9.1 Networking

Question 1

Topology

Answer 1

The structure of a network

Question 2

Physical Topology

Answer 2

The actual architecture of a network

Question 3

Physical Star Topology

Answer 3

• Each client has a direct connection to the central hub
• the hub receives packets for all the clients and delivers them to the correct recipient
• A server can be added by directly connecting it to the hub

Question 4

Advantages of Physical Star Topology

Answer 4

• Packets are sent directly to their recipient
• Other clients cant see the packets being sent
• Easy to add and remove clients
• No collisions as each cable connects only one device
• Failure of one cable doesnt effect the whole network

Question 5

Disadvantages of Physical Star Topology

Answer 5

• Central Hub Fails = Entire system fails
• Expensive (a lot of cabling)

Question 6

Physical Bus Topology

Answer 6

• Clients are connected to a single cable called the backbone.
• A terminator is placed at either end of the backbone
• The server can be connected to the backbone like a client

Question 7

Advantages of Physical Bus Topology

Answer 7

• No central hub reducing chance of network failure
• No central hub means cheaper
• Little cabling is required (inexpensive)

Question 8

Disadvantages of Physical Bus Toplogy

Answer 8

• Clients can see all the packets being sent on the backbone, including ones not intended for them
• Risk of collisions
• Backbone failure = Entire system fails

Question 9

Logical Network Topology

Answer 9

Flow of data packets within a network

Question 10

Logical Bus Network

Answer 10

Delivers packets to all clients

Question 11

Logical Star Network

Answer 11

Delivers packets only to the recipient

Question 12

Physical Star, Logical Bus

Answer 12

Running a bus protocol on the physical star network allows the hub to distribute packets to all connected clients, making it act like a bus network

Question 13

Host

Answer 13

Device which provides services
Usually a server

Question 14

Examples of services a host provides

Answer 14

File storage, printer sharing, internet access

Question 15

Client Server Networking

Answer 15

• Use one or more central servers to provide services to clients on the network
• Connected to the network the same way as clients, but are more powerful machines

Question 16

How Client Server Networking Works

Answer 16

• Clients on the network request services from the server which then responds with the services

Question 17

Advantages/Disadvantages of Client Server Networking

Answer 17

ADVANTAGES
- Allows for central management
- Improved security

DISADVANTAGES
- Fair degree of expertise to setup and manage

Question 18

Peer to Peer Networking

Answer 18

Services are provided by the clients themselves and every client has equal status

Question 19

Advantages and Disadvantages of Peer to Peer Networking

Answer 19

ADVANTAGES
- More cost effective
- Easier to set up and maintain

DISADVANTAGE
- All clients providing services must be running at all times

Question 20

Wireless Networking

Answer 20

Allow clients to communicate within a network without physically being connected to it.

Question 21

Structure of a Wireless Network

Answer 21

• A wireless access point that connects to a wired network
• A Wireless network adapter in the devices connected to the network

Question 22

WIFI

Answer 22

A Wireless Local Area Network that is based on international standards.

Question 23

WPA/WPA2

Answer 23

• Data is encrypted using WPA or WPA2.
• WPA stands for wifi protected access
• requires a new wireless client to enter a password to connect to the network

Question 24

SSID

Answer 24

• Disabling SSIID Broadcast improves security
• Stands for Service Set Identifier
• Stops wireless device within the range of the network from seeing the network is available, and requiring clients to know the SSID to connect.

Question 25

MAC Address Filtering

Answer 25

• Wireless networks can be protected by using MAC address filtering.
• Stands for media access control
• They are addresses assigned to every wireless device by their manufacturer.
• Using MAC Address whitelists allows only certain MAC Addresses to join the network
• Using MAC Address blacklists bans certain MAC Addresses from joining the network.

Question 26

CSMA/CA

Answer 26

• Stands for Carrier Sense Multiple Access With Collision Avoidance
• Avoids data collisions in wireless networks caused by multiple devices communicating simultaneously.

Question 27

How does Carrier Sense Multiple Access With Collision Avoidance

Answer 27

• A device listens to its communication channel to check if it’s idle.
• If yes, data is transmitted.
• If not, the device waits a random period of time before trying again.
• An exponential backoff algorithm increases the time for each wait period.

Question 28

Effectiveness of CSMA/CA

Answer 28

• Good at avoiding collisions in small networks
• Cannot overcome hidden nodes as they cannot see if there is communication.

Question 29

How to Get Around Hidden Nodes in CSMA/CA

Answer 29

-The protocol request to send/clear to send is used.
- Once the device has checked if the communication channel is clear, it sends a request to send message to the server.
- If the server is Idle, it’ll send back a clear to send. Transmission starts.
- If the server doesn’t send a clear to send the device waits a random period of time as the server is busy with a hidden node.