Network hardware

Q1. a)  What is a  computer network ? 

A Computer Network is a communication system with interconnected computing devices that exchange data and share resources with each other.

These networked devices use a system of rules, called communication protocols, to transmit information over physical or wireless technologies.

b)  Describe the following components of computer network.

• Node : A Node refers to any device that is connected to a network.
• Client : A Client is a node that requests and uses resources available from other nodes.
• Network Server : A powerful computer that provides various shared resources to workstations and other servers on a network. The shared resources can include disk space, hardware access and email services.
• File Server : A Server that provides access to files and folders. It acts as a central file storage location.
• Application Server :
  • A Server that manages the distribution of applications software.
  • Hosts Web Apps.
  • Network users may run and use applications without havint to install a copy.
  • May be a part of the world wide web or a local netwok.
• Proxy Server :
  • A Server that sits between client computer and the web server.
  • It accepts incoming traffic from the client and send it to the web server using its own IP-address, hiding the IP-address of client.
  • It filters the internet traffic against set criteria to allow or block access to a website
  • It protects direct attack on web-server by hackers.
  • It improve web performance by storing a copy of frequently used web-pages in its cache.

c)  Give the advantages and disadvantages of Network.

 ADVANTAGES :

1.  Computers can communicate with each other easily.
2.  Computers can share data and files.
3.  Storage facilities can be shared.
4.  Hardware peripherals such as printers can be shared.
5.  Have control over a user access.
6.  Data can easily be backed up centrally.

 DISADVANTAGES :

1.  A Virus can spread more easily across the network.
2.  There is a great need for Security, as data is shared.
3.  If the Server fails, all the workstations are affected.
4.  The cost of installing the equipment is greater.
5.  Damage to cables can isolate the computers.

Q2.  Describe the following network hardware needed to connect devices in a computer network.

a)  What is a  Network Interface Card (NIC). 

⇒  NIC is a hardware that allows a device to connect to the internet or a network.

⇒  It contains Media Access Control (MAC) address generated at the time of manufacturing.

⇒  It could be on a separate card, built into the motherboard or plugged into USB port.

⇒  NICs exist for both wired and wireless connections.

⇒  Wired NIC rely on an input jacks and wired LAN technology. Wireless NIC (WNIC) rely on an antenna to communicate through radio frequency waves (or microwaves) on Wi-Fi connection.

b)  What is a network  Switch  and how does it work?

⇒  Switch is a hardware that connects devices on a LAN (Local Area Network).

⇒  Switches receive data in units called frames or data packets, identifies its destination MAC address of the device and transmits it only to the device it is intended to reach.

c)  Describe the function of a  Router  in a network.

⇒  Router is a hardware used to connect atleast two different networks, like LAN (home or office) network to WAN (Internet) network.

⇒  Router receives data transmitted in one format from a network, and converts the data to another format understood by another network using its particular protocol.

⇒  A Router would typically have an Internet cable plugged into it and several cables connecting to computers and other devices on the LAN.

⇒  Router sit behind a firewall that protects the computers on a network.

⇒  Routers can be wired or wireless device.

Since every computer on the same network has the same part of an 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 destination MAC-address.

If the MAC address doesn't match to any device connected to the switch, it passes on to the another switch on the same network until the appropriate device is found.

Q3.  When the devices are connected to the Internet they are given IP addresses supplied by an ISP. IP addresses are necessary since the operation of the internet is based on a number of protocols.

a)  State what is meant by an  ISP (Internet Service Provider). 

⇒  Internet Service Provider (ISP) is the company that provides access to the internet to the user.

⇒  The ISP creates an user account for their client in their system, secured by Username and Password for providing Internet services.

⇒  A monthly fee is usually charged for this service.

b)  State what is meant by a  protocol. 

⇒  A protocol is a set of rules that determines how data is transmitted between different devices on a computer network or internet.

⇒  It allows the devices to communicate with each other, regardless of any differences in their internal process, structure or design.

⇒  Protocols are build into device software and hardware to perform primary network tasks of communication, management and security.

Q4. a)  Describe  Media Access Control (MAC)  address.

❋  MAC address is a unique 48-bits hardware identification number assigned to a Network Interface card (NIC) by its manufacturer.

❋  It contains 6-pairs of hexadecimal digits separated by colon (:) or hyphen (-). The first 3-pairs of hex-digits represents the manufacturer-ID and the last 3-pairs of hex-digits is the serial number of the device (written in the form A6-1C-B3-09-85-15).

❋  MAC address of each network device should be unique all over the world.

b)  Give difference between  Universally Administered MAC Address (UAA)  and  Locally Administered MAC Address (LAA). 

 Universally Administered MAC Address (UAA) : 

⇒  UAA is the most common type of MAC address set by the manufacturer at the factory which is permanent and never changes.

 Locally Administered MAC Address (LAA) : 

⇒  LAA is the MAC address assigned by the user or system administrator; to ensure the correct format for certain software’s to work properly.

⇒  It is an easy task to change MAC address but it will cause big problems if the changed address isn't unique.

c)  Give three reasons why the MAC address needs to be changed using LAA.

1. Certain software used on mainframe systems need all the MAC addresses of devices to fall into a strict format; because of this, it is necessary to change the MAC address of some devices to ensure they follow the correct format.
2. 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
3. Changing the MAC Address can help you bypass certain network restrictions by emulating an unrestricted MAC Address that are authorized.

Q5. a)  What is  Internet Protocol (IP) address  in networking ?

❋  IP address is a unique location address that identifies a device on a local area network (LAN) or internet a wide area network (WAN).

❋  It allows information to be sent between devices on a network and make devices accessible for communication.

❋  It is assigned automatically by ISP using DHCP server or manually configured by the user.

b)  State the difference between two versions of IP-address  IPv4  and  IPv6 .

1. IPv4 is a 32-bits address written in a group of four 8-bits denary numbers separated by dots (.).
   Example, 192.168.42.22
   IPv6 is a 128-bits address written in a group of eight 16-bits hex-digits separated by colons (:).
   Example, A8FB:7A88:FFF0:0FFF:3D21:2085:66FB:F0FA
2. IPv6 network can be configured automatically, while IPv4 networks have to be configured either manually or through DHCP.
3. IPv6 uses an IP security protocol (IPSec), while IPv4 relies on applications.

c)  Give the  characteristics  of an  IPv4  address.

1. IPv4 is a 32-bits address written in a group of four 8-bits denary numbers separated by dots (.).
2. It can be static assigned manually or dynamic assigned automatically by DHCP server.
3. It can be public or private; public IP is unique globally when connected to Internet; private IP is unique when connected in separate private network.
4. When a router connects to the Internet it is given a unique public IP-address.
5. All the devices connected a router have the same public IP-address as of the router.

d)  Give the  characteristics  of an  IPv6  address.

1. IPv6 is a 128-bits address written in a group of eight 16-bits hex-digits between 0000 and FFFF separated by colons (:).
2. It allows the Internet to grow with large number of devices on the network.
3. It removes the risk of IP-address collisions.
4. It contains built-in authentication checks.
5. It allows more efficient packet routing.

e)  What are the main  advantages of IPv6  compared to IPv4 ?

1. IPv6 is thousand times (1028) larger than IPv4, so it allows the internet to grow in size.
2. Removes the risk of IP-address collisions.
3. Has built-in authentication checks.
4. Provide auto-configuration capabilities.
5. Allows more efficient and hierarchical packet routing.

Q6. a)  What is the difference between  Private  and  Public IP-address. 

 Private IP-address :  

⇒  Private IP-address is assigned automatically by Router which are unique on that particular LAN network.

⇒  It is used to communicate within the network.

 Public IP-address :  

⇒  Public IP-address is assign automatically by internet service provider (ISP) using DHCP server which are unique on internet.

⇒  It is used to communicate over internet outside the LAN network.

b)  Explain why we need both Private and Public IP-address on a network.

⇒  Private IP-address is used to communicate within the network assigned by the Router, which is unique on that network.

⇒  Public IP-address is used to communicate over Internet outside the LAN, which is assigned by ISP when the Router is connected to the Internet.

⇒  All the devices connected to that router have the same public IP-address as of the router but each have their own different private IP-address on that network.

Q7. a)  Describe  Static  and  Dynamic IP-address. 

 Static IP-address :  

⇒  A Static IP-address is assigned and configured manually by the user/network administrator or internet service provider (ISP) which is permanent and does not change.

⇒  Static IP-addresses are generally used by switches, routers, network printers and remote servers like webserver, FTP-server or online database.

 Dynamic IP-address :  

⇒  Dynamic IP-address is assign automatically by Router or DHCP server which is temporary and always changes when a device logs onto the internet.

⇒  Dynamic IP-addresses are used by devices to communicate over internet.

b)  Give two features of Static IP-address.

1. Static IP-address do not change, so they can be located from anywhere in the world.
2. It is easier to locate shared devices, like network printer.
3. Offers stable connection, since IP-address never resets.
4. Provides faster download/upload speed.

c)  Give two features of Dynamic IP-address.

1. Dynamic IP-address is automatically assigned to a device by ISP using DHCP server.
2. Provides security, since they change each time a user logs on to internet.
3. Provide privacy by the use of VPN.
4. Avoids the problem of address conflicts when new devices are added.

d)  Explain why do we need both Static and Dynamic IP-address.

⇒  Static IP-addresses which don't change are used to share the network resources, like network servers and printers.

⇒  Dynamic IP-addresses which often changes are used by devices to communicate over internet.

Q8.  Describe three differences between MAC addresses and IP addresses.

MAC address	IP address
It is a unique 48-bits physical address assigned to a network interface card by its manufacturer.	It is a unique 32-bits or 128-bits location address assigned to a device.
It is assigned permanently by the manufacturer.	It is assigned automatically by ISP using DHCP server or manually configured by the user.
It is used to identify a device on the network.	It is used to locate a device on the network.
It should be unique all over the world.	It is unique on a network and could be re-used on separate other network.

Q9. a)  What is a  DHCP Server ?

⇒  Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol (IP) network.

⇒  It automatically provides and assigns a unique dynamic IP-addresses, default gateways and other network parameters to client computer/devices.

⇒  The IP-address information assigned by DHCP is only valid for a limited period of time.

b)  Where DHCP servers are located ?

⇒  DHCP server is in Router or switch, provides a private IP-address to each device for private LAN network.

⇒  Internet Service Provider (ISP) have their own DHCP server that provides dynamic public IP-address to each device for public internet connection.

Q10. a)  What is  DNS Server  and how it works ?

⇒  Domain Name System (DNS) is a computer servers that contains a database of public IP-addresses and their associated hostnames or website name.

⇒  It translates human readable domain name into corresponding numeric Internet Protocol (IP) address, which is used to identify and locate the resources on the Internet.

⇒  DNS servers run special software, and communicate with other servers at it's data center using special protocols.

⇒  When you type a website address into your browsers address bar and press Enter, the browser sends a request to the DNS server to finds the IP-address of the website you typed and send it back. The browser requests webserver to access the website using its IP-address.

b)  Where DNS server is located ?

⇒  DNS servers are located in ISP's data centers at different remote locations all over the world.

Q11. a)  What is  wired network ?

⇒  A wired network refers to a wire-based high-speed networking system called Ethernet to allow computer workstations, servers and printers to share data and resources.
Examples of wired network includes telephone networks, cable television, internet access and fiber-optic communication.

⇒  Wired networks use ethernet cables like, coaxial, twisted pair, and fiber-optic to transfer data between connected computers and devices.

⇒  Some advantages of wired network technology include enhanced speed, lack of interference, increased security, and the ability to connect systems across long distances.

⇒  Disadvantages can include high installation and replacement costs.

b)  Describe the following  types of Cables  used in a wired network.

1)   Coaxial cable :  

⇒  Coaxial cables are made of a single copper wire surrounded by a plastic layer for insulation and a metellic mesh which provides shielding from outside interferences.

⇒  It carries high frequency electrical signals used by TV cable operators, telephone companies, and Internet providers to transmit data, video and voice communications to customers.

2)   Twisted pair ethernet cable :  

⇒  Twisted pair ethernet cable contains four pairs of insulated copper wires which are twisted together to reduce internal interference.

⇒  The most common ethernet cables are CAT 5e and CAT 6 (CAT is short for 'Category') used to connect devices in a LAN.

⇒  Twisted pair cables provide high data transmission rates and bandwidth. They are thinner and less expensive.

3)   Fiber-optic cable :  

⇒  A Fiber Optic cable contains strands of one or more flexible insulated fibers of glass, slightly thicker than a human hair.

⇒  Each strand provides a pathway to transmit data in the form light pulses, that reflects light inward to avoid loss of signal and allow the light to pass through bends in the cable.

⇒  Fiber cables is capable of transmitting data over a very long distance with higher transmission rate and bandwidth, without losing its quality and strength.

Q12. a)  What is  wireless network  and how it works ?

⇒  A wireless network uses electromagnetic waves, like radio waves, microwaves or infrared to connect network nodes.
Examples include Cell-phone networks, wireless local area networks (WLANs), satellite communication networks, etc.

⇒  A computer's wireless adapter translates data into a radio signal and transmits it using an antenna.

⇒  A wireless router receives the signal and decodes it. The router sends the information to the internet using a physical, wired ethernet connection.

b)  Describe the following  types of wireless communication technologies  used to connect devices to a network.

1)   Bluetooth :  

⇒  Bluetooth is a short-range wireless communication technology that uses radio waves in 79 different frequencies known as channels, centered at a frequency of 2.45 GHz.

⇒  Bluetooth devices automatically detect and connect to each other, without interfering each other since each pair uses a different channel.

⇒  While connecting two devices called Pairing, each device is equiped with special security keys to encrypt data shared between them.

⇒  Bluetooth creates a secure wireless personal area network (WPAN), where data transmission rate and bandwidth is not crutial, like sharing data or listening musing from mobile phone using bluetooth devices.

2)   Wi-Fi :  

⇒  Wi-Fi is a wireless networking technology that allows Wi-Fi compatible devices such as laptops, smartphones and printers to connect with each other and share data using radio signals.

⇒  Wi-Fi enabled devices can access Internet through wireless Router or any Wireless Access Point (WAP) or "Hot spot" from any location within the network coverage area.

⇒  Wi-Fi offers much faster data transfer rate, better security and larger range than Bluetooth.

c)  Give difference between  Bluetooth  and  Wi-Fi  wireless communication technology.

1. Wi-Fi is used to create wireless LAN network, linking devices within the range of 100 meters using central wireless access point (WAP). Bluetooth has a much smaller range of 10 meters used to create wireless personal area network (WPAN).
2. Wi-Fi network relies on a Hub, that can connect a large number of devices through single wireless access poing (WAP), also called wireless Router. Bluetooth has no hub and each device can only connect upto seven other devices.
3. Wi-Fi has much higher data transmission rate of 300 Mbps than Bluetooth with 24 Mbps.
4. But Wi-Fi devices consumes more power than Bluetooth. Bluetooth's low power consumption makes it useful where power is limited, like headset, heart-rate monitors, sports watches and thermostats.

Note : Both Wi-Fi and Bluetooth uses the radio waves of same 2.4 GHz frequency. Many WiFI networks these days will run on both 2.4GHz and 5GHz frequencies.

Q13. a)  What is  Computer Port  ? Give example.

⇒  A Computer Port is an interface or a slot on the motherboard to connect peripheral devices with computer using cables.

⇒  The interaction of the ports with connected input and output devices is controlled by the control unit.

⇒  Based on the type of communication, computer ports are of two types, Serial and Parallel.

Example of Serial Ports are - COM1, COM2, USB, HDMI used to connect peripherals like Mouse, Modem, game controllers, printers, projectors, etc.

Example of Parallel Ports used in early computers are - PS/2, enhanced parallel port (EPP), extended capabilities port (ECP) used to connect mouse, keyboard, printer, scanner, etc.

b)  Describe  Universal Serial Bus (USB). 

⇒  USB is an external bus with plug-and-play interface.

⇒  It is used to connect external peripheral devices with computer.

⇒  It uses asynchronous serial data transmission. Allows both hulf-duplex and full-duplex.

⇒  It provides power supply to the peripheral devices.

⇒  The USB cable consists of a four-wired shielded cable, with two wires for power (red and black). The other two wires (white and green) are for data transmission.

c)  Give three reasons of using USB ports over other traditional Serial ports.

1. Data transfer rate of USB port is much higher (between 12 Mbps to 480 Mbps) than traditional Serial port (1 Mbps to 10 Mbps).
2. USB port is capable of supplying power to the peripheral devices.
3. USB port automatically detects the device and installs the correct driver.
4. USB ports are much more durable than serial ports because pins in serial ports are very easy to bend or break, whereas USB pins are more robust and much more difficult to damage.

Q14.  Give three benefits and drawbacks of using the USB System.

 Benefits : 

1. Automatically detects and installs the appropriate device drivers.
2. USB cables can only fit in one way that prevents incorrect connections.
3. USB supports different data transmission rates (from 1.5 Mbps to 5 Gpbs).
4. No need for external power supply since cable supplies +5V power.
5. USB protocol re-transmits data if any errors are detected; this leads to error-free data transmission.
6. USB connections can transfer data using half-duplex or full-duplex.
7. It is relatively easy to add more USB ports if necessary, by using USB hubs.
8. USB is backward compatible (that is, older versions are still supported).
9. USB has become an industry standard, which has replaced most serial ports in consumer-grade computing equipments.

 Drawbacks : 

1. Standard USB only supports a maximum cable lengh of 5 m, beyond that, USB hubs are needed to extend the cable length.
2. USB ports can transmit data in short distances beyond which you will need to use USB hubs.
3. Data transmission rate of even latest version USB V3 and V4 is much lower than FireWire and Ethernet Interfaces.

Q15.  Explain  what happens when a device is plugged into a computer using one of the USB ports.

⇒  The USB port provides power supply to the device, to activate and communicate with computer.

⇒  The OS (operating system) sends a request to the USB port to identify the device.

⇒  The unique vendor-id, serial number and type of the device stored in device descriptor is send to the OS.

⇒  The OS compares the information of device descriptor with the descriptor of the vendor specific device driver installed with OS.

⇒  If it matches, then it will be loaded the device driver automatically.

⇒  If it doesn’t match, then OS will ask the user to install the driver software for that device.

Q16.  Describe  High-definition Multimedia Interface (HDMI). 

⇒  HDMI port is the digital replacement of the older VGA analogue system.

⇒  HDMI ports allows both audio and visual output from a computer to an HDMI-enabled monitor or other devices.

⇒  HDMI supports high definition signals that modern HD televisions require (faster data transfer rate, e.g. 10 gitabits per second).

⇒  HDMI increases the bandwidth making it possible to supply the necessary data to produce high quality sound and visual effects.