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CPEN 100 - COMPUTER NETWORKS BACHELOR OF SCIENCE IN COMPUTER ENGINEERING Intern

CPEN 100 - COMPUTER NETWORKS BACHELOR OF SCIENCE IN COMPUTER ENGINEERING Internet. A global computer network that links information and people. Computer Network a system consisting of computers and devices connected via communications devices and media (e.g. switches or router) that allows users to, share resources or exchange files. It is a means by which computers can “talk” to one another through the use of cables, telephone lines, radio waves, satellites or infrared light beams that connect them. Figure 1. A Typical Computer Network Data Communication refers to the study on how devices, not necessarily computers, can transfer digital information (commonly known as “signals”) via wired or wireless transmission medium which include: For Electricity: copper wires coaxial cable. Twisted pair (UTP and STP) For Light: Infrared through air, laser through fiber optic cable For Electromagnetic Radiation: broadcast radio (radio frequencies), microwave, satellite Telecommunications comes from a contraction of the Greek “tele”, which means “far” and Latin root “communicare”, which means “discipline that studies the principles of transmitting information and the methods by which it is delivered”. It refers to any process that permits the exchange of information (e.g. voice, data, text, images and video signals) over great distances, in the form of electromagnetic signals electromagnetic system (e.g. satellite systems, broadband systems, microwave systems, digital networks, telephone networks, radio stations, LAN and wireless networks). Computer Network Advantages 1. Sharing information. Sharing is the real key to networking. By means of network, computers can share information – from files, to programs, to hardware devices or peripherals, regardless of the physical location of the resource and the user. With sharing, time, effort and money could be saved. 2. Sharing Hardware Resources. By means of network, electronic transfer is faster since computers can share peripherals (e.g. printer and hard disk drives) with any other computer. 3. Sharing Software Resources – by means of network, programs or applications used by computers to perform any useful function or to carry out daily basis task can be installed and configured centrally on a server and shared by all. With this, more time and disk space are saved. 4. Preserve Information – another advantage is the increase in security. By means of networking, regular backups of data that are kept on the server as well as on other connected computers on the network will not immediately result in loss of information, since these data are still accessible from other computers whenever required. 5. Communication – by means of the network, the office can be a paperless environment since users can instantly send messages to others and even check whether or not their messages have been received. Requirements for internet connection 1. Physical connection – it is used to transfer signals between PCs within the local network and to remote devices on the internet. 2. Logical connection – it uses a standard called protocols or a set of protocols lie TCP/IP 3. Application that interprets the data and display the information – it works with protocols to send and receive data across the Internet such as web browser, File Transfer Protocol (FTP) and etc. “Ping” command utility is used to verify network connectivity. It works by sending multiple IP packets to the specified destination and waiting for the packet replies. If the ping receives an echo reply, the CPEN 100 - COMPUTER NETWORKS BACHELOR OF SCIENCE IN COMPUTER ENGINEERING connectivity is verified. If it fails, however, it will show messages. The following examples describe the types of ping tests that are commonly used in a network  Ping 127.0.0.1 – it is called an internal loopback test.  Ping the IP address of host computer – it verifies connectivity to the host.  Ping default-gateway IP address – it verifies whether the router that connects the local network to other networks can be reached.  Ping remote destination IP address – it verifies connectivity to a remote host. Computers are one of the major categories of network “building blocks,” thus it is important to be able to identify and describe their major components, including both hardware and software which are involved with the internal processing. Computer Components: 1. Motherboard – it is the main printed circuit board of a computer. 2. Central Processing Unit (CPU) – it is the part of a computer that controls all the other components. It fetches instructions from memory and decodes them. This action may cause it to transfer to or from memory or to activate peripherals to perform input or output. 3. Bus – it is a collection of wires through which data is transmitted from one part of a computer to another. It connects all the internal computer components to the CPU. The Industry Standard Architecture (ISA) and the Peripheral Component Interconnect (PCI) are the two types of buses. 4. Random Access Memory (RAM) – it is also known as read-write computer memory that has new data written into it as well as stored data read from it. A drawback of RAM is that it requires electrical power to maintain data storage. If the computer is turned OFF or loses power, all data stored in RAM is lost, unless the data was saved to disk. 5. Read-Only-Memory (ROM) – it is a computer memory on which data has been prerecorded. Once data has been written onto a ROM chip, it cannot be removed and can only be read. 6. Power Supply – it is a component that supplies power to a computer and converts AC power to DC and breaks it into the amounts needed by different devices. 7. Hard Disk Drive (HDD) – it is a device that reads and writes data on a hard disk. Two main types of drive interfaces are current in today’s computers: Integrated Drive Electronics (IDE) drive and the Small Computer System Interface (SCSI; pronounced scuzzy) drive. 8. Operating System – it is a software that controls the operation of the computer (Windows, Macintosh, UNIX, and so on.) Components of a computer that required access from the outside 1. External Ports – these are connectors to which other devices attached, including the following:  Serial Port – it connects to asynchronous serial devices, such as an external modem.  Video Port – it connects to an external video monitor.  Ethernet Port – it connects to an Ethernet network data cable.  Universal Serial Bus (USB) Port – It is a standard connection port designed for connecting computer peripherals such as mouse, keyboard, joysticks, printers, scanners, digital cameras, flash drives, and external HDDs.  PS/2 Port – it is an external keyboard and mouse connection. 2. Compact disc read – only memory (CD- ROM) drive – it is a device into which CD can be inserted and the data read from it. 3. Compact disc read – write memory (CD- RW) drive it is a device into which a CD can be inserted and the data read from it; if writable CD media are used, data can also be stored on it. 4. Floppy Disk Drive – it is a disk that can read and write to floppy disks, usually in the “3 ½” 1.44-megabyte (MB) or “5 1/4“1.2 MB format. CPEN 100 - COMPUTER NETWORKS BACHELOR OF SCIENCE IN COMPUTER ENGINEERING Figure 2. An Idealized Computer: Information Flow Information that flows through the bus: 1. Boot Instructions – these are stored in ROM, until they are sent out. 2. Software Applications – these are stored in RAM after they have been loaded. 3. RAM and ROM – These two constantly talk to the CPU through the bus. 4. Application information – these are stored in RAM while applications are being used. 5. Saved Information – This flows from RAM to some form of storage device. 6. Exported Information – this flows from RAM and the CPU, through the bus and expansion slots, to the printer, video card, sound card, or network card. Network INTERFACE CARD (NIC) (a.k.a LAN Adapter) is an expansion board that provides network communication capabilities to and from a computer system. When selecting a network card, the following are to be considered:  Bus type (PCI, ISA, EISA, and so on)  Network Topology (bus, ring, star)  Medium Type (UTP, STP, 10Base2, 10Base5, 10BaseF)  Transport Speed (1 Mbps, 4 Mbps, 10 Mbps, 16 Mbps, 100 Mbps, 1000 Mbps) Types of network administration software are as follows: 1. Network Operating System (NOS) – this coordinates the activities of multiple computers across a network through the following remote services below. These remote services enable concurrent access to share resources, either by multiple clients (peer-to-peer networking operating system) or server systems responding to a client request (client/ server networking operating system)  Access to remote printers – the NOS allows one to manage the usage of printer as to when will it be used or what printer is connected to a certain computer. It also allows how print jobs are queued and managed and recognizes when devices are not available to the network. uploads/Management/ guide-outline.pdf