Chapter 7 Networks, Telecommunications, and Wireless
Networks and Telecommunications
Network Basics • Telecommunication system - enable the transmission of data over public or private networks • Network - a communications, data exchange, and resource-sharing system created by linking two or more computers and establishing standards, or protocols, so that they can work together • The three types of networks include: Local area network (LAN) Metropolitan area network (MAN) Wide area network (WAN) • Networks are differentiated by the following: – Architecture - peer-to-peer, client/server – Topology - bus, star, ring, hybrid, wireless – Protocols - Ethernet, Transmission Control Protocol/Internet Protocol (TCP/IP) – Media - coaxial, twisted-pair, fiber-optic
• There are two primary types of architectures – Peer-to-peer (P2P) network- any network without a central file server and in which all computers in the network have access to the public files located on all other workstations.
– Client/server network
Client - a computer that is designed to request information from a server.
Server - a computer that is dedicated to providing information in response to external requests.
Client/server network - model for applications in which the bulk of the back-end processing takes place on a server, while the front-end processing is handled by the clients.
Network operating system (NOS) - the operating system that runs a network, steering information between computers and managing security and users Packet-switching - occurs when the sending computer divides a message into a number of efficiently sized units called packets, each of which contains the address of the destination computer Router - an intelligent connecting device that examines each packet of data it receives and then decides which way to send it onward toward its destination. 20 million routers installed in 2002, 80 million in 2010.
BUS- 1 line, so if any part is down, whole network is down.
STAR- main hub, if 1 line goes down network can still operate
RING- travels around until a device picks it up. Prevents collisions. Only one device communicates at a time.
• Network topology - refers to the geometric arrangement of the actual physical organization of the computers and other network devices) in a network – Bus, Star, Ring, Hybrid, Wireless [pic]
Protocols (Ethernet not covered) Transmission Control Protocol / Internet Protocol (not covered) VOIP • Protocol - a standard that specifies the format of data as well as the rules to be followed during transmission • Interoperability - the capability of two or more computer systems to share data and resources, even though they are made by different manufacturers • Voice over IP (VoIP) - uses TCP/IP technology to transmit voice calls over long-distance telephone lines
Media: wire media, wireless media • Network transmission media - refers to the various types of media used to carry the signal between computers – Wire media (guided) – Wireless media (unguided) • Wire media - transmission material manufactured so that signals will be confined to a narrow path and will behave predictably
• Three most commonly used types include: – Twisted-pair wiring – Coaxial cable – Fiber optic (or optical fiber) – faster, emits light, harder to steal signal.
• Wireless media - natural parts of the Earth’s environment that can be used as physical paths to carry electrical signals
E-business Networks (not covered)
Wireless Fidelity (Wi-Fi) • Wireless fidelity