CCNA培訓(xùn)講義(1)

1、協(xié)議基礎(chǔ)OSI Model OverviewData Flow LayersTransportData-Link NetworkPhysicalApplication (Upper) LayersSessionPresentationApplicationRole of Application LayersTelnetFTPUser InterfaceExamplesApplicationTelnetFTPASCIIEBCDICJPEGUser InterfaceHow data is presentedSpecial processing such as encryptionExamples

2、PresentationApplicationRole of Application LayersTelnetFTPASCIIEBCDICJPEGKeeping different applications data separateUser InterfaceHow data is presentedSpecial processing such as encryptionOperating System/Application Access SchedulingExamplesSessionPresentationApplicationRole of Application LayersK

3、eeping different applications data separateUser interfaceHow data is presentedSpecial processing such as encryptionTelnetFTPASCIIEBCDICJPEGOperating System/Application Access SchedulingTransportData-Link NetworkPhysicalExamplesSessionPresentationApplicationRole of Application LayersRole of Data Flow

4、 LayersEIA/TIA-232V.35ExamplesPhysical Move bits between devicesSpecifies voltage, wire speed, and pin-out cables802.3 / 802.2HDLCEIA/TIA-232V.35ExamplesRole of Data Flow LayersData LinkPhysical Combines bits into bytes and bytes into framesAccess to media using MAC addressError detection not correc

5、tionMove bits between devicesSpecifies voltage, wire speed, and pin-out cables802.3 / 802.2HDLCEIA/TIA-232V.35IPIPXExamplesRole of Data Flow LayersNetwork Data LinkPhysical Combines bits into bytes and bytes into framesAccess to media using MAC addressError detection not correctionMove bits between

6、devicesSpecifies voltage, wire speed, and pin-out cablesProvide logical addressing that routers use for path determinationTCPUDPSPX802.3 / 802.2HDLCEIA/TIA-232V.35IPIPXExamplesRole of Data Flow LayersTransport Data LinkPhysical Reliable or unreliable deliveryError correction before retransmitCombine

7、s bits into bytes and bytes into framesAccess to media using MAC addressError detection not correctionMove bits between devicesSpecifies voltage, wire speed, and pin-out cablesNetwork Provide logical addressing that routers use for path determinationTCPUDPSPX802.3/802.2HDLCEIA/TIA-232V.35IPIPXPresen

8、tationApplicationSessionExamplesRole of Data Flow LayersReliable or unreliable deliveryError correction before retransmitCombines bits into bytes and bytes into framesAccess to media using MAC addressError detection, not correctionMove bits between devicesSpecifies voltage, wire speed, and pinout ca

9、blesTransport Data-LinkPhysical Network Provide logical addressing that routers use for path determinationEncapsulating DataTransport Data-LinkPhysical Network Upper-Layer DataUpper-Layer DataTCP HeaderDataIP HeaderDataLLC HeaderDataMAC HeaderPresentationApplicationSessionSegmentPacketBitsFramePDUFC

10、SFCSUpper-Layer DataDe-encapsulating DataLLC Hdr + IP + TCP + Upper-Layer DataMAC HeaderIP + TCP + Upper-Layer DataLLC HeaderTCP+ Upper-Layer DataIP HeaderUpper-Layer DataTCP HeaderTransport Data-LinkPhysical Network PresentationApplicationSessionTCP/IP Protocol Stack7654325432ApplicationPresentatio

11、nSessionTransportNetworkData-LinkPhysical1ApplicationTransportInternetData-LinkPhysical1Application Layer Overview*Used by the RouterApplicationTransportInternetData-LinkPhysical- TFTP*- FTP*- NFSE-Mail- SMTPRemote Login- Telnet*- rlogin*Network Management- SNMP*Name Management- DNS*Transport Layer

12、OverviewTransmission ControlProtocol (TCP)User Datagram Protocol (UDP)ApplicationTransportInternetData-LinkPhysicalConnection-OrientedConnectionlessTCP Segment FormatSource Port (16)Destination Port (16)Sequence Number (32)HeaderLength (4)Acknowledgment Number (32)Reserved (6)Code Bits (6)Window (16

13、)Checksum (16)Urgent (16)Options (0 or 32 if Any)Data (Varies)20BytesBit 0Bit 15Bit 16Bit 31Port NumbersTCPPort NumbersFTPTransportLayerTELNETDNSSNMPTFTPSMTPUDPApplicationLayer2123255369161RIP520TCP Port NumbersSourcePortDestinationPortHost A102823SPDPHost ZTelnet ZDestination port = 23.Send packet

14、to my Telnet application.Send SYN (seq = 100 ctl = SYN)SYN ReceivedHost AHost BTCP Three-Way Handshake/Open Connection1Send SYN (seq = 100 ctl = SYN)SYN ReceivedSend SYN, ACK (seq = 300 ack = 101 ctl = syn,ack)Host AHost BSYN Received12TCP Three-Way Handshake/Open ConnectionSend SYN (seq = 100 ctl =

15、 SYN)SYN ReceivedSend SYN, ACK (seq = 300 ack = 101 ctl = syn,ack)Established(seq = 101 ack = 301 ctl = ack)Host AHost B123SYN ReceivedTCP Three-Way Handshake/Open ConnectionTCP Simple AcknowledgmentWindow Size = 1 Sender ReceiverTCP Simple AcknowledgmentWindow Size = 1 Sender ReceiverSend 1Receive

16、1TCP Simple AcknowledgmentWindow Size = 1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2TCP Simple AcknowledgmentWindow Size = 1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2Send 2Receive 2TCP Simple AcknowledgmentWindow Size = 1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK

17、2Send 2Receive 2Receive ACK 3Send ACK 3TCP Simple AcknowledgmentWindow Size = 1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2Send 2Receive 2Receive ACK 3Send ACK 3Send 3Receive 3Window Size = 1 Sender ReceiverSend 1Receive 1Receive ACK 2 Send ACK 2Send 2Receive 2Receive ACK 3Send ACK 3Send

18、3Receive 3Receive ACK 4Send ACK 4TCP Simple AcknowledgmentTCP Sequence and Acknowledgment NumbersSourcePortDestinationPortSequenceAcknowledgmentSourceDest.Seq.Ack.102823101I justsent number10.TCP Sequence and Acknowledgment NumbersI just got number 10, now I need number 11.SourcePortDestinationPortS

19、equenceAcknowledgment102823SourceDest.10Seq.1Ack.102823SourceDest.11Seq.1Ack.I justsent number 10.TCP Sequence and Acknowledgment NumbersSourcePortDestinationPortSequenceAcknowledgment102823SourceDest.11Seq.2Ack.102823SourceDest.10Seq.1Ack.102823SourceDest.11Seq.1Ack.I just got number10, now I need

20、number 11.I justsent number11.TCP Sequence and Acknowledgment NumbersSourcePortDestinationPortSequenceAcknowledgment102823SourceDest.11Seq.101Ack.102823SourceDest.10Seq.100Ack.102823SourceDest.11Seq.100Ack.102823SourceDest.12Seq.101Ack.I just got number11, now I need number 12.I justsent number11.TC

21、P WindowingSenderReceiverTCP WindowingWindow Size = 3Send 2SenderReceiverWindow Size = 3Send 1Window Size = 3Send 3Window Size = 3Send 2TCP WindowingSenderWindow Size = 3Send 1Window Size = 3Send 3ACK 3Window Size = 2Packet 3 IsDroppedReceiverWindow Size = 3Send 2TCP WindowingSenderWindow Size = 3Se

22、nd 1Window Size = 3Send 3ACK 3Window Size = 2Packet 3 IsDroppedWindow Size = 3Send 4Window Size = 3Send 3ReceiverWindow Size = 3Send 2TCP WindowingSenderWindow Size = 3Send 1Window Size = 3Send 3ACK 3Window Size = 2Packet 3 IsDroppedWindow Size = 3Send 4Window Size = 3Send 3ACK 5Window Size = 2Recei

23、verWindow Size = 3No sequence or acknowledgment fieldsUDP Segment FormatSource Port (16)Destination Port (16)Length (16)Data (if Any)1Bit 0Bit 15Bit 16Bit 31Checksum (16)8BytesInternet Layer OverviewIn the OSI reference model, the network layer corresponds to the TCP/IP Internet layer.Internet Proto

24、col (IP)Internet Control MessageProtocol (ICMP)Address ResolutionProtocol (ARP)Reverse AddressResolution Protocol (RARP)ApplicationTransportInternetData-LinkPhysicalIP DatagramVersion(4)Destination IP Address (32)Options (0 or 32 if Any)Data (Varies if Any)1Bit 0Bit 15Bit 16Bit 31HeaderLength (4)Pri

25、ority &Type of Service (8)Total Length (16)Identification (16)Flags(3)Fragment Offset (13)Time-to-Live (8)Protocol (8)Header Checksum (16)Source IP Address (32)20BytesDetermines destination upper-layer protocol Protocol FieldTransportLayerInternetLayerTCPUDPProtocolNumbersIP176Internet Control Messa

26、ge ProtocolApplicationTransportInternetData-LinkPhysicalDestination UnreachableEcho (Ping)OtherICMP1Address Resolution ProtocolIP: = ?I need the Ethernet address of .Address Resolution ProtocolIP: = ?I heard that broadcast. The message is for me. Here is my Ethernet address.I need the Ethernet addre

27、ss of .Address Resolution ProtocolMap IP MAC Local ARPIP: Ethernet: 0800.0020.1111 IP: = ?I heard that broadcast. The message is for me. Here is my Ethernet address.I need the Ethernet address of .Not Local ARPRouter AExample 2: Destination not localHost ZHost YQueryResponseRouting Table:Net forHost

28、 ZMap IP EthernetBroadcastHost YMACIP: MAC?Host YMACRouter AMACIP: Ethernet: 0000.0c12.3456I want access theHost Z.Reverse ARPEthernet: 0800.0020.1111 IP = ?What is my IP address?Reverse ARPEthernet: 0800.0020.1111 IP = ?What is my IP address?I heard that broadcast. Your IP address is 5.Reverse ARPE

29、thernet: 0800.0020.1111IP: 5Ethernet: 0800.0020.1111 IP = ?What is my IP address?I heard that broadcast. Your IP address is 5.Reverse ARP Map MAC IPEthernet: 0800.0020.1111IP: 5Ethernet: 0800.0020.1111 IP = ?What is my IP address?I heard that broadcast. Your IP address is 5.Unique addressing allows

30、communication between end stations.Path choice is based on destination address.Location is represented by an addressIntroduction to TCP/IP AddressesSADAHDRDATAIP Addressing 255255 255 255DottedDecimalMaximumNetworkHost32 BitsIP Addressing 255255 255 255DottedDecimalMaximumNetworkHost1286432168421Bin

31、ary32 Bits1891617242532128643216842112864321684211286432168421IP Addressing 255255 255 255DottedDecimalMaximumNetworkHost1286432168421Binary32 Bits 172 16 122 204ExampleDecimalExampleBinary1891617242532128643216842112864321684211286432168421Class A: Class B: Class C: Class D: Multicast Class E: Rese

32、archIP Address ClassesNetworkHostHostHostNetworkNetworkHostHostNetworkNetworkNetworkHost8 Bits8 Bits8 Bits8 BitsIP Address Classes1Class A:Bits:0NNNNNNNHostHostHost891617242532Range (1-126)1Class B:Bits:10NNNNNNNetworkHostHost891617242532Range (128-191)1Class C:Bits:110NNNNNNetworkNetworkHost8916172

33、42532Range (192-223)1Class D:Bits:1110MMMMMulticast GroupMulticast GroupMulticast Group891617242532Range (224-239)Host Addresses02118E1172.161212NetworkHost.NetworkInterfaceE0E1Routing TableE0Determining Available Host Addresses 172 16 0 016151413121110 987654321NetworkHost.123655346553565536.265534

34、N2N 2 = 216 2 = 65534IP Address Classes ExerciseAddressClassNetworkHost004620IP Address Classes Exercise AnswersAddressClassNetworkHost004620ABCCBNonexistent0046Network Addressing Without Subnets.5354Network Addressing with SubnetsSubnet Addressing00600050E0172.16NetworkNetworkInterfaceE0E1New Routi

35、ng Table 2160Host.E1Subnet Addressing00600050E0E1172.162160NetworkHost.NetworkInterfaceE0E1New Routing TableSubnetSubnet Mask1721600255255002552552550IPAddressDefaultSubnetMask8-BitSubnetMaskNetworkHostNetworkHostNetworkSubnetHostAlso written as “/16, where 16 represents the number of 1s in the mask

36、Also written as “/24, where 24 represents the number of 1s in the mask 11111111 11111111Decimal Equivalents of Bit Patterns00000000=010000000=12811000000=19211100000=22411110000=24011111000=24811111100=25211111110=25411111111=255128 643216842116NetworkHost17200Subnets not in usethe defaultSubnet Mas

37、k Without Subnets60 NetworkNumberNetwork number extended by eight bitsSubnet Mask with Subnets16NetworkHost60 17220SubnetNetworkNumber128192224240248252254255Subnet Mask with Subnets (cont.)NetworkHost60 921100000010000000SubnetNetwork number extended by ten bits161722128Ne

38、tworkNumber128192224240248252254255128192224240248252254255Subnet Mask ExerciseAddressSubnet MaskClassSubnet002Subnet Mask Exercise AnswersAddressSubnet MaskClassSubnet002BAAThis approach may not fully utilize available allocation of host addresses29 /278 /273 /275 /277 /27S1S0E1E0E0A Requirement fo

39、r Only Two Host Addresses Forced to Allocate 30 Host AddressesFixed-Length Subnet MasksVariable-Length Subnet Masks29 /2709 /303 /275 /2710 /30S1S0E1E0E0A Requirement for Only Two Host AddressesVLSM Support Accommodates ThisBroadcast Addresses55(Directed Broadcast)55(Local Network Broadcast)X55(All

40、Subnets Broadcast)Addresses for Private NetworksClass Beginning Address Ending AddressClass A 55Class B 55Class C 55The others are registered addressesIf you are connected to the Internet, you must useregistered addressesIANA (Internet Assigned Numbers Authority)NAT a simple conceptNAT tableInternet

41、InsideHost B13SADASADA452Host CInside Global IP AddressOutside Global IP AddressInside Local IP AddressPrivate addresses Registered addresses OutsideCisco IOS 的命令行界面Network Structure Defined by Hierarchy Distribution LayerCore LayerAccessLayerCisco IOS software delivers network services and enables

42、networked applications.Cisco IOS SoftwareFind and check device hardware.Find and load Cisco IOS software image.Find and apply device configurations.An Overview of Cisco Device StartupConfigurations can come from many sources.Configurations will act in device memory.Console PortAuxiliary PortInterfac

43、esPC or UNIX ServerWeb or Network ManagementServerVirtual TerminalExternal Configuration SourcesTelnetTFTPUser ModeLimited examination of switch or routerCommand prompt: RouterThere are two main EXEC modes for entering commands.First Mode:Cisco IOS Software EXEC ModePrivileged (or Enabled) ModeDetai

44、led examination of switch or routerEnables configuration and debuggingPrerequisite for other configuration modesCommand prompt: Router#Second Mode (and Most Commonly Used): Cisco IOS Software EXEC Mode (cont.)System startup routines initiate router software.Router falls back to startup alternatives

45、if needed.Check hardwareFind and load Cisco IOSsoftware imageFind and apply routerconfiguration informationLoad Bootstrap1.Before you start the router, verify the power, cabling, and console connection.2.Push the power switch to “on.3.Observe the boot sequence:Cisco IOS software output text appears

46、on the console.Initial Startup of the Cisco RouterUnconfigured Versus Configured Router- System Configuration Dialog -Continue with configuration dialog? yes/no:yes At any point you may enter a question mark ? for help.Use ctrl-c to abort configuration dialog at any prompt.Default settings are in sq

47、uare brackets .Setup ModeRouter con0 is now availablePress RETURN to get started.User-Mode PromptRouterBootup Output from the RouterConsoleSetup: The Initial Configuration DialogRouter#setup - System Configuration Dialog -Continue with configuration dialog? yes/no: yAt any point you may enter a ques

48、tion mark ? for help.Use ctrl-c to abort configuration dialog at any prompt.Default settings are in square brackets .Basic management setup configures only enough connectivityfor management of the system, extended setup will ask youto configure each interface on the systemWould you like to enter bas

49、ic management setup? yes/no: nSetup Interface SummaryFirst, would you like to see the current interface summary? yes:Interface IP-Address OK? Method Status ProtocolBRI0 unassigned YES unset administratively down downBRI0:1 unassigned YES unset administratively down downBRI0:2 unassigned YES unset ad

50、ministratively down downEthernet0 unassigned YES unset administratively down downSerial0 unassigned YES unset administratively down downInterfaces Found During Startup Setup Global ParametersInitial Global ParametersConfiguring global parameters: Enter host name Router:wg_ro_c The enable secret is a

51、 password used to protect access to privileged EXEC and configuration modes. This password, after entered, becomes encrypted in the configuration. Enter enable secret: cisco The enable password is used when you do not specify an enable secret password, with some older software versions, and some boo

52、t images. Enter enable password: sanfran The virtual terminal password is used to protect access to the router over a network interface. Enter virtual terminal password: sanjose Configure SNMP Network Management? no: Setup Global Parameters (cont.)Initial Protocol Configurations Configure LAT? yes:

53、n Configure AppleTalk? no: Configure DECnet? no: Configure IP? yes: Configure IGRP routing? yes: n Configure RIP routing? no: Configure CLNS? no: Configure IPX? no: Configure Vines? no: Configure XNS? no: Configure Apollo? no:Setup Interface ParametersBRI interface needs isdn switch-type to be confi

54、gured Valid switch types are : 0 none.Only if you dont want to configure BRI. 1 basic-1tr6.1TR6 switch type for Germany 2 basic-5ess.AT&T 5ESS switch type for the US/Canada 3 basic-dms100.Northern DMS-100 switch type for US/Canada 4 basic-net3.NET3 switch type for UK and Europe 5 basic-ni.National I

55、SDN switch type 6 basic-ts013.TS013 switch type for Australia 7 ntt.NTT switch type for Japan 8 vn3.VN3 and VN4 switch types for France Choose ISDN BRI Switch Type 2:Configuring interface parameters:Do you want to configure BRI0 (BRI d-channel) interface? no:Do you want to configure Ethernet0 interf

56、ace? no: y Configure IP on this interface? no: y IP address for this interface: 3 Subnet mask for this interface : Class A network is , 24 subnet bits; mask is /24Do you want to configure Serial0 interface? no:Setup Script Review and UseThe following configuration command script was created:hostname

57、 Routerenable secret 5 $1$/CCk$4r7zDwDNeqkxFO.kJxC3G0enable password sanfranline vty 0 4password sanjoseno snmp-server!no appletalk routingno decnet routingip routingno clns routingno ipx routingno vines routingno xns routingno apollo routingisdn switch-type basic-5essinterface BRI0shutdownno ip add

58、ress!interface Ethernet0no shutdownip address 1 no mop enabled!interface Serial0shutdownno ip addressend0 Go to the IOS command prompt without saving this config.1 Return back to the setup without saving this config.2 Save this configuration to nvram and exit.Enter your selection 2:ConsoleRouterRout

59、erenableRouter#Router#disableRouterRouterlogoutRouter con0 is now availablePress RETURN to get started.User-Mode PromptPrivileged-Mode PromptLogging In to the RouterYou can abbreviate a command to the fewest characters that make a unique character string.Router User-Mode Command ListRouter?Exec comm

60、ands: access-enable Create a temporary Access-List entry atmsig Execute Atm Signalling Commands cd Change current device clear Reset functions connect Open a terminal connection dir List files on given device disable Turn off privileged commands disconnect Disconnect an existing network connection e