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Chapter2 ppp

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  • Graphic 2.2.1.1
  • Graphic 2.4.4.1
  • Graphic 2.4.5.1
  • Graphic 2.4.5.1
  • Graphic 2.4.5.1
  • Graphic 2.4.5.1
  • Graphic 2.4.6.1
  • Transcript

    • 1. Point-to-Point Protocol (PPP) Accessing the WAN – Chapter 2 Glenn AvendanoITE I Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 1
    • 2. Describe the Fundamental Concepts of Point-to-Point Serial Communication  If parallel is faster than serial, is parallel more suitable for connecting to a WAN? In reality, it is often the case that serial links can be clocked considerably faster than parallel links, and they achieve a higher data rate, because of two factors that affect parallel communications: clock skew and crosstalk interference.  The more wires one uses and the farther the connection reaches, compounds the problem and adds delay. The need for clocking slows parallel transmission well below theoretical expectations. Most serial links do not need clocking.  Since serial cables have fewer wires, there is less crosstalk, and network devices transmit serial communications at higher, more efficient frequencies.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 2
    • 3. Describe the Fundamental Concepts of Point-to-Point Serial Communication  Serial Communication Standards  RS-232 - Most serial ports on personal computers conform to the RS-232C or newer RS-422 and RS-423 standards. Both 9-pin and 25-pin connectors are used. Many network devices use RJ-45 connectors that also conform to the RS- 232 standard.  V.35 - Typically used for modem-to-multiplexer communication, this ITU standard for high-speed, synchronous data exchange combines the bandwidth of several telephone circuits. In the U.S., V.35 is the interface standard used by most routers and DSUs that connect to T1 carriers.  HSSI - A High-Speed Serial Interface (HSSI) supports transmission rates up to 52 Mbps. Engineers use HSSI to connect routers on LANs with WANs over high-speed lines such as T3 lines.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 3
    • 4. Describe the Fundamental Concepts of Point-to-Point Serial Communication  Explain how two or more data streams are transported across a single physical connection using TDMITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 4
    • 5. Describe the Fundamental Concepts of Point-to-Point Serial CommunicationITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 5
    • 6. Describe the Fundamental Concepts of Point-to-Point Serial Communication  Define the location of the demarcation point relative to customer and service provider networksITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 6
    • 7. Describe the Fundamental Concepts of Point-to-Point Serial Communication  Explain the terms DTE and DCE with relative to the location of devices in a networkITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 7
    • 8. Describe the Fundamental Concepts of Point-to-Point Serial Communication  Explain the terms DTE and DCE with relative to the location of devices in a networkITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 8
    • 9. Describe the Fundamental Concepts of Point-to-Point Serial Communication  Describe how high-level data link control (HDLC) uses one of three frame types to encapsulate dataITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 9
    • 10. Describe the Fundamental Concepts of Point-to-Point Serial CommunicationITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 10
    • 11. Describe the Fundamental Concepts of Point-to-Point Serial Communication  Cisco HDLC is the default encapsulation method used by Cisco devices on synchronous serial lines.  One may use Cisco HDLC as a point-to-point protocol on leased lines between two Cisco devices. If you are connecting to a non-Cisco device, use synchronous PPP.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 11
    • 12. Describe the Fundamental Concepts of Point-to-Point Serial Communication  Click the status button on page 2.1.7.1 to identify the following five possible problem states in the interface status line: <from sh int serial command>ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 12
    • 13. ActivityITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 13
    • 14. ActivityITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 14
    • 15. ActivityITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 15
    • 16. Describe Point-to-Point Concepts  HDLC is the default encapsulation method between Cisco routers. Use PPP to connect to a non-Cisco router.  The link quality management feature monitors the quality of the link. If too many errors are detected, PPP takes the link down.  PPP supports PAP and CHAP authentication.  PPP components: HDLC protocol for encapsulating datagrams over point-to-point links; Extensible Link Control Protocol (LCP) to establish, configure, and test the data link connection; family of Network Control Protocols (NCPs) for establishing and configuring different network layer protocols.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 16
    • 17. Describe Point-to-Point Concepts  PPP Architecture: Physical LayerITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 17
    • 18. Describe Point-to-Point Concepts The LCP provides automatic configuration of the interfaces at each end, including:  Handling varying limits on packet size  Detecting common misconfiguration errors  Terminating the link  Determining when a link is functioning properly or when it is failing –PPP also uses the LCP to agree automatically on encapsulation formats (authentication, compression, error detection) as soon as the link is established.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 18
    • 19. Describe Point-to-Point Concepts  PPP permits multiple network layer protocols to operate on the same communications link. For every network layer protocol used, PPP uses a separate NCP.  NCPs include functional fields containing standardized codes to indicate the network layer protocol that PPP encapsulates.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 19
    • 20. Describe Point-to-Point Concepts  Describe the purpose and format of each of the fields in a PPP frame Roll over the packet fields on page 2.2.3.1 to view descriptions.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 20
    • 21. Describe Point-to-Point Concepts  Define the three phases of PPP session establishmentITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 21
    • 22. Describe Point-to-Point Concepts  PPP can be configured to support various functions including: Authentication using either PAP or CHAP, Compression using either Stacker or Predictor, Multilink which combines two or more channels to increase the WAN bandwidth.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 25
    • 23. Activity 2 (page 2.2.6.2)ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 27
    • 24. Activity 4 (page 2.2.6.2)ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 28
    • 25. Configure PPP on a Serial InterfaceITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 30
    • 26. Configure PPP on a Serial Interface  Explain the output of the show interfaces serial commandITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 31
    • 27. Configure PPP on a Serial Interface  The no form of this command disables debugging output.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 32
    • 28. Configure PPP on a Serial Interface  The no form of this command disables debugging output.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 33
    • 29. Configure PPP on a Serial Interface  The figure shows the output of the debug ppp negotiation command in a normal negotiation, where both sides agree on network control program (NCP) parameters. In this case, protocol type IP is proposed and acknowledged.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 34
    • 30. Configuring PPP with Authentication  PPP Authentication – RFC 1334ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 35
    • 31. Configuring PPP with Authentication  PAP is not a strong authentication protocol. But, there are times when using PAP can be justified.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 36
    • 32. Configuring PPP with Authentication  Unlike PAP, which only authenticates once, CHAP conducts periodic challenges to make sure that the remote node still has a valid password value.ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 37
    • 33. Configuring PPP with Authentication  Configuring PAP DTE 1 7 2 .2 5 .3 .0 /2 4 DCE .2 /S 0 S e r ia l .1 /S 0hostname SantaCruz hostname HQusername HQ password HQpass username SantaCruz password SantaCruzpassinterface Serial0 interface Serial0 ip address 172.25.3.2 255.255.255.0 ip address 172.25.3.1 255.255.255.0 encapsulation ppp encapsulation ppp ppp authentication pap ppp authentication pap ppp pap sent-username SantaCruz ppp pap sent-username HQ password SantaCruzpass password HQpass ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 39
    • 34. Configuring PPP with Authentication  Configuring PAP DTE 1 7 2 .2 5 .3 .0 /2 4 DCE .2 /S 0 S e r ia l .1 /S 0hostname SantaCruz hostname HQusername HQ password HQpass username SantaCruz password SantaCruzpassinterface Serial0 interface Serial0 ip address 172.25.3.2 255.255.255.0 ip address 172.25.3.1 255.255.255.0 encapsulation ppp encapsulation ppp ppp authentication pap ppp authentication pap ppp pap sent-username SantaCruz ppp pap sent-username HQ password SantaCruzpass password HQpass Notes: sent-username and password must match remote username and password. Passwords are case-sensitive, but usernames are not. Hostnames are not involved. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 40
    • 35. Configuring PPP with Authentication  Configuring CHAP DTE 1 7 2 .2 5 .3 .0 /2 4 DCE .2 /S 0 S e r ia l .1 /S 0hostname SantaCruz hostname HQusername HQ password boardwalk username SantaCruz password boardwalkinterface Serial0 interface Serial0 ip address 172.25.3.2 255.255.255.0 ip address 172.25.3.1 255.255.255.0 encapsulation ppp encapsulation ppp ppp authentication chap ppp authentication chap ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 41
    • 36. Configuring PPP with Authentication  Explain how to configure a PPP connection with authenticationITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 42
    • 37. Configuring PPP with Authentication  Explain the output of the debug ppp authentication commandITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 43
    • 38. Summary  PPP is a widely used WAN protocol  PPP provides multi-protocol LAN to WAN connections  PPP session establishment – 4 phases Link establishment Link quality determination Network layer protocol configuration negotiation Link termination  WAN Encapsulation –HDLC default encapsulation –PPPITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 44
    • 39. Summary  PPP authentication –PAP •2 way handshake –CHAP •3 way handshake –Use debug ppp authentication to confirm authentication configuration  PPP configuration –Done on a serial interface  After PPP configuration, use show interfaces command to display: –LCP state –NCP stateITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 45
    • 40. ITE 1 Chapter 6 © 2006 Cisco Systems, Inc. All rights reserved. Cisco Public 46