Network Hardware

Network
Hardware
Network Interface Card (NIC)
● A network interface card (NIC) is

needed to allow a device to
connect to a network (such as the
internet).
● It is usually part of the device

hardware and contains the Media
Access Control (MAC) address
generated at the manufacturing
stage.
Network Interface Card (NIC)
● Wireless network interface

cards/controllers (WNICs) are the
same as NICs in that they are used to
connect devices to the internet or
other networks.
● However, they use wireless

connectivity utilising an antenna to
communicate with networks via
microwaves.
Media Access Control
A MAC address is made up
of 48 bits which are shown
as six groups of hexadecimal
digits with the general
format:
Media Access Control
● For example, 00 – 1C – B3 – 4F – 25 – FF where the first six hex

digits identify the device as made by, for example, Apple and
the second set of six hex digits are the serial number of the
device itself (this is unique).
● If the NIC card is replaced, the MAC address will also change.
Types of MAC Address
● It should finally be pointed out that there are two types of MAC
address: the Universally Administered MAC Address (UAA) and
the Locally Administered MAC Address (LAA).
● The UAA is by far the most common type of MAC address, and
this is the one set by the manufacturer at the factory. It is rare
for a user to want to change this MAC address
MAC Address
However, there are some occasions when a user or organisation wishes to
change their MAC address. This is a relatively easy task to carry out, but it will
cause big problems if the changed address isn’t unique.
There are a few reasons why the MAC address needs to be changed using LAA:
● Certain software used on mainframe systems need all the MAC addresses of
devices to fall into a strict format; because of this, it may be necessary to
change the MAC address of some devices to ensure they follow the correct
format
MAC Address
● It may be necessary to bypass a MAC address filter on a router or

a firewall; only MAC addresses with a certain format are allowed
through, otherwise the devices will be blocked if their MAC
address doesn’t adhere to the correct format
● To get past certain types of network restrictions it may be

necessary to emulate unrestricted MAC addresses; hence it may
require the MAC address to be changed on certain devices
connected to the network.
Internet Protocol (IP) Address
● When a device connects to a
private network, a router
assigns a private IP address to
it.
● That IP address is unique on
that network but might be the
same as an IP address on a
separate network. However,
when a router connects to the
internet it is given a unique
public IP address.
● This is usually supplied by the internet
service provider (ISP). No other device
on the internet has the same public IP
address.
● All the devices connected to that router

have the same public IP address as the
router, but each have their own different
private IP addresses on that network.
There are two versions of IP: IPv4 and IPv6. IPv4 is based on 32
bits and the address is written as four groups of eight bits (shown
in denary format); for example,
Because the use of only 32 bits considerably reduces the potential
number of devices and routers used on the internet at any one
time, a newer version called IPv6 is now used. This uses 128-bit
addresses that take the form of eight groups of hex digits; for
example
IPv6 has been designed to allow the internet to grow in terms of
the number of hosts and potential increase in the amount of data
traffic.
The main advantages of IPv6 compared to IPv4 are:
● Removes the risk of IP address collisions

● Has built-in authentication checks
● Allows for more efficient packet routes
Compares the features of MAC addresses and IP addresses:
Static and Dynamic IP Addresses
IP addresses can be either static (don’t change) or dynamic
(change every time a device connects to the internet).
Static
Static IP addresses are permanently assigned to a device by the
internet service provider (ISP); they don’t change each time a
device logs onto the internet.
Static IP addresses are usually assigned to:
● Remote servers which are hosting a website
● An online database
● A File Transfer Protocol (FTP) server. FTP servers are used when
files need to be transferred to various computers throughout
the network.
Dynamic
Dynamic IP addresses are assigned by the ISP each time a device
logs onto the internet.
This is done using Dynamic Host Configuration Protocol (DHCP).

A computer on the internet, configured as a DHCP server, is used
by the ISP to automatically assign an IP address to a device. As the
name suggests, a dynamic IP address could be different every time
a device connects to the internet.
● Figure 3.71 shows the sequence of events when either a
dynamic IP address or static IP address is assigned to a device
using the internet.
●
● The diagram shows how a device contacts web servers that are
also connected to the internet.
● A DHCP server supplies a dynamic IP address to the device, a

DNS server looks up the domain name of the desired website
into an IP address and a website server contains the web pages
of the desired website.
● Figure 3.71 shows the sequence of events when either a
dynamic IP address or static IP address is assigned to a device
using the internet.
●
● The diagram shows how a device contacts web servers that are
also connected to the internet.
● A DHCP server supplies a dynamic IP address to the device, a

DNS server looks up the domain name of the desired website
into an IP address and a website server contains the web pages
of the desired website.
Router
Routers enable data packets to be

routed between different networks,
for example, to join a LAN to a WAN.
The router takes data transmitted in
one format from a network (which is
using a particular protocol) and
converts the data to a protocol and
format understood by another
network, thereby allowing them to
communicate.
Router
● A router would typically have an internet cable plugged into it
and several cables connecting to computers and other devices
on the LAN.
Router
Broadband routers sit behind a firewall. The firewall protects the
computers on a network. The router’s main function is to transmit
internet and transmission protocols between two networks and
also allow private networks to be connected
together.
Router
● Routers inspect the data package sent to it from any computer on any of the
networks connected to it.
● Since every computer on the same network has the same part of an internet
protocol (IP) address, the router is able to send the data packet to the
appropriate switch, and the data will then be delivered to the correct device
using the MAC destination address.
● If the MAC address doesn’t match any device connected to the switch, it
passes on to another switch on the same network until the appropriate
device is found. Routers can be wired or
wireless devices.
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Network Hardware

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Network

● A network interface card (NIC) is

● It is usually part of the device

● Wireless network interface

● However, they use wireless

● For example, 00 – 1C – B3 – 4F – 25 – FF where the first six hex

● It may be necessary to bypass a MAC address filter on a router or

● To get past certain types of network restrictions it may be

● All the devices connected to that router

The main advantages of IPv6 compared to IPv4 are:

● Removes the risk of IP address collisions

● Remote servers which are hosting a website

This is done using Dynamic Host Configuration Protocol (DHCP).

● A DHCP server supplies a dynamic IP address to the device, a

● A DHCP server supplies a dynamic IP address to the device, a

Routers enable data packets to be

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