Welcome to MS Pantherina Online
	THE INTERNET The Internet is the worldwide "network of networks" that links millions of computers together via copper wires, fiber-optic cables, wireless connections, and other telecommunications channels. It is a massive network of networks, a networking infrastructure, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet. Information that travels over the Internet does so via a variety of languages known as protocols.This publicly accessible network of interconnected computer networks communicate using a set of protocols and standards, the most basic of which are TCP/IP. TCP/IP consists of the Transmission Control Protocol in conjuntion with the Internet Protocol. Other protocols such as DHCP, DNS, FTP, HTTP, IRC, MIME, POP3, SMTP, SSH, TELNET, RTP and many more help hold the whole thing together. This learning resource will look mostly at the technical aspects of the Internet, but may eventually cover social, economic, historical and other aspects. A popular way to visualize the complexity of the Internet is to see it as a stack of layers known as the OSI model, short for Open Systems Interconnection model. OSI Layers: * Layer 7: Application Layer – the main interface for the user(s) to interact with the application and therefore the network * Layer 6: Presentation Layer – transforms data to provide a standard interface for the Application layer * Layer 5: Session Layer – controls the dialogues (sessions) between computers * Layer 4: Transport Layer – provides transparent transfer of data between end users and machines * Layer 3: Network Layer – provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks * Layer 2: Data Link Layer – provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the physical layer * Layer 1: Physical Layer – defines all the electrical and physical specifications for devices and the communications media TYPES OF NETWORKS MAINFRAME Mainframe computers are typically large, metal boxed computers with large processing abilities. The terminals are called "dumb terminals" because they only send and receive data, leaving the processing to the mainframe. CLIENTS The client/server refers to the way two computer programs interact with each other. The client makes a request from the server, who then fulfills the request. Although this idea can be used on one computer it is an efficient way for a network of computers in different locations to interconnect. Local Area Network (LAN) The first LANs were created in the late 1970s. LANs are small networks constricted to a small area, like a city. LANs are used to share resources like storage, internet, et cetera. A 'node' on a LAN is a connected computer or device like a printer. Wide Area Network (WAN) WANs are very large networks that interconnect smaller LAN networks, for a large geographic area like a country (i. e., any network whose communications link crossmetropolitan, regional, or national boundaries.) WANs are usually for private companies, however, some built by internet service providers connect LANs to the internet. WAN can use a combination of satellites and microwaves, and can link a variety of computers from mainframes to terminals. A 'node' on a WAN is a LAN. Metro Area Network (MAN) Metropolitan area networks, or MANs, are large computer networks usually spanning a city. They typically use wireless infrastructure or Optical fiber connections to link their sites. When the LANs that you want to connect are not far apart, just blocks away, then you can make a MAN. The main difference between a WAN and a MAN network is the speed of the connection. Because the LANs are so close in a MAN, high speed fiberoptic cables are affordable. Campus area network (CAN) A Campus Area Network is a computer network made up of an interconnection of local area networks (LANs) within a limited geographical area. It can be considered one form of a metropolitan area network, specific to an academic setting. In the case of a university campus-based campus area network, the network is likely to link a variety of campus buildings including; academic departments, the university library and student residence halls. A campus area network is larger than a local area network but smaller than a wide area network (WAN). The main aim of a campus area network is to facilitate students accessing internet and university resources. Personal Area Network (PAN) A personal area network is a computer network used for communication among computer devices (including telephones and personal digital assistants) close to one person. The devices may or may not belong to the person in question. The reach of a PAN is typically a few meters. PANs can be used for communication among the personal devices themselves (intrapersonal communication), or for connecting to a higher level network and the Internet (an uplink). Home Area Network (HAN) The Home Area Network uses cable, wired, or wireless connections to connect a homes' digital devices. For example, fax machines, computers, DVD's etc. Garden Area Network (GAN) A Garden Area Network is a similar system and allows for one system to control such devices like garden lights, sprinkler systems and alarm systems.