Cisco ISDN BRI S/T Network Interface Modules Software Configuration Guide
Available Languages
Table of Contents
Cisco ISDN BRI S/T Network Interface Modules Software Configuration Guide
Request BRI Line and Switch Configuration from a Telco Service Provider
Interface Configuration Options
Multiple ISDN Switch Types Feature
Specify Interface Characteristics for an ISDN BRI
Configure Encapsulation on ISDN BRI
Configure TEI Negotiation Timing
Configure Called Party Number Verification
Configure ISDN Calling Number Identification
Configure the Line Speed for Calls Not ISDN End to End
Configure a Fast Rollover Delay
Override ISDN Application Default Cause Codes
Configure Inclusion of the Sending Complete Information Element
Configure DNIS-plus-ISDN-Subaddress Binding
Configure ISDN Semipermanent Connections
Configure ISDN BRI for Leased-Line Service
Configure Leased-Line Service at Normal Speeds
Configure Leased-Line Service at 128 Kbps
Monitor and Maintain ISDN Interfaces
Configuration Examples for ISDN BRI
Global ISDN and BRI Interface Switch Type Example
BRI Connected to a PBX Example
Multilink PPP on a BRI Interface Example
DNIS-plus-ISDN-Subaddress Binding Example
ISDN BRI Leased-Line Configuration Example
Cisco ISDN BRI S/T Network Interface Modules Software Configuration Guide
First Published: September 15, 2017
This document provides an overview of the software features and configuration information for Cisco ISDN BRI S/T Network Interface Modules (NIMs) on the Cisco 4000 Series Integrated Services Router.
For further information on the Cisco ISDN BRI S/T NIMs faceplates and LED descriptions, see Connect Cisco ISDN BRI S/T Network Interface Modules to a Network.
Contents
- ISDN Overview
- How to Configure ISDN BRI
- Monitor and Maintain ISDN Interfaces
- Troubleshoot ISDN Interfaces
- Configuration Examples for ISDN BRI
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.
To identify the hardware platform or software image information associated with a feature, use the Feature Navigator on Cisco.com to search for information about the feature or refer to the software release notes for a specific release.
For a complete description of the BRI commands in this document, refer to the Cisco IOS Dial Technologies Command Reference . To locate documentation of other commands that appear in this document, use the command reference master index or search online.
ISDN Overview
ISDN BRI provides two bearer (B) channels, each capable of transferring voice or data at 64 kbps, and one 16 kbps data (D) signaling 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 transmission speed of 128 kbps, but many users use only half the available bandwidth.
Request BRI Line and Switch Configuration from a Telco Service Provider
Before configuring ISDN BRI 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 for switches used in North America, request the BRI switch configuration attributes specified in Table 1 .
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.
Interface Configuration Options
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 Configuration” part of this publication. ISDN Cause Codes
A cause code is an information element (IE) that indicates why an ISDN call failed or was otherwise disconnected. When the originating gateway receives a Release Complete message, it generates a tone corresponding to the cause code in the message.
Table 2 lists the default cause codes that the VoIP (Voice over IP) gateway sends to the switch when a call fails at the gateway, and the corresponding tones that it generates.
Although the VoIP gateway generates the cause codes listed in Table 2 by default, there are commands introduced in previous Cisco IOS releases that can override these defaults, allowing the gateway to send different cause codes to the switch. The following commands override the default cause codes:
- isdn disconnect-cause —Sends the specified cause code to the switch when a call is disconnected.
- isdn network-failure-cause —Sends the specified cause code to the switch when a call fails because of internal network failures.
- isdn voice-call-failure —Sends the specified cause code to the switch when an inbound voice call fails with no specific cause code.
When you implement these commands, the configured cause codes are sent to the switch; otherwise, the default cause codes of the voice application are sent. For a complete description of these commands, refer to the Cisco IOS Dial Technologies Command Reference .
How to Configure ISDN BRI
To configure ISDN lines and interfaces, perform the tasks in the following sections:
- Configure the ISDN BRI Switch (Required)
- Specify Interface Characteristics for an ISDN BRI (As required)
- Configure ISDN Semipermanent Connections (As required)
- Configure ISDN BRI for Leased-Line Service (As required)
See the sections “Monitor and Maintain ISDN Interfaces” and “Troubleshoot ISDN Interfaces” later in this document for tips on maintaining your network. See the section “Configuration Examples for ISDN BRI” at the end of this document for configuration examples.
For information on ISDN Backup, refer to Cisco IOS Dial Technologies Configuration Guide .
Configure the ISDN BRI Switch
To configure the ISDN switch type, perform the following task:
- Configure the Switch Type (Required)
Also see to the “Multiple ISDN Switch Types Feature” section for information about configuring multiple switch types.
Configure the Switch Type
To configure the switch type, use the following command in global configuration mode:
Selects the service provider switch type; see Table 1 for switch types.
The section “Global ISDN and BRI Interface Switch Type Example” later in this document provides an example of configuring the ISDN BRI switch.
Table 3 lists the ISDN BRI service provider switch types.
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.
Specify 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.
- Specify the Interface (Required)
- Configure CLI Screening (As Required)
- Configure Encapsulation on ISDN BRI (Required)
- Configure Network Addressing (Required)
- Configure TEI Negotiation Timing (Optional)
- Configure Called Party Number Verification (Optional)
- Configure ISDN Calling Number Identification (Optional)
- Configure the Line Speed for Calls Not ISDN End to End (Optional)
- Configure a Fast Rollover Delay (Optional)
- Override ISDN Application Default Cause Codes (Optional)
- Configure Inclusion of the Sending Complete Information Element (Optional)
- Configure DNIS-plus-ISDN-Subaddress Binding (Optional)
- Configure ISDN Semipermanent Connections (Optional)
Specify the Interface
To specify an ISDN BRI and enter interface configuration mode, use the following command beginning in global configuration mode:
Specify 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 as needed:
Specifies a SPID and local directory number for the B1 channel.
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.
Configure 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 allows incoming calls over ISDN to be assigned an encapsulation type such as HDLC and PPP.
To configure encapsulation, use the following command in interface configuration mode:
Verify 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 Dialer100 (Encapsulation PPP)” indicates that this B interface is bound to the dialer 100 interface and the encapsulation running over this connection is PPP, which is the encapsulation configured on the Dialer interface and inherited by the B channel.
Any protocol configuration and states should be displayed from the dialer 100 interface.
Configure 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:
German networks allow semipermanent connections between customer routers with BRIs and the 1TR6 basic rate switches in the exchange. Semipermanent connections are less expensive than leased lines.
Note The access list reference in Step 5 of this task 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.
Configure 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:
Configure 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:
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 provides 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.
Configure 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:
Router(config-if)#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:
Configure 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:
This command can be used with all switch types except German 1TR6 ISDN BRI switches.
Configure 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:
Configure 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:
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.
Override 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:
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:
Verify 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 displays a report of any configuration irregularities.
Configure 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:
Configure DNIS-plus-ISDN-Subaddress Binding
To configure DNIS-plus-ISDN-subaddress binding, use the following command in global configuration mode:
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 Example” later in this document for a configuration example.
Configure ISDN Semipermanent Connections
German networks allow semipermanent connections between customer routers with BRI interfaces and the 1TR6 basic rate switches in the exchange. Australian networks allow semipermanent connections between ISDN PRI interfaces and the TS-014 primary rate switches in the exchange. Semipermanent connections are offered at better pricing than leased lines.
Configuring BRI interfaces for semipermanent connection requires only that you use a keyword that indicates semipermanent connections when you are setting up network addressing as described in the previous section of this document.
To configure a BRI for semipermanent connections, follow this procedure:
Step 1 Set up the ISDN lines and ports as described in the sections “Configure the ISDN BRI Switch” and “Specify Interface Characteristics for an ISDN BRI”.
Step 2 Configure DDR on a selected interface, as described in the “Dial-on-Demand Routing Configuration” part of this publication.
To begin DDR network addressing, use the following command in interface configuration mode
Configure ISDN BRI for Leased-Line Service
To configure ISDN BRI for leased line service, perform the tasks in one of the following sections as needed and available:
- Configure Leased-Line Service at Normal Speeds (Available in Japan and Germany)
- Configure Leased-Line Service at 128 Kbps (Available only in Japan)
Note Once an ISDN BRI interface is configured for access over leased lines, it is no longer a dialer interface, and signaling over the D channel no longer applies. Although the interface is called interface bri n, it is configured as a synchronous serial interface having the default High-Level Data Link (HDLC) encapsulation. However, the Cisco IOS commands that set the physical characteristics of a serial interface (such as the pulse time) do not apply to this interface.
Configure Leased-Line Service at Normal Speeds
This service is offered in Japan and Germany and no call setup or teardown is involved. Data is placed on the ISDN interface similar to the way data is placed on a leased line connected to a serial port.
To configure the BRI to use the ISDN connection as a leased-line service, use the following commands in global configuration mode:
To disable leased-line service if you no longer want to support it on a specified ISDN BRI, use the following command in global configuration mode:
Configure Leased-Line Service at 128 Kbps
The Cisco IOS software supports leased-line service at 128 kbps via ISDN BRI. This service combines two B channels into a single pipe. This feature requires one or more ISDN BRI hardware interfaces that support channel aggregation and service provider support for ISDN channel aggregation at 128 kbps. When this software first became available, service providers offered support for ISDN channel aggregation at 128 kbps only in Japan.
Note This feature is not supported on the Cisco 2500 series router because its BRI hardware does not support channel aggregation.
To enable leased-line service at 128 kbps on a specified ISDN BRI, use the following commands in global configuration mode:
To remove the leased-line service configuration from a specified ISDN BRI, use the following command in global configuration mode:
Monitor and Maintain ISDN Interfaces
To monitor and maintain ISDN interfaces, use the following commands in EXEC mode as needed:
Troubleshoot ISDN Interfaces
To test the ISDN configuration of the router, use the following commands in EXEC mode as needed:
Configuration Examples for ISDN BRI
This section provides the following ISDN BRI configuration examples:
- Global ISDN and BRI Interface Switch Type Example
- BRI Connected to a PBX Example
- Multilink PPP on a BRI Interface Example
- Dialer Rotary Groups Example
- Voice over ISDN Examples
- Multilink PPP on a BRI Interface Example
- Voice over ISDN Examples
- DNIS-plus-ISDN-Subaddress Binding Example
- ISDN BRI Leased-Line Configuration Example
Global ISDN and BRI Interface Switch Type Example
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/1/0:0
!
interface BRI0
isdn switch-type basic-net3BRI Connected to a PBX Example
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.
Dialer Rotary Groups Example
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.
Voice over ISDN Examples
The following example allows incoming voice calls to be answered on BRI 0/1/0:0:
The following example allows outgoing voice calls on BRI0/1/1:0:
For more configuration examples of voice calls over ISDN, refer to the Cisco IOS Voice, Video, and Fax Configuration Guide .
DNIS-plus-ISDN-Subaddress Binding Example
The following example configures a dialer profile for a receiver with DNIS 12345 and ISDN subaddress 6789:
ISDN BRI Leased-Line Configuration Example
The following example configures the BRI 0/1/0:0 interface for leased-line access at 128 kbps. Because of the leased-line–not dialed–environment, configuration of ISDN called and calling numbers are not needed and not used. The BRI 0/1/0:0 interface is henceforth treated as a synchronous serial interface, with the default HDLC encapsulation.
The ip address is configured on the D-channel in the case of 128 kbps leased-line. The following example configures the BRI 0/1/0:0 interface for PPP encapsulation:
The following example configures the BRI 0/1/0:0 interface for leased-line access at 64 kbps:
The ip address is configured on the B-channel in the case of 64 kbps leased-line. The following example configures the BRI 0/1/0:1 and 0/1/0:2 interface for PPP encapsulation:
FeedbackContact Cisco
- Open a Support Case
- (Requires a Cisco Service Contract)