9. What is wlan? What is wan? What are backbones?

• WLAN is network where cables or wires are replaced by radio waves.

• WANs (Wide Area Networks) have no geographical limit and may connect computers or LANs on opposite sides of the world.

• Backbones is the main transmission paths within a WAN are high-speed lines.

10. Speak about basic network topologies. What is a hub?

Topology refers to the shape of a network.

There are three basic topologies.

• Star: there is a central device to which all the workstations are directly connected.

• Bus: every workstation is connected to a main cable called a bus.

• Ring: the workstations are connected to one another in a closed loop configuration.

There are also mixed topologies like the tree, a group of stars connected to a central bus

Hub is connection point of the elements of a network that redistributes the data.

11. What is a router? What are the functions of a modem, a bridge and a gateway?

• A router, a device that forwards data packets, is needed to link a LAN to another network

• A modem is a device for converting digital signals to analogue signals and vice versa to

enable a computer to transmit and receive data using an ordinary telephone line.

• A bridge is a hardware and software combination used to connect the same type of networks. Bridges can also partition a large network into two smaller ones and connect two LANs that are nearby each other.

• A gateway is an interface that enables dissimilar networks to communicate, such as two LANs

based on different topologies or network operating systems.

12. What are advantages and disadvantages of using networks? How can the disadvantages be minimized?

The Internet is the largest source of information. Answer to any possible question can be found there. Apart from that, the Internet stores everything one might need. Books, movies, music, pictures, and so on. The Internet is a good educational platform

The Internet unites people, indeed. Unfortunately, some people spend too much time on social networks forgetting about face-to-face communication. Social networks and other online services will never replace communication in real life. That is why they should be used within reasonable limits.

13. How is network communication performed? Describe seven layers of data transmission.

• The application layer is the only part of a communications process that a user sees

• The presentation layer ensures that the message is transmitted in a language that the receiving computer can interpret.

• The session layer opens communications and has the job of keeping straight the communications among all nodes on the network.

• The transport layer protects the data being sent.

• The network layer selects a route for the message.

• The data-link layer supervises the transmission.

• The physical layer encodes the packets into the medium that will carry them - such as an analogue signal.

14. What is the Internet? What is the Internet protocol? What function does it perform?

• The Internet is an International computer Network composed of computer networks that allow users to access information from other computers.

• Protocols are sets of rules that machines follow to complete tasks. The protocols provide both the method and a common language for machines to transmit data.

15. What is the Internet address? Why is every computer in a network given an IP address?

Every computer is given an address or IP number. This is how one machine can find another

through the massive network.

16. What is an IP address expressed in? Why are IP addresses considered 32-bit numbers?

IP addresses are normally expressed in decimal format as a dotted decimal number. IP address considered 32-bit numbers because they have four octets, where one each have eight positions.

17. Which types of connection can an ISP offer? What were the disadvantages of a dial-up connection?

ISP (Internet Service Provider) which provides you with a broadband connection, a high data transmission rate Internet connection, either cable or ADSL (Asymmetric Digital Subscriber Line). ADSL allows you to use the same telephone line for fast access to the Internet. Cable connection is offered by most TV cable providers. (In the past most computers used a dial- up telephone connection.