BCA - SEMESTER V
CA5CRT14 : Computer Networks (Core)
Theory:3 hrs. per week
Credits:4
Unit 1: ( 10 hrs.)
Introduction to Networks, Data and signals-analog and digital, periodic analog signals, digital
signals, bitrate, baud rate, bandwidth.
Transmission impairments- attenuation, distortion and noise.
Data communication protocols and standards, Network models - OSI model-layers and their
functions.TCP/IP protocol suite.
Unit 2: (10 hrs.)
Bandwidth utilization Multiplexing: FDM, TDM, spread spectrum.
Transmission Media- guided media and unguided media.
Switching: message, Circuit and packet switched networks, datagram networks, virtual- circuit
networks.
Unit 3: (12 hrs.)
Data link layer: Error Detection and Correction, Framing, flow and error control, Protocols –
Noiseless channels (Simplest, Stop and Wait) and Noisy channels (Stop and Wait and Piggy
Backing).
Multiple Access Protocols. Random Access-ALOHA, CSMA.
Wired LANs-IEEE standards, wireless LANs-Bluetooth, Cellular Telephony
Unit 4: (12 hrs.)
Network layer and Transport layer: Repeaters, Bridges, Gateways and routers.
Logical addressing – IPV4 and IPV6 addressing, Internet protocol - IPV4 and IPV6.
Connectionless and Connection Oriented Services: UDP and TCP. Congestion Control, Quality
of Service.
Unit 5: (10 hrs.)
Application layer: HTTP, FTP, SMTP, DNS. Network security: Common Threats- Firewalls
(advantages and disadvantages), Cryptography.
Book of study:
1. B. A. Forouzan - Data communication and Networking, Fourth edition-,TMH
2. Andrew S Tanenbaum - Computer Networks ,Fourth Edition, Prentice Hall of India.
,UNIT -1:
Introduction to networks. Data and signals-analog and digital, periodic analog signals, digital
signals, bit rate, baud rate, bandwidth. Transmission impairments- attenuation distortion and
noise.
Data communication protocols and standards, Network models - OSI model-layers and their
functions. TCP/IP protocol suite.
DATA COMMUNICATION
Data communications are the exchange of data between two devices via some form of
transmission medium such as a wire cable. For data communications to occur, the
communicating devices must be part of a communication system made up of a combination
of hardware (physical equipment) and software (programs). The effectiveness of a data
communications system depends on four fundamental characteristics: delivery, accuracy,
timeliness, and jitter.
1. Delivery. The system must deliver data to the correct destination. Data must be received
by the intended device or user and only by that device or user.
2. Accuracy. The system must deliver the data accurately. Data that have been altered in
transmission and left uncorrected are unusable.
3. Timeliness. The system must deliver data in a timely manner. Data delivered late are
useless. In the case of video and audio, timely delivery means delivering data as they are
produced, in the same order that they are produced, and without significant delay. This kind
of delivery is called real-time transmission.
4. Jitter. Jitter refers to the variation in the packet arrival time. It is the uneven delay in the
delivery of audio or video packets. For example, let us assume that video packets are sent every
30 ms. If some of the packets arrive with 30-ms delay and others with 40-ms delay, an uneven
quality in the video is the result.
Components
A data communications system has five components (see Figure 1.1).
1. Message. The message is the information (data) to be communicated. Popular forms of
information include text, numbers, pictures, audio, and video.
2. Sender. The sender is the device that sends the data message. It can be a computer,
workstation, telephone handset, video camera, and so on.
3. Receiver. The receiver is the device that receives the message. It can be a computer,
workstation, telephone handset, television, and so on.
4. Transmission medium. The transmission medium is the physical path by which a
message travels from sender to receiver. Some examples of transmission media include
twisted-pair wire, coaxial cable, fiber-optic cable, and radio waves.
,5. Protocol. A protocol is a set of rules that govern data communications. It represents an
agreement between the communicating devices. Without a protocol, two devices may be
connected but not communicating, just as a person speaking French cannot be understood by
a person who speaks only Japanese.
Data Flow
Communication between two devices can be simplex, half-duplex, or full-duplex as shown in
Figure 1.2
Simplex
In simplex mode, the communication is unidirectional, as on a one-way street. Only one of
the two devices on a link can transmit; the other can only receive (see Figure 1.2a).
Keyboards and traditional monitors are examples of simplex devices. The keyboard can only
introduce input; the monitor can only accept output. The simplex mode can use the entire
capacity of the channel to send data in one direction.
Half-Duplex
In half-duplex mode, each station can both transmit and receive, but not at the same time.
When one device is sending, the other can only receive, and vice versa (see Figure 1.2b).
Walkie-talkies and CB (citizens band) radios are both half-duplex systems. The half-duplex
mode is used in cases where there is no need for communication in both directions at the
same time; the entire capacity of the channel can be utilized for each direction.
Full-Duplex
In full-duplex mode (also called duplex), both stations can transmit and receive
simultaneously (see Figure 1.2c).
In full-duplex mode, signals going in one direction share the capacity of the link: with signals
going in the other direction This sharing can occur in two ways: Either the link must contain
two physically separate transmission paths, one for sending and the other for receiving; or the
capacity of the channel is divided between signals travelling in both directions.
One common example of full-duplex communication is the telephone network. When two
people are communicating by a telephone line, both can talk and listen at the same time.
, The full-duplex mode is used when communication in both directions is required all the time.
The capacity of the channel, however, must be divided between the two directions.
Network
Physical Structures
Network Attributes
Type of Connection
A network is two or more devices connected through links. A link is a communications
pathway that transfers data from one device to another.
There are two possible types of connections:
Point-To-Point
Multipoint.
Point-to-Point :
A point-to-point connection provides a dedicated link between two devices. The entire
capacity of the link is reserved for transmission between those two devices. Most point-to-
point connections use an actual length of wire or cable to connect the two ends, but other
options, such as microwave or satellite links, are also possible (see Figure 1.3a). When we
change television channels by infrared remote control, we are establishing a point-to-point
connection between the remote control and the television's control system.
Multipoint :
A multipoint (also called multidrop) connection is one in which more than two specific
devices share a single link (see Figure 1.3b). In a multipoint environment, the capacity of the
channel is shared, either spatially or temporally. If several devices can use the link
simultaneously, it is a spatially shared connection. If users must take turns, it is a timeshared
connection.
.
Physical Topology
CA5CRT14 : Computer Networks (Core)
Theory:3 hrs. per week
Credits:4
Unit 1: ( 10 hrs.)
Introduction to Networks, Data and signals-analog and digital, periodic analog signals, digital
signals, bitrate, baud rate, bandwidth.
Transmission impairments- attenuation, distortion and noise.
Data communication protocols and standards, Network models - OSI model-layers and their
functions.TCP/IP protocol suite.
Unit 2: (10 hrs.)
Bandwidth utilization Multiplexing: FDM, TDM, spread spectrum.
Transmission Media- guided media and unguided media.
Switching: message, Circuit and packet switched networks, datagram networks, virtual- circuit
networks.
Unit 3: (12 hrs.)
Data link layer: Error Detection and Correction, Framing, flow and error control, Protocols –
Noiseless channels (Simplest, Stop and Wait) and Noisy channels (Stop and Wait and Piggy
Backing).
Multiple Access Protocols. Random Access-ALOHA, CSMA.
Wired LANs-IEEE standards, wireless LANs-Bluetooth, Cellular Telephony
Unit 4: (12 hrs.)
Network layer and Transport layer: Repeaters, Bridges, Gateways and routers.
Logical addressing – IPV4 and IPV6 addressing, Internet protocol - IPV4 and IPV6.
Connectionless and Connection Oriented Services: UDP and TCP. Congestion Control, Quality
of Service.
Unit 5: (10 hrs.)
Application layer: HTTP, FTP, SMTP, DNS. Network security: Common Threats- Firewalls
(advantages and disadvantages), Cryptography.
Book of study:
1. B. A. Forouzan - Data communication and Networking, Fourth edition-,TMH
2. Andrew S Tanenbaum - Computer Networks ,Fourth Edition, Prentice Hall of India.
,UNIT -1:
Introduction to networks. Data and signals-analog and digital, periodic analog signals, digital
signals, bit rate, baud rate, bandwidth. Transmission impairments- attenuation distortion and
noise.
Data communication protocols and standards, Network models - OSI model-layers and their
functions. TCP/IP protocol suite.
DATA COMMUNICATION
Data communications are the exchange of data between two devices via some form of
transmission medium such as a wire cable. For data communications to occur, the
communicating devices must be part of a communication system made up of a combination
of hardware (physical equipment) and software (programs). The effectiveness of a data
communications system depends on four fundamental characteristics: delivery, accuracy,
timeliness, and jitter.
1. Delivery. The system must deliver data to the correct destination. Data must be received
by the intended device or user and only by that device or user.
2. Accuracy. The system must deliver the data accurately. Data that have been altered in
transmission and left uncorrected are unusable.
3. Timeliness. The system must deliver data in a timely manner. Data delivered late are
useless. In the case of video and audio, timely delivery means delivering data as they are
produced, in the same order that they are produced, and without significant delay. This kind
of delivery is called real-time transmission.
4. Jitter. Jitter refers to the variation in the packet arrival time. It is the uneven delay in the
delivery of audio or video packets. For example, let us assume that video packets are sent every
30 ms. If some of the packets arrive with 30-ms delay and others with 40-ms delay, an uneven
quality in the video is the result.
Components
A data communications system has five components (see Figure 1.1).
1. Message. The message is the information (data) to be communicated. Popular forms of
information include text, numbers, pictures, audio, and video.
2. Sender. The sender is the device that sends the data message. It can be a computer,
workstation, telephone handset, video camera, and so on.
3. Receiver. The receiver is the device that receives the message. It can be a computer,
workstation, telephone handset, television, and so on.
4. Transmission medium. The transmission medium is the physical path by which a
message travels from sender to receiver. Some examples of transmission media include
twisted-pair wire, coaxial cable, fiber-optic cable, and radio waves.
,5. Protocol. A protocol is a set of rules that govern data communications. It represents an
agreement between the communicating devices. Without a protocol, two devices may be
connected but not communicating, just as a person speaking French cannot be understood by
a person who speaks only Japanese.
Data Flow
Communication between two devices can be simplex, half-duplex, or full-duplex as shown in
Figure 1.2
Simplex
In simplex mode, the communication is unidirectional, as on a one-way street. Only one of
the two devices on a link can transmit; the other can only receive (see Figure 1.2a).
Keyboards and traditional monitors are examples of simplex devices. The keyboard can only
introduce input; the monitor can only accept output. The simplex mode can use the entire
capacity of the channel to send data in one direction.
Half-Duplex
In half-duplex mode, each station can both transmit and receive, but not at the same time.
When one device is sending, the other can only receive, and vice versa (see Figure 1.2b).
Walkie-talkies and CB (citizens band) radios are both half-duplex systems. The half-duplex
mode is used in cases where there is no need for communication in both directions at the
same time; the entire capacity of the channel can be utilized for each direction.
Full-Duplex
In full-duplex mode (also called duplex), both stations can transmit and receive
simultaneously (see Figure 1.2c).
In full-duplex mode, signals going in one direction share the capacity of the link: with signals
going in the other direction This sharing can occur in two ways: Either the link must contain
two physically separate transmission paths, one for sending and the other for receiving; or the
capacity of the channel is divided between signals travelling in both directions.
One common example of full-duplex communication is the telephone network. When two
people are communicating by a telephone line, both can talk and listen at the same time.
, The full-duplex mode is used when communication in both directions is required all the time.
The capacity of the channel, however, must be divided between the two directions.
Network
Physical Structures
Network Attributes
Type of Connection
A network is two or more devices connected through links. A link is a communications
pathway that transfers data from one device to another.
There are two possible types of connections:
Point-To-Point
Multipoint.
Point-to-Point :
A point-to-point connection provides a dedicated link between two devices. The entire
capacity of the link is reserved for transmission between those two devices. Most point-to-
point connections use an actual length of wire or cable to connect the two ends, but other
options, such as microwave or satellite links, are also possible (see Figure 1.3a). When we
change television channels by infrared remote control, we are establishing a point-to-point
connection between the remote control and the television's control system.
Multipoint :
A multipoint (also called multidrop) connection is one in which more than two specific
devices share a single link (see Figure 1.3b). In a multipoint environment, the capacity of the
channel is shared, either spatially or temporally. If several devices can use the link
simultaneously, it is a spatially shared connection. If users must take turns, it is a timeshared
connection.
.
Physical Topology
