CCNA PPP and Frame Relay
-
date post
19-Oct-2014 -
Category
Technology
-
view
7.854 -
download
9
description
Transcript of CCNA PPP and Frame Relay
![Page 1: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/1.jpg)
CCNA Guide to Cisco Networking Fundamentals
Chapter 11PPP and Frame Relay
![Page 2: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/2.jpg)
CCNA Guide to Cisco Networking Fundamentals 2
Objectives
• Describe PPP encapsulation
• Configure PPP encapsulation and its options
• Describe and enable PPP multilink
• Understand Frame Relay standards and equipment
![Page 3: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/3.jpg)
CCNA Guide to Cisco Networking Fundamentals 3
Objectives (continued)
• Describe the role of virtual circuits and performance parameters in Frame Relay
• Understand the Frame Relay topologies
• Understand the difference between multipoint and point-to-point configurations
• Configure and monitor Frame Relay
![Page 4: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/4.jpg)
CCNA Guide to Cisco Networking Fundamentals 4
PPP
• PPP– Internet standard protocol defined in RFCs 2153 and
1661– Provide point-to-point, router-to-router, host-to-router,
and host-to-host connections– Considered a peer technology based on its point-to-
point physical configuration– Commonly used over dial-up or leased lines to provide
connections into IP networks
• Serial Line Internet Protocol (SLIP) was the predecessor to PPP
![Page 5: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/5.jpg)
CCNA Guide to Cisco Networking Fundamentals 5
PPP (continued)
• PPP can be used over several different physical interfaces, including the following:– Asynchronous serial– ISDN synchronous serial– High-Speed Serial Interface (HSSI)
![Page 6: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/6.jpg)
CCNA Guide to Cisco Networking Fundamentals 6
PPP in the Protocol Stack
• You can use PPP over both asynchronous and synchronous connections– At the Physical layer of the OSI reference model
• Link Control Protocol (LCP)– Used at the Data Link layer to establish, configure,
and test the connection
• Network Control Protocols (NCPs)– Allow the simultaneous use of multiple Network layer
protocols and are required for each protocol that uses PPP
![Page 7: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/7.jpg)
CCNA Guide to Cisco Networking Fundamentals 7
PPP in the Protocol Stack (continued)
![Page 8: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/8.jpg)
Frame Format
• PPP is based on the High-Level Data Link Control (HDLC) protocol
• The difference between PPP frames and HDLC frames is that PPP frames contain protocol and Link Control Protocol (LCP) fields
• LCP– Described in RFCs 1548, 1570, 1661, 2153, and
2484– Describes PPP organization and methodology,
including basic LCP extensions
CCNA Guide to Cisco Networking Fundamentals 8
![Page 9: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/9.jpg)
CCNA Guide to Cisco Networking Fundamentals 9
![Page 10: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/10.jpg)
Frame Format (continued)
• LCP field of the PPP packet can contain many different pieces of information, including the following:– Asynchronous character map– Maximum receive unit size– Compression– Authentication– Magic number– Link Quality Monitoring (LQM)– Multilink
CCNA Guide to Cisco Networking Fundamentals 10
![Page 11: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/11.jpg)
Frame Format (continued)
• LCP link configuration process– Modifies and enhances the default characteristics of
a PPP connection
• Includes the following actions:– Link establishment– Authentication (optional)– Link-quality determination (optional)– Network layer protocol configuration negotiation– Link termination
CCNA Guide to Cisco Networking Fundamentals 11
![Page 12: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/12.jpg)
Establishing PPP Communications
• Involves the following actions:– Link establishment– Optional authentication– Network layer protocol configuration negotiation
• The link establishment phase involves the configuration and testing of the data link
• The authentication process can use two authentication types with PPP connections: PAP and CHAP
CCNA Guide to Cisco Networking Fundamentals 12
![Page 13: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/13.jpg)
Establishing PPP Communications (continued)
• PPP is an encapsulation type for serial interface communications– To configure a PPP connection, you must access the
interface configuration mode for the specific interface you want to configure
• After LCP has finished negotiating the configuration parameters– Network layer protocols can be configured
individually by the appropriate NCP
CCNA Guide to Cisco Networking Fundamentals 13
![Page 14: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/14.jpg)
Establishing PPP Communications (continued)
CCNA Guide to Cisco Networking Fundamentals 14
![Page 15: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/15.jpg)
Establishing PPP Communications (continued)
• Configuring PPP Authentication– Using authentication with PPP connections is
optional– You must specifically configure PPP authentication
on each PPP host in order for the host to use it– You can choose to enable CHAP, PAP, or both on
your PPP connection, in either order
CCNA Guide to Cisco Networking Fundamentals 15
![Page 16: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/16.jpg)
Establishing PPP Communications (continued)
• Once you set the authentication type– You must still configure a username and password
for the authentication
• You must exit interface configuration mode and enter global configuration mode– Type username followed by the host name of the
remote router– Then type password followed by the password for
that connection
• Confirming PPP Communications– With the show interface command
CCNA Guide to Cisco Networking Fundamentals 16
![Page 17: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/17.jpg)
CCNA Guide to Cisco Networking Fundamentals 17
![Page 18: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/18.jpg)
Establishing PPP Communications (continued)
CCNA Guide to Cisco Networking Fundamentals 18
![Page 19: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/19.jpg)
Frame Relay Standards and Equipment
• Frame Relay– A packet switching and encapsulation technology
that functions at the Physical and Data Link layers of the OSI reference model
– A communications technique for sending data over high-speed digital connections
• ITU-T and ANSI define Frame Relay– As a connection between the data terminal
equipment (DTE) and the data communications equipment (DCE)
CCNA Guide to Cisco Networking Fundamentals 19
![Page 20: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/20.jpg)
Frame Relay Standards and Equipment (continued)
CCNA Guide to Cisco Networking Fundamentals 20
![Page 21: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/21.jpg)
Frame Relay Standards and Equipment (continued)
• The physical equipment that is used on a network may vary from one organization to another
• Some routers have built-in cards that allow them to make WAN connections
CCNA Guide to Cisco Networking Fundamentals 21
![Page 22: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/22.jpg)
Frame Relay Standards and Equipment (continued)
CCNA Guide to Cisco Networking Fundamentals 22
![Page 23: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/23.jpg)
CCNA Guide to Cisco Networking Fundamentals 23
![Page 24: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/24.jpg)
CCNA Guide to Cisco Networking Fundamentals 24
Frame Relay Standards and Equipment (continued)
• Frame Relay access device (FRAD)– Network device that connects to the Frame Relay
switch– Also known as Frame Relay
assembler/disassembler
• Frame Relay network device (FRND)– The Frame Relay switch
![Page 25: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/25.jpg)
CCNA Guide to Cisco Networking Fundamentals 25
Virtual Circuits
• You can use Frame Relay with nearly any serial interface– Operates by multiplexing
• Frame Relay separates each data stream into logical (software-maintained) connections– Called virtual circuits– Which carry the data transferred on the connection
• Two types of virtual circuits– Switched virtual circuits (SVC)– Permanent virtual circuits (PVC)
![Page 26: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/26.jpg)
DLCI
• Frame relay connections identify virtual circuits by Data Link Connection Identifier (DLCI) numbers
• A DLCI number associates an IP address with a specific virtual circuit
• DLCI numbers have only local significance
• DLCI numbers are usually assigned by the Frame Relay provider– Most likely not the same on either side of the Frame
Relay switch
CCNA Guide to Cisco Networking Fundamentals 26
![Page 27: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/27.jpg)
Frame Relay Map
• Frame Relay map– A table in RAM that defines the remote interface to
which a specific DLCI number is mapped
• The definition will contain a DLCI number and an interface identifier– Which is typically a remote IP address
• The Frame Relay map can be built automatically or statically depending on the Frame Relay topology
CCNA Guide to Cisco Networking Fundamentals 27
![Page 28: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/28.jpg)
CCNA Guide to Cisco Networking Fundamentals 28
![Page 29: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/29.jpg)
Frame Relay Map (continued)
• Subinterfaces– Virtual interfaces associated with a physical interface– Created by referencing the physical interface
followed by a period and a decimal number
• For the purposes of routing, however, subinterfaces are treated as physical interfaces
• With subinterfaces, the cost of implementing multiple Frame Relay virtual circuits is reduced– Because only one port is required on the router
CCNA Guide to Cisco Networking Fundamentals 29
![Page 30: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/30.jpg)
LMI
• LMI basically extended the functionality of Frame Relay by:– Making the DLCIs globally significant rather than
locally significant– Creating a signaling mechanism between the router
and the Frame Relay switch, which could report on the status of the link
– Supporting multicasting
• Providing DLCI numbers that are globally significant makes automatic configuration of the Frame Relay map possible
CCNA Guide to Cisco Networking Fundamentals 30
![Page 31: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/31.jpg)
LMI (continued)
• LMI uses keepalive packets to verify the Frame Relay link and to ensure the flow of data
• Each virtual circuit, represented by its DLCI number, can have one of three connection states:– Active– Inactive– Deleted
• The Frame Relay switch reports this status information to the Frame Relay map on the local router
CCNA Guide to Cisco Networking Fundamentals 31
![Page 32: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/32.jpg)
Inverse ARP
• In multipoint configurations– Routers use the protocol Inverse ARP to send a
query using the DLCI number to find a remote IP address
• As other routers respond to the Inverse ARP queries, the local router can build its Frame Relay map automatically
• To maintain the Frame Relay map, routers exchange Inverse ARP messages every 60 seconds by default
CCNA Guide to Cisco Networking Fundamentals 32
![Page 33: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/33.jpg)
Encapsulation Types
• LMI has several different protocol encapsulation types that it can use for management communications
• Cisco routers support these types of LMI encapsulation:– cisco– ansi– q933a
• Cisco routers (using IOS Release 11.2 or later) can “autosense” the LMI type used by the Frame Relay switch
CCNA Guide to Cisco Networking Fundamentals 33
![Page 34: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/34.jpg)
Encapsulation Types (continued)
• The basic LMI type has three information elements: report type, keepalive, and PVC status
• Information concerning the status of the virtual circuit:– New– Active– Receiver not ready– Minimum bandwidth– Global addressing– Multicasting– Provider-Initiated Status Update
CCNA Guide to Cisco Networking Fundamentals 34
![Page 35: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/35.jpg)
Encapsulation Types (continued)
• Split horizon– Routing technique that reduces the chance of routing
loops on a network– Prevents routing update information received on one
physical interface from being rebroadcast to other devices through that same physical interface
– People also refer to this rule as nonbroadcast multiaccess (NBMA)
– Can cause problems for Frame Relay routing updates
• The best solution is to configure separate point-to-point subinterfaces for each virtual connection
CCNA Guide to Cisco Networking Fundamentals 35
![Page 36: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/36.jpg)
CCNA Guide to Cisco Networking Fundamentals 36
![Page 37: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/37.jpg)
CCNA Guide to Cisco Networking Fundamentals 37
![Page 38: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/38.jpg)
CCNA Guide to Cisco Networking Fundamentals 38
![Page 39: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/39.jpg)
Performance Parameters
• Service contract specifies parameters by which the connection is expected to function:– Access rate– Committed Information Rate (CIR)– Committed Burst Size (CBS)– Excess Burst Size (EBS)– Oversubscription
CCNA Guide to Cisco Networking Fundamentals 39
![Page 40: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/40.jpg)
Congestion
• Frame Relay switches attempt to control congestion on the network
• When the Frame Relay switch recognizes congestion– Sends a forward explicit congestion notification
(FECN) message to the destination router
• In addition, the switch sends a backward explicit congestion notification (BECN) message to the transmitting, or source, router
CCNA Guide to Cisco Networking Fundamentals 40
![Page 41: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/41.jpg)
CCNA Guide to Cisco Networking Fundamentals 41
Frame Format
![Page 42: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/42.jpg)
Frame Relay Topologies
• Frame Relay can use many different WAN topologies: – Peer (point-to-point)– Star (hub and spoke)– Partial mesh– Full mesh physical
CCNA Guide to Cisco Networking Fundamentals 42
![Page 43: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/43.jpg)
CCNA Guide to Cisco Networking Fundamentals 43
![Page 44: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/44.jpg)
Frame Relay Configuration
• In this section, you will learn how to configure Frame Relay over serial interfaces– Using IP as the Network layer protocol
CCNA Guide to Cisco Networking Fundamentals 44
![Page 45: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/45.jpg)
Basic Multipoint Configuration with Two Routers
• LMI will notify the router about the available DLCI numbers– Inverse ARP will build the Frame Relay map
dynamically
CCNA Guide to Cisco Networking Fundamentals 45
![Page 46: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/46.jpg)
CCNA Guide to Cisco Networking Fundamentals 46
![Page 47: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/47.jpg)
CCNA Guide to Cisco Networking Fundamentals 47
![Page 48: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/48.jpg)
Basic Multipoint Configuration with Two Routers (continued)
CCNA Guide to Cisco Networking Fundamentals 48
![Page 49: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/49.jpg)
Multipoint Configuration Using a Subinterface
• The Frame Relay map will have to be built statically on RouterA– To configure a multipoint subinterface, you map it to
multiple remote routers using the same subnet mask, but different DLCI numbers
CCNA Guide to Cisco Networking Fundamentals 49
![Page 50: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/50.jpg)
Multipoint Configuration Using a Subinterface (continued)
CCNA Guide to Cisco Networking Fundamentals 50
![Page 51: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/51.jpg)
CCNA Guide to Cisco Networking Fundamentals 51
![Page 52: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/52.jpg)
Point-to-Point Configuration Using Subinterfaces
• Point-to-point Frame Relay configurations do not support Inverse ARP
• You will have to configure each subnet separately – Use the frame-relay interface-dlci command to
associate the DLCI numbers with a specific subinterface
CCNA Guide to Cisco Networking Fundamentals 52
![Page 53: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/53.jpg)
CCNA Guide to Cisco Networking Fundamentals 53
![Page 54: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/54.jpg)
CCNA Guide to Cisco Networking Fundamentals 54
![Page 55: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/55.jpg)
Frame Relay Static Mapping
• Sometimes you have to define the DLCI numbers manually– This is called making a static address to DLCI
Frame Relay map
• You statically configure your DLCI entries in the following situations:– The remote router does not support Inverse ARP– You need to assign specific subinterfaces to specific
DLCI connections– You want to reduce broadcast traffic– You are configuring OSPF over Frame Relay
CCNA Guide to Cisco Networking Fundamentals 55
![Page 56: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/56.jpg)
Non-Cisco Routers
• Non-Cisco routers use a different Frame Relay encapsulation than Cisco routers
• If you are configuring Cisco routers to connect to other Cisco routers– They will automatically use the Cisco Frame Relay
encapsulation
• If you are connecting a Cisco router to a non-Cisco router, you must specify ietf Frame Relay encapsulation using the following command:
RouterA(config-if)#encapsulation frame-relay ietf
CCNA Guide to Cisco Networking Fundamentals 56
![Page 57: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/57.jpg)
CCNA Guide to Cisco Networking Fundamentals 57
Keepalive Configuration
• By default, keepalive packets are sent out every 10 seconds to the Frame Relay switch
• You can change the keepalive period by typing keepalive followed by the time in seconds
RouterA(config-if)#keepalive 15
![Page 58: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/58.jpg)
CCNA Guide to Cisco Networking Fundamentals 58
Monitoring Frame Relay
• You can check your Frame Relay configuration by using show commands– These commands allow you to verify that the
commands you previously entered produced the desired effect on your router
• The most common show commands for monitoring Frame Relay operation are:
show interface
show frame-relay pvc
show frame-relay map
show frame-relay lmi
![Page 59: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/59.jpg)
CCNA Guide to Cisco Networking Fundamentals 59
![Page 60: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/60.jpg)
CCNA Guide to Cisco Networking Fundamentals 60
![Page 61: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/61.jpg)
CCNA Guide to Cisco Networking Fundamentals 61
![Page 62: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/62.jpg)
Summary
• Many WAN connectivity options are available for modern networks, including digital lines, Frame Relay, and analog modems
• The Point-to-Point Protocol (PPP) is the most widely used WAN protocol today
• PPP provides link establishment, quality determination, Network layer protocol encapsulation, and link termination services
• Frame relay is a flexible WAN technology that can be used to connect two geographically separate LANs
CCNA Guide to Cisco Networking Fundamentals 62
![Page 63: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/63.jpg)
Summary (continued)
• Frame relay is both a service and type of encapsulation
• Service parameters for Frame Relay include the access rate, Committed Information Rate (CIR), Committed Burst Size (CBS), and Excess Burst Size (EBS)
• Frame relay connections employ virtual circuits that can be either permanent or switched
• Virtual circuit connections across Frame Relay connections are defined by Data Link Connection Identifier (DLCI) numbers
CCNA Guide to Cisco Networking Fundamentals 63
![Page 64: CCNA PPP and Frame Relay](https://reader033.fdocuments.us/reader033/viewer/2022042512/5444b52db1af9fbc0e8b4a48/html5/thumbnails/64.jpg)
Summary (continued)
• Most Frame Relay providers support LMI, which allows Frame Relay maps to be dynamically created via Inverse ARP
• Static mappings of DLCI numbers to remote IP addresses can be configured when routers do not support Inverse ARP
• Inverse ARP is not enabled on point-to-point links because only one path is available
• Frame relay circuits can be established over serial interfaces or subinterfaces on Cisco routers
CCNA Guide to Cisco Networking Fundamentals 64