Page 14 - M. Abrahim Thesis

Chapter (1) Introduction to Networking

This introductory view might make the Internet seem like an overly simple process.
However, as this topic is explored in greater depth later in this book, it will become apparent
that sending data across the Internet is a complicated task.
https://www.youtube.com/watch?v=93-3zmVvCGU&t=22s

1.3 Network Interface Cards

NIC is a printed circuit board that provides network communication capabilities to and
from a PC. Also called a LAN adapter, a NIC plugs into a motherboard and provides a port for
connecting to the network. The NIC constitutes the computer interface with the LAN. The NIC
communicates with the network through a cable and with the computer via an expansion slot.
When a NIC is installed in a computer, it requires an interrupt request (IRQ) for service from the
CPU, as well as an input/output (I/O) address, a memory space for the operating system (such
as Linux or Windows), and drivers to perform its function. An IRQ is a signal that informs a CPU
that an event needing its attention has occurred. An IRQ is sent over a hardware line to the
microprocessor.

An example of an interrupt being issued is a key being pressed on the keyboard. The CPU
must move the character from the keyboard to RAM. An I/O address is a location in memory
used to enter data into or retrieve data from a computer using an auxiliary device.

When selecting a NIC for a network, consider the following:

• Type of network—Different types of networks use different types of NICs. For example,
Ethernet NICs are designed for Ethernet LANs. Some other types of networks include
Token Ring and Fiber Distributed Data Interface (FDDI). Ethernet is by far the most
common.
• Type of medium—The type of port or connector used by the NIC for network

connection is specific to the medium type, such as twisted-pair, coaxial, fiberoptic, or
wireless. Coaxial is becoming increasingly rare.
• Type of system bus—There are different types of system buses, such as PCI and ISA.
Because PCI slots are faster than ISA slots, the latter are being phased out.

https://www.youtube.com/watch?v=m9evUZtkEAc

1.3.1 NIC and Modem Installation

Connectivity to the Internet requires an adapter card, which might be a modem or NIC.
A modem is an electronic device that is used for computer communications through telephone
lines. It allows data transfer between one computer and another over the Public Switched
Telephone Network (PSTN).

Typically, modems send data in blocks of bytes. After each block, basic math is performed
to analyze the block, and the computer on the receiving end is asked whether it agrees with the
results. If any differences appear, the block is sent again. The modems convert digital data to

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