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This chapter does not address routing issues, dialer configuration, and dial backup. For information about those topics, see the "Dial-on-Demand Routing" part of this manual.
For hardware technical descriptions, and for information about installing the router interfaces, refer to the hardware installation and maintenance publication for your particular product.
For a complete description of the BRI commands in this chapter, refer to the "ISDN Basic Rate Service Setup Commands" chapter of the Dial Solutions Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.
Perform the tasks in the following sections to configure ISDN lines and interfaces:
You can also perform the following ISDN troubleshooting and maintenance tasks:
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 "Configuring Snapshot Routing" chapter in the "Cost-Control Solutions" part of this manual 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 manual. For command information, refer to the "Dial-on-Demand Routing" part of the Dial Solutions Command Reference.
To configure bandwidth on demand, see the "Configuring Legacy DDR Spokes" chapter or the "Configuring Legacy DDR Hubs" chapter of this manual.
See the end of this chapter for the "ISDN BRI Configuration Examples" section.
This process varies dramatically from provider to provider on a national and international basis. However, some general guidelines follow:
When you order ISDN service, request the BRI switch configuration attributes specified in Table 10.
| Switch Type | Configuration |
|---|---|
| DMS-100 BRI | 2 B channels for voice and data. |
| 5ESS Custom BRI | For Data Only
2 B channels for data. For Voice and Data (Use these values only if you have an ISDN telephone connected.) |
| 5ESS National ISDN (NI-1) BRI | Terminal type = A. |
To check the MTU size and the buffers and, if necessary, to configure the buffers and the MTU size, use the following commands beginning in EXEC mode:
| Command | Purpose |
|---|---|
show interfaces bri number | Check the MTU size. |
Check the free buffers. | |
configure terminal buffers big permanent number | Configure the buffers. |
To configure the ISDN global characteristics, complete the tasks in the following sections:
To configure the switch type, use the following command in global configuration mode:
| Command | Purpose |
|---|---|
Select the service provider switch type. |
Table 11 lists the ISDN BRI switch types for BRI interfaces.
| Keywords by Area | Switch Type |
none | No switch defined |
| Australia |
|
basic-ts013 | Australian TS013 switches |
| Europe |
|
basic-1tr6 | German 1TR6 ISDN switches |
basic-net3 | NET3 ISDN, Norway NET3, and New Zealand NET3 switches (covers the Euro-ISDN E-DSS1 signaling system and is ETSI-compliant) |
vn3 | French VN3 and VN4 ISDN BRI switches |
| Japan |
|
ntt | Japanese NTT ISDN switches |
| North America |
|
basic-5ess | AT&T basic rate switches |
basic-dms100 | Northern Telecom DMS-100 basic rate switches |
basic-ni | National ISDN switches |
By default TEI negotiation occurs when the router is powered on. To define when TEI negotiation will occur, use the following command in global configuration mode:
| Command | Purpose |
|---|---|
isdn tei [first-call | powerup] | Determine when ISDN TEI negotiation occurs. |
In addition, you can configure the following optional interface characteristics on the BRI:
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. This allows Basic Rate Interfaces (BRI) and Primary Rate Interfaces (PRI) to run simultaneously on platforms that support both interface types.
A global ISDN switch type is required and must be configured on the router before you can configure a switch type on an interface. To configure a global ISDN switch type, use the following command in global configuration mode:
| Command | Purpose |
|---|---|
isdn switch-type switch-type | Apply a global ISDN switch type. |
You must ensure that both global and interface level ISDN switch types are valid for the ISDN interfaces on the router. Table 11 lists valid ISDN switch types for ISDN BRI.
The following restrictions apply to Multiple ISDN Switch Types:
| Global Switch Type | BRI Interface | PRI Interface |
|---|---|---|
basic-net3 | basic-net3 | primary-net5 |
primary-ts014 | basic-ts013 | primary-ts014 |
primary-ni | basic-ni | primary-ni |
If, for example, you reconfigure the router to use global switch type basic-net3, the router will apply a primary-net5 switch type to PRI interfaces and basic-net3 to any BRI interfaces. You can override the default switch assignment by configuring a different ISDN switch type on the associated interface.
You can configure ISDN terminal endpoint identifier (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 dms100 switches that are designed to initiate TEI negotiation.
| Command | Purpose |
|---|---|
Determine when ISDN TEI negotiation occurs. |
To specify an ISDN Basic Rate Interface (BRI) and enter interface configuration mode, use the following command in global configuration mode:
| Command | Purpose |
|---|---|
interface bri number | Specify the interface and enter interface configuration mode. |
ip address address mask | Specify an IP address for the interface. |
PPP encapsulation is configured for most ISDN communication.
| Command | Purpose |
|---|---|
encapsulation ppp | Configure PPP Encapsulation. |
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. For more information, see the "Configuring Frame Relay on ISDN D and B Channels" and "Configuring X.25 on ISDN D and B Channels" chapters of this manual.
To configure the router for automatic detection of encapsulation type on incoming calls, or to configure encapsulation for Combinet compatibility, see the "Configuring Special ISDN Signaling" chapter of this manual.
The steps in this section support the primary goals of network addressing:
Intermediate steps that use shared argument values tie the host identification and dial string to the interesting packets to be transmitted to that host.
To configure network addressing, use the following command beginning in interface configuration mode:
| Step | Command | Purpose | ||
|---|---|---|---|---|
| dialer map protocol next-hop-address name hostname speed 56|64 dial-string[:isdn-subaddress] | (Most locations) Define 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. | ||
| dialer-group group-number | Assign the interface to a dialer group to control access to the interface. | ||
| dialer-list dialer-group list access-list-number | Associate the dialer group number with an access list number. | ||
| access-list access-list-number {deny | permit} protocol source address source-mask destination destination-mask | Define 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. |
For more information about defining outgoing call numbers, see the "Configuring DDR" chapter.
Currently, only the DMS-100 and NI-1 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 are never sent 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] | Specify a SPID and local directory number for the B1 channel. |
isdn spid2 spid-number [ldn] | Specify 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.
This task applies only to Cisco 2500 series, Cisco 3000 series, and Cisco 4000 series routers that have a BRI.
Calling line identification (CLI, also called caller ID) 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 caller ID screening, use the following command in interface configuration mode:
| Command | Purpose |
|---|---|
Configure caller ID screening. |
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 device's configured number or subaddress or both.
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] | Specify 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] | Specify that the router verify a second called-party number or subaddress number in the incoming setup message. |
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 | Specify the calling party number. |
This command can be used with all switch types except German 1TR6 ISDN BRI switches.
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} | Set the speed to be used for incoming calls recognized as not ISDN end-to-end. |
Sometimes a router attempts to dial a call on an ISDN B channel before a previous, failed 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 might occur in ISDN configurations where:
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 commands in interface configuration mode:
| Command | Purpose |
|---|---|
isdn fast-rollover-delay seconds | Define 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.
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 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 |
|---|---|
Include the Sending Complete information element in the outgoing call Setup message. |
To test the router's ISDN configuration, we suggest that you use the following commands in EXEC mode:
| Command | Purpose |
|---|---|
show controllers bri number | Check Layer 1 (physical layer) of the BRI. |
Check Layer 2 (data link layer). | |
Check Layer 3 (network layer). |
See the Debug Command Reference for information about the debug commands.
Use the following commands to monitor and maintain ISDN interfaces:
| Command | Purpose |
|---|---|
show interfaces bri number | Display information about the physical attributes of the ISDN BRI B and D channels. |
show controllers bri number | Display protocol information about the ISDN B and D channels. |
show isdn {active | history | memory | status | timers} | Display information about calls, history, memory, status, and Layer 2 and Layer 3 timers. |
show dialer interface bri number | Obtain general diagnostic information about the specified interface. |
This section provides the following ISDN BRI configuration examples:
The following example shows the global ISDN switch type of basic-ni and an interface level switch type of basic-net3. ISDN switch type basic-net3 is applied to BRI interface 0 and overrides the global switch setting.
isdn switch-type basic-ni
!
interface BRI0
isdn switch-type basic-net3
The following example shows BRI interface 0 configured for a basic-net3 switch type that will override the basic-ni switch type configured globally. The PRI interface (channelized T1 controller), is configured for ISDN switch type primary-net5 and is applied only to the PRI.
isdn switch-type basic-ni
!
interface BRI0
isdn switch-type basic-net3
interface serial0:23
! Apply the primary-net5 switch to this interface only
isdn switch-type primary-net5
In the following example, the global ISDN switch type setting is basic-net3 and the PRI interface (channelized T1 controller) is configured to use isdn switch-type primary-net5. BRI interface 0 is configured for isdn switch-type basic-ni and isdn tei first-call. TEI first-call negotiation configured on BRI interface 0 overrides the default value (isdn tei powerup).
isdn switch-type basic-net
!
interface serial0:23
isdn switch-type primary-net5
ip address 172.21.24.85 255.255.255.0!isdn switch-type basic-ni
interface BRI0
isdn tei first-call
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
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
The following example configures BRI interfaces to connect into a rotary group (dialer-group) 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
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
The following example enables PPP Multilink 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
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 places an outgoing call as a voice call 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
Posted: Mon May 3 11:40:09 PDT 1999
Copyright 1989-1999©Cisco Systems Inc.