This document describes the Integrated Services Digital Network (ISDN) interface. It includes the following topics:

ISDN Overview

The ISDN interface software allows you to interconnect routers over ISDN. You can set up the interface to act over a dedicated link or to initiate and accept switched-circuit connections, either on demand, automatically from restart, or on command by the operator.

BRI Interface

The BRI interface establishes connections with a peer router over an ISDN connection. It accepts or initiates connections on command from dial circuits. Once the ISDN interface establishes a connection, it transparently passes data to and from the dial circuit.

Some switches in North America do not provide 64 Kbps service for ISDN data calls; instead, they offer only 56 Kbps service. In this case, the ISDN software automatically falls back to 56 Kbps.

Addressing

You can add multiple numbers for each destination name. If you are using two ISDN directory numbers, you need to add both numbers for the same network address name.

If you define multiple numbers for a destination network dial address, the dial circuit attempts to call the first number. If the dial circuit is not able to complete the connection, it cycles through all of the defined numbers until it establishes the connection.

Cost Control Over Demand Circuits

Caller ID

DOSBS

Notes:

• Telephone carriers cannot guarantee the successful transmission of data over voice grade lines.

• At the present time, DOSBS can only be used with US switch variants.

The available DOSBS modes are:

• Voice_data

  Your router initiates a Voice call to the specified destination. If the Voice call fails completely, your router then tries the call again using Data.

• Voice_only

  Your router initiates a Voice call. If the Voice call fails, your router does not attempt to place a Data call. The call fails.

  Note: This is the default option when DOSBS is enabled.

• Data_only

  Your router initiates a Data call and tries to establish a 64 Kbps UDI link.

  Note: This is the default option when DOSBS is disabled.

Note: Because this is leased line, some of the ISDN commands and command options are not available. For example, set multipoint-selection is not available.

The default is to have Call-back disabled. If the remote router requests Call-back and Call-back is disabled on the local router, the local router rejects the request.

On an ISDN interface, you can set up Call-back so that the local router does not answer the incoming call, and the remote router does not incur the expense of placing the call. This feature is referred to as D-channel Call-back.

For additional information, see Call-back Feature in Using PPP Interfaces.

POTS

Notes:

• DOSBS is disabled in order to use analog equipment through POTS.

• For ISDN with POTS capability, you need to install either an ISDN U with POTS module or an ISDN S/T with POTS module in slot 3 (MD3) on a GTX 1000.

• OpenROUTE software supports ISDN with POTS on the USNI1, 5ESS, DMS-100, NET3, VN4, and INS64 switch variants.

Point-to-Point and Multipoint Configurations

In Figure 9, the GT 70 is sharing the ISDN line with another ISDN device in a multipoint configuration. In this case, the GT 70 and the other ISDN device each has access to the B channels.

Note: In both Figure 8 and Figure 9, the GT 70 is the S/T model.

ISDN With POTS

Switches Supported

Note: As of October, 1996, VN3 is obsolete in Europe.

ISDN Interface Restrictions

• Boot the router over an ISDN interface.

• Use the D channel for data traffic. The ISDN interface uses the D channel only for setting up and taking down B channel connections.

• Use X.25 connectivity on the B channels.

• Telephone number(s) of the local ISDN interface.

• Destination telephone numbers, including any telephone extensions.

• Type of switch to which the ISDN interface is connected. See Table 8 for a list of switches that Nx Networks routers support.

• The TEI (Terminal Endpoint Identifier) that your service provider assigns. For some North American switches, the service provider may assign a TEI for each B channel.

• Whether or not your service provider requires Service Profile IDs (SPIDs). SPIDs are used only in North America. If the router uses both
  B channels, you need a SPID for each B channel.

• Whether you are configured for point-to-point or multipoint.

1. At the Config> prompt, enter list interfaces to display a list of interfaces.

Config>list interfaces
Ifc   0, Ethernet/IEEE 802.3 (via device Ethernet)
Ifc   1, Point to Point (via device WAN1, with Dialer)
Ifc   2, Frame Relay (via device WAN2, with LAN Emulation)
Ifc   3, Point to Point (via device ISDN)
Ifc   4, Frame Relay (via device ISDN, with LAN Emulation)

2. At the Config> prompt, enter network followed by the number of one of the "via device ISDN" interfaces to display the Circuit Config <NET #> prompt. In this case, Ifc 3 or 4.

Note: It does not matter which "via device ISDN" interface number you enter.

Config>network
What is the network number [0]? 3
Circuit Configuration

Circuit Config <NET-3>

3. At the Circuit Config <NET-#> prompt, enter bri to display the
BRI Config <ISDN> prompt.

Circuit Config <NET-3> bri
Basic Rate ISDN user configuration

BRI Config <ISDN>

Configuration Procedures

1. Adding ISDN addresses

2. Configuring ISDN parameters

• Address name. Description of the address. You can use up to 35 printable ASCII characters. Address names are case sensitive.

• Network address. Directory number of the local or destination port. You can enter up to 25 numbers, as well as six other characters, including spaces and punctuation. The router uses only the numbers.

• Network subaddress. Optional. Additional part of the directory number, such as an extension, that gets interpreted once the interface connects to a PBX. You can enter up to 20 characters, as well as 11 additional spaces and punctuation. The router uses only the numbers.

BRI Config <ISDN> add address
Assign address name [1-35] chars? baltimore
Assign network dial address [1-25 digits]? 1-555-0983
Assign network subaddress [0-20 digits]? 23

To delete an ISDN address from your list, enter delete address at the BRI Config <ISDN> prompt.

The software prompts you for the dial and subdial address to distinguish between the primary telephone number and the sub-addresses of different ISDN peripherals at that number.

Multiple Numbers for an ISDN Address

To add two numbers for one address name, repeat the command using the same address name.

BRI Config <ISDN> add address
Assign address name [1-35] chars []? baltimore
Assign network dial address [1-15 digits][]? 1-555-2657
Assign network subdial address [0-20 digits] []? 24
BRI Config <ISDN> add address
Assign address name [1-35] chars []? baltimore
Assign network dial address [1-15 digits][]? 1-555-8797
Assign network subdial address [0-20 digits] []? 25

BRI Config <ISDN> del address
Delete address name [1-35] chars []? baltimore
Delete network dial address [1-15 digits][]? 
Really delete all addresses under this name?(Yes or [No]):yes

1. At the Config> prompt, enter network followed by the number of the ISDN interface that you want to configure to display the Circuit Config <NET #> prompt.

2. Enter bri to display the BRI Config <ISDN> prompt.

Circuit Config <NET-3> bri
Basic Rate ISDN user configuration

BRI Config <ISDN>

3. Specify the type of switch to which you connected this ISDN interface. See Table 11 for a list of switch variants.

BRI Config <ISDN>set switch-variant
Switch-Variant-Model []? usni1

4. Set the ISDN interface to either point-to-point (pp) or multipoint (mp). Some switches require you to configure the line as multipoint regardless of how many devices are on it. Check with your ISDN service provider.

BRI Config <ISDN>set multipoint-selection
Multipoint Selection [MP]? pp

5. If you set the switch-variant to any type other than INS64, set the directory number of the local ISDN interface. Be sure that your address is unique.

BRI Config <ISDN>set dn0
Enter DN0 (Directory-Number-0) [ ]?1-555-0983
BRI Config <ISDN>set dn0
Enter DN0 (Directory-Number-0) [ ]?1-555-0983:22

The colon (:) separates the address number from the sub-address.

6. If your service provider assigned a second directory number, set directory number one. ISDN lines that have two directory numbers can place or receive calls on either directory number. Therefore, you must configure both numbers or the interface may reject calls.

BRI Config <ISDN>set dn1
Enter DN1 (Directory-Number-1) [ ]?1-555-2037

You can assign a sub-address for dn1 in the same way as for dn0. (See step 5.)

BRI Config <ISDN>set dn1
Enter DN1 (Directory-Number-1) [ ]?1-555-2037:28

7. In North America, service providers may require Service Profile IDs (SPIDs). A SPID is a number that uniquely identifies a specific profile of service characteristics available on a particular access interface (such as a B channel). Your ISDN service provider assigns SPIDs. Generally, if your service provider assigns two directory numbers, they also assign two SPIDs.

BRI Config <ISDN>set spid
Which SPID [1]? 1
Enter Service Profile ID (SPID) []? 50855589530101

8. Set the TEI (Terminal Endpoint Identifier) to match the signalling TEI number of your ISDN switch. Check with your service provider to find out what TEI signalling the switch supports. The default TEI is automatic. If the ISDN switch does not support automatic TEI signalling, set the TEI to the value that your service provider assigns.

If you are connected to a 5ESS, USNI1, or DMS100 switch, you may need to set a TEI for each B channel. When you enter set tei, the router prompts you for which TEI to configure. In a multipoint configuration, setting both TEIs allows the router to use both B channels and can prevent other ISDN devices on the multipoint bus from using a B channel. If you configure only one TEI, the router can use only one B channel, leaving the other B channel available for the other ISDN devices.

BRI Config <ISDN>set tei
Which TEI [0]? 0
TEI [AUTO]? 10
BRI Config <ISDN>set tei
Which TEI [0]? 1
TEI [AUTO]? 12

9. Set the frame size so that it is greater than or equal to the frame size of the data link protocol (PPP) running on the link. The options are 1024, 2048, or 4096 bytes. The default is 2048. Nx Networks strongly recommends that you accept the default.

BRI Config <ISDN>set framesize
Framesize in bytes (1024/2048/4096) [2048]? 2048

10. Enable DOSBS, if you want voice-grade connections for your data.

BRI Config <ISDN>enable dosbs

The following procedure assumes communication between your local router and two remote routers.

1. Display the BRI Config <ISDN> prompt.

Config>network 3
Circuit Configuration

Circuit Config <NET-3> bri
Basic Rate ISDN user configuration

BRI Config <ISDN>

2. Add ISDN addresses for the two remote routers.

BRI Config <ISDN>add address
Assign address name [1-35] chars []? Remote1
Assign network dial address [1-15 digits][]? 555-2389
Assign network subdial address [0-20 digits] []? 
BRI Config <ISDN>add address
Assign address name [1-3535] chars []? Remote2
Assign network dial address [1-15 digits][]? 555-7925
Assign network subdial address [0-20 digits] []? 

3. Set the type of switch connected to the ISDN interface.

BRI Config <ISDN>set switch-variant
Switch-Variant-Model []? usni-1

4. Set directory number 0 (dn0) and directory number 1 (dn1). (Skip this step for the INS64 switch variant.) Use the network dial addresses assigned to you by the telephone company.

BRI Config <ISDN>set dn0
Enter DN0 (Directory-Number-0) [ ]?5559876
BRI Config <ISDN>set dn1
Enter DN1 (Directory-Number-1) [ ]?5554961

5. Set the ISDN interface to point-to-point (pp).

BRI Config <ISDN>set multipoint-selection
Multipoint Selection [MP]? pp

6. Enter the SPIDs the ISDN service provider assigned.

BRI Config <ISDN>set spid
Which SPID [1]? 0
Enter Service Profile ID (SPID) []? 508555987600
BRI Config <ISDN>set spid
Which SPID [1]? 1
Enter Service Profile ID (SPID) []? 508555496100

7. Set the TEI to match the TEI signalling of the ISDN switch.

BRI Config <ISDN>set tei
Which TEI [1]? 0
TEI [AUTO]?
BRI Config <ISDN>set tei
Which TEI [1]? 1
TEI [AUTO]?

8. Set the frame size.

BRI Config <ISDN>set framesize
Framesize in bytes (1024/2048/4096) [1024]? 2048

Figure 13 shows YOUR local router with a multipoint ISDN connection. The local router can connect to two remote routers.

To configure an ISDN multipoint connection, do the following:

1. Display the BRI Config <ISDN> prompt.

Config>network 3
Circuit Configuration

Circuit Config <NET-3> bri
Basic Rate ISDN user configuration

BRI Config <ISDN>

2. Add ISDN addresses for the two remote routers.

BRI Config <ISDN>add address
Assign address name [1-35] chars []? Remote1
Assign network dial address [1-15 digits][]? 555-2389
Assign network subdial address [0-20 digits] []? 
BRI Config <ISDN>add address
Assign address name [1-35] chars []? Remote2
Assign network dial address [1-15 digits][]? 555-7925
Assign network subdial address [0-20 digits] []? 

3. Set the type of switch variant connected to the ISDN interface.

BRI Config <ISDN>set switch-variant
Switch-Variant-Model []? usni1

4. If needed by the switch variant, set directory number 0 (dn0) of the local port that was assigned by the telephone company.

BRI Config <ISDN>set dn0
Enter DN0 (Directory-Number-0) [ ]?5559876

5. Set the ISDN interface to multipoint (mp).

BRI Config <ISDN>set multipoint-selection
Multipoint Selection [MP]? mp

6. If needed by the switch variant, enter one of the SPIDs the ISDN service provider assigned.

BRI Config <ISDN>set spid
Which SPID [1]? 0
Enter Service Profile ID (SPID) []? 508555987600

7. Set the TEI to match the TEI signalling of the ISDN switch variant. If the switch to which you are connected uses two TEIs, the software prompts you for which TEI to set (0 or 1). Because this is a multipoint configuration, set TEI 1 to none so that the router does not use both B channels.

BRI Config <ISDN>set tei
Which TEI [1]? 0
TEI [AUTO]?
BRI Config <ISDN>set tei
Which TEI [1]? 1
TEI [AUTO]? none

8. Set the frame size.

BRI Config <ISDN>set framesize
Framesize in bytes (1024/2048/4096) [1024]? 2048

1. At the Monitor> prompt, enter network followed by the number of one of the ISDN interfaces. (You can identify the ISDN interfaces by entering list interfaces at the Config> prompt.)

Monitor>network 3

Circuit <NET-3>

2. Enter bri.

Circuit <NET-3> bri
Basic Rate ISDN user console

BRI <ISDN>

Not all parameters apply to all router platforms. Press Space twice after you type a command to display the available parameters for each command. Enter help for information about using the command line interface.

[C] means the command is available at the BRI Config <ISDN> prompt.

[M] means the command is available at the BRI <ISDN> prompt.

Table 9 ISDN Commands

Command	Function
Accounting [M]	Displays a history for each accounting entry: calls placed to and from the entry, the number of calls that were refused and blocked, and the channel uptime for outbound calls.
Add [C]	Adds accounting entries and addresses to the ISDN configuration.
Calls [M]	Displays the name of the remote site, the number of calls made per channel, whether the calls were incoming or outgoing, the number that were refused, and the time the channel has been up.
Circuits [M]	Shows the status of all data circuits configured on the ISDN interface.
Conf_test_ cmds [M]	Do not use these commands. They are for use in a development environment only. They can disable the ISDN interface, requiring a router reset.
Delete [C]	Removes accounting entries and addresses from the ISDN configuration.
Disable [C]	Disables Data Over Speech Bearer (DOSBS) mode.
Enable [C]	Enables Data Over Speech Bearer (DOSBS) mode.
Exit [C] [M]	Returns to the previous prompt.
List [C]	Displays the ISDN addresses and configuration parameters.
Parameters [M]	Displays the current parameters for the ISDN interface.
Set [C]	Sets the POTS country profile (if router has a POTS module), frame size, local address, physical bus to either point-to-point or multipoint, SPIDs, no answer timeouts, number of retries after no answer, type of ISDN switch, directory numbers, and TEI.
Statistics [M]	Displays the current statistics for the ISDN interface.

Accounting [M]

Syntax: accounting

 AccountingName     Address       Total:  In   Out   Rfsd   Outb_UpTime 
 gt70-43            98983500               0    0      0      0:00:00 
 gt70-44            98983600               0    0      0      0:00:00 
 ----------------------------------------------------------------------
 (unknown)             -                   0    -      0         -  
 Total Blocked Calls:                           0

Add [C]

Syntax: add

accounting-entry

address

You can add up to eight entries for each ISDN interface.

Note: The accounting entry name must match one of the ISDN addresses you entered using the add address command.

Assign accounting entry name []? newark

It is important to add at least one ISDN address. This is the ISDN number of the remote router or server to which your router connects across ISDN. If the remote system has multiple numbers, then you must add each by using the add address command several times.

Example: add address

Assign address name [1-35] chars []? newark
Assign network dial address [1-25 digits] []? 123456789
Assign network subaddress [0-20 digits] []? 1011121314

Syntax: calls

 RemoteSite        Address         Calls:  In   Out  Rfsd  ElapsedTime
 (unknown)                                  0    0     0        -
 (unknown)                                  0    0     0        -

Unmapped connection indications:            0

Syntax: circuits

  B-channel     State          BearerType        Reason      Duration
      -         Idle               -               Down         -
      -         Idle               -               Down         - 

Conf_test_ cmds [M]

CAUTION:
These commands should never be used. Using these commands during normal router operation can cause erratic behavior of the ISDN interface, requiring the router to be reset.

Delete [C]

Syntax: delete

accounting-entry

address

Example: delete accounting-entry

Remove accounting entry name []? newark

The software prompts you for the dial and subdial address to distinguish between the primary telephone number and the sub-addresses of different ISDN peripherals at that number.

Note: If you want to delete all numbers for an address name that has multiple numbers, do not enter a network dial address when prompted.

Delete address name [1-35] chars []? newark
Delete network dial address [1-25 digits] []? 1-508-366-2345
Delete network subdial address [0-20 digits] []? 22

Syntax: disable dosbs destination name destination phone #

Enable [C]

Syntax: enable dosbs dest name dest phone # DOSBS mode

Exit [C] [M]

Syntax: exit

List [C]

Syntax: list

address

parameters

Example: list address

Address assigned name           Network Address    Network Subaddress
---------------------           ---------------    ------------------
newark                          123456789                  1011121314

Note: POTS parameters are displayed only for those platforms that have POTS hardware installed.

                  Basic Rate ISDN Configuration

Switch Variant                           = NT DMS-100
Multipoint Selection                     = Point-to-Point
DN0 (Directory Number 0)                 = 5559873
DN1 (Directory Number 1)                 = 5552845
SPID0 (Service Profile ID 0)             = 508555987300
SPID1 (Service Profile ID 1)             = 508555284500
TEI0                                     = Automatic
TEI1                                     = Automatic
Maximum frame size (bytes)               = 2048
Data Over Speech Bearer Service (DOSBS)  = Disabled
POTS country profile                     = United Kingdom
No circuit address accounting information being kept.

The following output displays parameters with the country profile set to custom.

Example: list parameters

              Basic Rate ISDN Configuration

Switch Variant                           = NT DMS-100
Multipoint Selection                     = Point-to-Point
DN0 (Directory Number 0)                 = 5559873
DN1 (Directory Number 1)                 = 5552845
SPID0 (Service Profile ID 0)             = 508555987300
SPID1 (Service Profile ID 1)             = 508555284500
TEI0                                     = Automatic
TEI1                                     = Automatic
Maximum frame size (bytes)               = 2048
Data Over Speech Bearer Service (DOSBS)  = Disabled
POTS country profile                     = Custom
POTS line impedance                      = 600 ohm
POTS ringer frequency (Hz)               = 25
POTS port 1 ringer cadence               = United Kingdom
POTS port 2 ringer cadence               = France
No circuit address accounting information being kept.

Syntax: parameters

                    Basic Rate ISDN Port Parameters:

 Switch Variant                            = US National ISDN-1
 Multipoint Selection                      = Point-to-Point
 DN0 (Directory Number 0)                  = 15551212
 DN1 (Directory Number 1)                  =
 SPID0  (Service Profile ID 0)             =
 SPID1  (Service Profile ID 1)             = 56789
 TEI0                                      = Automatic
 TEI1                                      = Automatic
 Maximum Frame Size                        = 2048
 Data Over Speech Bearer Service (DOSBS)   = Disabled
 POTS country profile                      = United Kingdom

Basic Rate ISDN Port Parameters:

 Switch Variant                            = US National ISDN-1
 Multipoint Selection                      = Point-to-Point
 DN0 (Directory Number 0)                  = 15551212
 DN1 (Directory Number 1)                  =
 SPID0  (Service Profile ID 0)             =
 SPID1  (Service Profile ID 1)             = 56789
 TEI0                                      = Automatic
 TEI1                                      = Automatic
 Maximum Frame Size                        = 2048
 Data Over Speech Bearer Service (DOSBS)   = Disabled
 POTS country profile                      = Custom
 POTS line impedance                       = 600 ohm
 POTS ringer frequency (Hz)                = 25
 POTS port 1 ringer cadence                = United Kingdom
 POTS port 2 ringer cadence                = France
 No circuit address accounting information being kept.

Syntax: set

country

dn0

dn1

framesize

multipoint

preferred

spid

switch

tei

Note: You can also customize your settings for these parameters.

POTS country profile [NA]?
Valid profiles are:
NA (North America)
UK (United Kingdom)
FRA (France)
GER (Germany)
EUR (Europe)
JAP (Japan)
CUST (Custom)

POTS line impedance [TBR21]? 600
POTS ringer frequency in hertz [20]? 25
POTS port 1 ringer cadence pattern [NA]? uk
POTS port 2 ringer cadence pattern [NA]? fra

Example: set dn0

Enter DN0 (Directory-Number-0) [ ]? 1-555-1234

ISDN Config>set dn0
Enter DN0 (Directory-Number-0) [ ]?1-555-1234:45

dn1 network dial address

If your service provider assigned a second directory number, set dn1. ISDN lines that have two directory numbers can place or receive calls on either directory number. Therefore, you must configure both numbers or the interface may reject calls.

Example: set dn1

Enter DN1 (Directory-Number-1) [ ]? 1-555-2345

ISDN Config>set dn1
Enter DN1 (Directory-Number-1) [ ]?1-555-2345:47

Example: set framesize

Framesize in bytes (1024/2048/4096) [1024]? 2048

Example: set multipoint-selection

Multipoint Selection [PP]? 

Select 3.1KHz if both your ISDN provider and ISP support it. It is the safter mode to use because it does not confuse your calls with real voice ISDN calls. If either your ISDN provider or your ISP does not support 3.1KHz, you must select speech.

Example: set preferred

Preferred_Voice_Mode?SPEECH or 3_1KH

Check with your ISDN service provider to determine whether or not your provider requires you to use a SPID. If you are using two directory numbers, you need to configure two SPIDs, 0 and 1.

Example: set spid

Which SPID [0]? 1
Enter Service Profile ID (SPID) []? 508555123400

The ISDN interface supports the switch variants listed in Table 11.

Table 11 ISDN Switch Variants Supported

Location	If you want this switch standard . . .	Set the software to . . .
North America	United States National ISDN-1 United States National ISDN-2 AT&T 5ESS Custom Northern Telecom DMS-100 Custom	USNI1 USNI2 5ESS DMS-100
Europe	European ETSI NET3, VN4 VN3 (See the Note below.)	NET3 VN3
Japan	INSNet64 JPNLSD	INS64 JPNLSD
Australia	TS013	AUS

Note: As of October 18, 1996, VN3 is obsolete in Europe. It has been succeeded by VN4.

tei auto or value or none

Valid values are 0 through 63, Auto, or None. The default is Auto. The software lets you set a TEI for each B channel for switch variants that require this capability.

For ISDN lines that use a single TEI, setting the TEI to None disables the ISDN interface. For ISDN lines that use multiple TEIs, setting one of the TEIs to None prevents the interface from accessing one B channel.

5ESS, DMS100, and USNI1 switches require that you set the TEI for each B channel (TEI 0 or TEI 1). If you set the switch variant to one of those switches, entering set tei prompts you for which TEI to configure. In a multipoint configuration, you should set TEI 1 to None. Otherwise, the router could allocate both B channels and prevent other ISDN devices on the multipoint bus from accessing a B channel.

Example: set tei

Which TEI ? [0]? 1
TEI  [NONE]?

Syntax: statistics

  Link: Inactive    BRI Firmware:   0.0    Handler State: Installed
                   	D Channel     B1 Channel     B2 Channel

Total Transmits            0              0              0
Total Receives             0              0              0
Transmit Bytes             0              0              0
Receive Bytes              0              0              0
Invalid Interrupts         0              0              0

Transmit:   D       B1       B2    Receive:        D       B1       B2
  
Error       0        0        0    Error           0        0        0
Overflow    0        0        0    Overflow        0        0        0
Underrun    0        0        0    Overrun         0        0        0
Abort       0        0        0    Abort           0        0        0
                                   CRC Error       0        0        0