BUSINESS DRIVEN TECHNOLOGY Plug-In T2 Networks and Telecommunications

1. BUSINESS DRIVEN TECHNOLOGY Plug-In T2 Networks and Telecommunications

2. LEARNING OUTCOMES • Summarize the individual components of a computer network • Describe the three main network topologies • Explain the difference between the three main forms of network access methods • Summarize the difference between guided media and unguided media

3. LEARNING OUTCOMES • Explain how a network operating system works • List the transmitting and receiving devices used in a computer network • Describe the function of TCP/IP • Summarize the use of a virtual private network (VPN)

4. Introduction • The core chapters introduced the concept of computer networks • Computer network (or just network) - a group of two or more computer systems linked together using wires or radio waves over a geographical area • Computer networks that do not use physical wires are called wireless • This plug-in takes a detailed look at the key concepts that are integrating computer networks and data communications

5. Introduction Start

6. The Need for Networking • A network provides two principle benefits: • The ability to communicate • The ability to share • A network supports communication among users in ways that other media cannot • Groupware - software that supports team interactions and dynamics including calendaring, scheduling, and videoconferencing

7. THE BENEFITS OF COMPUTER NETWORKING • Store virtually any kind of information at, and retrieve it from, a central location on the network • Combines the power and capabilities of diverse equipment providing a collaborative medium to combine the skills of different people, regardless of physical location • Enables people to share information and ideas easily • They can work more efficiently and productively

8. NETWORKING BASICS • Networks are assembled according to certain rules: • Cabling, has to be a certain length • Each cabling strand can only support a certain amount of network traffic, etc • Topology - the actual physical organization of the computers (and other network devices) including connections • Bandwidth - indicates how much information can be carried in a given time period (usually a second) over a wired or wireless communications link

9. NETWORKING BASICS • The network industry refers to nearly every type of network as an “area network”: • Local Area Network (LAN) - connects network devices over a relatively short distance • Wide Area Network (WAN) – is a geographically dispersed telecommunications network • Metropolitan Area Network (MAN) - interconnects users in a geographic area or region larger than a local area network, but smaller than a wide area network

10. NETWORKING BASICS

11. Local Area Network (LAN) Basics • A networked office building, school, or home usually contains a single LAN • Sometimes one building will contain a few small LANs, and occasionally a LAN will span a group of nearby buildings

12. Wide Area Network (WAN) Basics • A WAN like the Internet spans most of the world • A WAN is a geographically dispersed telecommunications network • A WAN may be privately owned or rented, but the term implies the inclusion of public networks

13. Metropolitan Area Network (MAN) Basics • A MANconnects an area larger than a LAN but smaller than a WAN, such as a city • Example: A university or college may have a MAN that joins together many of their local area networks situated around its campus • From their MAN they could have several wide area network links to other universities or the Internet

14. Networks – The Big Picture • A network is made up of many physical elements: • Computers, printers, and other devices • The manner in which all these items are connected is referred to as the network topology • Networks must be arranged in a particular way in order to work properly • Network topologies are further subdivided into two categories: • Physical topologies • Logical topologies

15. PHYSICAL TOPOLOGIES • Physical topology - the actual physical organization of the computers on the network and its connections • There are five principal topologies used in LANs: • Bus topology - all devices are connected to a central cable • Startopology - all devices are connected to a hub • Ring topology - all devices are connected to one another in a closed loop • Tree topology – combines the characteristics of the bus and star topologies • Wireless topology - all devices are connected by a receiver/transmitter to a special network interface card that transmits signals between a computer and a server; all within an acceptable transmission range

16. PHYSICAL TOPOLOGIES Start

17. PHYSICAL TOPOLOGIES

18. PHYSICAL TOPOLOGIES

19. NETWORK ACCESS METHODS (PROTOCOLS) • Protocol - the predefined way that someone (who wants to use a service) talks with or utilizes that service • The most popular LAN protocols include: • Token Ring • Ethernet • Fiber Distributed Data Interface (FDDI)

20. Token Ring • Token ring network - a LAN in which all computers are connected in a ring or star topology and a token-passing schema is used in order to prevent the collision of data between two computers that want to send messages at the same time • Second most widely used protocol on local area networks • IBM originally developed the Token Ring network in the 1970s • Data transfer rates of either 4 or 16 megabits per second

21. Ethernet • Ethernet - a physical and data layer technology for LAN networking • Ethernet is the most widely installed LAN access method originally developed by Xerox • When it first began to be widely deployed in the 1980s, Ethernet supported a maximum theoretical data rate of 10 megabits per second (Mbps) • Fast Ethernet standards have extended traditional Ethernet technology to 100 Mbps peak • Gigabit Ethernet technology extends performance up to 1000 Mbps

22. Ethernet • Ethernet and Token Ring Network

23. Fiber Distributed Data Interface (FDDI) • Fiber Distributed Data Interface (FDDI) - a set of protocols for sending digital data over fiber optic cable • FDDI networks are token-passing networks that supports data rates of up to 100 megabits per second • FDDI networks are typically used as backbones for wide area networks

24. Fiber Distributed Data Interface (FDDI) • Fiber Distributed Data Interface

25. Networking Hardware • To be sent from one location to another, a signal must travel along a physical path • The physical path that is used to carry a signal between a signal transmitter and a signal receiver is called the transmission medium • Network transmission media - the various types of media used to carry the signal between computers • There are two types of transmission media: • Guided • Unguided

26. GUIDED MEDIA • Guided media - transmissions material manufactured so that signals will be confined to a narrow path and will behave predictably

27. GUIDED MEDIA • The three most common types of guided media include twisted-pair wiring, coaxial cable, and fiber optic cable

28. Twisted-Pair Wiring • Twisted-pair wiring - a type of cable composed of four (or more) copper wires twisted around each other within a plastic sheath • The wires are twisted to reduce outside electrical interference • The RJ-45 connectors on twisted-pair cables resemble large telephone jacks

29. Coaxial Cable • Coaxial cable - cable that can carry a wide range of frequencies with low signal loss • Consists of a metallic shield with a single wire placed along the center of a shield and isolated from the shield by an insulator • Coaxial cable is divided into two different types: • Thinnet coaxial cable - similar to the cable used by cable television companies • Thicknetcoaxial cable - similar to thinnet except that it is larger in diameter

30. Fiber Optic Cable • Fiber optic (or "optical fiber") - the technology associated with the transmission of information as light impulses along a glass or plastic wire or fiber • Optical fiber cable can transmit data over long distances with little loss in data integrity • Optical fiber is not subject to interference

31. Fiber Optic Cable • Cable Summary

32. UNGUIDED MEDIA • Unguided media - natural parts of the Earth’s environment that can be used as physical paths to carry electrical signals • Examples include microwaves, infrared light waves, and radio waves

33. TRANSMITTING AND RECEIVING DEVICES • Transmitting and receiving devices include: • Network adapters • Modems • Repeaters • Wiring concentrators, hubs, and switches • Bridges, routers, and gateways • Microwave transmitters • Infrared and laser transmitters • Cellular transmitters • Wireless LAN transmitters

34. Network Adapters • Network adapter - the hardware installed in computers that enables them to communicate on a network • The most common form is designed to be installed directly into a standard expansion slot inside a PC • Network adapters are manufactured for connection, including twisted-pair wire, coaxial cable, and fiber-optic cable

35. Modems • Modems - provide the means to transmit digital computer data typically over ordinary telephone lines • The transmitting modem converts the encoded data signal to an audible signal and transmits it • A modem connected at the other end of the line receives the audible signal and converts it back into a digital signal for the receiving computer • Modems are commonly used for inexpensive communications between a network and geographically isolated computers

36. Modems Start

37. Modems - Connecting to the Internet Start

38. Repeaters • Repeaters - used to increase the distance over which a network signal can be propagated • A signal travels through a transmission medium, it encounters resistance and gradually becomes weak and distorted • The repeater receives the network signal and retransmits it at the original transmission strength

39. Concentrators, Hubs, and Switches • Concentrators, hubs, and switches - provide a common physical connection point for computing devices • Most hubs and all wiring concentrators and switches have built-in signal repeating capability to perform signal repair and retransmission

40. Bridges, Routers, and Gateways • The devices used to interconnect network segments are divided into three classifications: • Bridges • Routers • Gateways • Bridges and routers - generally used to connect networks that use similar protocols; example includes TCP/IP • Gateways - used to connect networks that use dissimilar protocols; examples includes TCP/IP and IPX

41. Microwave Transmitters • Microwave transmitters and receivers - commonly used to transmit network signals over great distances

42. Infrared and Laser Transmitters • Infrared and laser transmitters - similar to microwave systems: they use the atmosphere and outer space as transmission media • They require a line-of-sight transmission path • Useful for signaling across short distances where it is impractical to lay cable

43. Cellular Transmitters • Cellular transmitters - radio transmissions and therefore have the advantage of being able to penetrate solid objects • A cellular base station at the center of each cell contains: • Low-power transmitters • Receivers • Antennas • Common control computer equipment • Cellular devices are configured to operate at low power to avoid interfering with other cellular devices in the area

44. Wireless LAN Transmitters • Wireless LAN transmitters (or access points) - function like hubs and switches in a wired environment, only they propagate signals through radio waves or infrared light instead of wires

45. The Network Operating System • Network operating system (NOS) - an operating system that includes special functions for connecting computers and devices into a local area network • The NOS is the “brain” of the entire network • Network operating systems are divided into two categories: • Client-server • Peer-to-peer

46. The Network Operating System Start

47. CLIENT-SERVER NETWORKS • Client-server network - a versatile, message-based, and modular infrastructure that is intended to improve usability, flexibility, interoperability, andscalability as compared to centralized, mainframe computing

48. CLIENT-SERVER NETWORKS Start

49. THIN CLIENT-SERVER NETWORKS • Thin clients - similar to terminals connected to mainframes, the server performs the bulk of the processing, and the client presents the interface • Thin clients are usually devoid of floppy drives, expansion slots, and hard disks; consequently, the “box” or central processing unit is much smaller than that of a conventional PC

50. PEER-TO-PEER NETWORKS • Peer-to-peer networks - enable networked computers to function as both servers and workstations