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Computer Network Basics.pdf
- 1. Copyright © 2006by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Technology Education Network Basics
- 2. Network Definition • Setof technologies that connects computers • Allows communication and collaboration between users 2
- 3. Figure : Thedefinition of a computer network: a set of transmission paths, interconnected at nodes 3
- 4. Components of acomputer network A computer network is composed of: Hosts (PCs, laptops, handhelds) Routers & switches (IP router, Ethernet switch) Links (wired, wireless) Protocols (IP, TCP, CSMA/CD, CSMA/CA) Applications (network services) Humans and service agents 9A-4
- 5. 5 The Uses ofa Network • Simultaneous access to data – Data files are shared • Access can be limited – Shared files stored on a server – Software can be shared • Site licenses • Network versions • Application servers
- 6. 6 The Uses ofa Network • Shared peripheral device – Printers and faxes are common shares – Reduces the cost per user – Devices can be connected to the network – Print servers control network printing • Manage the print queue
- 7. 7 Sharing Data File servercontains documents used by other computers.
- 8. 8 The Uses ofa Network • Personal communication – Email • Instantaneous communication – Conferencing • Tele conferencing • Videoconferencing • Audio-conferencing • Data-conferencing – Voice over IP • Phone communication over network wires
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- 10. 10 The Uses ofa Network • Easier data backup – Backup copies data to removable media – Server data backed up in one step
- 11. Common Network Types LocalArea Network (LAN) – Contains printers, servers and computers – Systems are close to each other – Contained in one office or building – Organizations often have several LANS 11
- 12. Common Network Types WideArea Networks (WAN) – Two or more LANs connected – Over a large geographic area – Typically use public or leased lines • Phone lines • Satellite – The Internet is a WAN 12 communicatio ns satellite
- 13. 13 Hybrid Network Types CampusArea Networks (CAN) – A LAN in one large geographic area – Resources related to the same organization – Each department shares the LAN
- 14. Hybrid Network Types MetropolitanArea Network (MAN) – Large network that connects different organizations – Shares regional resources – A network provider sells time 14
- 15. 15 Hybrid Network Types HomeArea Network (HAN) – Small scale network – Connects computers and entertainment appliances – Found mainly in the home
- 16. 16 Hybrid Network Types PersonalArea Network (PAN) – Very small scale network – Range is less than 2 meters – Cell phones, PDAs, MP3 players
- 17. Network Architecture The designof computers, devices, and media on a network is sometimes called the network architecture. Can be categorized as: Client/server network Peer-to-peer network Internet Peer-to-peer network 17
- 18. 18 How Networks AreStructured • Server based network – Node is any network device – Servers control what the node accesses – Users gain access by logging in – Server is the most important computer
- 19. How Networks AreStructured • Client/Server network – Nodes and servers share data roles – Nodes are called clients – Servers are used to control access – Database software • Access to data controlled by server – Server is the most important computer 19
- 20. How Networks AreStructured • Peer –to- peer network Simple network that connects fewer than 10 computers Each computer, or peer, has equal capabilities 20
- 21. How Networks AreStructured • Internet Peer – to - peer networks (P2PN) – All nodes are equal – Nodes access resources on other nodes – Each node controls its own resources – Most modern OS allow P2PN – Distributing computing is a form 21
- 22. Network Topologies A Networktopology refers to the layout of the computers and devices in a communication network. Star Network Bus Network Ring Network Mesh Network Tree Network 22
- 23. 23 Network Topologies • Topology –Choice affects • Network performance • Network size • Network collision detection – Several different types
- 24. 24 Network Topologies • Packets –Pieces of data transmitted over a network • Packets are created by sending node • Data is reassembled by receiving node – Packet header • Sending and receiving address – Packet payload • Number and size of data • Actual data – Packet error control
- 25. Network Topologies • Bustopology – Also called linear bus – One wire connects all nodes – Terminator ends the wires – Advantages • Easy to setup • Small amount of wire – Disadvantages • Slow • Easy to crash 25
- 26. 26 Network Topologies • Startopology – All nodes connect to a hub • Packets sent to hub • Hub sends packet to destination – Advantages • Easy to setup • One cable can not crash network – Disadvantages • One hub crashing downs entire network • Uses lots of cable – Most common topology
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- 28. Network Topologies • Ringtopology – Nodes connected in a circle – Tokens used to transmit data • Nodes must wait for token to send – Advantages • Time to send data is known • No data collisions – Disadvantages • Slow • Lots of cable 28
- 29. 29 Network Topologies • Meshtopology – All computers connected together – Internet is a mesh network – Advantage • Data will always be delivered – Disadvantages • Lots of cable • Hard to setup
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- 31. 31 Network Media • Linksthat connect nodes • Choice impacts – Speed – Security – Size
- 32. 32 Wire Based Media •Twisted-pair cabling – Most common LAN cable – Called Cat5 or 100BaseT – Four pairs of copper cable twisted – May be shielded from interference – Speeds range from 1 Mbps to 1,000 Mbps
- 33. 33 Wire Based Media •Coaxial cable – Similar to cable TV wire – One wire runs through cable – Shielded from interference – Speeds up to 10 Mbps – Nearly obsolete
- 34. 34 Wire Based Media •Fiber-optic cable – Data is transmitted with light pulses – Glass strand instead of cable – Immune to interference – Very secure – Hard to work with – Speeds up to 100 Gbps
- 35. 35 Wireless Media • Datatransmitted through the air • LANs use radio waves • WANs use microwave signals • Easy to setup • Difficult to secure
- 36. 36 Network Hardware • Networkinterface cards – Network adapter – Connects node to the media – Unique Machine Access Code (MAC)
- 37. 37 Network Hardware • Networklinking devices – Connect nodes in the network – Cable runs from node to device – Crossover cable connects two computers
- 38. 38 Network Hardware • Hubs –Center of a star network – All nodes receive transmitted packets – Slow and insecure
- 39. 39 Network Hardware • Switches –Replacement for hubs – Only intended node receives transmission – Fast and secure
- 40. 40 Network Hardware • Bridge –Connects two or more LANs together – Packets sent to remote LAN cross • Other packets do not cross – Segments the network on MAC addresses
- 41. 41 Network Hardware • Router –Connects two or more LANs together – Packets sent to remote LAN cross – Network is segmented by IP address – Connect internal networks to the Internet – Need configured before installation
- 42. 42 Network Hardware • Gateway –Connects two dissimilar networks – Connects coax to twisted pair – Most gateways contained in other devices
- 43. 43 Network Cabling • Cablingspecifications – Bandwidth measures cable speed • Typically measured in Mbps – Maximum cable length – Connector describes the type of plug
- 44. 44 Network Cabling • Ethernet –Very popular cabling technology – 10 Base T, 10Base2, 10Base5 – Maximum bandwidth 10 Mbps – Maximum distances100 to 500 meters
- 45. 45 Network Cabling • FastEthernet – Newer version of Ethernet – Bandwidth is 100 Mbps – Uses Cat5 or greater cable • Sometimes called 100Base T – Requires a switch
- 46. 46 Network Cabling • GigabitEthernet – High bandwidth version of Ethernet – 1 to 10 Gbps – Cat 5 or fiber optic cable – Video applications
- 47. 47 Network Cabling • Tokenring – Uses shielded twisted pair cabling – Bandwidth between 10 and 25 Mbps – Uses a multiple access unit (MAU) – Popular in manufacturing and finance
- 48. 48 Network Protocols • Languageof the network – Rules of communication – Error resolution – Defines collision and collision recovery – Size of packet – Naming rules for computers
- 49. 49 Network Protocols • TCP/IP –Transmission Control Protocol/Internet Protocol – Most popular protocol – Machines assigned a name of 4 numbers • IP address • 209.8.166.179 is the White House’s web site – Dynamic Host Configuration Protocol • Simplifies assignment of IP addresses – Required for Internet access
- 50. 50 Network Protocols • IPX/SPX –Internet Packet Exchange/Sequenced Packet Exchange – Older protocol – Associated with Novell Netware – Replaced by TCP/IP
- 51. 51 Network Protocols • NetBEUI –Network BIOS Extended User Interface – Used by Windows to name computers – Transmission details handled by TCP/IP
- 52. 52 Network Protocols • Tokenring – Popular in manufacturing and finance – Nodes communicate when they have the token
- 53. Copyright © 2006by The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill Technology Education End of Presentation