3.Types of networks.

Computer networks can be classified in different measures. When categorizing networks, attributes such as size or the number of nodes in the network, the geographical spreading of the network and the technology used by the network are taken into account.  The computer network has two types: peer to peer and server based In peer to peer network, all computers have equal rights: there is no hierarchy among the computers and there is no allocated (dedicated) server. Each computer functions as both a client and a server. There is no defence, it’s no centralized, used if less than 10 people,protection is not actual. In Server based network, there can be used by one or more servers that control the jobs. Power and performance distinguishe the Server, it is very quickly processes user requests and its operation controlled by system administrator. Server based network gives protection ,used when more than 10 people, The most popular way of sorting network types depends on the geographical extend of the network. By organizing networks in this manner, we can identify some types of networks.  Local area network (LAN) ---A Local Area Network is a small computer network usually set up within a single building. As a rule, the communication links are high-speed connections. ( Network within your office)  Metropolitan area network (MAN) ---This type of a network covers a metropolitan or a municipality area. Communication links may include low to high-speed connections.  Wide area network (WAN) ----This is a network that covers a large geographical area - may be a country or a continent. This type of networks typically use low-speed links for data transfer. (the Internet)  There are two more types of networks defined, based on the span of the network services. Personal Area Network (PAN) is a later added category, which resembles a network used around a single person. The model is centered on Bluetooth technology. Global Area Network (GAN), representing a very large network that has a global coverage, by using a combination of different technologies such as satellite communication. 

4.Basic topology of the network, give an example Star :this topology have the highest performance possible, as the data transferred between workstations via a central node for the individual lines, which are used exclusively by these stations.  In its simplest form, a star network consists of one central switch, hub or computer, which acts as a conduit to transmit messages. The frequency of requests for information transfer between stations is relatively small. LAN performance is directly dependent on the power the file server. If the central node fails, the network also stops. Network management is carried out from its center, in the center of the mechanism is implemented of data protection. The hub, switch, or concentrator manages and controls all functions of the network. It also acts as a repeater for the data flow. Ring : Ring topology local area network means that the workstations are connected to each other in a circle: the first with the second, the third to the fourth, and so on. The last station is connected with the first, closing the ring. The complexity and cost of cabling between workstations depends on the geographical locations of the stations to each other. Data transfer is performed in a circle. Workstation receives a request from the ring, and then sends the information to a particular address. Transmission system LAN is a very effective, because you can send messages to each other rather quickly, in addition to easily send a request to all the workstations of the ring. Time transmission of information increases with the number of stations on the LAN. The minus of local networks with a ring topology is that in case of failure of at least one workstation, the all network becomes unusable. Any failure of the cable connection to the network is easy to detect. Data send trough marker .Here is no queue, and so the data doesn’t run into with each other, and signal increases. Bus: Bus topology network suggests that environment for data transmission is a communication path that is connected to all the workstations. Each of the stations in the network may come into contact with any other station LAN. Connecting or disconnecting the workstations is carried out without interrupting LAN working, status of individual work stations is not affected on the performance of the whole network.

5.Classification networks. Local and global networks. Network departments, campuses, corporations. The most popular way of sorting network types depends on the geographical extend of the network. By organizing networks in this way, we can identify some types of networks: PAN (Personal Area Network) - is a computer network used for communication  among  computerized  devices, including  telephones and personal digital assistants. PANs can be used for communication among the personal devices themselves. A PAN may also be carried over wired computer buses such as USB and FireWire.  LAN (Local Area Network) - LANs with separate infrastructure before entering the service providers. The term «LAN» can describe, and a small office network, and the network-level large factory, which occupies several hundred acres. Foreign sources give even a close estimate - about six miles (10 km) in radius. LANs are networks closed, access is allowed only a limited number of users who work in such a network is directly related to their professional activities. CAN (Campus Area Network - Campus) - unites local network of closely spaced buildings . Used to inter-connect networks in limited geographical locality like university campus, military bases, or organizational campuses etc.  It can be taken as the metropolitan network that has the specific settings at the small area just like a computer lab in the university. A CAN is also known as a corporate area network (CAN). MAN (Metropolitan Area Network) - a computer network in which two or more computers or communicating devices or networks which are geographically separated but in same metropolitian city and are connected to each other are said to be connected on MAN.The limits of Metropolitian cities are determined by local municipal corporations and we cannot define them. Hence, the bigger the Metropolitian city the bigger the MAN,smaller a metro city smaller the MAN. WAN (Wide Area Network) - a global network covering a large geographical region, including both local networks and other telecommunications networks and devices. Example WAN - packet-switched network (Frame relay), through which can "talk" between different computer networks. Global networks are open and focused on the service of any user.