Setting Up Basic ISDN Service

This chapter describes configuration of the ISDN BRI. See the chapter "Configuring ISDN PRI and Other Signalling on E1 and T1 Lines" for information about configuring the ISDN PRI.

This chapter does not address routing issues, dialer configuration, and dial backup. For information about those topics, see the chapters in the "Dial-on-Demand Routing" part of this publication.

For hardware technical descriptions, and for information about installing the router interfaces, refer to the appropriate hardware installation and maintenance publication for your particular product.

For a complete description of the BRI commands in this chapter, see the Cisco IOS Dial Services Command Reference publication. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

ISDN Overview

Basic ISDN service is described in the section "ISDN Service" in the chapter "Interfaces, Controllers, and Lines Used for Dial Access Overview." To summarize, Cisco IOS software supports both the ISDN BRI and ISDN PRI.

ISDN BRI provides two bearer (B) channels, each capable of transferring voice or data at 64 kbps, and one 16-kbps data (D) signalling channel, which is used by the telephone network to carry instructions about how to handle each of the B channels. ISDN BRI (also referred to as 2 B + D) provides a maximum of 128 kbps transmission speed, but many users use only half the available bandwidth.

Figure 11 in the chapter "Interfaces, Controllers, and Lines Used for Dial Access Overview" illustrates the channel assignment for each ISDN type.

Requesting BRI Line and Switch Configuration from a Telco Service Provider

Before configuring the ISDN BRI interface on your Cisco router, you must order a correctly configured ISDN line from your telecommunications service provider. This process varies from provider to provider on a national and international basis. However, some general guidelines follow:

Ask for two channels to be called by one number.

Ask for delivery of calling line identification. Providers sometimes call this CLI or automatic number identification (ANI).

If the router will be the only device attached to the BRI, ask for point-to-point service and a data-only line.
If the router will be attached to an ISDN bus (to which other ISDN devices might be attached), ask for point-to-multipoint service (subaddressing is required) and a voice-and-data line.

When you order ISDN service, request the BRI switch configuration attributes specified in Table 14.

Table 14: ISDN BRI Switch Type Configuration Information

Switch Type Configuration

DMS-100 BRI Custom
2 B channels for voice and data.
2 directory numbers assigned by service provider.
2 service profile identifiers (SPIDs) required; assigned by service provider.
Functional signalling.
Dynamic terminal endpoint identifier (TEI) assignment.
Maximum number of keys = 64.
Release key = no, or key number = no.
Ringing indicator = no.
EKTS = no.
PVC = 2.
Request delivery of calling line ID on Centrex lines.
Set speed for ISDN calls to 56 kbps outside local exchange.
Directory number 1 can hunt to directory number 2.

5ESS Custom BRI For Data Only
2 B channels for data.
Point to point.
Terminal type = E.
1 directory number (DN) assigned by service provider.
MTERM = 1.
Request delivery of calling line ID on Centrex lines.
Set speed for ISDN calls to 56 kbps outside local exchange.
For Voice and Data
(Use these values only if you have an ISDN telephone connected.)
2 B channels for voice or data.
Multipoint.
Terminal type = D.
2 directory numbers assigned by service provider.
2 SPIDs required; assigned by service provider.
MTERM = 2.
Number of call appearances = 1.
Display = No.
Ringing/idle call appearances = idle.
Autohold = no.
Onetouch = no.
Request delivery of calling line ID on Centrex lines.
Set speed for ISDN calls to 56 kbps outside local exchange.
Directory number 1 can hunt to directory number 2.

5ESS National ISDN (NI) BRI
Terminal type = A.
2 B channels for voice and data.
2 directory numbers assigned by service provider.
2 SPIDs required; assigned by service provider.
Set speed for ISDN calls to 56 kbps outside local exchange.
Directory number 1 can hunt to directory number 2.

EZ-ISDN 1 For Voice and Data ISDN Ordering Code for Cisco 766/776 Series = Capability S
ISDN Ordering Code for Cisco 1604 Series = Capability R
2 B channels featuring alternate voice and circuit-switched data. Non-EKTS voice features include:

Flexible Calling

Call Forwarding Variable

Additional Call Offering

Calling Number Identification (includes Redirecting Number Delivery)

Switch Type	Configuration
DMS-100 BRI Custom	2 B channels for voice and data. 2 directory numbers assigned by service provider. 2 service profile identifiers (SPIDs) required; assigned by service provider. Functional signalling. Dynamic terminal endpoint identifier (TEI) assignment. Maximum number of keys = 64. Release key = no, or key number = no. Ringing indicator = no. EKTS = no. PVC = 2. Request delivery of calling line ID on Centrex lines. Set speed for ISDN calls to 56 kbps outside local exchange. Directory number 1 can hunt to directory number 2.
5ESS Custom BRI	For Data Only 2 B channels for data. Point to point. Terminal type = E. 1 directory number (DN) assigned by service provider. MTERM = 1. Request delivery of calling line ID on Centrex lines. Set speed for ISDN calls to 56 kbps outside local exchange. For Voice and Data (Use these values only if you have an ISDN telephone connected.) 2 B channels for voice or data. Multipoint. Terminal type = D. 2 directory numbers assigned by service provider. 2 SPIDs required; assigned by service provider. MTERM = 2. Number of call appearances = 1. Display = No. Ringing/idle call appearances = idle. Autohold = no. Onetouch = no. Request delivery of calling line ID on Centrex lines. Set speed for ISDN calls to 56 kbps outside local exchange. Directory number 1 can hunt to directory number 2.
5ESS National ISDN (NI) BRI	Terminal type = A. 2 B channels for voice and data. 2 directory numbers assigned by service provider. 2 SPIDs required; assigned by service provider. Set speed for ISDN calls to 56 kbps outside local exchange. Directory number 1 can hunt to directory number 2.
EZ-ISDN 1	For Voice and Data ISDN Ordering Code for Cisco 766/776 Series = Capability S ISDN Ordering Code for Cisco 1604 Series = Capability R 2 B channels featuring alternate voice and circuit-switched data. Non-EKTS voice features include: Flexible Calling Call Forwarding Variable Additional Call Offering Calling Number Identification (includes Redirecting Number Delivery)

Multiple ISDN Switch Types Feature

The Cisco IOS software provides an enhanced Multiple ISDN Switch Types feature that allows you to apply an ISDN switch type to a specific ISDN interface and configure more than one ISDN switch type per router. This feature allows both ISDN BRI and ISDN PRI to run simultaneously on platforms that support both interface types. See the section "Configuring Multiple ISDN Switch Types" in the chapter "Configuring ISDN PRI and Other Signalling on E1 and T1 Lines" for information about configuring this feature.

Interface Configuration

The Cisco IOS software also provides custom features for configuring the ISDN BRI interface that provide such capability as call screening, called party number verification, ISDN default cause code override, and for European and Australian customers, Dialed Number Identification Service (DNIS)-plus-ISDN-subaddress binding to allow multiple binds between a dialer profile and an ISDN B channel.

Dynamic Multiple Encapsulations

Prior to Cisco IOS Release 12.1, encapsulation techniques such as Frame Relay, High-Level Data Link Control (HDLC), Link Access Procedure, Balanced- Terminal Adapter (LAPB-TA), and X.25 could support only one ISDN B-channel connection over the entire link. HDLC and PPP could support multiple B channels, but the entire ISDN link needed to use the same encapsulation. The Dynamic Multiple Encapsulations feature introduced in Cisco IOS Release 12.1 allows various encapsulation types and per-user configurations on the same ISDN B channel at different times according to the type of incoming call.

With the Dynamic Multiple Encapsulations feature, once calling line identification (CLID) binding is completed, the topmost interface is always used for all configuration and data structures. The ISDN B channel becomes a forwarding device, and the configuration on the D channel is ignored, thereby allowing the different encapsulation types and per-user configurations. Dynamic multiple encapsulations provide support for packet assembler/disassembler (PAD) traffic and X.25 encapsulated and switched packets. For X.25 encapsulations, the configurations reside on the dialer profile.

Dynamic multiple encapsulation is especially important in Europe, where ISDN is relatively expensive and maximum use of all 30 B channels on the same ISDN link is desirable. Further, the feature removes the need to statically dedicate channels to a particular encapsulation and configuration type, and improves channel usage.

Figure 37 shows a typical configuration for an X.25 network in Europe. The Dynamic Multiple Encapsulations feature allows use of all 30 B channels, and supports calls that originate in diverse areas of the network and converge on the same ISDN PRI.

Figure 37: European X.25 Network

Other Interface Configuration Options

You can also optionally configure snapshot routing for ISDN interfaces. Snapshot routing is a method of learning remote routes dynamically and keeping the routes available for a specified period of time, even though routing updates are not exchanged during that period. See the chapter "Configuring Snapshot Routing" in the "Cost-Control Solutions" part of the Cisco IOS Dial Services Configuration Guide: Network Services publication for detailed information about snapshot routing.

To place calls on an ISDN interface, you must configure it with dial-on-demand routing (DDR). For configuration information about ISDN using DDR, see the "Dial-on-Demand Routing" part of this publication. For command information, see the Cisco IOS Dial Services Command Reference publication.

To configure bandwidth on demand, see the chapters "Configuring Legacy DDR Spokes" or "Configuring Legacy DDR Hubs" later in this publication.

ISDN BRI Configuration Task List

To configure ISDN lines and interfaces, perform the tasks in the following sections:

Configuring the ISDN BRI Switch (Required)
Specifying Interface Characteristics for an ISDN BRI (As Required)

See the sections "Monitoring and Maintaining ISDN Interfaces" and "Troubleshooting ISDN Interfaces" later in this chapter for tips on maintaining your network. See the section "ISDN BRI Configuration Examples" at the end of this chapter for configuration examples.

Configuring the ISDN BRI Switch

To configure the ISDN switch type, perform the following tasks:

Configuring the Switch Type (Required)
Checking and Setting the Buffers (As Required)

Configuring the Switch Type

To configure the switch type, use the following command in global configuration mode:

Command Purpose

isdn switch-type switch-type
Selects the service provider switch type; see Table 14 for switch types.

Command	Purpose
isdn switch-type switch-type	Selects the service provider switch type; see Table 14 for switch types.

The section "Global ISDN and BRI Interface Switch Type" later in this chapter provides an example of configuring the ISDN BRI switch.

Note You can apply an ISDN switch type to a specific BRI interface and configure more than one ISDN switch type per router using the Multiple ISDN Switch Types feature , thus extending the existing global isdn switch-type command to the interface level. A global ISDN switch type is required and must be configured on the router before you can configure a switch type on an interface. See the section "Configuring Multiple ISDN Switch Types" in the chapter "Configuring ISDN PRI and Other Signalling on E1 and T1 Lines" for information about configuring this feature.

Table 15 lists the ISDN BRI service provider switch types.

Table 15: ISDN Service Provider BRI Switch Types

Keywords by Area Switch Type

none

No switch defined

Japan

ntt

Japanese NTT ISDN switches

Europe

basic-1tr6

German 1TR6 ISDN switches

basic-net3

NET3 ISDN, Norway NET3, Australia NET3, and New Zealand NET3 switches (covers the Euro-ISDN E-DSS1 signalling system and is ETSI-compliant)

vn3

French VN3 and VN4 ISDN BRI switches

North America

basic-5ess

AT&T basic rate switches

basic-dms100

Northern Telecom DMS-100 basic rate switches

basic-ni

National ISDN switches

Note The command parser will still accept the following switch type keywords: basic-nwnet3, vn2, and basic-net3; however, when viewing the NVRAM configuration, the basic-net3 or vn3 switch type keywords are displayed respectively.

Checking and Setting the Buffers

When configuring a BRI, after the system comes up, make sure enough buffers are in the free list of the buffer pool that matches the maximum transmission unit (MTU) of your BRI interface. If not, you must reconfigure buffers in order for the BRI interfaces to function properly.

To check the MTU size and the buffers and, if necessary, to configure the buffers and the MTU size, use any of the following commands beginning in EXEC mode:

Command Purpose

show interfaces bri number
Checks the MTU size.

show buffers
Checks the free buffers.

configure terminal buffers big permanent number
buffers big max-free number
buffers big min-free number
buffers big initial number
Configures the buffers.

Command	Purpose
show interfaces bri number	Checks the MTU size.
show buffers	Checks the free buffers.
configure terminal buffers big permanent number buffers big max-free number buffers big min-free number buffers big initial number	Configures the buffers.

Specifying Interface Characteristics for an ISDN BRI

Perform the tasks in the following sections to set interface characteristics for an ISDN BRI, whether it is the only BRI in a router or is one of many. Each of the BRIs can be configured separately.

Specifying the Interface and Its IP Address (Required)
Configuring CLI Screening (As Required)
Configuring Encapsulation on ISDN BRI (Required)
Configuring Network Addressing (Required)
Configuring TEI Negotiation Timing (Optional)
Configuring CLI Screening (Optional)
Configuring Called Party Number Verification (Optional)
Configuring ISDN Calling Number Identification (Optional)
Configuring the Line Speed for Calls Not ISDN End to End (Optional)
Configuring a Fast Rollover Delay (Optional)
Overriding ISDN Application Default Cause Codes (Optional)
Configuring Inclusion of the Sending Complete Information Element (Optional)
Configuring DNIS-plus-ISDN-Subaddress Binding (Optional)

Specifying the Interface and Its IP Address

To specify an ISDN BRI and enter interface configuration mode, use the following commands in global configuration mode:

Command Purpose

interface bri number
or

interface bri slot/port
(Cisco 7200 series)

Specifies the interface and enter interface configuration mode.

ip address address mask
Specifies an IP address for the interface.

Command	Purpose
interface bri number or interface bri slot/port (Cisco 7200 series)	Specifies the interface and enter interface configuration mode.
ip address address mask	Specifies an IP address for the interface.

Specifying ISDN SPIDs

Some service providers use SPIDs to define the services subscribed to by the ISDN device that is accessing the ISDN service provider. The service provider assigns the ISDN device one or more SPIDs when you first subscribe to the service. If you are using a service provider that requires SPIDs, your ISDN device cannot place or receive calls until it sends a valid, assigned SPID to the service provider when accessing the switch to initialize the connection.

Currently, only the DMS-100 and NI switch types require SPIDs. The AT&T 5ESS switch type may support a SPID, but we recommend that you set up that ISDN service without SPIDs. In addition, SPIDs have significance at the local access ISDN interface only. Remote routers never receive the SPID.

A SPID is usually a seven-digit telephone number with some optional numbers. However, service providers may use different numbering schemes. For the DMS-100 switch type, two SPIDs are assigned, one for each B channel.

To define the SPIDs and the local directory number (LDN) on the router, use the following commands in interface configuration mode:

Command Purpose

isdn spid1 spid-number [ldn]
Specifies a SPID and local directory number for the B1 channel.

isdn spid2 spid-number [ldn]
Specifies a SPID and local directory number for the B2 channel.

Command	Purpose
isdn spid1 spid-number [ldn]	Specifies a SPID and local directory number for the B1 channel.
isdn spid2 spid-number [ldn]	Specifies a SPID and local directory number for the B2 channel.

The LDN is optional but might be necessary if the router is to answer calls made to the second directory number.

Configuring Encapsulation on ISDN BRI

Each ISDN B channel is treated as a synchronous serial line, and the default serial encapsulation is HDLC. The Dynamic Multiple Encapsulations feature introduced in Cisco IOS Release 12.1 allows incoming calls over ISDN to be assigned an encapsulation type such as Frame Relay, PPP, and X.25 based on CLID or DNIS. PPP encapsulation is configured for most ISDN communication.

To configure encapsulation, use the following command in interface configuration mode:

Command Purpose

encapsulation [ppp | lapb | frame-relay]
Configures encapsulation type.

Command	Purpose
encapsulation [ppp \| lapb \| frame-relay]	Configures encapsulation type.

Verifying the Dynamic Multiple Encapsulations Feature

To verify dialer interfaces configured for binding and see statistics on each physical interface bound to the dialer interface, use the show interfaces EXEC command.

The following example shows that the output under the B channel keeps all hardware counts that are not displayed under any logical or virtual access interface. The line in the report that states "Interface is bound to Dialer0 (Encapsulation LAPB)" indicates that this B interface is bound to the dialer 0 interface and the encapsulation running over this connection is LAPB, not PPP, which is the encapsulation configured on the D interface and inherited by the B channel.

Router# show interfaces bri0:1
 
BRI0:1 is up, line protocol is up 
  Hardware is BRI
  MTU 1500 bytes, BW 64 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation PPP, loopback not set, keepalive not set
  Interface is bound to Dialer0 (Encapsulation LAPB)
  LCP Open, multilink Open
  Last input 00:00:31, output 00:00:03, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 0/75, 0 drops
  5 minute input rate 0 bits/sec, 1 packets/sec
  5 minute output rate 0 bits/sec, 1 packets/sec
     110 packets input, 13994 bytes, 0 no buffer
     Received 91 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     135 packets output, 14175 bytes, 0 underruns
     0 output errors, 0 collisions, 12 interface resets
     0 output buffer failures, 0 output buffers swapped out
     8 carrier transitions

Any protocol configuration and states should be displayed from the dialer 0 interface.

Encapsulation Configuration Notes

The router might need to communicate with devices that require a different encapsulation protocol or the router might send traffic over a Frame Relay or X.25 network. The Dynamic Multiple Encapsulations feature provides bidirectional support of all serial encapsulations except Frame Relay.

For more information, see the sections "Sending Traffic over Frame Relay, X.25, or LAPB Networks" in the chapters "Configuring Legacy DDR Spokes" and "Configuring Legacy DDR Hubs" later in this publication.

To configure the router for automatic detection of encapsulation type on incoming calls, or to configure encapsulation for Cisco 700 and 800 series (formerly Combinet) router compatibility, see the section "Configuring Automatic Detection of Encapsulation Type" in the chapter "Configuring ISDN Special Signalling" later in this publication.

Configuring Network Addressing

The steps in this section support the primary goals of network addressing:

Define which packets are interesting—and will thus cause the router to make an outgoing call.
Define the remote host where the calls are going.
Specify whether broadcast messages will be sent.
Specify the dialing string to use in the call.

Intermediate steps that use shared argument values tie the host identification and dial string to the interesting packets to be sent to that host.

To configure network addressing, use the following commands beginning in interface configuration mode:

Command Purpose

Step 1

dialer map protocol next-hop-address name hostname speed 56|64 dial-string[:isdn-subaddress]

or

dialer map protocol next-hop-address name hostname spc [speed 56 | 64] [broadcast] dial-string[:isdn-subaddress]
(Most locations) Defines the remote recipient's protocol address, host name, and dialing string; optionally, provide the ISDN subaddress; set the dialer speed to 56 or 64 kbps, as needed.

(Germany) Uses the command keyword that enables ISDN semipermanent connections.

Step 2

dialer-group group-number
Assigns the interface to a dialer group to control access to the interface.

Step 3

dialer-list dialer-group list access-list-number
Associates the dialer group number with an access list number.

Step 4

access-list access-list-number {deny | permit} protocol source address source-mask destination destination-mask
Defines an access list permitting or denying access to specified protocols, sources, or destinations. Permitted packets cause the router to place a call to the destination protocol address.

	Command	Purpose
Step 1	dialer map protocol next-hop-address name hostname speed 56\|64 dial-string[:isdn-subaddress] or dialer map protocol next-hop-address name hostname spc [speed 56 \| 64] [broadcast] dial-string[:isdn-subaddress]	(Most locations) Defines the remote recipient's protocol address, host name, and dialing string; optionally, provide the ISDN subaddress; set the dialer speed to 56 or 64 kbps, as needed. (Germany) Uses the command keyword that enables ISDN semipermanent connections.
Step 2	dialer-group group-number	Assigns the interface to a dialer group to control access to the interface.
Step 3	dialer-list dialer-group list access-list-number	Associates the dialer group number with an access list number.
Step 4	access-list access-list-number {deny \| permit} protocol source address source-mask destination destination-mask	Defines an access list permitting or denying access to specified protocols, sources, or destinations. Permitted packets cause the router to place a call to the destination protocol address.

German networks allow semipermanent connections between customer routers with BRIs and the 1TR6 basic rate switches in the exchange. Semipermanent connections are offered at better pricing than leased lines.

Note The access list reference in Step 4 of this task list is an example of the access-list commands allowed by different protocols. Some protocols might require a different command form or might require multiple commands. Refer to the relevant protocol chapter in the network protocol configuration guide (the Cisco IOS AppleTalk and Novell IPX Configuration Guide, for example) for more information about setting up access lists for a protocol.

For more information about defining outgoing call numbers, see the chapters "Configuring Legacy DDR Hubs" and "Configuring Legacy DDR Spokes" later in this publication.

Configuring TEI Negotiation Timing

You can configure ISDN TEI negotiation on individual ISDN interfaces. TEI negotiation is useful for switches that may deactivate Layers 1 or 2 when there are no active calls. Typically, this setting is used for ISDN service offerings in Europe and connections to DMS-100 switches that are designed to initiate TEI negotiation.

By default, TEI negotiation occurs when the router is powered up . The TEI negotiation value configured on an interface overrides the default or global TEI value. For example, if you configure isdn tei first-call globally and isdn tei powerup on BRI interface 0, then TEI negotiation powerup is the value applied to BRI interface 0. It is not necessary to configure TEI negotiation unless you wish to override the default value (isdn tei powerup).

To apply TEI negotiation to a specific BRI interface, use the following command in interface configuration mode:

Command Purpose

isdn tei [first-call | powerup]
Determines when ISDN TEI negotiation occurs.

Command	Purpose
isdn tei [first-call \| powerup]	Determines when ISDN TEI negotiation occurs.

Configuring CLI Screening

CLI screening adds a level of security by allowing you to screen incoming calls. You can verify that the calling line ID is from an expected origin. CLI screening requires a local switch that is capable of delivering the CLI to the router.

To configure CLI screening, use the following command in interface configuration mode:

Command Purpose

isdn caller number
Configures caller ID screening.

Command	Purpose
isdn caller number	Configures caller ID screening.

Note If caller ID screening is configured and the local switch does not deliver caller IDs, the router rejects all calls.

Note In earlier releases of the Cisco IOS software, ISDN accepted all synchronous calls and performed some minimal CLI screening before accepting or rejecting a call. Beginning with Cisco IOS Release 12.1 software, DDR provided a separate process that screens for the profile of the caller. The new screening process also checks that enough resources are available to accept the call and that the call conforms to predetermined rules. When the call is found acceptable, the screening process searches for a matching profile for the caller. The call is accepted only when there is a matching profile.

Configuring Called Party Number Verification

When multiple devices are attached to an ISDN BRI, you can ensure that only a single device answers an incoming call by verifying the number or subaddress in the incoming call against the configured number or subaddress or both of the device.

You can specify that the router verify a called-party number or subaddress number in the incoming setup message for ISDN BRI calls, if the number is delivered by the switch. You can do so by configuring the number that is allowed. To configure verification, use the following command in interface configuration mode:

Command Purpose

isdn answer1 [called-party-number][:subaddress]
Specifies that the router verify a called-party number or subaddress number in the incoming setup message.

Command	Purpose
isdn answer1 [called-party-number][:subaddress]	Specifies that the router verify a called-party number or subaddress number in the incoming setup message.

Verifying the called-party number ensures that only the desired router responds to an incoming call. If you want to allow an additional number for the router, you can configure it, too.

To configure a second number to be allowed, use the following command in interface configuration mode:

Command Purpose

isdn answer2 [called-party-number][:subaddress]
Specifies that the router verify a second called-party number or subaddress number in the incoming setup message.

Command	Purpose
isdn answer2 [called-party-number][:subaddress]	Specifies that the router verify a second called-party number or subaddress number in the incoming setup message.

Configuring ISDN Calling Number Identification

A router with an ISDN BRI interface might need to supply the ISDN network with a billing number for outgoing calls. Some networks offer better pricing on calls in which the number is presented. When configured, this information is included in the outgoing call Setup message.

To configure the interface to identify the billing number, use the following command in interface configuration mode:

Command Purpose

isdn calling-number calling-number
Specifies the calling party number.

Command	Purpose
isdn calling-number calling-number	Specifies the calling party number.

This command can be used with all switch types except German 1TR6 ISDN BRI switches.

Configuring the Line Speed for Calls Not ISDN End to End

When calls are made at 56 kbps but delivered by the ISDN network at 64 kbps, the incoming data can be corrupted. However, on ISDN calls, if the receiving side is informed that the call is not an ISDN call from end to end, it can set the line speed for the incoming call.

To set the speed for incoming calls recognized as not ISDN end to end, use the following command in interface configuration mode:

Command Purpose

isdn not-end-to-end {56 | 64}
Sets the speed to be used for incoming calls recognized as not ISDN end to end.

Command	Purpose
isdn not-end-to-end {56 \| 64}	Sets the speed to be used for incoming calls recognized as not ISDN end to end.

Configuring a Fast Rollover Delay

Sometimes a router attempts to dial a call on an ISDN B channel before a previous call is completely torn down. The fast rollover fails because the second call is made to a different number before the
B channel is released from the unsuccessful call. This failure might occur in the following ISDN configurations:

The two B channels of the BRI are not configured as a hunt group, but have separate numbers defined.
The B channel is not released by the ISDN switch until after Release Complete signal is processed.

You need to configure this delay if a BRI on a remote peer has two phone numbers configured one for each B channel you are dialing into this BRI, you have a dialer map for each phone number, and the first call succeeds but a second call fails with no channel available.

To configure a fast rollover delay, use the following command in interface configuration mode:

Command Purpose

isdn fast-rollover-delay seconds
Defines a fast rollover delay.

Command	Purpose
isdn fast-rollover-delay seconds	Defines a fast rollover delay.

A delay of 5 seconds should cover most cases. Configure sufficient delay to make sure the ISDN RELEASE_COMPLETE message has been sent or received before making the fast rollover call. Use the debug isdn q931 command to display this information. This pattern of failed second calls is a rare occurrence.

Overriding ISDN Application Default Cause Codes

The ISDN Cause Code Override function is useful for overriding the default cause code of ISDN applications. When this feature is implemented, the configured cause code is sent to the switch; otherwise, default cause codes of the application are sent.

To configure ISDN cause code overrides, use the following command in interface configuration mode:

Command Purpose

Router(config-if)#isdn disconnect-cause {cause-code-number| busy | not-available}
Specifies the ISDN cause code to send to the switch.

Command	Purpose
Router(config-if)#isdn disconnect-cause {cause-code-number\| busy \| not-available}	Specifies the ISDN cause code to send to the switch.

ISDN Cause Code Override Configuration Example

The following example sends a BUSY cause code to the switch when an application fails to complete the call:

interface serial0:23
 isdn disconnect-cause busy

Verifying ISDN Cause Code Override

To verify that the ISDN Cause Code Override feature is operating correctly, enter the debug q931 command. The debug q931 command will display a report of any configuration irregularities.

Configuring Inclusion of the Sending Complete Information Element

In some geographic locations, such as Hong Kong and Taiwan, ISDN switches require that the Sending Complete information element be included in the outgoing Setup message to indicate that the entire number is included. This information element is generally not required in other locations.

To configure the interface to include the Sending Complete information element in the outgoing call Setup message, use the following command in interface configuration mode:

Command Purpose

isdn sending-complete
Includes the Sending Complete information element in the outgoing call Setup message.

Command	Purpose
isdn sending-complete	Includes the Sending Complete information element in the outgoing call Setup message.

Configuring DNIS-plus-ISDN-Subaddress Binding

To configure DNIS-plus-ISDN-subaddress binding, use the following command in global configuration mode:

Command Purpose

Router(config)#dialer called DNIS:subaddress
Binds a DNIS to an ISDN subaddress.

Command	Purpose
Router(config)#dialer called DNIS:subaddress	Binds a DNIS to an ISDN subaddress.

Note This command allows multiple binds between a dialer profile and an ISDN B channel. The configuration requires an ISDN subaddress, which is used in Europe and Australia.

See the section "DNIS-plus-ISDN-Subaddress Binding" later in this chapter for a configuration example.

Monitoring and Maintaining ISDN Interfaces

To monitor and maintain ISDN interfaces, use any of the following commands:

Command Purpose

show interfaces bri number
show interfaces bri slot/port
(Cisco 7200 series)

Displays information about the physical attributes of the ISDN BRI B and D channels.

show controllers bri number
show controllers bri slot/port
(Cisco 7200 series)

Displays protocol information about the ISDN B and D channels.

show isdn {active | history | memory | status | timers}
Displays information about calls, history, memory, status, and Layer 2 and Layer 3 timers.

show dialer interface bri number
Obtains general diagnostic information about the specified interface.

Command	Purpose
show interfaces bri number show interfaces bri slot/port (Cisco 7200 series)	Displays information about the physical attributes of the ISDN BRI B and D channels.
show controllers bri number show controllers bri slot/port (Cisco 7200 series)	Displays protocol information about the ISDN B and D channels.
show isdn {active \| history \| memory \| status \| timers}	Displays information about calls, history, memory, status, and Layer 2 and Layer 3 timers.
show dialer interface bri number	Obtains general diagnostic information about the specified interface.

Troubleshooting ISDN Interfaces

To test the ISDN configuration of the router, use any of the following commands in EXEC mode:

Command Purpose

show controllers bri number
Checks Layer 1 (physical layer) of the BRI.

debug q921
Checks Layer 2 (data link layer).

debug isdn events debug q931 debug dialer show dialer
Checks Layer 3 (network layer).

Command	Purpose
show controllers bri number	Checks Layer 1 (physical layer) of the BRI.
debug q921	Checks Layer 2 (data link layer).
debug isdn events debug q931 debug dialer show dialer	Checks Layer 3 (network layer).

See the Cisco IOS Debug Command Reference publication for more information about the debug commands.

ISDN BRI Configuration Examples

This section provides the following ISDN BRI configuration examples:

Global ISDN and BRI Interface Switch Type

The following example shows a global National ISDN switch type (keyword basic-ni) and an interface-level NET3 ISDN switch type (keyword basic-net3). The basic-net3 keyword is applied to BRI interface 0 and overrides the global switch setting.

isdn switch-type basic-ni ! interface BRI0 isdn switch-type basic-net3

BRI Connected to a PBX

The following example provides a simple partial configuration of a BRI interface that is connected to a PBX. This interface is connected to a switch that uses SPID numbers.

interface BRI0
 description connected to pbx line 61885
 ip address 7.1.1.3 255.255.255.0
 encapsulation ppp
 isdn spid1 123
 dialer map ip 7.1.1.1 name oldie 61886
 dialer map ip 7.1.1.2 name rudder 61884
 dialer map ip 7.1.1.4 name seinfeld 61888
 dialer-group 1
 no fair-queue
 ppp authentication chap

Multilink PPP on a BRI Interface

The following example enables Multilink PPP on BRI 0:

interface BRI0
 description Enables PPP Multilink on BRI 0
 ip address 7.1.1.1 255.255.255.0
 encapsulation ppp
 dialer map ip 7.1.1.2 name starbuck 14195291357
 dialer map ip 7.1.1.3 name roaster speed 56 14098759854
 ppp authentication chap
 ppp multilink
 dialer-group 1

Dialer Rotary Groups

The following example configures BRI interfaces to connect into a rotary group (using the dialer-group command) and then configures a dialer interface for that dialer group. This configuration permits IP packets to trigger calls.

interface BRI 0
 description connected into a rotary group 
 encapsulation ppp
 dialer rotary-group 1
 
interface BRI 1
 no ip address
 encapsulation ppp
 dialer rotary-group 1
 
interface BRI 2
 encapsulation ppp
 dialer rotary-group 1
 
interface BRI 3
 no ip address
 encapsulation ppp
 dialer rotary-group 1
 
interface BRI 4
 encapsulation ppp
 dialer rotary-group 1
 
interface Dialer 0
 description Dialer group controlling the BRIs
 ip address 8.1.1.1 255.255.255.0
 encapsulation ppp
 dialer map ip 8.1.1.2 name angus 14802616900
 dialer-group 1
 ppp authentication chap
 
dialer-list 1 protocol ip permit

Compression Examples

The following example enables predictor compression on BRI 0:

interface BRI0
 description Enables predictor compression on BRI 0
 ip address 7.1.1.1 255.255.255.0 
 encapsulation ppp
 dialer map ip 7.1.1.2 name starbuck 14195291357
 compress predictor
 ppp authentication chap
 dialer-group 1

The following example enables Stacker compression on BRI 0:

interface BRI0
 description Enables stac compression on BRI 0
 ip address 7.1.1.1 255.255.255.0 
 encapsulation ppp
 dialer map ip 7.1.1.2 name starbuck 14195291357
 compress stac 
 ppp authentication chap
 dialer-group 1

Multilink PPP and Compression

The following example enables Multilink PPP and Stacker compression on BRI 0:

interface BRI0
 description Enables PPP Multilink and stac compression on BRI 0
 ip address 7.1.1.1 255.255.255.0 
 encapsulation ppp
 dialer map ip 7.1.1.2 name starbuck 14195291357
 ppp authentication chap
 compress stac
 ppp multilink
 dialer-group 1

Voice over ISDN

The following example allows incoming voice calls to be answered on BRI 0:

interface bri0
 description Allows incoming voice calls to be answered on BRI 0
 ip address 7.1.1.1 255.255.255.0 
 encapsulation ppp
 isdn incoming-voice data
 dialer map ip 7.1.1.2 name starstruck 14038182344
 ppp authentication chap
 dialer-group 1

The following example allows outgoing voice calls on BRI 1:

interface bri1
 description Places an outgoing call as a voice call on BRI 1
 ip address 9.1.1.1 255.255.255.0 
 encapsulation ppp
 dialer map ip 9.1.1.2 name angus class calltype 19091238877 
 ppp authentication chap
 dialer-group 1
 
map-class dialer calltype 
 dialer voice-call

DNIS-plus-ISDN-Subaddress Binding

The following example configures a dialer profile for a receiver with DNIS 12345 and ISDN subaddress 6789:

dialer called 12345:6789

For additional configuration examples, see the sections "Dynamic Multiple Encapsulations over ISDN" and "Verifying the Dynamic Multiple Encapsulations Feature" in the chapter "Configuring Peer-to-Peer DDR with Dialer Profiles" in this publication.

Keywords by Area	Switch Type
none	No switch defined
Japan
ntt	Japanese NTT ISDN switches
Europe
basic-1tr6	German 1TR6 ISDN switches
basic-net3	NET3 ISDN, Norway NET3, Australia NET3, and New Zealand NET3 switches (covers the Euro-ISDN E-DSS1 signalling system and is ETSI-compliant)
vn3	French VN3 and VN4 ISDN BRI switches
North America
basic-5ess	AT&T basic rate switches
basic-dms100	Northern Telecom DMS-100 basic rate switches
basic-ni	National ISDN switches

Table of Contents

Setting Up Basic ISDN Service

Encapsulation Configuration Notes

Verifying ISDN Cause Code Override