CISCO CCNA ICND PPT D20S08L01

8/14/2019 CISCO CCNA ICND PPT D20S08L01

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2002, Cisco Systems, Inc. All rights reserved.


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2002, Cisco Systems, Inc. All rights reserved. 2

Establishing Frame Relay

ConnectionsModule 8


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2002, Cisco Systems, Inc. All rights reserved. ICND v2.08-3

Objectives

Upon completing this module, you will beable to:

Use Cisco IOS commands to configure an operationalserial Frame Relay connection and Frame Relay

subinterfaces, given a functioning router

Use show commands to identify anomalies in anoperational serial Frame Relay connection and FrameRelay subinterfaces, given a functioning router

Use debug commands to identify events and anomaliesin an operational serial Frame Relay connection andFrame Relay subinterfaces, given a functioning routerand an operational serial Frame Relay connection


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2002, Cisco Systems, Inc. All rights reserved. 4

Frame Relay Overview


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Objectives

Upon completing this lesson, you will beable to:

Describe the features and operation of a FrameRelay network

Define important Frame Relay terms includinglocal access rate, virtual circuit, PVC, SVC, DLCI,

CIR, InARP, LMI, FECN, and BECN


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Frame Relay Overview

Connections made by virtual circuits

Connection-oriented service


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Frame Relay Stack

OSI Reference Model Frame Relay

Physical

Presentation

Session

Transport

Network

Data-Link

Application

EIA/TIA-232,

EIA/TIA-449, V.35,

X.21, EIA/TIA-530

Frame Relay

IP/IPX/AppleTalk, etc.



Frame Relay Terminology



Frame Relay default: nonbroadcast, multiaccess (NBMA)

Selecting a Frame Relay Topology



Reachability Issues with Routing Updates

Problem:

Broadcast traffic must be replicated foreach active connection.

Split-horizon rule prevents routing updates received onone interface from being forwarded out the same interface.



Resolving Reachability Issues

Split horizon can cause problems in NBMA environments.

Subinterfaces can resolve split horizon issues.

Solution: A single physical interface simulates multiple logicalinterfaces.



Frame Relay Address Mapping

Use LMI to get locally significant DLCI from the Frame Relayswitch.

Use Inverse ARP to map the local DLCI to the remote routers

network layer address.



Frame Relay Signaling

Cisco supports three LMI standards: Cisco

ANSI T1.617 Annex D

ITU-T Q.933 Annex A



Frame Relay Inverse ARPand LMI Signaling



Stages of Inverse ARPand LMI Operation



How Service Providers Map FrameRelay DLCIs: Service Provider View



How Service Providers Map FrameRelay DLCIs: Enterprise View



Service ProviderFrame Relay-to-ATM Interworking



FRF.8 Service Interworking



Summary

Frame Relay is an ITU-T and ANSI standard that definesthe process for sending data over a public data network.

The core aspects of Frame Relay function at the lowertwo layers of the OSI reference model.

Knowing the terms that are used frequently whendiscussing Frame Relay is important to understandingthe operation and configuration of Frame Relay services.

Frame Relay allows you to interconnect your remote sitesin a variety of topologies including star, full mesh, andpartial mesh.

A Frame Relay NBMA topology may cause routing updatereachability issues, which are solved by usingsubinterfaces.


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Summary (Cont.)

A Frame Relay connection requires that, on a VC, thelocal DLCI be mapped to a destination network layeraddress such as an IP address.

LMI is a signaling standard between the router and theFrame Relay switch that is responsible for managing the

connection and maintaining status between the devices.

Service providers map Frame Relay DLCIs so that DLCIswith local significance appear at each end of a FrameRelay connection.

FRF.5 provides network interworking functionality thatallows Frame Relay end users to communicate over anintermediate ATM network that supports FRF.5. FRF.8provides service interworking functionality that allows aFrame Relay end user to communicate with an ATM

end user.


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CISCO CCNA ICND PPT D20S08L01