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CCNA 4 v3.0 Module 4ISDN and DDR

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Objectives

• ISDN concepts

• ISDN configuration

• DDR configuration

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Digital Communication with ISDN

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ISDN Benefits

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ISDN Standards

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ISDN Standards

• E Protocols – Recommend telephone network standards for ISDN. For example, the E.164 protocol describes international addressing for ISDN.

• I Protocols – Deal with concepts, terminology, and general methods. The I.100 series includes general ISDN concepts and the structure of other I-series recommendations. I.200 deals with service aspects of ISDN. I.300 describes network aspects. I.400 describes how the UNI is provided.

• Q Protocols – Cover how switching and signaling should operate. The term signaling in this context means the process of establishing an ISDN call.

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ISDN Access Options

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ISDN 3-Layer Model

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Q.931 Messaging-Call Setup Example

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Call Processing

1. The D channel is used to send the called number to the local ISDN switch.

2. The local switch uses the SS7 signaling protocol to set up a path and pass the called number to the remote ISDN switch.

3. The remote ISDN switch signals the destination over the D channel.

4. The destination ISDN NT-1 device sends the remote ISDN switch a call-connect message.

5. The remote ISDN switch uses SS7 to send a call-connect message to the local switch.

6. The local ISDN switch connects one B channel end-to-end, leaving the other B channel available for a new conversation or data transfer. Both B channels can be used simultaneously.

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ISDN Functions and Reference Points

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ISDN Functions and Reference Points

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BRI Reference Points

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Cisco ISDN BRI Interfaces

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ISDN Interfaces

S/T ISDN Interface

U ISDN Interface

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ISDN Switch Types

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Configuring ISDN BRI

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Configuring ISDN BRI

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Configuring ISDN PRI

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Switch Types Available for ISDN PRI Configuration

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ISDN PRI Examples

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Verifying ISDN Configuration

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Troubleshooting ISDN Configuration

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DDR Operation

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Legacy DDR

• Legacy DDR is a term used to define a very basic DDR configuration in which a single set of dialer parameters is applied to an interface. If multiple unique dialer configurations are needed on one interface, then dialer profiles should be used.

• To configure legacy DDR perform the following steps:

• Define static routes

• Specify interesting traffic

• Configure the dialer information

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DDR Operation

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Configuring Legacy DDR

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Defining Static Routes

• When configuring static routes, consider the following:

By default, a static route will take precedence over a dynamic route because of its lower administrative distance. Without additional configuration, a dynamic route to a network will be ignored if a static route is present in the routing table for the same network.

To reduce the number of static route entries, define a summarized or default static route

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Specifying Interesting Traffic

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Configuring Dialer Information - PPP

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The dialer-group Command

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The dialer-map Command

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The dialer idle-timeout Command

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Dialer Profiles Overview

• Define encapsulation and access control lists

• Determine minimum or maximum calls

• Turn features on or off

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Dialer Profile Elements

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Configuring Dialer Interfaces

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Verifying DDR

• show dialer

• show dialer interface [BRI]

• show isdn active

• show isdn status

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clear interface bri

• This command will clear the hardware logic for the specified slot/port. This is often used with ISDN BRI interfaces to force the interface to resend the SPIDs.

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Troubleshooting DDR

• debug isdn q921

• debug isdn q931

• debug dialer [events|packets]

• isdn call interface

• clear interface bri

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Objectives

• ISDN concepts

• ISDN configuration

• DDR configuration