Sybex CCNA 640-802
Chapter 14: Wide Area Networks
Instructor & Todd Lammle
Chapter 14 Objectives
The CCNA Topics Covered in this chapter
include:
• Introduction to WAN’s
• HDLC
• PPP
• Frame Relay
...
Defining WAN Terms
• Customer Premises Equipment
(CPE)
• Demarcation (demarc)
• Local loop
• Central Office (CO)
• Toll ne...
WAN Connection Types
DTE-DCE-DTE
WAN Support
• Frame Relay
• ISDN
• LAPB
• LAPD
• HDLC
• PPP
• ATM
HDLC Protocol
• Bit-oriented Data Link layer ISO
standard protocol
• Specifies a data encapsulation
method
• No authentica...
HDLC Frame Format
Point-to-Point Protocol (PPP)
• Purpose:
– Transport layer-3 packets across a
Data Link layer point-to-point link
• Can be...
Point-to-Point Protocol Stack
PPP Main Components
• EIA/TIA-232-C
– Intl. Std. for serial communications
• HDLC
– Serial link datagram encapsulation met...
LCP Configuration Options
• Authentication
– PAP
– CHAP
• Compression
– Stacker
– Predictor
• Error detection
– Quality
– ...
PPP Session Establishment
• Link-establishment phase
• Authentication phase
• Network-layer protocol phase
PPP Session Establishment
PPP Authentication Methods
• Password Authentication
Protocol (PAP)
– Passwords sent in clear text
– Remote node returns u...
Configuring PPP
• Step #1: Configure PPP on RouterA & RouterB:
Router__#config t
Router__(config)#int s0
Router__(config-i...
PPP Example 1
PPP Example 2
PPP Example 3
PPP Example 4
Frame Relay
• Background
– High-performance WAN
encapsulation method
– OSI Physical & data Link layer
– Originally designe...
Before Frame Relay
After Frame Relay
Frame Relay
• Purpose
– Provide a communications
interface between DTE & DCE
equipment
– Connection-oriented Data Link
lay...
Frame Relay Terminology
Frame Relay Encapsulation
• Specified on serial interfaces
• Encapsulation types:
– Cisco (default encapsulation type)
– I...
Data Link Connection Identifiers
(DLCIs)
• Frame Relay PVCs are identified by DLCIs
• IP end devices are mapped to DLCIs
–...
DLCI’s are Locally Significant
Local Management
Interface (LMI)
• Background
• Purpose
• LMI Messages
– Keepalives
– Multicasting
– Multicast addressing
...
LMI Types
• Configuration:
RouterA(config-if)#frame-relay lmi-type ?
cisco
ansi
q933a
– Beginning with IOS ver 11.2+ the L...
Sub-interfaces
• Definition
– Multiple virtual circuits on a single
serial interface
– Enables the assignment of different...
Partial Meshed Networks
Creating Sub-interfaces
Configuration:
#1: Set the encapsulation on the serial interface
#2: Define the subinterface
Route...
Mapping Frame Relay
Necessary to IP end devices to
communicate
– Addresses must be mapped to
the DLCIs
– Methods:
• Frame ...
Using the map command
RouterA(config)#int s0
RouterA(config-if)#encap frame
RouterA(config-if)#int s0.16 point-to-point
Ro...
Using the inverse arp
command
RouterA(config)#int s0.16 point-to-point
RouterA(config-if)#encap frame-relay ietf
RouterA(c...
Congestion Control
• Discard Eligibility (DE)
• Forward-Explicit Congestion
Notification (FECN)
• Backward-Explicit Conges...
Committed Information
Rate (CIR)
• Definition: Provision allowing
customers to purchase amounts of
bandwidth lower than wh...
Monitoring Frame Relay
RouterA>sho frame ?
ip show frame relay IP statistics
lmi show frame relay lmi statistics
map Frame...
Troubleshooting Frame Relay
Why can’t RouterA talk to RouterB?Why can’t RouterA talk to RouterB?
Troubleshooting Frame Relay
Why is RIP not sent across the PVC?Why is RIP not sent across the PVC?
Introduction to VPN’s
• VPNs are used daily to give
remote users and disjointed
networks connectivity over a
public medium...
Types of VPN’s
• REMOTE ACCESS VPNS
Remote access VPNs allow remote users like telecommuters to securely
access the corpor...
Written Labs and Review
Questions
– Open your books and go through all the
written labs and the review questions.
– Review...
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Chapter14ccna

  1. 1. Sybex CCNA 640-802 Chapter 14: Wide Area Networks Instructor & Todd Lammle
  2. 2. Chapter 14 Objectives The CCNA Topics Covered in this chapter include: • Introduction to WAN’s • HDLC • PPP • Frame Relay • Introduction to VPN’s 2
  3. 3. Defining WAN Terms • Customer Premises Equipment (CPE) • Demarcation (demarc) • Local loop • Central Office (CO) • Toll network
  4. 4. WAN Connection Types
  5. 5. DTE-DCE-DTE
  6. 6. WAN Support • Frame Relay • ISDN • LAPB • LAPD • HDLC • PPP • ATM
  7. 7. HDLC Protocol • Bit-oriented Data Link layer ISO standard protocol • Specifies a data encapsulation method • No authentication can be used
  8. 8. HDLC Frame Format
  9. 9. Point-to-Point Protocol (PPP) • Purpose: – Transport layer-3 packets across a Data Link layer point-to-point link • Can be used over asynchronous serial (dial-up) or synchronous serial (ISDN) media – Uses Link Control Protocol (LCP) • Builds & maintains data-link connections
  10. 10. Point-to-Point Protocol Stack
  11. 11. PPP Main Components • EIA/TIA-232-C – Intl. Std. for serial communications • HDLC – Serial link datagram encapsulation method • LCP – Used in P-t-P connections: • Establishing • Maintaining • Terminating • NCP – Method of establishing & configuring Network Layer protocols – Allows simultaneous use of multiple Network layer protocols
  12. 12. LCP Configuration Options • Authentication – PAP – CHAP • Compression – Stacker – Predictor • Error detection – Quality – Magic Number • Multilink – Splits the load for PPP over 2+ parallel circuits; a bundle
  13. 13. PPP Session Establishment • Link-establishment phase • Authentication phase • Network-layer protocol phase
  14. 14. PPP Session Establishment
  15. 15. PPP Authentication Methods • Password Authentication Protocol (PAP) – Passwords sent in clear text – Remote node returns username & password • Challenge Authentication Protocol (CHAP) – Done at start-up & periodically – Challenge & Reply • Remote router sends a one-way hash ~ MD5
  16. 16. Configuring PPP • Step #1: Configure PPP on RouterA & RouterB: Router__#config t Router__(config)#int s0 Router__(config-if)#encapsulation ppp Router__(config-if)#^Z • Step #2: Define the username & password on each router: – RouterA: RouterA(config)#username RouterB password cisco – RouterB: RouterB(config)#username RouterA password cisco NOTE: (1) Username maps to the remoteremote router (2) Passwords must match • Step #3: Choose Authentication type for each router; CHAP/PAP Router__(Config)#int s0 Router__(config-if)#ppp authentication chap Router__(config-if)#ppp authentication pap Router__(config-if)#^Z
  17. 17. PPP Example 1
  18. 18. PPP Example 2
  19. 19. PPP Example 3
  20. 20. PPP Example 4
  21. 21. Frame Relay • Background – High-performance WAN encapsulation method – OSI Physical & data Link layer – Originally designed for use across ISDN • Supported Protocols – IP, DECnet, AppleTalk, Xerox Network Service (XNS), Novell IPX, Banyan Vines, Transparent Bridging, & ISO
  22. 22. Before Frame Relay
  23. 23. After Frame Relay
  24. 24. Frame Relay • Purpose – Provide a communications interface between DTE & DCE equipment – Connection-oriented Data Link layer communication • Via virtual circuits • Provides a complete path from the source to destination before sending the first frame
  25. 25. Frame Relay Terminology
  26. 26. Frame Relay Encapsulation • Specified on serial interfaces • Encapsulation types: – Cisco (default encapsulation type) – IETF (used between Cisco & non- Cisco devices) RouterA(config)#int s0 RouterA(config-if)#encapsulation frame- relay ? ietf Use RFC1490 encapsulation <cr>
  27. 27. Data Link Connection Identifiers (DLCIs) • Frame Relay PVCs are identified by DLCIs • IP end devices are mapped to DLCIs – Mapped dynamically or mapped by IARP • Global Significance: – Advertised to all remote sites as the same PVC • Local Significance: – DLCIs do not need to be unique • Configuration RouterA(config-if)#frame-relay interface-dlci ? <16-1007> Define a DLCI as part of the current subinterface RouterA(config-if)#frame-relay interface-dlci 16
  28. 28. DLCI’s are Locally Significant
  29. 29. Local Management Interface (LMI) • Background • Purpose • LMI Messages – Keepalives – Multicasting – Multicast addressing – Status of virtual circuits
  30. 30. LMI Types • Configuration: RouterA(config-if)#frame-relay lmi-type ? cisco ansi q933a – Beginning with IOS ver 11.2+ the LMI type is auto-sensed – Default type: cisco • Virtual circuit status: – Active – Inactive – Deleted
  31. 31. Sub-interfaces • Definition – Multiple virtual circuits on a single serial interface – Enables the assignment of different network-layer characteristics to each sub-interface • IP routing on one sub-interface • IPX routing on another – Mitigates difficulties associated with: • Partial meshed Frame Relay networks • Split Horizon protocols
  32. 32. Partial Meshed Networks
  33. 33. Creating Sub-interfaces Configuration: #1: Set the encapsulation on the serial interface #2: Define the subinterface RouterA(config)#int s0 RouterA(config)#encapsulation frame-relay RouterA(config)#int s0.? <0-4294967295> Serial interface number RouterA(config)#int s0.16 ? multipoint Treat as a multipoint link point-to-point Treat as a point-to-point link
  34. 34. Mapping Frame Relay Necessary to IP end devices to communicate – Addresses must be mapped to the DLCIs – Methods: • Frame Relay map command • Inverse-arp function
  35. 35. Using the map command RouterA(config)#int s0 RouterA(config-if)#encap frame RouterA(config-if)#int s0.16 point-to-point RouterA(config-if)#no inverse-arp RouterA(config-if)#ip address 172.16.30.1 255.255.255.0 RouterA(config-if)#frame-relay map ip 172.16.30.17 16 ietf broadcast RouterA(config-if)#frame-relay map ip 172.16.30.18 17 broadcast RouterA(config-if)#frame-relay map ip 172.16.30.19 18
  36. 36. Using the inverse arp command RouterA(config)#int s0.16 point-to-point RouterA(config-if)#encap frame-relay ietf RouterA(config-if)#ip address 172.16.30.1 255.255.255.0
  37. 37. Congestion Control • Discard Eligibility (DE) • Forward-Explicit Congestion Notification (FECN) • Backward-Explicit Congestion Notification (BECN)
  38. 38. Committed Information Rate (CIR) • Definition: Provision allowing customers to purchase amounts of bandwidth lower than what they might need – Cost savings – Good for bursty traffic – Not good for constant amounts of data transmission
  39. 39. Monitoring Frame Relay RouterA>sho frame ? ip show frame relay IP statistics lmi show frame relay lmi statistics map Frame-Relay map table pvc show frame relay pvc statistics route show frame relay route traffic Frame-Relay protocol statistics RouterA#sho int s0 RouterB#show frame map Router#debug frame-relay lmi
  40. 40. Troubleshooting Frame Relay Why can’t RouterA talk to RouterB?Why can’t RouterA talk to RouterB?
  41. 41. Troubleshooting Frame Relay Why is RIP not sent across the PVC?Why is RIP not sent across the PVC?
  42. 42. Introduction to VPN’s • VPNs are used daily to give remote users and disjointed networks connectivity over a public medium like the Internet instead of using more expensive permanent means. 42
  43. 43. Types of VPN’s • REMOTE ACCESS VPNS Remote access VPNs allow remote users like telecommuters to securely access the corporate network wherever and whenever they need to. • SITE-TO-SITE VPNS Site-to-site VPNs, or, intranet VPNs, allow a company to connect its remote sites to the corporate backbone securely over a public medium like the Internet instead of requiring more expensive WAN connections like Frame Relay. • EXTRANET VPNS Extranet VPNs allow an organization’s suppliers, partners, and customers to be connected to the corporate network in a limited way for business-to- business (B2B) communications. 43
  44. 44. Written Labs and Review Questions – Open your books and go through all the written labs and the review questions. – Review the answers in class. 44

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