Intro To Computer Networks Basics

Objectives Explain digital vs. analog communications List types of cables List network devices Explain packet switching and circuit switching Describe role of protocols Describe various networks Recount basics of Internet and Internet access 11/11/2018 M. Eyadat

Network-Basics A communications network is a collection of computers and other devices that communicate to share data, hardware and software In order to communicate, information must be transformed into the format the network uses 11/11/2018 M. Eyadat

Network-Basics Computers use several coding schemes based on binary digits ASCII EBCDIC Unicode Binary numbers When data is transmitted, it usually takes the form of an electromagnetic signal On a communication network, your data may be converted into several different types of waves 11/11/2018 M. Eyadat

Network-Basics Data can travel from one network device to another over a cable or through the air A communications channel is a physical path or a frequency for a signal frequency Networks use different types of cables 11/11/2018 M. Eyadat

Transmission Media Wired Network twisted-pair cables- phone coaxial cable- TV Fiber-optic cable is a bundle of extremely thin tubes of glass Wireless Network Microwaves provide another option for transporting data Radio and microwave transmissions are bent around the surface of the earth to reach towers Communications satellites play an important part in long-distance communications A transponder on the satellite receives the signal, amplifies it, and retransmits the signal back to a ground station 11/11/2018 M. Eyadat

Network-Basics Bandwidth is the transmission capacity of a communications channel High-bandwidth communications systems, such as cable TV, are sometimes referred to as broadband Systems with less capacity, such as the telephone system, are referred to as narrowband The bandwidth of a digital channel is usually measured in bits per second (bps) 11/11/2018 M. Eyadat

Network Components Each device that is connected to a network is referred to as a node The term workstation usually refers to a personal computer connected to a local area network (LAN), it is also called a client A modem is a device that converts signals from a computer into a signal that can travel over a wide area network 11/11/2018 M. Eyadat

Network Components A network interface card (NIC) is the key hardware component for connecting a computer to a local area network. small circuit board that sends data to and from workstation to network A server refers to any computer on a LAN or the Internet that contains the software to manage and process files for other network nodes 11/11/2018 M. Eyadat

Network Components A host computer usually refers to any computer that provides services to network users A hub is a device that connects several nodes of a LAN A router is a device that is connected to at least two networks and makes decisions about the best route for data A gateway is a device that performs functions similar to a router A repeater amplifies and regenerates signals so they can retain the strength to reach their destinations 11/11/2018 M. Eyadat

Protocols Communications protocol refers to set of rules for transmitting data from one node to another Protocols allow two devices to negotiate and agree on how data will be transmitted 11/11/2018 M. Eyadat

Network-Basics Simplex – signal travels in only one direction Half duplex – signal travels in both directions, but only one direction at a time Full duplex – signal travels in both directions at the same time 11/11/2018 M. Eyadat

Network Classifications Internetwork – a network composed of many smaller networks Intranet – uses TCP/IP protocols but owned by a private business and does not typically allow remote access Extranet – similar to intranet except that it allows remote password-protected access WAN – (wide area network) covers a large geographical area and may consist of smaller networks LAN (local area network) – typically covers a very limited geographical area 11/11/2018 M. Eyadat