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

2. Summarize the individual components of a computer network
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
1. Summarize the individual components of a computer network
Protocols
Guided and unguided media, such as Twisted-pair wiring, Coaxial cable, Fiber optic cable, Microwave, infrared, and radio waves,
Transmitting and receiving devices, such as: Network adapters, Modems, Repeaters, Wiring concentrators, hubs, and switches, Bridges, routers, and gateways, Microwave transmitters, Infrared and laser transmitters, Cellular transmitters, Wireless LAN transmitters, Network operating system
2. Describe the three main network topologies
Local Area Network (LAN) - connects network devices over a relatively short distance. A networked office building, school, or home usually contains a single LAN, though sometimes one building will contain a few small LANs, and occasionally a LAN will span a group of nearby buildings
Wide Area Network (WAN) – is a geographically dispersed telecommunications network. A WAN like the Internet spans most of the world. A wide area network is a geographically dispersed telecommunications network. A wide area network may be privately owned or rented, but the term usually implies the inclusion of public (shared user) networks
Metropolitan Area Network (MAN) - interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network, but smaller than the area covered by a wide area network
3. Explain the difference between the three main forms of network access methods
Token Ring - a LAN in which all computers are connected in a ring or star topology and a token-passing scheme is used in order to prevent the collision of data between two computers that want to send messages at the same time
Ethernet - a physical and data layer technology for LAN networking. Widely installed for LAN access originally developed by Xerox and then developed further by Xerox, Digital Equipment Corporation, and Intel
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
4. Summarize the difference between guided media and unguided media
Guided media - transmission material manufactured so that signals will be confined to a narrow path and will behave predictably
Unguided media - natural parts of the Earth’s environment that can be used as physical paths to carry electrical signals. The atmosphere and outer space are examples of unguided media that are commonly used to carry signals. These media can carry such electromagnetic signals as microwave, infrared light waves, and radio waves

3. Explain how a network operating system works
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)
5. Explain how a network operating system works
The network operating system (NOS) is 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, acting as the command center and enabling the network hardware and software to function as one cohesive system.
6. List the transmitting and receiving devices used in a computer network
Transmitting and receiving devices used in a computer network: Network adapters, Modems, Repeaters, Wiring concentrators, hubs, and switches, Bridges, routers, and gateways, Microwave transmitters, Infrared and laser transmitters, Cellular transmitters, Wireless LAN transmitters
7. Describe the function of TCP/IP
Transmission Control Protocol/Internet Protocol (TCP/IP) is a group, or suite, of networking protocols used to connect computers on the Internet. TCP and IP are the two main protocols in the suite. TCP provides transport functions, ensuring, among other things, that the amount of data received is the same as the amount transmitted. IP provides the addressing and routing mechanism.
8. Summarize the use of a virtual private network (VPN)
A virtual private network (VPN) is a way to use the public telecommunication infrastructure (e.g., Internet) to provide secure access to an organization's network

4. The core chapters introduced the concept of computer networks
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
This slide offers a brief introduction to computer networks
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Networks connect two or more computers so they can communicate with each other and share resources. In order for a computer to be connected to a network, it must have a network interface card. Most local area networks use a hub as the central point where all the nodes connect. Cabling connects each node to the hub. If the network is linked to another network, a bridge or a gateway is required to make that connection.
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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
, the most popular form of network communication
Sharing involves not only information (database records, , graphics, etc.), but also resources (applications, printers, modems, disk space, scanners, etc.)

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. Networks are assembled according to certain rules:
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
Figure T2.1 – LAN, WAN, and MAN Network Diagram

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 MAN connects 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
Star topology - 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
This slide offers a brief introduction to physical topologies
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The network's topology determines how data moves between nodes. In a bus topology, all nodes can send data requests at the same time, sometimes resulting in collisions. In a star topology, data requests are managed by a central hub or server. There is no danger of data collision. In a ring topology, data requests move from node-to-node in a prescribed circular path. There is no danger of a data collision.
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17. PHYSICAL TOPOLOGIES
Figure T2.2 – Bus, Star, and Ring Topology

18. PHYSICAL TOPOLOGIES
Figure T2.3 – Tree and Wireless Topology

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)

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
Thicknet coaxial 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
Recent advances in radio hardware technology have produced significant advancements in wireless networking devices: the cellular telephone, wireless modems, and wireless LANs. These devices use technology that in some cases has been around for decades but until recently was too impractical or expensive for widespread use.

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 This slide offers a brief introduction to modems
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If you are connecting to the Internet through a telephone line or through cable, you'll need a modem to convert the analog signal into a digital signal that your computer can understand. Modems can be internal or external and connect your computer to the data connection through a cable. The modem you use will depend on the type connection you have. The data line then plugs into a network of either phone lines or cables, which connect to a router at the cable or telephone company. A router is a special type of computer that controls the inflow and outflow of data on networks connected to the Internet. The router sends the data where it needs to go through the interconnected networks of the Internet.
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37. Modems - Connecting to the Internet
This slide offers a brief introduction to how to connect to the Internet
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To connect your computer to your service provider, you have two options: With a dial-up account, your computer dials a specific phone number when you open your Web browser. With a connection that is always on (like DSL or cable), there is no need for an access phone number, so you can simply open your Web browser. This connects your computer to the service provider - essentially joining your computer to the service provider's network. The service provider has what is known as a Point of Presence (POP) - a high speed connection to the other service providers through the Network Access Points (NAP), creating a network of networks. Each NAP is connected to other NAPs through one of the Internet "backbones" - groups of super high speed optic cables that form the foundation of the Internet network.
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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
A microwave transmitter uses the atmosphere or outer space as the transmission medium to send the signal to a microwave receiver

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
This slide offers a brief introduction to network operating systems
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Network operating system software offers tools essential for network management. One of the most important functions is to manage network user accounts. The network administrator can add a new user, assigning a user name and password. When a user is assigned to a group, he inherits the rights and permissions of that group. Network operating system software also allows the administrator to control which resources are shared and which groups or individual users have access to those resources.
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47. CLIENT-SERVER NETWORKS
Client-server network - a versatile, message-based, and modular infrastructure that is intended to improve usability, flexibility, interoperability, and scalability as compared to centralized, mainframe computing

48. CLIENT-SERVER NETWORKS
This slide offers a brief introduction to client-server networks
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In a client/server relationship the server controls access to shared services and data. The client sends requests to the server to access those resources. For example, the client sends a log-in request. The server checks the user name and password to see if that request is valid. If it is, then the client can access the network. That doesn't give the client the right to use all the network's resources. For additional requests, such as viewing shared network files, the server checks to see if the client has permission for that specific action. If yes, then the request is granted. If no, the request is denied.
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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
Peer-to-peer networks provide fewer services than client-server networks

51. PEER-TO-PEER NETWORKS
This slide offers a brief introduction to peer-to-peer networks
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In a peer-to-peer network, computers on the network have access to the shared resources of all the other computers. You can share files, printers, and Internet access without requiring a server.
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52. The Internet is the world’s largest computer network
Internet Technology
The Internet is the world’s largest computer network
Two of the most influential technologies are:
Transmission Control Protocol/Internet Protocol (TCP/IP) suite
World Wide Web (WWW)

53. TRANSMISSION CONTROL PROTOCOL/INTERNET PROTOCOL (TCP/IP)
Transmission Control Protocol/Internet Protocol (TCP/IP) - a group, or suite, of networking protocols used to connect computers on the Internet
TCP and IP are the two main protocols in the suite
TCP provides transport functions, ensuring, among other things, that the amount of data received is the same as the amount transmitted
The IP part of TCP/IP provides the addressing and routing mechanism

54. Transmission Control Protocol/Internet Protocol (TCP/IP)
The TCP/IP suite of applications include:
File Transfer Protocol (FTP) - allows files to be downloaded off or uploaded onto a network
Simple Mail Transfer Protocol (SMTP)-TCP/IP’s own messaging system for
Telnet protocol - provides terminal emulation
Hypertext Transfer Protocol (HTTP) - allows Web browsers and servers to send and receive Web pages
Simple Network Management Protocol (SNTP) - allows the management of networked nodes to be managed from a single point

55. Transmission Control Protocol/Internet Protocol (TCP/IP)
The TCP/IP Protocol Suite

56. WORLD WIDE WEB The World Wide Web is a client-server environment
Information is managed through Web sites on computers called Web servers
Accessing Web sites is done through the use of client software (i.e., a browser) and the Internet’s HTTP
Computers and Web sites on the Internet are linked through documents called Web pages written in HTML

57. Intranet
Intranet – an internalized portion of the Internet, protected from outside access, that allows an organization to provide access to information and application software to only its employees
An intranet enables a business to collect, manage, and disseminate information more quickly and easily

58. Extranet
Extranet - a private network that uses the Internet protocol and the public telecommunication system to securely share part of a business's information or operations with suppliers, vendors, partners, customers, or other businesses
Companies create extranets that:
Consolidate data gathering and share data
To jointly develop and share training programs
To coordinate project management for a common work project

59. Virtual Private Network (VPN)
Virtual private network (VPN) - a private WAN that uses the Internet as a low-cost WAN backbone to transport data between tow or more geographically separate sites
Advantages that a VPN has over a dedicated-line WAN:
The cost of implementation
No need to lay cable or lease dedicated lines between the remote sites needing to connect
Additional Internet connection would be required
Businesses can network remote offices into one large WAN and provide access to the Internet

60. Virtual Private Network (VPN)
Intranet, Extranet, and VPN Technologies