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NETWORK DEVICES DATA COMMUNICATION SYSTEM

There are various devices used in a network. These include: Data communication is the process of exchanging data between two devices.
Network Interface Card (NIC): A device attached to a computer
that enables communication over a network. The NIC contains a
ROM chip that has a unique number called the Media Access Sender Message Receiver
Control (MAC) address, identifies the computer on the network.
Transmission Medium
Rule 1, Rule 2, ... Rule n Rule 1, Rule 2, ... Rule n
Modem: A device that allows computers and other devices to connect to Protocol Protocol
the internet. It converts digital data into analog signals for transmission over
telephone lines and vice versa. There are five main components in a data communication system:
Message: This refers to data or a piece of information that is to be communicated.
Hub: A device that joins multiple computers to form a single network Sender: This is a source in a data communication system. It is a device that sends a
segment. It forwards data to all connected computers.
data message.

Receiver: This is the destination of the final message sent by the source. It is a device that
Switch: A device that connects multiple computers within a Local
Area Network (LAN). It manages data traffic to ensure that data receives messages.
reaches only the intended destination. Unlike a hub, a switch Transmission medium: This is the channel or bridge through which the message travels from
forwards data only to the target device. the sender to the receiver.
Protocol: This refers to a set of rules or guidelines that defines how data is transmitted and
Router: A device that connects different networks and directs data received over a network.
packets between them based on their IP addresses.

Network repeater: A device that boosts incoming electrical, wireless or optical NETWORK PROTOCOLS
signals. It amplifies signals to prevent them from becoming too weak or corrupted
during transmission. A network protocol is a set of rules that are applicable for a network to define how data is
transmitted and received between the devices connected to the network. Some commonly used

Gateway: A device that connects dissimilar networks those using different network protocols include:
protocols. A gateway takes data from one system, interprets it and Transmission Control Protocol/Internet Protocol (TCP/IP): The protocol that is used to
transfers it to another system. connect devices on the Internet. It sends data in the form of packets and reassembles them at
the destination.

Bridge: A device that connects similar networks, usually LANs using Hypertext Transfer Protocol (HTTP): The protocol that ensures smooth transfer of web pages
the same hardware and protocols. It reduces the traffic on other between a server and browser.
network segments as it filters the data based on the MAC addresses Hypertext Transfer Protocol Secure (HTTPS): A secure version of HTTP that encrypts the
of the source and destination before forwarding it.
communication between browser and server.

File Transfer Protocol (FTP): A standard network protocol that is used to transfer files from
Imagine computer networks as highways in the sky. What kinds of vehicles would one computer (host) to another.
travel on these highways and what destinations would they reach?
Simple Mail Transfer Protocol (SMTP): An Internet standard used for sending emails.

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Networks Around Us