Notes on Class 2

1. CITY UNIVERSITY
Department of Computer Science and Engineering
Class note
Course Title: Data Communication
Course Code: CSE 313
Submitted to:
PRANAB BANDHU NATH
Senior Lecturer
Dept. Of CSE
City University
Submitted By:
Md. Zillur Rahman
ID: 1834902144
Dept.: CSE

2. Notes on Class 2
Transmission Modes in Computer Networks:
Simplex: The communication between the sender and the receiver occurs in only
one direction in simplex transmission mode. The data can only be sent bythe sender,
and the data can only bereceived bythe recipient. The recipient is unable to respond
to the sender.
Half-duplex: Half-duplex transmission allows communication between the sender
and receiver in both directions, but only one at a time. Both the sender and the
receiver can send and receive data, but only one of them can send at any one time.
A half duplex is still considered a one-way road, which means that a vehicle moving
in the opposite direction of traffic must wait until the road is clear before passing.
Full-duplex: In full duplex transmission mode, the sender and receiver can
communicate at the same time. Both the transmitter and the receiver can send and
receive data at the same time. Full duplex transmission mode is analogous to a two-
way street, with traffic flowing in both directions at the same time.

3. Analog Signal: An analog signal is a continuous signal whose time-varying feature
is a representation of another time-varying quantity. Human voice, thermometer,
analog phones, and so on.
Digital signal: The data is represented as a series of discrete numbers in a digital
signal. A digital signal can only take one value from a finite set of possible values at
any one time. Computers, digital phones, and other electronic devices are examples.
Intranet: An intranet is a private network that can only be accessed by authorized
users. Intranets serve many different purposes, but their primary objective is to
facilitate internal communication.
Internet: The internet is a worldwide network system that connects a broad
collection ofprivate, public, business, academic, and government networks to enable
global communication and access to data resources.
NIC: A Network Interface Card (NIC) is a piece of hardware that is installed on a
computer to allow it to connect to the internet. It's also known as a network adapter
or Ethernet card. Every NIC has a 48-bit serial number known as a MAC address
that is stored in ROM on the card.
MAC Address: A MAC (Media access control) address is a unique identifier
assigned to a network interface controller for use as a network address in

4. communications within a network segment. MAC address provides a secure way to
find senders or receivers in the network and helps prevent unwanted network access.
It also referred as hardware addresses.
Types of Computer Network:
Local Area Network (LAN): The LAN, or Local Area Network, is a network that
allows personal computers and workstations to share data, tools, and programs. A
switch, or stackof switches, connects a set of computers and devices using a private
addressing system provided by the TCP/IP protocol. In comparison to other
computers on the local network, private addresses are unique. Routers are located at
the LAN's edge, linking it to the broader WAN.
Examples of Local Area Network (LAN):
• Networking in home, office.
• Networking in school, laboratory, university campus.
• Networking between two computers.
• Wi-Fi (When we consider wireless LAN).
Metropolitan Area Network: A Metropolitan Area Network, or MAN, is a
computer network that spans a city, a college campus, or a small area. This network

5. is much larger than a LAN, which is usually restricted to a single building or
location. This type of network can cover a range of distances from a few miles to
tens of miles, depending on the arrangement.
Example of Metropolitan Area Network:
• Cable TV network.
• Telephone networks providing high-speed DSL lines.
Campus Area Network (CAN): A Campus Area Network (CAN) is a collection of
interconnected Local Area Networks that span a specific geographic area, such as a
schoolcampus, a university campus, a military post, ororganizational campuses and
corporate buildings. A Campus Area Network (CAN) is larger than a Local Area
Network (LAN), but it is smaller than a Metropolitan Area Network (MAN).
Example of Campus Area Network:
• Network between school, library and hostel.
• Network between houses.
Wide Area Network (WAN): Another important computer network that spans a
broad geographical area is the WAN (Wide Area Network). A WAN network system

6. could be a LAN link that uses telephone lines and radio waves to connect to other
LANs. It is usually restricted to a single company or group.
Reference: Book: Data Communication and Networking By Behrouz A.Forouzan