4. Networks and the Effects of Using Them

Question 1

State the purpose of a router

Answer 1

1. Connect networks and devices to the internet
2. Storing computer addresses
3. Routing data packets

Question 2

State the operation of a router

Answer 2

Main points:
1. Connects: To a modem using an Ethernet cable
2. Splits: Data into data packets. Which contains the IP address and the data
3. Sends/receives: Data packets to/from different networks
4. Stores: IP addresses in its routing table (can store a route to the target device)
5. Reads: The destination IP address. Consequently, checking the IP address against its routing table
6. Forwards: Data packet to the appropriate network segment

Question 3

Explain the common network devices including: network interface cards (NIC), hubs, bridges, switches

Answer 3

a) Network interface card: Required for a computer to connect to a network (can be wired or wireless)
- Allows computers to send and receive data over a network
b) Hubs: Connects multiple devices in a network
- Pass on anything received on one connection to all other connections
c) Bridges: Connect two local area networks (LANs) together to create one larger network
d) Switches: Connects multiple devices on a network together
- Only sends data to the device it was intended for. Improving network efficiency
- After receiving a data packet, switches examine the destination MAC address of the packet. Looking up that address in the lookup table
- Once it has found the matching MAC address, it forwards the data packet to the corresponding device

Question 4

Explain the uses of wi-fi and Bluetooth

Answer 4

a) Wi-Fi (e.g. used in laptops, tablets and smartphones)
1. Full-scale networks
2. When the data transfer rate is crucial
3. Where a higher range and better security are required
b) Bluetooth (e.g. used in headphones, controllers and mice)
1. When transferring data between 2 or more devices that are very close together
2. When the speed of data transmission isn’t crucial
3. For low-bandwidth applications

Question 5

Explain how to connect a device to a network using: wi-fi

Answer 5

1. Data: From the device is sent to its wireless adapter
2. Conversion: Data is converted into radio waves. Which are transmitted and received by a wireless adapter. That converts radio waves into data
3. Handshake: Initiated by the computer to the wireless router. Which responds, establishing a session/pairing
4. Password: Has to be entered by the user for known connections. The wireless router checks if it’s correct. If so, data is transmitted

Question 6

Explain how to connect a device to a network using: bluetooth

Answer 6

1. Data: From Device A is sent to its bluetooth connector
2. Conversion: Data is converted to radio waves
3. Automatically: Device A detects nearby devices. Pairing to the other device if in range
4. Channels: 79 possible channels are randomly chosen by Device A. If the channel is in use, another channel is randomly chosen. Every few seconds, the connection changes channels
5. Sends: Radio wave to the other device

Question 7

State the similarities and differences between Bluetooth and wi-fi

Answer 7

a) Frequency:
- Bluetooth operates at 2.4 GHz.
- Wi-Fi operates across 2.4 GHz to 5.0 GHz.
b) Data Transfer Speed:
- Wi-Fi provides a much faster data transfer rate compared to Bluetooth.
c) Range:
- Wi-Fi has a significantly larger coverage area.
- Bluetooth is limited to short-range communication.
d) Device Connections:
- Bluetooth supports a maximum of 7 connected devices at once.
- Wi-Fi can support many more devices, depending on the router’s capacity.
e) Security:
- Bluetooth uses key-matching encryption.
- Wi-Fi uses WPA (Wi-Fi Protected Access) and WEP (Wired Equivalent Privacy) protocols for stronger security.