1. © 2009 Pearson Education, Inc. Publishing as Prentice Hall An Introduction to Networking Chapter 1 Raymond Panko’s Business Data Networks and Telecommunications, 7th edition

2. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-2 Builds Slides with the blue mouse icon in the upper right hand corner are “build” slides Not everything on the slide will appear at once Each time the mouse click icon is clicked, more information on the slide will appear The number by the mouse icon gives the number of builds on the slide (the number of mouse clicks) 2

3. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-3 1-1: Black Box View of Networks What Is a Network? –Preliminary definition: A network is a communication system that allows application programs on different hosts to work together Application 1 Application 2 Host A Host B Network

4. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-4 Hosts –Any computer attached to a network is called a host –Including client PCs, servers, mobile phones, etc. Host Cat (Ignores Internet)

5. © 2009 Pearson Education, Inc. Publishing as Prentice Hall Networked Applications

6. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-6 Application Standards Application standards govern communication between application programs –Allow products from different vendors cannot talk to one another The Hypertext Transfer Protocol (HTTP) standardizes communication between browsers and Web servers –Standards are also called protocols –HTTP is an open standard (not controlled by any vendor) Open standards drive down product costs Vendor-controlled standards are called proprietary standards

7. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-7 1-2: Hypertext Transfer Protocol (HTTP) Client Host Web server Program Browser HTTP Request Message (Asks for File) HTTP Response Message (Contains the Requested File) HTTP is a Client/Server Protocol –The client is the browser; it sends a request –The server is the Web server; it sends a response –Most application standards are client/server protocols 1

8. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-8 1-3: The ARPANET and the Internet ARPANET –Some of the first networked applications were created for the ARPANET –Created by the Defense Advanced Research Projects Agency (DARPA) around 1970 Served researchers doing business with DARPA Connected many sites around the United States

9. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-9 1-3: The ARPANET and the Internet Soon, Many Similar Networks Appeared –CSNET in computer science –BITNET in business and the social sciences –Tower of Babel situation—no interconnection –This was frustrating to users

10. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-10 1-3: The ARPANET and the Internet Next, DARPA Created the Internet in 1980 to Connect Networks Together –Initially, commercial activity was forbidden –Became commercial in 1995 –Today, the Internet is almost entirely commercial –Almost no government money flowing in to run the Internet

11. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-11 1-4: Traditional Internet Applications File Transfer Protocol (FTP) E-Mail The World Wide Web (WWW) E-Commerce –Buying and selling on the Internet

12. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-12 1-5: The Internet Versus the World Wide Web (and Other Applications) World Wide Web (Application) E-Mail (Application) FTP (Application) Other Applications The Internet (Transmission System) The Internet is a global transmission system. The WWW, e-mail, etc., are applications that run over the Internet global transmission system

13. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-13 1-6: Newer Internet Applications Instant Messaging (IM) Streaming Audio and Video –No need to wait until the entire file is downloaded before beginning to see or hear it Voice over IP (VoIP) –Telephony over the Internet or other IP networks Peer-to-Peer (P2P) Applications –Growing processing power of PCs allows PCs to serve other PCs directly 3

14. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-14 1-6: Newer Internet Applications Web 2.0 –A hazy term that focuses on using the Internet to facilitate communication among people –Including the creation of communities –In addition, the users themselves typically generate the content –Blogs, wikis, podcasts –Community building sites such as MySpace and Facebook, video sharing sites such as YouTube, virtual worlds such as Second Life, and specific information sharing sites, such as craigslist

15. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-15 1-7: Corporate Network Applications Applications Specific to Businesses –Can consume far more corporate network resources than traditional and new Internet applications combined Transaction-Processing Applications –Simple, high-volume repetitive clerical transaction applications –Accounting, payroll, billing, manufacturing, etc. 1

16. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-16 1-7: Corporate Network Applications Enterprise Resource Planning (ERP) Applications –Serve individual business functions while providing integration between functional modules Sales Purchasing Manufacturing Shipping Warehousing Accounting Billing Inter-Function Transaction Inter-Function Transaction Inter-Function Transaction

17. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-17 1-7: Corporate Network Applications Organizational Communication Applications –E-mail, etc. –Groupware Integrate multiple types of communication, organize communication for retrieval, and provide multiple ways to disseminate and retrieve information

18. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-18 1-7: Corporate Network Applications Converged Networks –Voice and data traditionally have needed different networks –Convergence: Moving voice/video and data networks to a single network –Can save the corporation a great deal of money by only having a single network –Many technical issues remain

19. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-19 1-8: File Service File Server 1. User saves data file to file server, which is backed up nightly 2 2. Later, user can retrieve the data file from any other computer 3. Others can retrieve the file and even edit it if they are given permission

20. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-20 1-8: File Service File Server 1. A program is Installed on the file server; Less expensive than installing it on many individual PCs 2. A multiuser version of the program is required 3 4. Note that the program is executed on the client PC, not on the file server! 4. Note that the program is executed on the client PC, not on the file server! 3. For execution, a copy is downloaded from the file server

21. © 2009 Pearson Education, Inc. Publishing as Prentice Hall Quality of Service (QoS)

22. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-22 1-9: Network Quality of Service (QoS) Quality of Service (QoS) –Indicators of network performance Metrics –Ways of measuring specific network quality-of-service variables

23. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-23 1-10: Transmission Speed Measuring Transmission Speed –Measured in bits per second (bps) –In metric notation: Increasing factors of 1,000 … –Not factors of 1,024 Kilobits per second (kbps)-note the lowercase k Megabits per second (Mbps) Gigabits per second (Gbps) Terabits per second (Tbps)

24. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-24 1-10: Transmission Speed Measuring Transmission Speed –What is 23,000 bps in metric notation? –What is 3,000,000,000 bps in metric notation? –What is 15,100,000 bps in metric notation? Occasionally measured in bytes per second –If so, written as Bps –Usually seen only in file download speeds

25. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-25 1-10: Transmission Speed Writing Transmission Speeds in Proper Form –The rule for writing speeds (and metric numbers in general) in proper form is that there should be 1 to 3 places before the decimal point –23.72 Mbps is correct (2 places before the decimal point) –2,300 Mbps has four places before the decimal point, so it should be rewritten as 2.3 Gbps (1 place) –0.5 Mbps has zero places to the left of the decimal point. It should be written as 500 kbps (3 places) 3

26. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-26 1-10: Transmission Speed Writing Transmission Speeds in Proper Form –How to convert 1,200 Mbps to proper form, to 12.02 Gbps NumberSuffix 12,020Mbps Divide by 1,000Multiply by 1,000 12.02Gbps

27. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-27 1-10: Transmission Speed Writing Transmission Speeds in Proper Form –How to convert.2346 Mbps to proper form, to 234.6 kbps NumberSuffix 0.2346Mbps Multiply by 1,000Divide by 1,000 234.6kbps

28. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-28 1-10: Transmission Speed Writing Transmission Speeds in Proper Form –How should you write the following in proper form? 549.73 kbps 0.47 Gbps 11,200 Mbps.0021 Gbps

29. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-29 1-10: Transmission Speed Rated Speed –The speed in bits per second that you should get (advertised or specified in the standard) Throughput –The speed you actually get –Almost always lower than the rated speed On Shared Transmission Lines –Aggregate throughput—total throughput for all users –Individual throughput—the individual user’s share of the aggregate throughput

30. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-30 1-11: Cost Network Demand, Budgets, and Decisions –Figure 1-12 shows that network demand is growing explosively, while network budgets are growing slowly –This creates a cost squeeze that affects every decision –Overspending in one area will result in the inability to fund other projects Figure 1-12

31. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-31 1-11: Cost Systems Development Life Cycle Costs –Hardware: Full price: advertised base price plus necessary options –Software: Full price: advertised base price plus necessary options –Labor costs: Networking staff and user costs –Outsourcing development costs –Total development investment

32. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-32 1-11: Cost Systems Life Cycle (SLC) Costs –System development life cycle (SDLC) versus system life cycle (SLC) SLC has ongoing costs after development –Total cost of ownership (TCO) Total cost over entire life cycle SLC includes carrier costs –Carrier pricing is complex and difficult to analyze –Must deal with leases, which lock the firm in for months or years 1

33. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-33 1-13: Other Quality-of-Service Metrics We Have Already Seen Speed and Cost Availability –The percentage of time a network is available for use –“Our availability last year was 99.9%” Downtime is the amount of time a network is unavailable –Measured in minutes, hours, etc. –“In July, we had five minutes of downtime.”

34. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-34 1-13: Other Quality-of-Service Metrics Error Rates –Packet error rate: the percentage of packets lost or damaged –Bit error rate: the percentage of bits lost or damaged

35. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-35 1-13: Other Quality-of-Service Metrics Latency and Jitter –Latency Delivery delay, measured in milliseconds –For instance, 250 ms is a quarter of a second Bad for real-time applications –Voice and video –Network control messages

36. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-36 1-13: Other Quality-of-Service Metrics Latency and Jitter –Jitter Variation in latency between successive packets Makes voice sound jittery Figure 1-14

37. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-37 1-13: Other Quality-of-Service Metrics Service Level Agreements –Customers want guarantees for performance –Provider pays penalties if the network does not meet its service metrics guarantees –Often specified on a percentage basis At least 100 Mbps 99.5% of the time

38. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-38 1-13: Other Quality-of-Service Metrics Service Level Agreements –Specify a worst case –Speed SLAs Low speed is the worst case So an SLA would guarantee a lowest speed E.g., no worse than 1 Mbps) Customer would like higher speeds But wants no less than 1 Mbps

39. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-39 1-13: Other Quality-of-Service Metrics Service Level Agreements –Latency Would an SLA specify a lowest latency or a highest latency? Ask yourself, “Which is worse: large latency or small latency?” The answer: Large latency is worse So specify a maximum latency No more than 100 ms 99% of the time

40. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-40 1-13: Other Quality-of-Service Metrics Service Level Agreements –What would an SLA guarantee for availability?

41. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-41 1-13: Other Quality-of-Service Metrics Service Level Agreements –What would an SLA guarantee for error rates?

42. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-42 1-15: Network Security Security –Security attacks can be extremely expensive –Companies need to install defenses against attacks –Chapter 9 discusses network security in depth

43. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-43 1-15: Network Security Authentication –Goal is to stop impostors –Supplicant attempts to prove its identity to a verifier –Example: user logging into a server is a supplicant; the server is a verifier –Proofs of identity are called credentials Supplicant: True User? Verifier: Server Credentials: Password

44. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-44 1-15: Network Security Cryptographic Protections –Eavesdroppers may intercept your messages Read and even change messages Send new messages impersonating the other side –Cryptography is the use of mathematics to protect information in storage or in transit –Encryption for confidentiality An eavesdropper cannot read encrypted messages Legitimate receiver, however, can decrypt the message 2

45. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-45 1-15: Network Security Firewall –Examines each packet passing through it –Drops and logs provable attack packets –It lets other packets get through, even if suspicious Arriving Packet Arriving Packet Provable Attack Packet Provable Attack Packet Other Packets Other Packets Drops Passes

46. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-46 1-15: Network Security Host Hardening –Some attacks will inevitably get past safeguards and reach hosts –Hosts must be “hardened” to withstand attacks –Hardening is a set of protections we will see in Chapter 9 Example: installing antivirus software on the host Example: downloading security updates

47. © 2009 Pearson Education, Inc. Publishing as Prentice Hall Switched Networks

48. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-48 Figure 1-16: Ethernet Switch Operation Ethernet Switch A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65 D4-47-55-C4-B6-9F C3-2D-55-3B-A9-4F In switched networks, Messages are called frames Host A1-… wishes to send a frame to Host C3 The frame must pass Through the switch In switched networks, Messages are called frames Host A1-… wishes to send a frame to Host C3 The frame must pass Through the switch

49. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-49 Figure 1-16: Ethernet Switch Operation UTP Ethernet Switch A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65 D4-47-55-C4-B6-9F C3-2D-55-3B-A9-4F Frame To C3… Host A1-… sends the frame to the switch Host A1-… sends the frame to the switch

50. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-50 Figure 1-16: Ethernet Switch Operation Switching Table Port Host 10 A1-44-D5-1F-AA-4C 13 B2-CD-13-5B-E4-65 15 C3-2D-55-3B-A9-4F 16 D4-47-55-C4-B6-9F UTP Ethernet Switch A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65 D4-47-55-C4-B6-9F C3-2D-55-3B-A9-4F Frame To C3… The switch reads the destination address in the frame. It looks up the address (C3-…) in the switching table. It reads the port number (15) The switch reads the destination address in the frame. It looks up the address (C3-…) in the switching table. It reads the port number (15)

51. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-51 Figure 1-16: Ethernet Switch Operation Switching Table Port Host 10 A1-44-D5-1F-AA-4C 13 B2-CD-13-5B-E4-65 15 C3-2D-55-3B-A9-4F 16 D4-47-55-C4-B6-9F Ethernet Switch A1-44-D5-1F-AA-4C B2-CD-13-5B-E4-65 D4-47-55-C4-B6-9F C3-2D-55-3B-A9-4F Frame To C3… The switch sends the frame out Port 15, to the destination host. The switch sends the frame out Port 15, to the destination host.

52. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-52 1-17: Switched Network in a Multistory Building On each floor, hosts connect to a workgroup switch via wire or wireless transmission A core switch connects the workgroup switches to each other

53. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-53 1-17: Switched Network in a Multistory Building Router Core Switch Workgroup Switch 2 Workgroup Switch 1 Wall Jack To WAN Wall Jack Server Client Frames from the client to the server go through Workgroup Switch 2, through the Core Switch, through Workgroup Switch 1, and then to the server 3

54. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-54 Figure 1-18: Four-Pair Unshielded Twisted Pair (UTP) Copper Wiring

55. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-55 1-19: Packet Switching and Multiplexing In packet switching, the sending host breaks each message into many smaller packets Sends these packets out one at a time Packets are routed to the destination host In packet switching, the sending host breaks each message into many smaller packets Sends these packets out one at a time Packets are routed to the destination host

56. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-56 1-19: Packet Switching and Multiplexing Multiplexing reduces cost. Each conversation only has to pay for its share of the trunk lines it uses Multiplexing reduces cost. Each conversation only has to pay for its share of the trunk lines it uses

57. © 2009 Pearson Education, Inc. Publishing as Prentice Hall Routed Networks (Internets)

58. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-58 1-20: Routed Networks The 1980s: A Switched Tower of Babel –At first, there were only switched networks –Soon, there were many incompatible switched networks –Users on different switched networks could not communicate with each other SW Switched Network 1 Switched Network 2

59. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-59 1-20: Routed Networks Routers and Routed Networks –Routers were created connect different switched networks together –Routed networks are also called internets SW Switched Network 1Switched Network 2 Router Routed Network (Internet)

60. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-60 1-20: Routed Networks Routers and Routed Networks –Routers are more complex (and expensive) than switches Designed to work no matter how complex the internet Require more hands-on administration than switches SW Switched Network 1Switched Network 2 Router Routed Network (Internet)

61. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-61 Terminology Capitalization of “Internet” –“Internet” with a capital “I” is used for the global Internet we all use each day –“internet” with a lower-case “i” is used when talking about a smaller internet or about internets in general

62. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-62 1-20: Routed Networks Hosts Have Two Addresses IP Address –This is the host’s unique official address on its internet –Used by routers to forward the packet –32 bits long –Expressed for people in dotted decimal notation (e.g., 128, 171, 17.13) Single Switched Network Addresses –This is the host’s address on its single network –Used by switches to forward the frame

63. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-63 1-20: Routed Networks Packets and Frames –Packets are called frames in switched networks –Packets are called packets in routed networks –A packet is carried in a frame within each switched network Packet Frame

64. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-64 Routers, Frames, and Packets A frame arrives at a router –The frame contains a packet The router takes the packet out of the frame –The router puts the packet into a new frame appropriate for the next network and sends it out Router Packet Frame 1 Packet Frame 2 Packet

65. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-65 1-21: Routed Network (Internet) 2. Packet travels through three switched networks 2 1. When a packet is sent, the packet travels all the way from the source host to the destination host 3. The packet travels in three frames—one in each switched network

66. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-66 1-21: Routed Network (Internet) In this example, the internet has three networks –When a packet is sent –The one packet goes all the way from the source host to the destination host –It travels in three different frames along the way, one in each network

67. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-67 1-21: Routed Network (Internet) Suppose that a packet has to travel through seven networks –When a packet was sent –How many packets go from the source host to the destination host? –How many frames will there be along the way?

68. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-68 1-22: The Global Internet 2. User PC’s Internet Service Provider 2. Web server’s Internet Service Provider ISP 1. User PC Host Computer 1. Web server Host Computer 4. NAPs = Network Access Points Connect ISPs Router NAP ISP 3. Internet Backbone (Multiple ISP Carriers) Access Line Access Line 4

69. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-69 1-22: The Global Internet How is the Internet Financed? –Through ISP subscriber payments Residences typically pay $10 to $50 per month Business typically pay thousands or tens of thousands of dollars per month –Like the telephone network The telephone network is supported by customer payments to telephone carriers –Almost no government money involved

70. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-70 1-22: The Internet The TCP/IP Standards –The set of protocols that governs the Internet –Standards for both applications and packet delivery –Created by the Internet Engineering Task Force (IETF)

71. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-71 1-23: Domain Name System (DNS) Domain Name System (DNS) –IP addresses are official addresses on the Internet and other internets –Hosts can also have host names (e.g., cnn.com) Not official—like nicknames –If you only know the host name of a host that you want to reach, your computer must learn its IP address DNS servers tell our computer the IP address of a target host whose name you know –Like looking up someone’s name in a telephone directory

72. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-72 1-23: Domain Name System (DNS) Host NameIP Address…… Voyager.cba.hawaii.edu128.171.17.13… Host NameIP Address…… Voyager.cba.hawaii.edu128.171.17.13… DNS Table 1. Client Host wishes to reach Voyager.cba.hawaii.edu; Needs to know its IP Address 2. Sends DNS Request Message “The host name is Voyager.cba.hawaii.edu” Voyager.cba.hawaii.edu 128.171.17.13 Local DNS Host 1

73. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-73 1-23: Domain Name System (DNS) Host NameIP Address…… Voyager.cba.hawaii.edu128.171.17.13… Host NameIP Address…… Voyager.cba.hawaii.edu128.171.17.13… DNS Table 4. DNS Response Message “The IP address is 128.171.17.13” Voyager.cba.hawaii.edu 128.171.17.13 5. Client sends packets to 128.171.17.13 3. DNS Host looks up the target host’s IP address DNS Host 2

74. © 2009 Pearson Education, Inc. Publishing as Prentice Hall LANs and WANs

75. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-75 1-25: LANs and WANs (Study Figure) CategoryLocal Area NetworksWide Area Networks AbbreviationLANWAN Distance SpanCustomer premises (apartment, office, building, campus, etc.) Between sites within a corporation or between different corporations Wide Area Network Building LAN Home LAN Campus LAN

76. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-76 1-25: LANs and WANs CategoryLocal Area NetworksWide Area Networks Can use switched network technology? Yes Can use routed network technology? Yes, especially in large LANs Yes, in fact, that is what the Internet is Many students are surprised that LANs can be routed and that WANs can be switched Many students are surprised that LANs can be routed and that WANs can be switched

77. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-77 1-25: LANs and WANs CategoryLocal Area NetworksWide Area Networks ImplementationDo it yourselfMust use a carrier with rights of way Ability to choose technologies HighLow Need to manage technologies HighLow

78. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-78 1-25: LANs and WANs CategoryLocal Area NetworksWide Area Networks Cost per bit transmittedLowHigh with arbitrary Changes unrelated to costs Therefore, typical transmission speed Usually 100 Mbps to 10 Gbps About 256 kbps to 50 Mbps In economics, you learned that when unit price goes up, people will purchase less of the product Because WANs cost much more per bit, companies learn to live with fewer bits per second

79. © 2009 Pearson Education, Inc. Publishing as Prentice Hall Network Management

80. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-80 1-26: Network Management Strategic Network Management –As far as possible, build a coherent roadmap –Pay special attention to decisions that lock you in for long periods of time –Legacy technologies are technologies selected previously that limit services today For upgrading, service benefits must exceed update costs

81. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-81 1-26: Network Management Product Selection with Multicriteria Decision Making –The entire systems development life cycle (SDLC) must be followed –For network products, corporations buy instead of make network elements Must use multicriteria decision making (Figure 1-26) Select purchasing criteria (speed, cost, etc.) Give each criterion an importance weight Rate each product on each purchasing criteria

82. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-82 1-27: Multicriteria Decision Making in Purchase Decisions Product AProduct B CriterionCriterion Weight (Max: 5) Criterion Rating (Max: 10) Criterion Score Product Rating (Max: 10) Criterion Score Functionality5945735 Availability27147 Cost5420945 Ease of Management 4832624 Electrical Efficiency 19988 Total Score120126

83. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-83 1-28: Network Management Ongoing Management –After the SDLC ends –The most important (and expensive) part of the systems life cycle –Often discussed in terms of OAM&P –Operations, administration, maintenance, and provisioning

84. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-84 1-28: Network Management Ongoing Management (OAM&P) –Operations Moment-by-moment traffic management Network operations center (NOC) using SNMP (see Figure 1-29)

85. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-85 1-28: Network Management Ongoing Management (OAM&P) –Maintenance Fixing things that go wrong Conducting preventative maintenance Should be separate from the operations staff

86. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-86 1-28: Network Management Ongoing Management (OAM&P) –Provisioning (Providing Service) Includes physical installation Includes setting up user accounts and services Reprovisioning when things change Deprovisioning when accounts and services are no longer permitted Collectively extremely expensive

87. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-87 1-28: Network Management Ongoing Management (OAM&P) –Administration High end: planning Middle: analysis of operations to indicate needed changes Low: paying bills, managing contracts, etc.

88. © 2009 Pearson Education, Inc. Publishing as Prentice Hall Simple Network Management Protocol (SNMP)

89. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-89 1-29: Simple Network Management Protocol (SNMP) Network Management Software (Manager) Managed Device Managed Device The manager manages multiple managed devices from a central location Collects information about each managed device Can sometimes reconfigure managed devices remotely

90. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-90 Figure 10-13: Simple Network Management Protocol (SNMP) Network Management Software (Manager) Managed Device Network Management Agent (Agent), Objects Manager talks to a network management agent on each managed device—not to the managed device directly

91. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-91 Manager collects data about each device; stores the data in a Management Information Base (MIB) Figure 10-13: Simple Network Management Protocol (SNMP) Management Information Base (MIB) Network Management Software (Manager) Data

92. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-92 Figure 10-13: Simple Network Management Protocol (SNMP) Network Management Software (Manager) Simple Network Management Protocol (SNMP) Messages Managed Device 1. Command (Get, Set, etc.) 2. Response 3. Trap (Alarm) Initiated by a Managed Device

93. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-93 1-29: Simple Network Management Protocol (SNMP) Notes –Remote management can greatly reduce the TCO by reducing labor costs, despite the higher cost of managed devices Central Management No Central Management Device costsHigherLower Labor costsMuch LowerMuch Higher TCOLowerHigher

94. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-94 Key Points Perspective –Definition of a network –Networked applications –Quality of Service Network Technology –Switched versus routed networks (internets) –The global Internet –LANs versus WANs Network Management

95. © 2009 Pearson Education, Inc. Publishing as Prentice Hall1-95 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. Copyright © 2009 Pearson Education, Inc. Copyright © 2009 Pearson Education, Inc. Publishing as Prentice Hall