).

ANS. FDDI stands for Fiber Distributed Data Interface. It is a collection of ANSI and ISO standards
for data transmission on fiber-optic lines in a local area network (LAN) that can broaden in the range
up to 200 km (124 miles). The FDDI protocol depends on the token ring protocol.
FDDI cabling consists of two fiber rings, one transmitting clockwise and the other transmitting
counterclockwise. Fiber Distributed Data Interface (FDDI) is generally implemented as a dual token-
passing ring within a ring topology (for campus networks) or star topology (inside a building). The
dual ring includes a primary and secondary ring.
The primary ring transport data. The counter-rotating secondary ring can hold data in the opposite
direction but is more frequently reserved as an alternative in case the primary ring goes below. This
supports FDDI with the cost of fault tolerance essential for network backbones.
FDDI allows nodes to connect to the network by means of a single cable, such nodes are called single
attainment (SAS), and their dual-connected counterpart is called dual attachment station (DAS).

There are two types of traffic in FDDI, which are as follows−

 Synchronous FDDI: It means that the traffic is delay sensitive, used to send voice or video. Whenever
a node receives a token, it is allowed to send synchronous data without regard to whether the token is
early or late.
 Asynchronous FDDI: It is used only when the token is early.

In the FDDI mechanism, Token is always in circulation & different from 802.5. All rings on FDDI monitor
that token is not lost. FDDI MAC protocol uses three timers as the first one is holding a timer to determine
how long a station may-continue to transmit once it has acquired a token. The second rotation timer is restarted
every time the token is seen. If the timer expires, it means that the one has not been sighted for two Rings on
interval or has been lost. The third timer is the transmission timer used to time out and recover from certain
transient ring errors.

b) What is Ethernet? Explain about Ethernet. (K2).

ANS. The original Ethernet was created in 1976 at Xerox's Palo Alto Research Center (PARC). Since
then, it has gone through four generations: Standard Ethernet (lot Mbps), Fast Ethernet (100 Mbps),
Gigabit Ethernet(l Gbps), and Ten-Gigabit Ethernet(l0 Gbps), as shown in Figure 13.3. We briefly
discuss all these generations starting with the first, Standard (or traditional) Ethernet.
 MAC Sublayer In Standard Ethernet, the MAC sublayer governs the operation of the access method. It
also frames data received from the upper layer and passes them to the physical layer. Frame Format
The Ethernet frame contains seven fields: preamble, SFD, DA, SA, length or type of protocol data unit
(PDU), upper-layer data, and the CRC. Ethernet does not provide any mechanism for acknowledging
received frames, making it what is known as an unreliable medium. Acknowledgments must be
implemented at the higher layers. The format of the MAC frame is shown in Figure

 Preamble. The first field of the 802.3 frame contains 7 bytes (56 bits) of alternating 0s and Is that
alerts the receiving system to the coming frame and enables it to synchronize its input timing. The
pattern provides only an alert and a timing pulse. The 56-bit pattern allows the stations to miss
some bits at the beginning of the frame. The preamble is actually added at the physical layer and is
not (formally) part of the frame.
 Start frame delimiter (SFD). The second field (l byte: 10101011) signals the beginning of the
frame. The SFD warns the station or stations that this is the last chance for synchronization. The
last 2 bits is 11 and alerts the receiver that the next field is the destination address.
 Destination address (DA). The DA field is 6 bytes and contains the physical address of the
destination station or stations to receive the packet. We will discuss addressing shortly.
 Source address (SA). The SA field is also 6 bytes and contains the physical address of the sender
of the packet. We will discuss addressing shortly.
 Length or type. This field is defined as a type field or length field. The original Ethernet used this
field as the type field to define the upper-layer protocol using the MAC frame. The IEEE standard
used it as the length field to define the number of bytes in the data field. Both uses are common
today.
 Data. This field carries data encapsulated from the upper-layer protocols. It is a minimum of46
and a maximum of1500 bytes

c) Describe the working principle and architecture of Bluetooth IEEE802.16 Standard. (K2).

ANS. Bluetooth Bluetooth is a wireless LAN technology designed to connect devices of different
functions such as telephones, notebooks, computers (desktop and laptop), cameras, printers, coffee
makers, and so on. A Bluetooth LAN is an ad hoc network, which means that the network is formed
spontaneously; the devices, sometimes called gadgets, find each other and make a network called a
piconet. A Bluetooth LAN can even be connected to the Internet if one of the gadgets has this
capability. A Bluetooth LAN, by nature, cannot be large. If there are many gadgets that try to
connect, there is chaos. Bluetooth technology has several applications. Peripheral devices such as
A wireless mouse or keyboard can communicate with the computer through this technology.
Monitoring devices can communicate with sensor devices in a small health care center. Home
security devices can use this technology to connect different sensors to the main security controller.
Conference attendees can synchronize their laptop computers at a conference.

Bluetooth was originally started as a project by the Ericsson Company. It is named for Harald
Blaatand, the king of Denmark (940-981) who united Denmark and Norway. Blaatand translates to
Bluetooth in English. Today, Bluetooth technology is the implementation of a protocol defined by
the IEEE 802.15 standard. The standard defines a wireless personal-area network (PAN) operable in
an area the size of a room or a hall.
 A) ARCHITECTURE
Bluetooth defines two types of networks: piconet and scatternet.

Piconets

A Bluetooth network is called a piconet, or a small net. A piconet can have up to eight stations, one of
which is called the primary the rest are called secondary. All the secondary stations synchronize their
clocks and hopping sequence with the primary. Note that a piconet can have only one primary station.
The communication between the primary and the secondary can be one-to-one or one-to-many. Fig.
shows a piconet.

Fig. Piconet

Although a piconet can have a maximum of seven secondaries, an additional eight secondaries can be
in the parked state. A secondary in a parked state is synchronized with the primary, but cannot take
part in communication until it is moved from the parked state. Because only eight stations can be
active in a piconet, activating a station from the parked state means that an active station must go to
the parked state. Scatternet Piconets can be combined to form what is called a scatternet. A secondary
station in one piconet can be the primary in another piconet. This station can receive messages from
the primary in the first piconet (as a secondary) and, acting as a primary, deliver them to secondaries in
the second piconet. A station can be a member of two piconets. Fig. illustrates a scatternet.

Fig. Scatternet

B) BLUETOOTH LAYERS Bluetooth uses several layers that do not exactly match those of the
Internet model Fig. shows these layers.
 Fig. Bluetooth layers

Radio Layer The radio layer is roughly equivalent to the physical layer of the Internet model.
Bluetooth devices are low-power and have a range of 10 m. Bluetooth uses a 2.4-GHz ISM band
divided into 79 channels of 1 MHz each. Bluetooth uses the frequency-hopping spread spectrum
(FHSS) method in the physical layer to avoid interference from other devices or other networks.
Bluetooth hops 1600 times per second, which means that each device changes its modulation
frequency 1600 times per second. To transform bits to a signal, Bluetooth uses a sophisticated version
of FSK, called GFSK.

Baseband Layer The baseband layer is roughly equivalent to the MAC sublayer in LANs. The
access method is TDMA. The primary and secondary communicate with each other using time slots.
The length of a time slot is exactly the same as the dwell time, 625µs. This means that during the time
that one frequency is used, a sender sends a frame to a secondary, or a secondary sends a frame to the
primary. Note that the communication is only between the primary and a secondary; secondaries
cannot communicate directly with one another.

L2CAP The Logical Link Control and Adaptation Protocol, or L2CAP (L2 here means LL), is
roughly equivalent to the LLC sublayer in LANs. It is used for data exchange on an ACL link; SCQ
channels do not use L2CAP. Figure 14.25 shows the format of the data packet at this level. The I6-bit
length field defines the size of the data, in bytes, coming from the upper layers. Data can be up to
65,535 bytes. The channel ID (CID) defines a unique identifier for the virtual channel created at this
level (see below). The L2CAP has specific duties: multiplexing, segmentation and reassembly,
quality of service (QoS), and group management.

d) What is CSMA/CD? Explain in details. (K1).

Ans: The CSMA method does not specify the procedure following a collision. Carrier sense
multiple access with collision detection (CSMA/CD) augments the algorithm to handle the
collision In this method, a station monitors the medium after it sends a frame to see if the
transmission was successful. If so, the station is finished. If, however, there is a collision, the
frame is sent again. To better understand CSMA/CD, let us look at the first bits transmitted by
the two stations involved in the collision. Although each station continues to send bits in the
frame until it detects the collision, we show what happens as the first bits collide. In Fig.
stations A and C are involved in the collision.

Fig. Collision of the first bit in CSMA/CD

At time t1, station A has executed its persistence procedure and starts sending the bits of its frame. At
time t2, station C has not yet sensed the first bit sent by A. Station C executes its persistence
procedure and starts sending the bits in its frame, which propagate both to the left and to the right.
The collision occurs sometime after time t2' Station C detects a collision at time t3 when it receives
the first bit of A's frame. Station C immediately (or after a short time, but we assume immediately)
aborts transmission. Station A detects collision at time t4 when it receives the first bit of C's frame; it
also immediately aborts transmission. Looking at the figure, we see that A transmits for the duration
t4 - tl; C transmits for the duration t3 - t2' Later we show that, for the protocol to work, the length of
any frame divided by the bit rate in this protocol must be more than either of these durations. At time
t4, the transmission of A: s frame, though incomplete, is aborted; at time t3, the transmission of B's
frame, though incomplete, is aborted. Now that we know the time durations for the two transmissions,
we can show a more complete graph in Fig.

Fig. Collision and abortion in CSMA/CD

Procedure Now let us look at the flow diagram for CSMAlCD in Fig. It is similar to the one for the
ALOHA protocol, but there are differences. The first difference is the addition of the persistence
process. We need to sense the channel before we start sending the frame by using one of the
persistence processes. The second difference is the frame transmission. In ALOHA, we first transmit
the entire frame and then wait for an acknowledgment. In CSMA/CD, transmission and collision
detection is a continuous process. We do not send the entire frame and then look for a collision. The
station transmits and receives continuously and simultaneously (using two different ports). We use a
loop to show that transmission is a continuous process. We constantly monitor in order to detect one
of two conditions: either transmission is finished or a collision is detected. Either event stops
transmission. When we come out of the loop, if a collision has not been detected, it means that
transmission is complete; the entire frame is transmitted. Otherwise, a collision has occurred. The
third difference is the sending of a short jamming signal that enforces the collision in case other
stations have not yet sensed the collision. The throughput of CSMAlCD is greater than that of pure or
slotted ALOHA. The maximum throughput occurs at a different value of G and is based on the
persistence method and the value of p in the p-persistent approach.
 Fig. Flow diagram for the CSMA/CD

Section – B (CO - 4 ) # Attempt both the questions # 20 Marks

Q.3 : Attempt any FIVE questions (Short Answer Type). Each question is of two marks. (5 x 2 = 10
Marks)

a) What do you understand by Design Issues? (K1).

ANS. Computer networks are the lifelines of our digital era, supporting the flow of
information, data, and communication across a wide range of devices and in an
increasingly linked world. However, the complicated web of interconnected networks that
enables our daily interactions and global connectedness is anything from simple. To ensure
the seamless operation and scalability of computer networks, one must delve into the
intricacies of design issues that span the layers of these intricate systems.

b) What do you mean by Errors during the transmission? (K1).

ANS. During the data transmission phase, data may be transmitted inaccurately due to
many reasons like external electromagnetic interference, interrupted/degraded signal
faulty hardware, etc. This leads to loss of data or corrupted data packets and
inconsistency in data packet arrivals which triggers non-reliable data communication.
This type of mis-transmission of data is called Transmission error. Transmission errors
can easily resolved by using error detection and correction mechanisms (CRC, Checksum
etc.) etc.), and high-quality networking equipment and data cables can reduce this error.
 c) What do you mean by Packet? (K1).
ANS. A packet is a small segment of a larger message that is sent over computer networks,
such as the Internet. Data sent over these networks is divided into packets, which are then
recombined by the receiving device1. This process is similar to breaking a letter into
smaller sections to fit through a small mail slot and then reassembling it at the destination.

d) What is Routing? (K1).

ANS. Routing refers to the process of directing a data packet from one node to another. It
is an autonomous process handled by the network devices to direct a data packet to its
intended destination.

e) Explain function of network layer. (K1).

ANS. The Network Layer, also known as Layer 3 of the OSI (Open Systems
Interconnection) model, is crucial for the delivery of data packets from the source to the
destination across multiple hops or links. It controls the operation of the subnet and ensures
that data is transmitted efficiently and accurately.

f) Write short note on broadcasting. (K1).

ANS. Broadcasting is a method of sharing information, entertainment, or messages with a
wide audience. It's the art and science of dispersing audio, video, or data signals to reach as
many people as possible.

Q.4 : Attempt any TWO questions (Medium Answer Type). Each question is of 5 marks. (2 x 5 = 10
Marks)

a) Define routing & explain distance vector routing in details. (K2).

ANS. In distance vector routing, the least-cost route between any two nodes is the route with
minimum distance. In this protocol, as the name implies, each node maintains a vector (table)
of minimum distances to every node. The table at each node also guides the packets to the
desired node by showing the next stop in the route (next-hop routing). We can think of nodes
as the cities in an area and the lines as the roads connecting them. A table can show a tourist
the minimum distance between cities. In table below we show a system of five nodes with
their corresponding tables.

Distance vector routing tables

The table for node A shows how we can reach any node from this node. For example, our least cost to
reach node E is 6. The route passes through C. Initialization The tables in Figure are stable; each node
knows how to reach any other node and the cost. At the beginning, however, this is not the case. Each
node can know only the distance between itself and its immediate neighbors, those directly connected
to it. So for the moment, we assume that each node can send a message to the immediate neighbors
and find the distance between itself and these neighbors. Table shows the initial tables for each node.
The distance for any entry that is not a neighbor is marked as infinite (unreachable).

Initialization of tables in distance vector routing

Sharing E's table The whole idea of distance vector routing is the sharing of information between
neighbors. Although node A does not know about node E, node C does. So if node C shares its
routing table with A, node A can also know how to reach node E. On the other hand, node C does not
know how to reach node D, but node A does. If node A shares its routing table with node C, node C
also knows how to reach node D. In other words, nodes A and C, as immediate neighbors, can
improve their routing tables if they help each other. There is only one problem. How much of the
table must be shared with each neighbor? A node is not aware of a neighbor's table. The best solution
for each node is to send its entire table to the neighbor and let the neighbor decide what part to use
and what part to discard. However, the third column of a table (next stop) is not useful for the
neighbor. When the neighbor receives a table, this column needs to be replaced with the sender's
name. If any of the rows can be used, the next node is the sender of the table. A node therefore can
send only the first two columns of its table to any neighbor. In other words, sharing here means
sharing only the first two columns.

Updating
When a node receives a two-column table from a neighbor, it needs to update its routing table.
Updating takes three steps:
1. The receiving node needs to add the cost between itself and the sending node to each
value in the second column. The logic is clear. If node C claims that its distance to a
destination is x mi, and the distance between A and C is y mi, then the distance
between A and that destination, via C, is x + y mi.
2. The receiving node needs to add the name of the sending node to each row as the third
column if the receiving node uses information from any row. The sending node is the
next node in the route.
3. The receiving node needs to compare each row of its old table with the corresponding
row of he modified version of the received table.
a) If the next-node entry is different, the receiving node chooses the row with the
smaller cost. If there is a tie, the old one is kept.
b) If the next-node entry is the same, the receiving node chooses the new row. For
example, suppose node C has previously advertised a route to node X with
distance 3. Suppose that now there is no path between C and X; node C now
advertises this route with a distance of infinity. Node A must not ignore this
value even though its old entry is smaller. The old route does not exist any more.
The new route has a distance of infinity.
Given Table shows how node A updates its routing table after receiving the partial table from node C.

Updating in distance vector routing

b) What do you mean by IPv4? Explain in details. (K1).

ANS. The Internet Protocol version 4 (IPv4) is the delivery mechanism used by the TCP/IP protocols.
Internet Protocol Version 4 (IPv4) is the fourth revision of the IP and a widely used protocol in data
communication over different kinds of networks. IPv4 is a connectionless protocol used in packet-
switched layer networks, such as Ethernet. It provides the logical connection between network devices
by providing identification for each device. There are many ways to configure IPv4 with all kinds of
devices - including manual and automatic configurations - depending on the network type.

IPv4 is based on the best-effort model. This model guarantees neither delivery nor avoidance
of duplicate delivery; these aspects are handled by the upper layer transport. IPv4 is defined
and specified in IETF publication RCF 791. It is used in the packet-switched link layer in the
OSI model.
IPv4 uses 32-bit addresses for Ethernet communication in five classes, named A, B, C, D and
E. Classes A, B and C have a different bit length for addressing the network host. Class D
addresses are reserved for multicasting, while class E addresses are reserved for future use.
Class A has subnet mask 255.0.0.0 or /8, B has subnet mask 255.255.0.0 or /16 and class C
has subnet mask 255.255.255.0 or /24. For example, with a /16 subnet mask, the network
192.168.0.0 may use the address range of 192.168.0.0 to 192.168.255.255. Network hosts can
take any address from this range; however, address 192.168.255.255 is reserved for broadcast
within the network. The maximum number of host addresses IPv4 can assign to end users is
232. IPv6 presents a standardized solution to overcome IPv4's limitations. Because of its 128-
bit address length, it can define up to 2,128 addresses. Internet Protocol being a layer-3
protocol (OSI) takes data Segments from layer-4 (Transport) and divides it into what’s called
packet. IP packet encapsulates data unit received from above layer and adds its own header
information. The encapsulated data is referred to as IP Payload. IP header contains all the
necessary information to deliver the packet at the other end.

IP header includes many relevant information including Version Number, which, in this
context, is 4. Other details are as follows:
o Version: Version no. of Internet Protocol used (e.g. IPv4)
o IHL: Internet Header Length, Length of entire IP header
o DSCP: Differentiated Services Code Point, This is Type of Service
 o ECN: Explicit Congestion Notification, carries information about the congestion seen
in the route.
o Total Length: Length of entire IP Packet (including IP header and IP Payload)
o Identification: If IP packet is fragmented during the transmission, all the fragments
contain same identification no. to identify original IP packet they belong to.
o Flags: As required by the network resources, if IP Packet is too large to handle these
‘flags’ tell that if they can be fragmented or not. In this 3-bit flag, the MSB is always
set to ‘0’.

o Fragment Offset: This offset tells the exact position of the fragment in the original IP
Packet. ·Time to Live: To avoid looping in the network, every packet is sent with
some TTL value set, which tells the network how many routers (hops) this packet can
cross. At each hop, its value is decremented by one and when the value reaches zero,
the packet is discarded.
o Protocol: Tells the Network layer at the destination host, to which Protocol this packet
belongs to, i.e. the next level Protocol. For example protocol number of ICMP is 1,
TCP is 6 and UDP is 17.
o Header Checksum: This field is used to keep checksum value of entire header which
is then used to check if the packet is received error-free.
o Source Address: 32-bit address of the Sender (or source) of the packet.
o Destination Address: 32-bit address of the Receiver (or destination) of the packet.
o Options: This is optional field, which is used if the value of IHL is greater than 5.
These options may contain values for options such as Security, Record Route, Time
Stamp etc.

c) Give a detailed description on various design goals of Network Security. (K2).

ANS. Network security refers to the strategies and measures taken to protect computer networks from
unauthorized access, misuse, or data breaches. It includes both hardware and software tools that help
maintain the confidentiality, integrity, and availability of data. At its core, network security
fundamentals involve protecting your network from attackers who try to steal, destroy, or tamper with
your data. Understanding network security basics is essential for anyone using digital devices connected
to the internet.
Key Principles of Network Security
If you're starting with network security for beginners, it's important to first understand the core
principles that protect any network. These principles are the building blocks of network security
fundamentals and help ensure that information stays safe and systems run smoothly.

 Confidentiality: This means only the right people should have access to specific information.
For example, your bank account details should be visible only to you and the bank, not anyone
 else. Confidentiality protects personal and sensitive data from being seen by unauthorized
users.
 Integrity: Data should always be accurate and unchanged. If someone alters a message or file
during transfer, it could cause serious problems. Integrity makes sure that information stays the
same from the moment it’s sent to when it’s received.
 Availability: Users should be able to access the systems and data they need whenever
required. If a website or service goes down because of an attack, it affects both businesses and
users. Availability ensures that networks and systems are up and running when people need
them.
 Authentication: Before giving access to any system or data, it’s important to confirm who the
user is. This is done through usernames, passwords, and sometimes extra steps like OTPs
(One-Time Passwords). Authentication makes sure that only real users can get in.
 Non-repudiation: This ensures that once someone sends a message or completes a transaction,
they can’t deny doing it. It’s like having a digital signature that proves the action was taken by
that specific person.

These five principles form the heart of network security fundamentals. Understanding and applying
them is key for building strong, safe, and trustworthy networks. They are the reason why secure
systems can protect data, prevent misuse, and keep users safe online.

d) Describe the working of Datagram Switching and Virtual Circuit Switching using suitable
diagrams. (K2).
ANS. In networking, two important switching methods are Datagram Switching and Virtual Circuit
Switching which are used for data transmission. These methods indicate the way data packets are
transmitted in a network, and the path that packet has to follow. In this article, both techniques will
be described in detail, as well as their merits compared to identify the major differences between
them.

Datagram switching is a packet switching method that treats each packet, or datagram, as a
separate entity. Each packet is routed via the network on its own. It is a service that does not require
a connection. Because there is no specific channel for a connection session, there is no need to
reserve resources. As a result, packets have a header with all the destination’s information. The
intermediate nodes assess a packet’s header and select an appropriate link to a different node closer
to the destination.

Advantages of Datagram Switching

 Scalability: Datagram switching is highly scalable and can handle large amounts of traffic on a
network.
 Flexibility: Datagram switching is flexible and can support variable packet sizes and data rates.
 Simple routing: Datagram switching does not require a pre-established path for each packet,
allowing packets to be routed dynamically.
 Lower latency: Datagram switching typically has lower latency than virtual circuit switching, as
packets are sent immediately without any delay for setup.
Disadvantages of Datagram Switching
 Higher error rates: Datagram switching is more susceptible to errors than virtual circuit
switching, as there is no guaranteed delivery or error correction.
 Lack of QoS: Datagram switching does not provide any Quality of Service guarantees, meaning
that different types of traffic may be treated equally.
 Increased network congestion: Without a pre-established path for each packet, datagram
switching can lead to increased network congestion and potential delays.

Virtual packet switching approach in which a path is built between the source and the final
destination through which all packets are routed throughout a call is known as virtual circuit
switching. Because the connection looks to the user to be an infatuated physical circuit, this path is
referred to as a virtual circuit. Other communications, on the other hand, may be sharing parts of
the same path. Before the data transmission can commence, the source and destination must agree
on a virtual circuit path. For the decision, all intermediary nodes between the two places add a
routing entry to their routing database. Additional parameters, like the utmost packet size, also are
exchanged between the source and therefore the destination during call setup. The virtual circuit is
cleared after the info transfer is completed.

Advantages of Virtual Circuit Switching

 Guaranteed delivery: Virtual circuit switching provides guaranteed delivery of packets,
reducing the likelihood of lost or corrupted data.
 Lower error rates: Virtual circuit switching typically has lower error rates than datagram
switching due to its error correction mechanisms.
 QoS support: Virtual circuit switching supports Quality of Service guarantees, allowing for
prioritization of different types of traffic.
 Efficient use of bandwidth: Virtual circuit switching establishes a pre-determined path for each
packet, resulting in efficient use of bandwidth.

Disadvantages of Virtual Circuit Switching

 Limited scalability: Virtual circuit switching is less scalable than datagram switching and may
not be suitable for large networks.
 Increased setup time: Virtual circuit switching requires a setup time for each connection, which
can lead to increased latency and delay.
 Fixed data rates: Virtual circuit switching typically supports fixed data rates, which may not be
suitable for applications that require variable packet sizes or data rates.

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