Networking - example questions

Give two advantages of a client-server network over a peer-to-peer network.

- A central server manages security and backup - Complex processing tasks may be performed by a more powerful server enabling less powerful client terminals to be used.

Office staff notice that the network is running slowly compared to their home network connections. Explain two factors that can affect network performance.

- Bandwidth: the amount of data that can be transferred at one time. - Latency: the speed that data travels during transfer (or delay in receiving). - Error rate: the number of collisions in high network traffic. - Retransmission rate: how promptly corrupted or last packets can be resent.

State two types of network transmission media.

- Copper cable (twisted pair Ethernet cable) - Fibre optic cable - Wireless (WiFi) signals.

Give two advantages to using cloud-based services over local storage.

- Data can be accessed from any computer in the world, not just your own local machine. - Local storage on your hard disk is significantly reduced if software and files are stored remotely. - Backing up is no longer crucial since cloud service providers will include this as part of their service.

Name three advantages of linking computers in a small office in a peer-to-peer network.

- Individual computers can share hardware such as printer, scanner, router, modem - Users can communicate directly with each other and share each other's files - Easy and cheap to set up and no special software required

The file server manages data files held on the server. What other types of server may be needed to run the school network efficiently? Explain briefly what each one does.

- Print server to organise printing - An email server may receive emails, detect and block spam, distribute emails to users - A web server may host the school's external website - A database server to hold school records

A classroom in a primary school has 6 standalone computers. The school decides to connect them to form a LAN in a star topology. Explain, with reasons, what additional hardware will be required to create this LAN.

- The star topology requires all workstations to be connected to a central point so a hub/switch is needed. - The computers need to be physically or wirelessly connected to the hub so cables and network interface cards or a wireless access point and WiFi adapters will be needed.

State two advantages of connecting the computers to create a local area network.

- To share the printer. - To share the internet connection. - To share files. - To communicate with each other e.g. by email.

A school decides to use the star topology to create the LAN. Describe what is meant by a star topology. You may use a diagram.

A hub/server at the centre of the network. All computers attached to the hub/server. Resources (e.g. printer) can also be connected to the hub/server.

Describe, using a diagram, how the computers can be connected to each other using a bus topology, stating what hardware will be needed.

Bus line shown. Terminators shown at each end of the bus. Three computers attached to bus. Printer attached to bus. Internet connection connected to a router. Network adaptors required on each computer. Router needed to share the internet connection. Cables needed to connect the different devices.

A library has several computers available to the general public. Explain why the libraries need the following security measures: i. User access levels ii. Firewalls

i. Different users only have permissions to files/areas/services of the network which they actually need eg the public should only be able to search eg only employees should issue books eg only managers can look at pay records. To prevent malicious or accidental corruption of parts of the network. ii. Stops all access to/from the WAN unless it has been authorised Eg requests from other libraries. Prevents hackers from compromising the system.

A website is written in HTML. i. Describe HTML. ii. Explain the importance of HTML in the creation of web pages.

i. HyperText Mark-up Language. Text file containing the text to be displayed. Uses tags which indicate how to display the text and location of pictures/other elements to include and hyperlinks to other locations/URLs. ii. Web browser used to interpret the file and display the data correctly. HTML is an open/accepted standard so data will be display correctly on all browsers which conform to the standard.

Some of the file formats use compression. i. Explain the importance of compressing files when transmitting them via the internet. ii. Describe the difference between lossy and lossless compression and give an example where each would be used.

i. It reduces the size of the file which needs to be transmitted. Shortens download time and reduces internet traffic. ii. In lossy compression, when the data is uncompressed it is not exactly the same as the original but the difference is so small that it cannot normally be noticed e.g. music files (mp3) and images (jpg). In lossless compression, when the data is uncompressed it is restored completely to the original file e.g. compressed text files or programs.

A large company with 200 employees uses a local area network (LAN) which includes all the computers in its head office. Describe the security measures and network policies which can be used to safeguard the security and privacy of the company's data on the network.

Points may include: - Physical security measures - computers/servers in locked rooms, lockdown cables for laptops. - Firewalls - allow only authorised access to the network. - User groups/access levels - different users are given different rights to data according to their responsibility/need to protect privacy. - Passwords enforced - should be strong and changed regularly. Ensures privacy and protects files being accessed by malicious hackers. - Encryption of data on the network. - WiFi access security. - Get employees to sign an Acceptable Use Policy as part of their contract to ensure they do not put data at risk of corruption and to abide by data protection legislation.

A user types the address www.ocr.org.uk into a web browser. Describe how a DNS server is used to access this website and explain the advantages of using DNS servers.

Points to be made include: How DNS servers are used: DNS severs have a database of IP addresses. Constantly updated by other DNS servers. When you request an address (URL), the DNS server looks up the URL and returns the IP address, or searches for the address from other DNS servers. Advantages: People do not need to remember IP addresses. Easily upgradeable (eg IPv4 to IPv6) without all web addresses needing to be the same. As long as you are connected to a DNS server you can have access to all the addresses.

Briefly describe what is meant by 'The Cloud'

Remote servers that host your data, resources and applications; via the Internet.

Describe one scenario where a peer-to-peer network would be advantageous over a client-server network, and suggest why.

Small business, online gaming groups or another other acceptable suggestions. Reasons include simpler set up, no central network administration required, no special software to manage the network.

Describe how a web server may deal with a request from a client-browser to display a web page.

The client browser sends a request for the web page to the local server, the request is passed on to the web server of the requested website. The local server becomes a client and waits for the request back from the server.

Briefly explain the role of the client computer in this relationship.

The client sends a request to the server and waits for the server to reply with the requested data.

Briefly explain the role of a server (in a client-server network) when a file is requested by a client terminal

The server waits for a client request, the request is acknowledged, the data is fetched and sent back to the client.