Networks

1. Router
a. The operations and purpose of a router. Routers are used to route data
packets from one network to another, based on IP addresses. It can do
that because each router has its own IP address. Routers are used to join
a LAN to the internet. When a data packet is received at one of its ports,
the router inspects the IP address and determines whether the data
packet is meant for its own network or for another external network. If
the data packet is meant for its own network, then data packet is routed
to the local switch or hub. Otherwise, it will be transmitted to a different
router.
 Connecting networks and devices to the internet
 Storing computer addresses in a router (routing table)
 Routing data packets
2. Common network devices
a. Network interface cards (NIC) is needed to allow a device to connect to a
network, usually integrated into the motherboard on most modern
computers.
Each NIC has a unique hardwired media access control (MAC) address.
Wireless NICs are the same but they use wireless connectivity.
b. Hubs are hardware devices that can have a number of other devices
connected to them. They are used primarily to connect devices together
to form a Local area network (often in the same building). A hub will take
the data packet received at one of its ports and broadcast it to every
device connected to it.
c. Bridges are devices that connect one LAN to another LAN that uses the
same protocol.
d. Switches are intelligent versions of hubs. Unlike hubs, a switch stores
the MAC addresses of all devices on the network. Therefore the switch
only redirects the data packets to the correct device. (Look-up table)
3. Wi-Fi and Bluetooth
a. Uses: both offer wireless communication between devices. Both use
electromagnetic radiation as the carrier of the data transmission.
b. Connecting devices to a network using
 Wi-Fi
 Sends and receives the data in several frequency bands, the
most common ones are 2.4 GHz and 5 GHz, each band has
several channels.
  Best suited for full-scale network (where faster data
transfer rates, better range and security is required). A Wi-
Fi enabled device can access the internet wirelessly.
 Bluetooth
 Has different 79 channels (constantly changing while
transmitting data in order to minimize the risk of data
interference). This is known as spread-spectrum frequency
hopping.
 Useful when transferring data between 2 or more very
close devices or when the speed of data transmitting is not
critical. Also it’s useful for low-bandwidth applications.
c. Similarities and differences between Wi-Fi and Bluetooth

4. Cloud computing
a. Characteristics. Data is stored on remote servers allowing the client to
access data at any time (even in case of server maintenance or repair)
which is called Data redundancy.
b. Issues. There is a risk that important data could be lost from cloud
storage facilities. Actions from hackers could lead to loss or corruption
of data.
c. Advantages and disadvantages
Advantages Disadvantages
Data can be accessed at any time, Security aspects
from any device
Client don’t need to carry an Having a slow internet connection
external storage device might affect the data access or
downloading it
The cloud provides the user with Cost can be high
remote backup of the data
Cloud storage allow the recovery The potential failure of the cloud
of the data (in case of a failure of storage is always possible
 hard disk)
Unlimited storage capacity

5. Common network environments (to be explained in chapter 10)

a. Extranet (characteristics, uses and purpose)
b. Intranet (characteristics, uses and purpose)
c. Internet (characteristics, uses and purpose)
d. Extranet, Intranet and internet similarities and differences
6. Network types
a. Local Area Network (LAN): usually within one building or geographically
near each other. A number of terminals connected to hubs or switches.
b. Wireless Local Area Network (WLAN): similar to LANs, but there are no
wires or cables (wireless network communications over fairly short
distance).
 Access points (Aps) connected to a wired network are needed to
extend the range of the wireless network.
c. Wide Area Network (WAN): are used where computers or networks are
situated a long distance from each other geographically. A number of
LANs are joined together using a router, and then they can from a WAN.
The network of ATMs used by banks is one of the most common
examples of the use of a WAN.
 WANs usually make use of some public communication network
(such as telephone lines) and also can use dedicated or leased
communication lines.
7. Passwords are used in many instances when accessing the internet.
a. Avoiding password interception
 Running anti-spyware software
 Change passwords on a regular basis
 Passwords should not be easy to crack
 Strong password should contain:
 At least one capital letter
 At least one numerical value
 At least one special character (@ # % $)
8. Other authentication methods
a. Zero login and biometric methods: allows the user to login to computer
systems without the need to type in a password. Zero login essentially
relies on devices being smart and secure enough to instantly recognize a
user by a number of features based on biometrics and behavior patterns.
 Such as fingerprints, face recognition also the typing speed, the normal
location and how you swipe the screen as well.
b. Magnetic stripe: covered in unit 2 and 6
c. Smart cards.
By inserting a tag into a security card, it can act as smart (contactless
card). Smart cards can be used as security devices.
d. Physical tokens (hardware) – Refer to the book page 90 for further
details
e. Electronic tokens (software) – refer to the book page 91 for further
details.
9. Anti-malware software
a. The use of anti-virus. Anti-virus should be loaded onto a computer and
then run to allow all software and devices to be scanned for viruses.
10. Electronic conferencing
a. Video conferencing is a communication method (face to face interaction)
that uses both video and sound,
 Hardware
 Webcams
 Large monitors
 Microphones
 Speakers
 Software
 Webcam and microphone software drivers
 CODEC (Coder-Decoder)
 Echo cancellation software

Advantages Disadvantages
 Easier to access important  Potential time lag in
documents or bring in responses
(experts) at key part of the  Image can jerk
conference  It can be very expensive to
 Possible to hold set up in the first place
conference at short notice  Problem with the different
 Reduce the travelling cost time zones
 Better than travelling to  Training people to use the
unsafe places system can be costly and
 Better for the environment time consuming
 Connects people in an  The whole system relies on
organization who might be a good network connection
otherwise left out
b. Audio conferencing
 Hardware
 A computer with built in microphone and speaker
 External microphone/ speakers
 Internet phone (VoIP) Voice over Internet Protocol
 Standard phone
c. Web conferencing (mainly to share data, documents, presentations and
content). Often referred to as webinar or webcasts.
 Business meetings
 Presentations
 Online education or training
 The only requirement is a computer with high-speed, stable
internet connection.
 Each user should download an application or log on to a website
from a link supplied.